january 2014 masterbuilder

50 The Masterbuilder - January 2014 • www.masterbuilder.co.in

Mass Housing

Realty-The Reality: The Growing National Housing Crisis

Bridging the Urban Housing Shortage in India, amidst the rising trend of urbanization and

the looming urban housing shortage as also fulfilling the rural shelters’ is-sue is no doubt a monumental task in the hands of all stakeholders. The con-straints faced by real estate developers if they venture to bridge the gap through affordable housing is also real.

Credible measures need to be taken by various stakeholders so as to make housing affordable for the urban & rural masses in India.

In the urban areas, an estimate puts the housing units shortage to be about 26.35 million units and in the rural areas about 47.53 million units. At this stage, housing shortage under the XII plan can safely be assumed to be of the order of about 40 million. (Assuming 90% of total Rural Housing Shortage for BPL families 2012-2017 ie 43.93)

Perhaps more importantly, in the urban areas 99 per cent of the total housing shortage (24.71 million units) pertains to the economically weaker sections (EWS) and low-income groups LIG).

“In the rural areas, more than 90 per cent of the total housing shortage (47.43 million units) belongs to lower-income families,” it is said.

Urban population set to outgrow over-all population growth

India’s urban population has grown at a CAGR of 2.8 percent over 2001-2011, resulting in an increase in the urbanization rate from 27.8 percent to 31.2 percent. Out of India’s 1.21 billion population, 377 million people are urban dwellers.

Sadagopan SeshadriChief - Content Development,CE - Infrastructure - Environment


www.masterbuilder.co.in • The Masterbuilder - January 2014 51

This continues to be aggravated with the ever growing concentration of mi-grating people into urban areas creating more and more of slums and squatter settle-ments.

A substantial housing shortage looms in Urban India with a wide gap between the demand and supply of housing in terms of not only quantity but also in the quality. India’s urban housing shortage has been estimated at nearly

18.78 million households in 2012 (Tech-nical committee Report to the Ministry of Housing and Urban Poverty Allevia-tion MHUPA).

Besides 80 percent of these house-holds living in congested houses require new houses. The report also highlights that nearly one million households are living in non serviceable katcha houses, while over half a million households are in homeless conditions. (See Fig.2 )

The Federation of Indian Chambers of Commerce (FICCI) estimates that by 2050, the country’s cities would witness a net increase of 900 million people. Furthermore, over 2012-2050, the pace of urbanization is likely to increase at a CAGR of 2.1 percent – double than that of China.

Considering that agriculture sector has a limited scope, urbanization growth is expected to be a consequence of rural-to-urban migration. India’s manu-facturing and services sector continues to show sizeable influx in employment from the rural youth. This will be a long term trend with expected rapid indust-rialization leading to migration from rural to urban India. (see Fig.1)

Looming housing shortage in urban India

Steeply climbing land and real es-tate prices in urban areas have forced the poor and the economically weaker sections of the society to settle for the marginal lands typified by poor housing stock, congestion and obsolescence. Figure 1 Urbanization growth (Source: Census of India 2011)

Housing fulfills physical needs by providing security and shelter from weather and climate. It fulfills psycho-logical needs by providing a sense of personal space and privacy. It fulfills social needs by providing a gathering area and communal space for the hu-man family, the basic unit of society. In many societies, it also fulfills econom-ic needs by functioning as a center for commercial production.The human right to adequate housing is the right of every woman, man, youth and child to acquire and sustain a se-cure home and community in which to live in peace and dignity. The right to housing is codified as a human right in the Universal Declaration of Hu-man Rights:”Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family, including food, clothing,

housing and medical care and nec-essary social services, and the right to security in the event of unemploy-ment, sickness, disability, widowhood, old age or other lack of livelihood in circumstances beyond his control.” (article 25(1)) The Commission on Hu-man Settlements’ Global Strategy for Shelter to the Year 2000(1998) pro-vides another definition of adequacy:“Adequate shelter means ... adequate privacy, adequate space, adequate se-curity, adequate lighting and ventilation, adequate basic infrastructure and ad-equate location with regard to work and basic facilities - all at a reasonable cost.”Population growth, migration to urban areas, conflicting needs for existing land, and insufficient financial and nat-ural resources have resulted in wide-spread homelessness and habitation in inadequate housing. In every coun-

try children, men and women sleep on sidewalks, under bridges, in cars, subway stations, and public parks, live in ghettos and slums, or “squat” in buildings other people have aban-doned. The United Nations estimates that there are over 100 million home-less people and over 1 billion people worldwide inadequately housed.By 2050, 900 million people will be added to Indian cities . The rapid pace of urbanization owing to the rural–ur-ban migration is putting a strain on the urban infrastructure in these cities. As urban development takes place, a growing concern for India’s urban planners massive urban hous-ing shortage plaguing the country. The shortage, prominent within EWS (economically weaker sections) and LIG (lower income groups), is estimat-ed at million households in 2012

Mass Housing


An important point to note is that of the total urban housing shortage, nearly 62 percent houses are self-owned, while 38 percent families live in rented homes which is a sizeable chunk.

10 States contribute to three-fourths of the urban housing shortage

Development does not guarantee better conditions as it is seen that a mixed picture exists with both developed as well as less developed states have families living in poor housing conditions. Uttar Pradesh has a housing shortage of over three million homes followed by Maha-rashtra (1.97 mn), West Bengal (1.33 mn), Andhra Pradesh (1.27 mn) and Tamil Nadu (1.25 mn).

The top 10 states, in terms of urban housing shortage, contribute to 14.3 million or 76 percent of housing shortage.

EWS - The worst hit

Housing shortage unfortunately has hit badly the economically weaker sections (EWS) and low income groups (LIG) that

comprise over 95 percent of the total housing shortage. The shortage amongst the middle income groups (MIG) and above is estimated at 4.38 percent.

Affordable housing – The buzz word now

Although India’s urban housing shortage is being primarily driven by the EWS and LIG categories, ironically

majority of the housing supply that has been built across urban India is beyond the affordability of the EWS and LIG segment. Real estate developers, private players in particular, primarily targeted luxury, high-end and upper-mid housing segment owing to the higher returns that can be gained from such projects. (see Fig.4)

A plethora of deterrents like high land costs, outdated building bye laws & li-censing norms, project approval delays coupled with unfriendly banking poli-cies have made low cost housing proj-ects uneconomical for private develop-ers. Affordable housing for EWS and LIG segments has to be satisfy the low cost criterion.

Hence, traditionally, low cost hous-ing has been the domain of the govern-ment.

The Government’s laudable measures

In the past three decades, govern-ment has adopted several policies as-sisting the delivery of affordable housing for the EWS, LIG and lower MIG. These policy initiatives focused on transition of public sector role as f̀acilitator’, increased role of the private sector, decentraliza-tion, development of fiscal incentives and concessions, accelerated flow of housing finance and promotion of envi-ronment friendly, cost-effective and pro-poor technology.

Taking into account the emerging

Figure 2 Urban housing shortage

Tenure

Number of families

living in old houses

Families living in katcha houses

Number of families living in

congestion

Families without homes

Total Urban housing shortage

Self-owned 1,395,735 770,0817 9,188,746 326,430 11,681,728

Rented 870,417 219,183 5,700,019 203,570 6,993,189

Source: Report of the Technical Urban Group (TG-12) on urban Housing shortage 2012-17, Ministry of Housing and Urban Poverty Alleviation, September 2012

The table 1 illustrates the break-up of housing shortage in both these categories in urban India.

Table 1 Large population in rented accommodation

Source: Report of the Technical Urban Group (TG-12) on Urban Housing Shortage 2012-17, Ministry of Housing and Urban Poverty Alleviation, September 2012Figure 3: 10 States contribute to three-fourths of the urban housing shortage

Mass Housing


challenges of required shelter and growth of slums in urban areas, government fur-ther launched Jawaharlal Nehru National Urban Renewal Mission (JNNURM) in 2005 and formulated the National Urban Housing and Habitat Policy in Decem-ber 2007.

The population of India’s homeless has fallen both as a proportion of the to-tal population and in absolute terms be-tween 2001 and 2011 as per the latest census data. The data also reveals that while there has been a sharp reduction of homeless people in rural India, their numbers in towns and cities have in-creased by almost 21%. This could be an indicator of policy moving in right direc-tion and motivation to speed up the work.

Global crisis: Boon for Affordable housing?

The real estate sector in India under-went considerable changes post the global liquidity crisis. Downturn and liquidity crunch forced developers to adopt a

two pronged strategy - smaller units at lesser prices. Only this pushed develop-ers to focus on the Affordable Housing segment, which has become the buzz word in the real estate market for the last few years. During 2009–2012, real estate developers in the country launched proj-ects in the affordable segment across Indian cities, with units priced between INR 5-10 Lakhs (USD 10,000–20,000)

Understanding ‘Affordability’

In analyzing India’s problem with providing housing for low-income fami-lies, policy-makers continue trying to fo-cus in on how to close the affordability gap. There is a significant gap between borrowers’ repayment capacities and the price of the dwelling units.

It is just not fair to load the burden of the affordability gap on institutional lend-ers and it is but natural that they are re-luctant to provide housing loans to low-income borrowers; The great difficulty in meeting lower-income citizens’ housing demands has been approached by the government in different ways. As has been seen here in above Indian govern-ments have developed and implement-ed many specific housing initiatives for the poor, but still affordability continues to be a key issue.

Affordability, should be understood in terms of being ‘relative by nature’ and in the case of ‘housing’, to be dependent on an individual’s income or capacity to afford housing; that should in include three basic elements:

- affordable land and infrastructure- affordable building design, technol-

ogy, materials and labor- affordable housing finance

So the term affordable housing in India should not be misunderstood to be ‘low-income housing’ which is an al-together different concept. However by default the low cost criterion becomes the ruling factor when it comes to EWS. But the rider here is that:

“Affordable housing does not trans-late into low cost , poor or low quality housing.”

India’s definition of affordable housing

India’s National Urban Housing and Habitat Policy (NUHHP) in 2007 estab-lished a task force that tried to define what constituted affordable housing. It sep-arated its definition into three parame-ters: size, cost and estimated monthly payment or rent and developed these parameters for two income groups the EWS/ LIG low income group and mid-

Figure 4 Affordable Housing

Size EMI or Rent

EWSMinimum of 300 sq ft super built-up areaMinimum of 269 sq ft (25 sq m) carpet area

not exceeding 30 - 40 % of gross monthly income of buyer

LIGMinimum of 500 sq ft super built-up areaMinimum of 517 sq ft (48 sqm) carpet area

MIG600-1,200 sq ft super built-up areaMinimum of 861 sq ft (80 sqm) carpet area

Source: Guidelines for Affordable Housing in Partnership (Amended), MHUPA, 2011

Chart IA Affordable Housing MHUPA 2011

Minimum Volume of Habitation Provision of Basic Amenities Cost of the House Location of the House

EWS Minimum of 250 sq ft carpet areaMInimum of 2,250 cu ft internal volume

Sanitation, adequate water supply and Powerprovision of community spaces and amenities such as parks, schools and healthcare facilities, either within the project or in the neighbourhood, depending upon the size and location of the housing project

Cost of the house such that EMI does not exceed 30-40% of gross monthly income of the buyerreasonable maintenance costs

Located within 20 km of a major workplace hub (could be suburban hubs as well) in the cityadequately connected to major public transit hubs

LIG 300-600 sq ft carpet area2,700-5,400 cu ft internal volume

MIG 600-1,200 sq ft carpet area5,400-10,800 cu ft internal volume

Source: Johns Lang LaSalle Research 2012Chart IB Affordable Housing Johns Lang LaSalle 2012

Mass Housing


Mass Housing

dle-income home buyers. MHUPA,2011 Guidelines (Chart IA) are current gov-ernment guidelines while the Johns Lang LaSalle’s criteria includes volume and location too (see Chart IB).

The Affordable Housing Development

The affordable housing projects launched by private developers have significantly contributed to the 25 per-cent decline in urban housing shortage in the last five years. Although, the urban housing shortage remains substantial, it is clear that active participation from pri-vate developers could help in tackling the urban housing shortage in India. (See illustration in Fig 5: The Affordable Housing Development Landscape)

However, affordable housing devel-opment continues to be a challenging proposition for developers and further policies need to be formulated by the Government to encourage greater par-ticipation from the private sector in the form of technological solutions, project financing and project delivery

Figure 5: The Affordable Hous-ing Development Landscape (INR 10 Lacs/unit ) - Major Cities

Constraints for Real Estate Developers

State cannot be a solo player in meeting housing shortage and to rope in Private sector the constraints faced by them will have to be removed so that they get incentivized to take up larger stakes and deliver efficiently. Main is-sues that plague are:

Unavailability of urban land

High population density in urban areas has triggered a huge demand for urban land. There is a urgent need to eliminate artificial land shortage that has pushed up land prices in India. Government support can aid release of land banks unutilized and through possible change in land use pattern. Larger availability of land in urban areas makes it viable for developers to take up affordable housing projects. Land parcels present in centrally located ar-eas should be prudently put to use so

as to arrest the on-going proliferation of slums and squatter settlements in these areas.

Approval Delays

Real estate developers are required to pass through an unending list of ap-provals in central and state governments and municipal corporations. The ensu-ing delays in project approvals could add 25-30 percent to the project cost. Currently, it takes nearly two to three years for a developer to commence construction after having entered into an agreement for land purchase. Mul-tiple and statutory approvals adds 2-2.5 years to the preconstruction process.

Rising construction costs

Construction cost minimization is a vital aspect of making affordable hous-ing projects viable.

Prices of affordable homes are pri-marily driven by the cost of construc-tion unlike premium residential projects, where pricing is largely guided by land costs. Construction costs form nearly 50 percent to 60 percent of the total sell-ing price in affordable housing projects while for luxury projects it is 18 percent to 20 percent

Owing to the success of the Na-tional Rural Employment Guarantee Act (NREGA) scheme, the labor shortage in construction has risen and this has further impacted the construction costs as it has lead to a considerable rise in wage levels.

Lack of skilled manpower

India’s real estate sector continues to grapple with the issue of manpower shortage which can have an adverse im-pact on the delivery and cost of afford-able housing projects. There is need to enhance the education and training to meet the demand in the Indian labor market.(see Fig.7)

Overcoming financing constraints for low-income groups

Housing finance companies (HFCs) are unable to serve the LIG and EWS

Mumbai

Ambivali 65

Karjat 80

Palghar 100

Boisar 110

Major DevelopersTata Housing, HDIL, S Raheja, Matheran Realty, Haware Builders, Neptune Group, Poddar Devel-opers, Usha Breco Realty, Nirman Group, Sriram Properties, Karjat Land Developers, Panvelkar Group, Recharge Homes.

Delhi (NCR)

Bhiwadi 75

Bawal 100

Major DevelopersAshray Homes, Surefin Builders, Avalon Group, Arun Dev Builders

Bangalore

Anekal Road 30

Major DevelopersVBHC, Janaadhar

Pune

Uralikanchan 30

Yavat 45

Major DevelopersTrishul Builders, Dreams Group, Vastushodh

Kolkata

Sonarpur 20

Barasat 100

Major DevelopersBGA Realtors, Magnolia Infrastructure, Pushpak Infrastructure, Shapoorji Pallonji

Ahmedabad

New Maninagar 15

Narol 15

Vatwa 20

Kathwada 30

Major DevelopersSantosh Associates, Foliage, Galaxy Developer, Dharmadev Builders DBS Affordable Home, Shree Ram Developers

Chennai

Nanmangalam 25

Oragadam 45

Cheyur ECR 95

Major DevelopersVBHC, TVS Housing, Marg Constructions, Annai Builders

Constraints for Real Estate Developers


categories owing to their inability to provide the required documentation for hassle free disbursal of loans.

Commercial banks and other tradi-tional means of housing finance typi-cally do not serve low-income groups, whose income may vary with crop sea-sons, or is below the ‘viable’ threshold to ensure repayment, or who cannot provide collateral for loans. As a result, the households falling under LIG and EWS category find it difficult to secure formal housing finance

The loan market of INR 3-10 lakhs is estimated at a whopping INR 1,100, 000 crore and should be definitely tapped. However less than 20 percent of the INR 55, 200 crore worth of housing loans disbursed by HFCs in FY2011 were in the loan bracket of INR 3-10 lakhs

This anomaly should be urgently corrected.(see Fig. 8 )

Limited financing avenues for developers

Banks have curtailed their exposure to real estate citing cautious measures leaving high cost finance options such as Non-banking Financial Compa-nies (NBFCs) and Private Equity (PE) funding as the only source of finance. Moreover, high cost of finance coupled with the waning demand has disrupted the cash flow situation of developers. Hence, developers are now deferring their project launches, thereby altering the slated supply.

Also, high cost of finance is restrain-ing them from lowering housing prices.

Need to relook laws and building guidelines

By formulating more clear and de-fined guidelines within building bylaws and rules for Floor Space Index (FSI), zoning and development plans the lo-cal urban authorities in India can reduce the difficulties faced in planning for construction projects in India. Some of these measures are already on going.

Besides, regulations such as the Rent Control Act, that are a deterrent in the development of rental houses and redevelopment of areas with old prop-

erties should be scrapped or adapted to today’s realities.

Rationalizing Taxation

The Government also needs to over-haul all real estate regulations including stamp duty, various taxations and bring uniformity between state and central im-positions.

A once for all answer to whether ‘the real estate property’ is a product or service is to be provided by the Govern-ment, thus allowing developers to gain a breather from the current double taxa-tion regime.

The ‘Affordable- Supply’ Recipe

The right mix of ‘need satisfying in-gredients’ for all stakeholders is a pre requisite for the right recipe which will work towards ensuring to nullify the shortage of affordable housing for all sections of society on a sustained fash-ion. Summing up,

Improve land planning and utiliza-tion: Ensuring adequate availability of land for housing and infrastructure can be done by computerization of land records, use of Geographical Informa-tion Systems, efficient dispute redressal mechanisms and implementation of

master plans including identifying dedicated zones for development of af-fordable housing and developing them within planned schedules.

Business models should incentiv-ize private sector participation: Moti-vate private real estate developers to participate actively and aggressively in affordable housing segment by allow-ing access to cheaper land, awarding higher FSI, reduction in the number and the time taken for approvals, assisting with infrastructure development, easier home loans and interest rate and tax subsidies.

Provide incentives on construction and other allied costs: Possible incen-tives to reduce the construction cost for developers would help project viability for developers while making them af-fordable for the buyers. As already noted construction costs drive the pric-ing in case of affordable housing units. Measures that help in construction costs reductions as already discussed are:

- Single window approval for projects

- construction costs subsidy by ex-emption on taxes and duties on con-struction materials; provide subsidy to developers for R&D in new low cost materials and technologies;

Figure 6 The Bad Cactus of Constraints

Mass Housing


In Financing by lowering borrowing cost for affordable housing projects by granting guarantee on the loans etc.

- Providing exemption from sales tax and reduction in stamp dutyEncourage micro mortgage financ-

ing mechanisms: Innovations over tra-ditional mortgage-lending model which could enable the informal salaried and self-employed population, who belong to the LIG and EWS segments, in availing housing loans are the key. The Gov-ernment could encourage effective fi-nancing through micro mortgages by utilizing the reach of Self-Help Groups (SHGs) and other innovative financing mechanisms. This would ensure that housing finance is available to large sections of LIG and EWS populations. Flexible payment mechanisms should be put into place considering the fact that households in LIG typically have variable income flows.

Improve penetration of rental housing in urban areas

Rental housing in India has very low penetration unlike many developed economies which have emphasized on affordable or social rental housing that constitutes up to 20-30 percent of their housing stock. However in these coun-tries, governments have a large role to play in promoting social housing as most of the rental houses are provided by government or by limited or non-profit housing associations that utilize government incentives.

In India too, authorities like the MMRDA have launched affordable rent-al housing scheme. with limited suc-cess but same should be followed up with professional rental management to make it sustainable.

Initiatives to build talent capacity: This is underway but a massive thrust by all stakeholders in an integrated manner is required.

Promote innovative and low ‘effective cost’ technologies:

The goal is effective construction cost to be curtailed which means in-

tegration of right cost of manpower, material, construction technology for quicker quality and quantity construc-tion; low-cost technologies such as pre-fabrication, which can be used to construct affordable houses quickly and cost–effectively.15-20 percent pre-fab costlier aspect is compensated by much higher gains from the dual ben-efits of higher efficiency and lower labor costs. In Europe and the Middle East, the use of precast concrete and engi-neering homes technology has enabled certain developers in saving up to 64 percent of the total man hours needed using conventional methods. In India too savings are assured especially in mass housing.

The last word

The Housing shortage gap is formi-dable but can be bridged making hous-ing at all levels more affordable. Land becomes more affordable if supply side increased . NUHHP task force recom-mended approvals’& conversions sim-plification with posting all land related information should be placed in the public domain

In terms of more affordable technol-ogy measures adopted to encourage innovation and implementation of cost-effective housing materials and technol-ogy through subsides and incentives should help.

As growth percolates and spreads, there will be a cascading effect even-tually smaller cities progressively shall start bursting on their seams. Thus the core-housing-needs concept should be considered and implemented on ‘pres-ent’ small towns too to make develop-ment needs most cost-effective. Finally, Policy makers should work for increas-ing supply of rental housing stock to en-sure affordability of shelter for all keep-ing in context that this step can also address arresting slum proliferation.

Projected Human Resource Requirement (in ‘000) 2008 2012 2018 2022 Incremental

Real Estate 10,790 14,515 20,692 24,981 14,191

Source: Human Resource and Skil Requirements in Building, Construction Industry and Real Estate Services, NSDC

Figure 7 Growing Skilled Manpower shortage Projection 2022

Source: Report on Trend and Progress of Housing in India, National Housing Bank, 2011Figure 8: Size-wise loan disbursement by HFC’s in India

Mass Housing


Why do Many ‘EPC Projects’ Face Schedule Overrun?

It is not an exception to hear that many EPC (Engineering, Procurement, Construction) Projects in India often face schedule overruns. Almost all Projects, be it Government or

Private, face some kind of schedule slippages due to various reasons that are attributable to various stakeholders. There are several causes for schedule slippages of EPC projects, that are “Controllable” by some of the key stakeholders which, when controlled may reduce or mitigate the schedule overruns.

One of the major reasons, according to the author is the scheduling method used by the EPC Contractor or the Consultant to arrive at the project completion time. There are several scheduling methods like, CPM, PERT, GERT, Monte Carlo Simulation, etc. Of these methods the one that is more widely used by many EPC Contractors / Owners / Consultants is the Critical Path Method (CPM). Although CPM has been in use for several decades, to find out the Critical Path within the Project Network & the total project duration based on the Critical Path, it is surprising to note that not many planners, schedulers & Project Managers are aware of the fact that CPM is not a good / efficient scheduling method.

CPM gives a project completion time that has only 50% probability of success. In other words, an EPC project that is managed by monitoring and controlling a Critical path found by CPM has 50% chances of facing schedule overruns. This is one of the main reasons why many EPC projects are being reported as schedule overruns. The truth is that many PMs, Contractors, Schedulers, Sponsors, Clients are not aware of this fact and get into litigation or LD claims, when in fact it should not be the case if the project completion time is rightly scheduled.

Still many planners, schedulers, PMs, consultants use this CPM method without tweaking the estimated project completion duration found by it and eventually end up in a false schedule overrun.

Key Project Stakeholders

The key stakeholders that are directly or indirectly responsible

for the schedule overruns are the Owners, the Contractors, the Consultants. Unfortunately the Schedulers & Project Managers are using mainly CPM to find out the minimum total project duration needed to complete a project.

The Owner – Consultant – Contractor Interactions

O. Arivazhagan CEO, International Institute of Project Management

In general, all the three key stakeholders are responsible for the schedule overruns of Projects. However, in many cases, the contractor is made the party that is mainly responsible for any schedule overruns. It is because of the communication / interaction equations amongst these three & differing levels of authority in approving or rejecting Baseline information with respect to initial schedule & project completion time for the project. As shown in the above sketch, the contractor is at the receiving end of communications related to project information and approval for majority of the EPC contracts. The project completion time is normally stated in the bidding documents. This project completion time is generally arrived by the consultant in coordination with the owner & using mostly CPM technique during pre-bid stage.

The consultant scheduler uses a scheduling tool such as MS Project / Primavera, which in turn uses CPM as a technique to find out the minimum time required to complete the project (Total estimated project duration) which is what stated in the bidding documents as the contractual completion time. The main point that is missed by the owners & consultants at this

Project Management


early stage i.e., pre-bid stage is that the project completion time arrived during bidding stage & that is stated in the bidding documents as the contractual completion time, has only 50% chances of being successful i.e., the project, if awarded to any contractor, has only 50% probability of being executed by the time found by the CPM technique.

Why CPM technique is inefficient?

As the name indicates, CPM technique relies on the total duration of activities that lie on the critical path within the project network to estimate the minimum time required to complete the project. However, this total project duration estimate found by CPM technique is based on 2 major assumptions by the estimators or schedulers & unfortunately both of the assumptions are not valid for majority of the project situations.

Assumption 1 – Resources available are unlimited for the EPC project.

Assumption 2 – Estimated activity durations are single point, deterministic durations which are mostly the modal estimates. The modal estimate is the one that is most frequently occurring estimate when the activity is done by the same team several times under given site conditions.

If you construct a histogram of estimated duration required to complete the the activity (Excavation) using the above data, it would look like the following.

Activity Duration with Right Skewed Distribution

However, this modal estimate is mostly found to be skewed to the right, thereby implying a probability of less than the mean duration which will have 50% probability. If a scheduler adds all the activity durations of a critical path using the above modal estimate, the total project duration is likely to have less than 50% probability of being successful. For eg., if the total duration of an EPC project is calculated using CPM technique as 16 months, there is a 50% chance that the project will not be completed within 16 months and the project completion time is likely to go beyond 16 months even if all the activities of the critical path are completed on time.

We tend to estimate durations that are closer to optimistic than pessimistic. This is why the modal estimates in a right skewed distribution gets less than 50% probability.

If you take an estimated duration from 15 persons for an activity in an EPC project say excavation, the following could be the duration estimates in days.

5, 7, 8, 10, 10, 18, 15, 25, 10, 15, 15, 10, 8, 8, 10

One can notice that the modal estimate of 10 days is the one normally taken as the single point deterministic estimates by the PMs / Schedulers to determine the Critical Path, you may notice also that the modal estimate has less than 50% chance of being achieved if all the Critical Path activity durations are added (which are nothing but model estimates) then the resulting total Project duration will also have 50% probability only.

The Uncertainty in Project Schedule

It may be observed from the above points that the total project duration, arrived by the Owner / Consultants using CPM & that is stated in the bidding documents as contractual completion time, has only at the best 50% probability of being achieved.

Knowingly or unknowingly EPC contractors do not object / challenge this estimated completion time during bidding stage & silently agree to complete the project within this duration by signing the contract. It clearly indicates that it is detrimental / suicidal for the contractors to sign such contracts without validating the practicability of such completion time stated in the contracts. Hence, all projects that were scheduled using CPM technique are bound to exceed the contractual completion time if enough contingency amount is not added to the total project duration at the outset itself. It may also be stated that the schedule slippages of several projects could be false overruns, as the contractual completion time stated has only 50% probability.

Possible Solution

To overcome this situation and to possibly avoid or minimize the Liquidated Damages (LD) due to schedule slippages, the author suggests to the contractors to go in for simple probabilistic methods of duration estimates like PERT (3-point estimates) and / or advanced Simulation techniques like Monte Carlo to arrive at a total project duration that has at least 98% probability of success (3 sigma), assuming other constraints are managed well.

Project Management


Floating Concrete by using Thermocole

The construction industry everywhere faces the problems and challenges, two-third of the world surface is covered with water. It is therefore not surprising that there has

been much activity with concrete in the sea in recent decades.The disadvantage of the conventional concrete is the high self weight concrete, where as the density is in the order of 2200 to 2600 Kg/m3. In this technique the self weight of the concrete is reduce to attain the efficiency of the concrete as structural material. The light weight concrete has the density of 300 to 1850Kg/m3, it helps to reduce the dead weight of the structure.

Scope of Work

In this technique the thermocole is used for preparation of the light weight concrete and density is reduced to attain the maximum efficiency, whereas the self weight of the structure is minimized.

Research Siginificance

- Light weight concrete - To reduce the self weight of the structure- Constructions on water bodies- Used as an acoustic medium- Low thermal conductivity

Materials Used

- Cement- Thermocole- Water

Properties of Thermocole

Low density, low conductivity, floating, acoustic.

Experimentel Work

To study the floating property of the Light weight concrete

Cement &Thermocole

In this concrete aggregate is replaced by the Thermocole,where the density of the thermocole is too less compare to the aggregate,hence it satisfy the floating property.

Density of Thermocole = 1.64g/cm3

Mixing of cement with Thermocole on suitable water cement ratios.

Experimental Procedure

- We have casted two types of slab and one cube.- The purpose of casting slab is to find whether the slab

float or not and to find out how many Kg of weight it can carry.

- The purpose of casting cube is to find the compressive strength.

- First thermocole was made into small balls.- Next thermocole balls mixed with cement(OPC 43 grade)

and with suitable water cement ratio.- Cast it into slab and cube .- After 24hours demould it, cure it and test the specimen.

Test Specimen

- Cube (150 mm * 150 mm * 150 mm)- Slab

N. Raj, M. Rajesh, R. Manoj Kannan, M. MadhavanFinal Year Civil Engg., Nehru Institute of Technology, Coimbatore

This paper investigates the properties of the light weight concrete by using a Thermocole. In this technique the Thermocole is used for preparation of the light weight concrete and density is reduced to attain the maximum efficiency, whereas the self weight of the structure is minimized thereby reducing the dead load on structure.

Concrete: Student Research


- (500 mm * 300 mm * 50 mm)- (1000 mm * 500 mm * 60mm)

Application

- Light weight concrete - To reduce the self weight of the structure- Constructions on water bodies- Used as an acoustic medium - Low thermal conductivity- Weathering course- Flooring- Ceiling - Wall pannel

Result

The compressive strength of the cube is found to be 2.5 to 3 N/mm2 and the Unit weight of the concrete is 450Kg/m3.

Conclusion

The concrete slab(1000mm x 500mm x 60mm) can carry a weight of up to 13Kg load when it floats in the water.Hence it can used in water body construction. Further experiment may be carried out to find the usage of light weight concrete over sea for the structural construction.

Reference

- Concrete technology (Theory and Practice) by M.S.Shetty.- Concrete technology by A.R.Santha Kumar.- Engineering materials (Including construction materials) by

R.K.Rajput.- ‘New concrete products, precast concrete production techniques

and light weight concrete’ Report on roving seminar in modern concrete construction practices, ICI.

- Anon: Structural lightweight aggregate concrete in India. Indian Concrete Journal, Vol.

- 60, No. 9, sep. 1986, pp 219-220, 2 pp.- Dhir, R.K.: Durability potential of lightweight aggregate concrete.

Concrete, April 1987,- 1 pp.- Concrete technology by M L Gambhir.

Concrete: Student Research


Improving Seismic Resistance of Hydraulic Structures Using Soil Improvement Techniques

Soil improvement researches dealt with the ability of soil improvement methods to resist the expected soil impacts of earthquakes. Most of these researches have focused only on the soil liquefaction problem. Despite the importance of this problem, the studies have stopped at this point and went mostly to the comparison between the efficiency of each different type of soil improvement methods. Most researches did not address the possibility of using soil improvement techniques to improve the seismic soil factor of the foundation soil as one of the factors affecting the structures seismic design loads.

The main purpose of this research is to increase the earthquake resistance of structures lie on weak soils by using soil improve-ment methods to improve the most stressed bulb zone under the structure. Controlled soil jet grouting technique could be used for the existing structures. Other types of soil improve-ment techniques such as soil mixing could be used for new structures or other types of earth structures.

To investigate the effect of these techniques, Finite element model for soil layers consists of poorly graded sand was developed. Non linear dynamic time history was performed using acceleration time history of a real earthquake. The response of the ground surface was obtained. Then, soil grouting with a specific dimensions was added to the model to model the case of improvement soil. Then, the same earth-quake was applied to the model. The response of the ground surface in case of soil without grouting and in case of soil

with grouting was compared to investigate the effect of grout on the seismic force at the foundation level of the structure.Different grout depths and widths were examined in the research to investigate the suitable grouting depth.

Also, experimental tests were carried out using box filled with sand and exposed to two types of dynamic loading. One of them was cycling loadings applied by shaking table and the other was impulse loading applied by impact hammer. Soil Grouting with specific location and dimensions was done at the sand surface. The site responses due to the applied dynamic loads were measured at the location of normal soil and at the location of improved soil. The two responses were compared to study the effect of soil improvement on soil dynamic behavior. The experimental results obtained from the dynamic tests were used to validate the results of the numerical model. The proposed technique was investigated numerically using real soil strata under a typical old barrage in Delta region in Egypt. This barrage was built on layer of poorly graded sand. Finite element model for the soil layers was developed. Non linear dynamic time history was performed using acceleration time history. Then, soil grouting for the poorly graded sand layer under the foundation of the barrage was added to the model. A comparison between the response of the ground surface for the model with and without soil improvement was carried to evaluate the effect of the soil improvement on the site seismic response.

Dr. Ahmad Hashad1, Dr. Yasser El-Hakem2, Dr. Ashraf El-Ashaal31Associate Professor, Construction Research Institute, N.W.R.C, Egypt.2Associate Professor, Construction Research Institute,N.W.R.C, Egypt.3Professor, Construction Research Institute,N.W.R.C, Egypt.

Most of the Egyptian irrigation structures were built many decades ago. Most of these structures may be classified as unsafe structures when making an assessment of their resistance to earthquake loads in accordance with the current specifications. This research suggests a technique to increase the ability of these structures to resist seismic loads. The suggested technique depends on using soil improvement methods to improve the most stressed soil bulb zone under the structure. The effect of seismic site soil factor will be decreased by improving this part of soil. Controlled soil jet grouting technique could be used for the existing structures. Other types of soil improvement techniques such as soil mixing could be used for new structures or other types of earth structures. Numerical study was performed to investigate the feasibility of the suggested method. Experimental study was carried out to validate the numerical study. The dynamic responses of an improved location and normal location were measured. The two locations were subjected to the same excitation force. The measured responses were compared and evaluated. Based on the results of the suggested technique, a real site condition for an existing barrage structure was numerically analyzed before and after soil improvement to examine the suggested technique.

Ground Engineering: Soil Improvement


Background

Many researchers studied the effect of soil grouting of loose layers to decrease the liquefaction potential or to increase the bearing capacity. Paul et al., [1] studied the increase in shear modulus by soil mix and jet grout methods to determine the decrease in liquefaction potential and earthquake-induced permanent deformations. Saravut J.[2] presented an innovative use of soil-cement mixing method using jet grouting technique to improve the bearing capacity of sub-base foundation for road construction. Jafarzade et al., [3] Compared the experimental results obtained from dynamic tests carried out by shaking table on loose and dense sand models using cyclic loads with the numerical simulation results.

ALKAYA et al., [4] studied the performance of stone columns and jet-grouting practices carried out in the location of railway which is dominated by poor soil conditions. The soil conditions obtained with jet grouting practices are higher than those of stone column practices. These results were checked by both seismic refraction and on-site tests. The results shown the grouting jet technique update the soil site condition from class D to class C according to Euro code. Barron et al., [5] concluded that the use of proper Cement Deep Soil Mix (CDSM) construction method could result in significant strength increases and relatively uniform ground improvement from loose to medium dense sands. The design of the CDSM treatment to improve the weak foundation was able to meet the seismic performance objectives that were established for a project. To increase the ability of soft soils at shallow depth to resist seismic horizontal loads Mseda et al., [6] proposed a methodology depends on forming a cement soil mass composed of steel piles and soft soil improved by cement mixing method.

This research studies the effect of soil improvement methods (see figure 1) on the dynamic response of the soil at the contact surface with the superstructure. The expected improvement on the soil properties will affect the amount of response of the improved soil to the earthquake movement. This improvement may be used to increase the structure capacity to resistance earthquake loads. This technique may be used in the case of re-rehabilitation of hydraulic structures to upgrade its seismic loads capacity. In other words, the proposed technique can be applied when the need to increase the structures resistance to earthquake loads is required.

Numerical Model

Soil strata consists of one layer of loose sand with 20.0 m depth and 100.0 m width rested one bed rock layer was subjected to seismic wave. A finite element numerical analysis using nonlinear time history dynamic analysis was performed using Plaxis 8 professional version [7]. For avoiding reflect of waves from side boundaries into the model, an absorbent boundaries were used and the breadth of soil was chosen relatively far from the region of interest (100.0 m). Figure 2 shows the Finite element model of the soil strata.

a) jet-grouting technique b) Cement deep soil mixing

c) Soil mixing machine d) Stone column technique

Figure1. Soil Improvement Techniques

Figure 2. Finite element model

in the study The soil strata subjected to real earthquake waves (upland earthquake) which occurred in 1990. Figure 3 shows the acceleration time history for Upland earthquake. The peak acceleration of this earthquake was 2.34 m/s2.

Figure3. Acceleration time history for upland earthquake

Plane strain elements with 15 nodes and Mohr-Coulomb soil model were used to model the soil as shown in Fig. 2. Tension cut off was used to prevent the tensile stress which is not allowed in the soil element during the analysis. The soil properties were chosen to model poorly graded sand. Modulus of elasticity, angle of internal friction, and density were taken as 20,000 KN/m2, 20o, and 17 KN/m3, respectively.

The location of improved soil was simulated with plane strain elements with 15 nodes and linear elastic model were used to model the grout effect. In this study, the properties of soil-cement (grouted soil) elements are shown in table 1.



The depth of the grout in the finite element mesh was taken as 1m, 5m, 10m, and 15m which represents 0.05, 0.25, 0.5, and 0.75 of the total depth, respectively. The breadth of the grout was taken as 6m, 10m, 20m, and 30m.

Numerical Model Results

The effects of grouting depth and breadth on the site dynamic responses were studied. Cases of no grout (normal soil) and cases with the same grout breadth but with different grout depths were performed to study the effect of grout depth only on site dynamic response. Figure 4 displays the analytical acceleration time record for the site responses.

Cases of different grout breadths with the same grout depth were carried out to study the effect of grout breadth only on site dynamic response. Other cases with different grouting depths were solved to study the site dynamic response sensitivity to grouting depth. Figure 5 displays the analytical acceleration time record for site responses.

One of the most important information in the dynamic analyses is the frequency content. The relation between frequency

content of excitation seismic waves and frequency content of site response should be considered and studied. Generally it is normal to have some changes in frequency content or frequency shifting between excitation force and site response. The amount of changes depends on soil type and distance between excitation source and the considered site location.

shear strength(-) 100 kPa

replacement ratio ( ) 35%

composite modulus (Ec) 200,000 kN/m2

Density 22 KN/m3

Posson’s ratio 0.2

Table 1 properties of grouted soil elements

a) Comparison between no grout and grout with depth = 5.0m

b) Comparison between grout depths= 10.0 m & 15.0 m

Figure.4 Site Response Acceleration Time Record - Studying grouting depth

a) Grouting breadth = 10.0m with 5.0m depth

b) Grouting breadth = 30.0m with 5.0m depth

c) Grouting breadth = 100.0m with 5.0m depth

d) Grouting breadth = 20.0m with 10.0m depth

Figure.5 Site Response Acceleration Time Record - Studying grouting breadth



The dynamic behavior of the improved soil was studied in terms of frequency content. Figure.6 shows the frequency content of the site responses for cases of no grout (normal soil) and grouting with different depths and breadths.

Figure 7 shows the relation between the percentage of the decrease in the site response acceleration and the grouting breadth. The relation was calculated at two different grouting depths.

As shown in Figure 7. For grout depth=5m (25% of the layer total depth), the percentage of decrease in the acceleration were 44.16%, and 37.4% for 20m, and 10m grout breadth, respectively. While for grout depth=10m (50% of the layer

total depth), the percentage of decrease in the acceleration were 72.93%, and 51.78% for 20m, and 10m grout breadth, respectively. This means that, for the same grout depth and when the grout breadth increases, the percentage of decrease in the acceleration increases until it reaches a breadth to depth ratio = 2. The increase of the breadth above this ratio has a little effect on the results. Figure 8, displays the percentage of the decrease in the site response acceleration and the grouting depth. The relation was calculated at two different grouting breadths. When grout breadth was 10.0m, this decrease reached 51.78 for grout depth=10.0m. Also, when grout breadth was 6.0m, this decrease reached 33.16 for grout depth=15.0m.

This means that, for the same grout breadth and when the grout depth increases, the percentage of decrease in the acceleration increases. The decrease in acceleration site response is limited for grouting depths more than 15.0 m.

a) Comparison bet. no grout case and 10.0m grouting depth Noting that there is some changes in peaks amplitude and some high frequencies disappeared from grouting depth = 10.0 m

c) Comparison bet. grouting depth = 5.0m & 15.0mNoting that there is negligible changes in peaks amplitude and almostno changes in frequency content.

b) Comparison bet. grouting breadth = 10.0m & 30.0mNoting that there is some changes in peaks amplitude and some highfrequencies disappeared from grouting breadth = 6.0 m

Figure 6 Acceleration response spectra

Figure 7. Effect of grout breadth on the acceleration site response

Figure 8. Effect of Grout Depth on the Acceleration Site Response

From the results the seismic forces applied on the structures could be reduced to a considerable amount by improving the local soil area beneath the structure. These results also lead to reduce the cost of new structures and lead to maintain old structures instead of reconstruction solutions when seismic resistance capacity is considered.

Application

A case study was performed using the proposed technique to




reduce the seismic force on an existing hydraulic structure. A real soil stratum under a typical old barrage in Delta region in Egypt was used. Finite element model for the barrage site soil layers was developed. Figure 9 shows the soil strata under the barrage site. This strata consists of poorly graded sand layer with 7m depth, Clay layer with 4m depth, and poorly graded dense sand with 14m depth [8]. The different properties of soil layers are shown in table 2.

Non linear dynamic time history analysis was performed using normal soil conditions. Then, the effect of soil grouting for the poorly graded sand layer under the barrage foundation was added to the model. Two earthquakes (Upland and Loma Perta earthquakes) were used in the analysis.

The grouted area was 26.0m in breadth and 7.0m depth. The ground water level was taken at the top of the poorly graded sand layer (under the structure). The acceleration response time history at the ground surface for soil with and without grout, also the properties of excitation earthquake used in the analysis are shown in Figure 10.

It was found that the peak ground response acceleration for the soil without improvement = 6.16 m/s2 and 1.86 m/s2 under the effect of Upland and Loma Perta earthquakes respectively.

The peak ground response acceleration was 3.17 m/s2 and 1.12 m/s2 when using the proposed technique for the soil site improvement.

This means that the proposed technique could reduce the peak acceleration by about 40% to 49 %.

Experimental Work

Experimental work was carried out to verify the previous results. A physical model for sand layer with dimensions of 1×1×1 m was constructed using box container. This box was put on a shaking table and exposed to lateral vibrations with harmonic motion and pulse load by using impact hammer. Two cycling motions with 1.80 Hz and 2.80 Hz were used in the test also impact loads applied at two different points were considered. Soil improvement location was done using grouting mix. The area of the improved location was 0.40×0.40 and with

Layer [KN/m3] E[KN/m2] C[KN/m2] ø µ

Poorly g. sand 1.6 27000 0 29o 0.2

Clay 1.8 5300 64 0 0.3

Sand 1.7 60000 0 35o 0.25Table 2. Zefta Barrage Soil Layers Properties

Figure 9. Soil Profile

a) Loma Perta earthquake with P.G.A. =2.2 m/s2

b) Frequency content for the two input earthquakes

c) Comparison between with and without grouting for Upland

d) Comparison between with and without grouting for Loma PertaFigure10. Site excitation earthquake properties and acceleration site responses results


0.20 m depth. The used grout mixture was made by water to cement ratio = 1.0, grout volume was 40% of the soil volume and the dry cement to soil ratio was 450 kg/m3. The values of sand properties are summarized in table 3. The grouted soil properties are usually obtained by performing unconfined compressive strength tests of a specific mixture specimen.

The acceleration responses during shaking and during hammering the soil box container were measured. Accelero meters were placed at top surface for normal soil and improved soil in order to measure the behavior of the soil during excitations at the same time. The box, configuration of the instruments and unconfined compression test for grouting specimen is shown in Figure 11.

The accelerometer sensors send the measured signals to a conditioner unit which in turn sends the conditioned signal to a data acquisition card through connecting cables. The acquisition card passes the digital data to a laptop computer for the purpose of data storage and analysis. The logging software controls the measuring process and converts analog signals to digital ones. The data is filtered and analyzed using the signal processing techniques. These techniques were applied on the measured acceleration time record. These techniques such as Cut-off frequency technique filter to be used to remove noises to get signal-to-noise ratio acceptable. the type of the data acquisition cards is PCD-320A. The software produced by KYOWA is used to control and filter the measurements. The data analysis software used is Seismosignal.

Two harmonic excitation of 20 sec. time length with Peak Acceleration (P.A) = 0.26, 8.00 m/s2 and with single frequency content of 1.80, 2.80 hz each respectively were applied on the tested soil separately to represent cycling loadings.

Impact load was applied at two points one of them at the center line between improved and unimproved locations and defined as near point. The other point was at box side nearer to the accelerometer at the grout than that at the normal soil. This point is defined as far point. These pulse loads represent the earthquake at base rock applied to the soil layer strata in the box container.

The Max. Void ratio for the sand was 0.307 while the Min. void ratio was 0.235. The sand density varies from Min. density of 1.42 gm/cm3 to Max. density 1.85 gm/cm3. Settlement about 2.50 cm occurred in the sand layer at the end of the two tests.

Experimental Work Results

Experimental results obtained from the dynamic tests are compared with numerical analyses performed. The measured results show agreement with the numerical experimental analysis results. Figure 12 (a & b) shows the acceleration time record for the two input motions. Also Figure 12 (c & d) shows comparison between measured time record acceleration response of normal soil and improved one for the two input motions.

The percentage of decrease in the acceleration is 4.50% for input motion with P.A=0.26 m/s2 and single frequency content of 1.80 hz. While The percentage of decrease in the acceleration is 2.80% for input motion with P.A=8.00 m/s2 and single frequency content of 2.80 hz.

The percentage of decrease in the acceleration is 58% for pulse load at near point. While the percentage of decrease in the acceleration is 22% for pulse load at far point.

Also, to validate the experimental work, a numerical model was developed for the box filled with sand with and without grouted location and exposed to cyclic loading with frequency =1.80hz and amplitude =1.0cm to simulate the experimental work. The results of the numerical model show that the percentage of decrease in the acceleration is 7.5%. These results were matched with the experimental results during the cyclic loads.

Layer [KN/m3] E[KN/m2] Estimated C[KN/m2] Ø Specific Weight

Tested sand 1.85 27000 0 38.7o 2.44Table 3. Tested Sand Properties

a) Sand box container b) Accelerometer fixed at the grouted Area

c) Unconfiened compression test

Figure 11. Test configuration

shows a photo of one of the grouted sand tested specimen after unconfined compression test done.

shows a photo of one of these ac-celerometers during installation. The type of accelerometers used is ICP.

shows sand box container fixed over the shaking table.



Conclusion

This study leads to the following conclusions:

- The seismic forces applied on the structures could be reduced to a considerable amount by improving the local soil area beneath the structure which leads to reduce

a) Input motion with frequency = 1.80 hz

b) Input motion with frequency = 2.80 hz

c) Response of grouting and No grouting locations for 1.80 hz. motion

d) Response of grouting and No grouting locations for 2.80 hz. motion

e) Response of grouting and No grouting locations for near pulse

f) Response of grouting and No grouting locations for far pulseFigure 12. Test results


the cost of new structures and to maintain old structures instead of reconstruction solutions when seismic resistance capacity is considered.

- For the same grout depth and when the grout breadth increases, the percentage of decrease in the acceleration increases until it reaches a breadth to depth ratio =2. The increase of the breadth above this ratio has a little effect on the results.

- When the grout depth increases, the percentage of decrease in the acceleration increases.

Refernce

- Paul, J. A., and Timothy, D. S., “Increase in Shear Modulus by Soil Mix and Jet Grout Methods”, DFI Journal, Vol. 2 No. 1 November 2008.

- Saravut J., “ Design Concept of the Soil Improvement for Road Construction on Soft Clay”, Proceedings of the Eastern Asia Society for Transportation Studies, Vol.4, October, 2003

- Jafarzadeh, F., Faghihi, D., and Ehsani, M.,”Numerical Simulation of Shaking Tables Tests on Dynamic Response of Dry Sand”, The 14 th World Conference on Earthquake Engineering, Beijing, China, 2008.

- Alkaya, D., Cobanoglu, I., Yesil B., and Yildiz, M., “The evaluation of stone column and jet grouting soil improvement with seismic refraction method: Example of Poti (Georgia) railway”, International Journal of the Physical Sciences Vol. 6(28), pp. 6565-6571, 9 November, 2011.

- Barron, R. F., Kramer, C., Herlache, W. A., Wright, J., Fung, H., and Chu Liu., “Cement Deep Soil Mixing Remediation of Sunset North Basin Dam”. http://www.cement.org/water/dams_sc_cdsm.asp. (2006).

- Mseda, Y., Wada, N., Kouno, M., Xu, G., and Nakatani, T., “A New Composite foundation of steel pile with soil improved”, Proceedings of JSCE Japan Society of Civil Engineers, Vol.;No.686 , pp. 91-107, 2001

- Plaxis Professional Ver. 8, “Dynamic Manual”, Delft University of Technology and Plaxis b. v., The Netherlands, 2002.

- “Final Geotechnical Survey Report for Feasibility Study for Rehabilitation/Reconstruction of the Zefta Barrage”, Misr Raymond Foundations, 2011.


Soil Nailing: An Innovative Ground Improvement Technology

A soil-nailed system is considered as a soil-nailed retaining wall if the facing of the system is sub-vertical, and it is designed to perform as a structural member that

provides retention action to the ground by virtue of its self-weight, bending strength or stiffness. For example, if soil nails are installed into a gravity, reinforced concrete or cantilevered retaining wall, the system is considered as a soil-nailed retaining wall. On the contrary, if the facing serves mainly the function of surface protection or connection between individual soil nails, such as a sprayed concrete facing, the system should be regarded as a soil-nailed slope. Also, in this document, a soil-nailed system is considered to be a soil-nailed excavation if the reinforcing bars in an excavation, which carry either transient

or sustained loads, are designed to perform as soil nails. Refer Figure 1 for Soil Nail Wall.

The soil nailing technique was developed in the early 1960s, partly from the techniques for rock bolting and multi-anchorage systems, and partly from reinforced fill technique. The New Austrian Tunnelling Method introduced in the early 1960s was the premier prototype to use steel bars and shotcrete to reinforce the ground. With the increasing use of the technique, semi-empirical designs for soil nailing began to evolve in the early 1970s. The first systematic research on soil nailing, involving both model tests and full-scale field tests, was carried out in Germany in the mid-1970s. Subsequent development

Sonjoy Deb, B.Tech, Civil Associate Editor

Ground Improvement: Soil Nailing


work was initiated in France and the United States in the early 1990s. The result of this research and development work formed the basis for the formulation of the design and construction approach for the soil nailing technique in the subsequent decades.

The soil nailing technique was introduced to Hong Kong in the 1980s. Soil nailing was first used in Hong Kong as a prescriptive method to provide support to deeply weathered zones in otherwise sound material. This was followed by a few cases where passive anchors or tie-back systems were used. Some of the impetus for these early cases came no doubt from the desire to find an alternative to prestressed ground anchors, which require long-term monitoring. In the mid-1980s a small number of soil-nailed supports to temporary cuts were made. In the early 1990s, the experience of design and construction of soil nails was summarised by Watkins & Powell (1992), which soon became the standard practice in Hong Kong.

Along with the increasing number of existing slopes and retaining walls upgraded by the Government and private owners, the soil nailing technique has gained popularity since the mid-1990s.

Areas of Application

Given that some subtle adverse geological features could be missed by ground investigation, robust design solutions that are less sensitive to local adverse ground and groundwater conditions are recommended. Large unsupported cuts, particularly those with significant consequence-to-life or major economic consequence in the event of slope failure, should

be avoided as far as practicable. Due to lack of robustness, such cut slopes are especially vulnerable to undetected adverse ground and groundwater conditions. Positive slope support or reinforcement systems, supplemented with surface and subsurface drainage measures where necessary, are generally preferred to cutting back alone even though the calculated factors of safety of different schemes based on conventional limit equilibrium analysis may be the same. A soil-nailed system can override local weaknesses in the ground through stress redistribution and is less vulnerable than unsupported cuts to undetected adverse ground and groundwater conditions that have not been accounted for in the slope stability analysis. In Hong Kong, most soil nailing works are associated with the stabilisation of existing soil cut slopes and retaining walls. They are also used for reinforcing new soil cut slopes, existing fill slopes, disturbed terrain and natural hillsides. The use of soil nails in new retaining walls and new fill slopes is rare in Hong Kong. Apart from permanent works, soil nails may be used in temporary excavations. Refer Figure 2 for application of solar nail.

Figurue 1: Soil Nail Wall

Figure 2: Soil Nail Application

Installation Methods

There are a variety of soil nail installation methods. The choice of installation method depends on a number of factors such as cost, site access, working space, and ground and groundwater conditions. A brief description of the commonly available soil nail installation methods is given below.

(1) Drill-and-grout. This is the most common installation method, both in Hong Kong and overseas. In this method, soil-nail reinforcement is inserted into a pre-drilled hole, which is then cement-grouted under gravity or low pressure. Various drilling techniques, e.g., rotary, rotary percussive and down-the-hole hammer, are available to suit different ground conditions. The advantage of this method is that it can overcome under-ground obstructions, e.g., corestones, and the drilling spoil can provide information about the ground. In addition, long soil nails can be installed using the method. The size and alignment of the drillholes can be checked before the insertion of reinforcement, if needed. However, the drill-and-grout method



may result in a hole collapse. To overcome this problem, casing is required. The drilling and grouting process may also cause disturbance to the ground.

(2) Self-drilling. This is a relatively new method when compared with the drill-and-grout method. The soil-nail reinforcement is directly drilled into the ground using a sacrificial drill bit. The reinforcement, which is hollow, serves as both the drill rod and the grout pipe. The installation process is rapid as the drilling and grouting are carried out simultaneously. Instead of using air or water, cement grout is used as the flushing medium, which has the benefit of maintaining hole stability. Centralisers and grout pipes are not needed, and casing is usually not required. However, self-drilling soil nails may not be suitable for the ground containing corestones as they cannot penetrate through rock efficiently. It may be difficult to ensure the alignment of long soil nails due to the flexibility of reinforcement. Durability may also be a concern if it relies on the integrity of the corrosion protection measures in the form of grout cover and corrosion protective coatings to steel reinforcement. This is because the specified minimum grout cover may not be achieved in the absence of centralisers and the corrosion protective coatings could be damaged during installation. Non-corrodible reinforcement may be explored to overcome the durability problem.

(3) Driven. Soil-nail reinforcement is directly driven into the ground by the ballistic method using a compressed air launcher, by the percussive method using hammering equipment, or by the vibratory method using a vibrator. During the driving process, the ground around the reinforcement will be displaced and compressed. The installation process is rapid and it causes minimal ground disruption. However, due to the limited power of the equipment, this method can only be used to install soil nails of relatively short length. Moreover, the soil-nail reinforce-ment may be damaged by the excessive buckling stress induced during the installation process, and hence it is not suitable for sites that contain stiff soil or corestones. As the soil-nail reinforcement is in direct contact with the ground, it is susceptible to corrosion unless non-corrodible reinforcement is used.

Basic Elements of a Soil-nailed System:

A soil-nailed system formed by the drill-and-grout method comprises the following basic elements:

(1) Soil-nail Reinforcement. Soil-nail reinforcement is the main element of a soil-nailed system. Its primary function is to provide tensile resistance. The reinforcement is typically a solid high yield deformed steel bar. Other types of materials, such as fibre reinforced polymer, can also be used as soil-nail reinforcement.

(2) Reinforcement Connector (Coupler). Couplers are used for joining sections of soil-nail reinforcing bars.

(3) Cement Grout Sleeve. Cement grout, made of Portland cement and water, is placed in a pre-drilled hole after the insertion of a soil-nail reinforcement. The cement grout sleeve serves the primary function of transferring stresses between the ground and the soil-nail reinforcement. It also provides a nominal level of corrosion protection to the reinforcement.

(4) Corrosion Protection Measures. Different types of corrosion protection measures are required depending on the design life and soil aggressivity. Common types of corrosion protection measures are hot-dip galvanising and corrugated plastic sheathing. Heat-shrinkable sleeves made of polyethylene and anti-corrosion mastic sealant material are commonly used to protect couplers.

(5) Soil-nail Head. A soil-nail head typically comprises a reinforced concrete pad, a steel bearing plate and nuts. Its primary function is to provide a reaction for individual soil nails to mobilise tensile force. It also promotes local stability of the ground near the slope surface and between soil nails.

(6) Slope Facing. A slope facing generally serves to provide the slope with surface protection, and to minimise erosion and other adverse effects of surface water on the slope. It may be soft, flexible, hard, or a combination of the three. A soft slope facing is non-structural, whereas a flexible or hard slope facing can be either structural or non-structural. A structural slope facing can enhance the stability of a soil-nailed system by the transfer of loads from the free surface in between the soil-nail heads to the soil nails and redistribution of forces between soil nails. The most common type of soft facing is vegetation cover, often in association with an erosion control mat and a steel wire mesh. Some proprietary products of flexible facing are available. Hard facing includes sprayed concrete, reinforced concrete and stone pitching. Structural beams and grillages can also be constructed on the slope surface to connect the soil-nail heads together to promote the

Figurue 3: Basic elements of a Soil Nail



integral action of the soil-nailed system. Refer Figure 3 for basics of a soil nail. Refer Figure 4 for Soil Nailing Process.

Design Considerations

A soil-nailed system is required to fulfill fundamental requirements of stability, serviceability and durability during construction and throughout its design life. Other issues such as cost and environmental impact are also important design considerations.

(1) Stability. The stability of a soil-nailed system throughout its design life should be assessed. Its performance should not exceed a state at which failure mechanisms can form in the ground or within the soil-nailed system, or when movement of the soil-nailed system can lead to severe damage to its structural elements or nearby structures, facilities or services.

(2) Serviceability. The performance of a soil-nailed system should not exceed a state at which the movement of the system affects its appearance or the efficient use of nearby structures, facilities or services, which rely upon it.

(3) Durability. The environmental conditions should be investi-gated at the design stage to assess their significance in relation to the durability of soil nails.

(4) Economic Considerations. The construction cost of a soil-nailed system depends on the material cost, construction method, temporary works requirements, buildability, corrosion protection requirements, soil-nail layout, type of facing, etc.

(5) Environmental Considerations. The construction of a soil-nailed system may disturb the ground ecosystem, induce nuisance and pollution during construction, and cause visual impact to the existing environment.

Merits And Limitations

The soil nailing technique offers an alternative design solution to the conventional techniques of cutting back and retaining wall construction.

The following are typical merits of adopting the soil nailing technique in respect of construction, cost and performance:

(a) It is suitable for cramped sites with difficult access because the construction plant required for soil nail installation is small and mobile.

(a)

(b)

(c)Figurue 4: Soil Nailing Process



(b) It can easily cope with site constraints and variations in ground conditions encountered during construction, e.g., by adjusting the location and length of the soil nails to suit the site conditions.

(c) During construction, it causes less environmental impact than cutting back and retaining wall construction as no major earthworks and tree felling are needed.

(d) There could be time and cost savings compared to conventional techniques of cutting back and retaining wall construction which usually involve substantial earthworks and temporary works.

(e) It is less sensitive to undetected adverse geological features, and thus more robust and reliable than un-supported cuts. In addition, it renders higher system redundancy than unsupported cuts or anchored slopes due to the presence of a large number of soil nails.

(f) The failure mode of a soil-nailed system is likely to be ductile, thus providing warning signs before failure.

The soil nailing technique has the following main limitations

(a) The presence of utilities, underground structures or other buried obstructions poses restrictions to the length and layout of soil nails.

(b) The zone occupied by soil nails is sterilised and the site poses constraints to future development.

(c) Permission has to be obtained from the owners of the adjacent land for the installation of soil nails beyond the lot boundary. This places restrictions on the layout of soil nails.

(d) The presence of high groundwater levels may lead to construction difficulties in hole drilling and grouting, and instability problems of slope surface in the case of soil-nailed excavations.

(e) The effectiveness of soil nails may be compromised at sites with past large landslides involving deep-seated failure due to disturbance of the ground.

(f) The presence of permeable ground, such as ground with many cobbles, boulders, highly fractured rocks, open joints, or voids, presents construction difficulties due to potential grout leakage problems.

(g) The presence of ground with a high content of fines may lead to problems of creeping between the ground and soil nails.

(h) Long soil nails are difficult to install, and thus the soil nailing technique may not be appropriate for deep-seated landslides and large slopes.

(i) Because soil nails are not prestressed, mobilisation of soil-nail forces will be accompanied by ground deformation. The effects on nearby structures, facilities or services may

have to be considered, particularly in the case of soil-nailed excavations.

(j) Soil nails are not effective in stabilising localized steep slope profiles, back scarps, overhangs or in areas of high erosion potential. Suitable measures, e.g., local trimming, should be considered prior to soil nail installation.

Conclusion

The soil nailing technique improves the stability of slopes, retaining walls and excavations principally through the mobilisation of tension in the soil nails. The tensile forces are developed in the soil nails primarily through the frictional interaction between the soil nails and the ground as well as the reactions provided by soil-nail heads/facing. The tensile forces in the soil nails reinforce the ground by directly supporting some of the applied shear loadings and by increasing the normal stresses in the soil on the potential failure surface, thereby allowing higher shearing resistance to be mobilised. Soil-nail heads and the facing also provide a confinement effect by limiting the ground deformation close to normal to the slope surface. As a result, the mean effective stress and the shearing resistance of the soil behind the soil-nail heads will increase. They also help to prevent local failures near the surface of a slope, and to promote an integral action of the reinforced soil mass through the redistribution of forces among soil nails. The resistance against pullout failure of the soil nails is provided by the part of soil nail that is embedded into the ground behind the potential failure surface. The nail-ground interaction is complex, and the forces developed in the soil nails are influenced by many factors. These factors include the mechanical properties of the soil nails (i.e., tensile strength, shear strength and bending capacity), the inclination and orientation of the soil nails, the shear strength of the ground, the relative stiffness of the soil nails and the ground, the friction between the soil nails and the ground, the size of soil-nail heads and the nature of the slope facing.

Reference

- Lui, B.L.S. & Shiu, Y.K. (2005). Prescriptive Soil Nail Design for Concrete and Masonry Retaining Walls (GEO Report No. 165). Geotechnical Engineering Office, Civil Engineering and Development Department, Hong Kong, 76 p.

- Ng, F.H., Lau, M.F., Shum, K.W. & Cheung, W.M. (2008). Review of Selected Landslides involving Soil-nailed Slopes (GEO Report No. 222). Geotechnical Engineering Office, Civil Engineering and Development Department, Hong Kong, 98 p.

- CIRIA (2005). Soil Nailing - Best Practice Guidance. Construction Industry Research & Information Association, London, UK, Report No. C637, 286 p.

- Guide To Soil Nail Design And Construction, Geotechnical Engineering Office Civil Engineering And Development Department The Government Of The Hong Kong Special Administrative Region.



Steel Fibre Reinforced Concrete (SFRC): Areas of Application

The use of steel fibres in grade slabs such as industrial floors, warehouses, ports and highway pavements has been prevalent in many countries for over 4 decades.

They are known to have been widely used in Hydro sector, particularly tunnel linings and slope stabilization. In India, thanks to the improvements in steel fibre technology and more user experiences in terms of economy and durability, the use of Steel Fibre Reinforced Concrete (SFRC) is gaining traction. Advancements in admixture technologies over the last few decades coupled with developments in fibre manufacturing technology (e.g. collated /glued fibres) have enabled easier mixing, batching and improved workability of SFRC. There is an increased understanding in the industry that each fibre type behaves differently and this fact must be considered while specifying steel fibres and designing SFRC elements in various projects. However, it is also true that absence of appropriate material specifications for SFRC and lack of Indian standards for testing and design has led to a rather slow acceptance of the concept.

Behaviour and Characterization of SFRC

SFRC is a concrete that has a homogenous distribution of randomly oriented discontinuous and discrete steel fibres. Steel fibres are introduced in the concrete matrix during the mixing of its constituent ingredients. Upon hardening, these fibres improve the properties of concrete such as ductility, fracture toughness, energy dissipation, impact resistance, fatigue resistance and limiting of crack propagation. Under tension, as cracks start propagating inside concrete, steel fibres present in the matrix bridge the cracks and transfer the tension across them during this process. Thus, SFRC actually causes no considerable increase in the flexural strength (modulus of rupture) of the concrete yet contributes in improving the load carrying capacity of a structural system on account of increased toughness and rotation capacity.

The behaviour of plain concrete and SFRC is made clear with the help of a four point beam bending test as illustrated in Figure 1. It is observed that for plain concrete, a sudden and brittle mode of failure occurs after the peak load is reached which then is used to calculate the flexural strength of the concrete. When sufficient ductility is ensured in the beam with the addition of steel fibres in concrete, a strain softening

Navneet T. Narayan

phenomenon is observed after the load at first crack or peak load in the beam. Thus, with this kind of toughening behaviour in the beam, post-crack flexural strength of SFRC is guaranteed.

Figure 1: Behaviour of SFRC

Adding steel fibres purely on a volume fraction basis has its disadvantages in that it fails to differentiate between various kinds of steel fibres and considers the volume of steel added as the only criterion. This is obviously not true because for a given volume of fibres, smaller diameter fibres are more in number than the larger ones. This consequently results in a larger network of fibres within the concrete matrix which would definitely alter the performance of the concrete due to higher confinement. Similarly, aspect ratio (length/diameter) of the fibre has a greater bearing in the performance of SFRC in that higher aspect ratios yield better performance due to longer anchorage lengths and fibre network. Apart from the differences in sizes and aspect ratios, steel fibres may come to differ in shape (straight/hooked end/ undulated), form (fibres glued together with water soluble glue/ loose), tensile strength (high/medium/low) and materials (mild steel/galvanized/stainless). Thus, all fibres are not alike (Figure 2) and must be selected based on the requirements of the user and applications they will be put to use.

SFRC Applications

One of the major goals of design of structures is to provide for predictable ductile failure modes and avoid brittle unpredicted modes. In other words, the first crack in the structural system must never be the last crack and there should be multiple load paths to have some redundancy. In all systems where this holds (meaning statically indeterminate structures), steel fibres come across as excellent substitutes to conventional

Concrete: Steel Fibre


concrete. Moreover, the fibres contribute to the bending stress block by allowing the tension side of concrete to be used in the moment resistance calculations as shown in Figure 3. The following paragraphs list appropriate applications for SFRC use in both ULS:

loads. Such a scenario in slabs leads to large cracks which require costly repairs. SFRC slabs on the other hand work on the principle of load redistribution which allows the use of a plastic design approach where the stresses in the slab are not just limited to an elastic threshold value, but are allowed to go beyond by the sheer capability of this transformed material. The plastic design approach allows for the full properties of SFRC to be put to use.

Real scale lab tests performed to characterize the behaviour of plain concrete vis-à-vis SFRC reveal a lot of differences. Results show distinct and large cracks appearing in plain concrete slabs that run through the section, dividing the slab into various pieces as soon as the moment capacity is reached while SFRC on the contrary allows for yielding of the slab by progressively smearing the excess moments, leading to finer cracks as illustrated (Figure 5).

Figure 2: Fibres Galore – All Fibres are not alike

Fibres working in Ultimate Limit State(ULS)

Grade Slabs

One of the major application areas of SFRC happens to be “slab-on-grade” (industrial flooring, concrete pavements, ground slabs etc.) where it has been a well- established building material and a meaningful alternative to plain or reinforced concrete. Slab-on-grade can be defined as a slab that can be fully supported by a sufficiently compacted sub-base (see Figure 4). The general loading cases in such a structure include stationary loads due to racks, pallets, containers etc. and moving loads like trucks, stackers and fork-lifts.

As a design basis, bending moments are calculated according to the appropriate ground support and loading conditions. Depending on whether the slab is plain concrete or SFRC, appropriate design approaches have to be used. Conventional plain concrete slabs work only up to a point where the stresses in the slab lie within the elastic range of the material. As soon as the stresses in the slab exceed the elastic threshold range, the plain concrete cracks in a brittle manner, losing its capability to carry any further substantial

Figure 4: Grade Slab Example – A Container Freight Station made of SFRC

Figure 5: Plain Concrete Slab – Brittle Failure and SFRC Slab – Ductile failure

Shotcrete Tunnel Linings

Construction of tunnel linings forms an integral part of any tunnel drilling activity. After the drill and blast operation inside a tunnel, the surrounding rock mass requires some kind



of a temporary support which is typically provided by thin shotcrete linings. The role of such a shotcrete lining is not to try and support the original ground pressures but to stabilise the deformations required to mobilise the inherent ground strength. Consider an illustration (Figure 6) which details the Ground-Lining interaction inside a tunnel. As excavation proceeds, ground moves into the tunnel and radial pressure required for equilibrium reduces as the ground strength is mobilized. Following completion of lining at B, load from the ground causes inward movement of lining until a point C of equilibrium at which radial pressure required for equilibrium is provided by the lining.

on a case-to-case basis. For example, the world famous Oceanographic Park at Valencia, Spain (Figure 9) had steel fibres shotcreted in conjunction with steel mesh to allow for an easy installation due to the curvature of the structure and accommodate the limited design shell thickness (6 cm to 12 cm). Similarly, fibres have been known to reduce congestion of reinforcements in link beams and beam column junctions in tall buildings.

Rafts and Foundation Slabs of Buildings have also been getting equal attention in extreme cases where the regular reinforcements are too congested and the bar diameters are already too high (≥ 32 mm) to allow for further increase. In such cases, steel fibres become most suited as they contribute substantially to the moment capacity of the sections.

Fibres working in Serviceability Limit State(SLS)

Apart from bending, fibres work in containing cracks in axial direction as well. Steel fibres lead to formation of controlled crack patterns with reduced crack widths, and thus appropriate for crack width design. Consequently, in cases where clients impose stringent limits on crack-widths and liquid tightness, less rebar reinforcements are required (smaller diameter, larger distances) and the durability and serviceability of the structural elements is greatly improved.

Figure 6: Working of SFRC Tunnel Linings

Rock supports in tunnels involve a constant risk of unexpected loads and deformations. In such a case, the best safety is achieved by having a shotcrete layer support that allows for the highest possible fracture energy i.e. toughness or ductility.

Segmental Linings

Segmental linings are the support system for shield Tunnel Boring Machine (TBM) excavated tunnels. Precast concrete segments are assembled inside the shield to form a series of rings (Figure 7) that become the support structure of the tunnel. Such tunnels are mainly used for Water Transportation and Metro Rail Projects. It is possible to partially or fully replace conventional steel bar reinforcement with steel fibres in recast segments based on the loads acting in the ring section. Steel Fibres in precast segments help in decongesting steel reinforcement cages and are greatly reduce the chipping and spalling of concrete in segments during handling, stacking and installation (Figure 8). Unreinforced concrete cover areas even in heavy conventional rebar reinforced segments are often prone to damage. Steel Fibres provide a 3 dimensional reinforcement in the entire section of the segments greatly reducing the extent of such damages.

Structural Elements

Steel Fibres have been used in structural elements world over to achieve a variety of objectives best suited and justified

Figure 7: SFRC Segmental Lining Tunnel

Figure 8: Spalling of Unreinforced Segment Edges



Liquid Tight Floors

Some industrial/warehouse floors need to be designed in such a manner that they have to act as a secondary barrier against hazardous goods that may leak from the storage containers. Usually a very stringent crack-width limit of 0.1 mm is imposed on the floor in such industries (Figure 11). Such projects are almost certainly required to be combined reinforcement (Mesh + Fibres) to fully leverage the benefits of the composite system in an optimal manner.

Water Tight Raft Foundations

Similar in concept to the liquid tight floors, the primary concern for rafts is the seepage due to uplift forces of water from beneath which can lead to certain crack-width requirements for the structure. For example, the project illustrated in Figure 12 involved the use of combined steel fibres + rebar

Figure 9: The Oceanographic Park, Valencia

reinforcement to reinforce the load bearing foundation slab. Calculated crack width was 0.2 mm. The 60 cm thick slab had an uneven bottom and was founded on rock, crushed rock and piles which increased the possibility of restraint cracks. A combined fibres + rebar solution got rid of the problem and led to major savings for the contractor due to reduction in construction time because of simplification of the slab reinforcing scheme.

Fibres working in Serviceability Limit State(SLS)

Figure 11: Example- An SFRC liquid tight floor in Waldenburg, Germany

Conclusion

We have seen until now as to how steel fibres have certain technical advantages that make then suitable and preferable for the applications listed. However, one must also not forget that using fibres to replace steel reinforcements in part or whole make sense practically on site as well in terms of saving man-hours (with the reduction/elimination of bar bending activities) and construction time (no rebars to be laid). With increased understanding of properties of SFRC, coupled with standardization and further improvements in fibre manufacturing, one is bound to see an increase in the use of Steel Fibres in Construction in the coming years.

Figure 12: Example- “Court House”, Flemmingsberg, Sweden



A Boon for Construction Projects…Indian Vastushastra

It can be said with assertiveness that all Vastu defects can be overcome with proper use of the ancient Indian principles of Vastushastra. All the projects can then come out of

darkness and move forward with renewed speed and efficiency. With Vastushastra, we can mitigate all the Vastu defects and generate positive vibes for the whole humanity…

Thinking about the connection between the economic slow-down, rising prices and the problems arising out of these with Vastushastra, we must first of all understand that every aspect of human life is influenced by Vastushastra. It has been proved over time that right from the prosperity touching your home to its stability and improvement, from educational progress and health to happier marital status and progeny and from career, development and stability to professional and industrial progress everything is deeply influenced by Vastushastra.

In the recent past we have witnessed major problems in many industries as well as in construction projects due to various reasons. When the events were analyzed with the principles of Vastu, it clearly came to the fore that both the roots of the problems and their answers are found in the principles of this ancient Indian science.

Public outcry, disagreements, facing action due to huge neglect of Government rules and also Court proceedings are all results from one or more Vastu defects in the North West direction. In some of the projects the North West had a hill and a lake as two prominent Vastu defects. In a prominent location in Mumbai, the Court and Government action was caused by a slope in North West with a huge lake. In an another incident the 2nd phase of the project started from North West and sustained major problems for almost 3 years. An industrial worker dispute aggravated due to Vastu defects in the North West and another huge and ambitious project is held up due to a couple of serious natural Vastu defects. At the same time it can be said with assertiveness that all these Vastu defects can be overcome and the projects can

come out of the darkness and move forward efficiently. It is only with the proper use of the ancient Indian principles of Vastushastra that we can mitigate all the Vastu defects and generate positive vibes.

Normally construction professional get the plans approved and as soon as the permissions are on hand they start the project construction. During this period they have to undergo many obstacles which may result in stalling or delaying of the project as also escalation of the costs of the project. Once they are trapped in such a vicious circle they approach Vasturaviraj, place their problems before us and seek solutions and remedial measures.

We specifically tell them not to specify the problems in any manner because our analysis of the project provides us all the inputs of the problems being faced. Normally a Vastu Expert is able to understand all the problems concerning a project after he conducts an analysis of the same.

The Analysis Procedure

One of our Vastu Experts visits the project and the project in charge is asked to keep the maps and drawings etec for

Dr. Raviraj Ahirrao, Ph. D.Dr. Raviraj Vastu Spiritual Services (P) Ltd.

Vasthu Consultant


analysis. The Vastu analysis consists of analyzing plot of land and a detailed study and analysis of the entire project. The required information is obtained from the concerned authorities at the Project. The Expert then places Positive and Negative points of the project and prepares a Report which states the fact that are positive and tnose negative as per Vastushastra. If there are certain corrections to be made concerning the Government regulations the same are also mentioned in the Report. In the last part of the Report the Expert sp0ecifies the Remedial Measures that need to be taken in order to mitigate the Vastu defects found during analysis along with a probable expenditure for the same.

Normally, Vasturaviraj uses its own and proven manufactured items for remedial measures using high quality crystals, pyramids, Yantra and others. These are proven and dedicated items from Vasturaviraj and therefore bring the desired results within specified time. It is almost impossible to find any other manufacturer to provide matching quality of materials. These remedial measures are fitted either in the land or in the buildings as specified and required and the process is carried out in the presence of our experts. The work progresses well without any obstacles and the builder gains desired success.

The project thus completed is then eligible for provision of a Certificate “VASTURAVIRAJ VASTU DEFECTS FREE PROJECT”. It is also mentioned in the Certificate that the project has gone through the Vastu Defect Neutralization process. At the same time the project officers and marketing personnel are trained in the various aspects of Vastushastra and cause and effects of the Vastu defects. Thus these people can address all questions from the customers.

Vasturaviraj also undertakes to clarify all the doubts raised

during completion of the project. At the same time the project is accorded permission to share the name “Vastu Consultants-Vasturaviraj” to be exhibited with other consultants for the project.

Project planning and design as per Vastushastra

In this process the whole procedure of Planning and design from selection of a plot of land to the construction of a residential building or office, factory or a unit is carried out fully as per the principles of Vastushastra. The work is carried out in the following pattern:

- Selection of the plot of land

- Preparation of a project outline in consultation with Developer-Architect and Vastu Expert.

- In a residential project the plan for each apartment is made positive as per principles of Vastushastra.

- In the whole process Vasturaviraj totally reveres the Architecture and it also follows all the laid out Government regulations for a project, including the aspirations of the developer as well in successful Planning and Designing of the project.

- We are proud of our achievement of bringing success to many project in India and abroad for many developers and Architects as well. In all these projects we achieve a huge success rate of 75% Vastushastra.

- The remaining vastu defects are removed with the help of Remedial Measures to bring 100% positive apartment from Vastushastra point of view.

- A Vastushastra Complaint Project Certificate is awarded. Vasturaviraj also undertakes the responsibility of essential training of personnel from the Project in Vastushastra and customer complaint compliance in terms of Vastu till the project is completed.

The trend to create structures without considering Vastu Vastupurush

Certificate for Vastu Project

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culminating in defects and problems of serious nature has been observed. The idea of bandaging the wound with remedial measures is an afterthought. If only we could go by the principles of Vastushastra and plan our projects effectively, it would be a boon to everyone connected with the project.

The initiation for any construction project is with acquisition of land. Ancient Indian Vastushastra has preferred eight important commandments for selection of plot of land. In the 21st Century today we are faced with population explosion and lack of availability of land clubbed with fierce competition. It is therefore very difficult to find a plot of land totally suitable as per Vastushastra. However the ancient saints and sages were true visionaries. Therefore even in our world today even if we are not able to get a proper plot of land we can create a square or rectangular plot, with an underground wall and copper strips as well as Pyramids in appropriate quantity which would provide all the benefits of success and energy. One can then place the project details in this plot of land. In the Vastu Science nomenclature this is called Linearization of the Plot.

The entire construction project arena has 5 major problems to deal with. These are:

1. Acquisition of Plot and litigation, court matters and heated discussions while taking possession.

2. Lack of coordination in decision on a project after the land is in possession as well as delays encountered.

3. To acquire all the Government permissions and Licenses for Construction project.

4. Lack of the desired speed and progress in spite of huge investments, availability of materials and full quantum of labor force.

5. Lack of success in marketing even with the best progress in construction activities.

Most importantly the root cause of all these matters is in Vastushastra.

Problem 1 is that of purchase of land or problems while taking possession of the land. This is a sure sign of a Vastu defect in the North to West area of the plot. The part may be quite higher or it may have a larger slope or a ditch, water, a huge extension or a Cut in the part, a crematorium, temple, hospital or such Vastu defects. These result in quarrels between owners of land and further eclipse the project just at the beginning. If there are Vastu defects in North West as well as East to South the results are mostly seen in serious problems and even court cases.

Problem 2 reflects the indecision after the plot of land is in possession. This is regarding the use of the plot either for residential, commercial or both. Many times the difference of opinion between the developer, architects and other stake holders reach a stage which results in inordinate delay. Finally the plan is somehow agreed and sent for various Government approvals.

Problem 3 relates to the obstacles in receiving various sanctions such as objections and others. These again result in delays, escalating costs and discontent.

Just as in problem 1, the other two problems also mean delays, obstacles, escalating costs and mental agony. When your plot of land has serious Vastu defects in North West plus South East the type of problems are sure to bother you.

- From the weight point of view in Vastushastra the second heaviest area should be South East and North West should be third heaviest part. If this proportion is hampered or out of phase the troubles will ensue in full.

- South East direction is the base of FIRE element. The Electric Substation is the most well placed entity here. However if this area is encroached by an element of water, the same results in natural imbalance, Vastu defects and negativity. This has been proved universally.

Distribution of Weight

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- South East part is the base for FIRE element. If this area is encroached by any other element such as water, air, earth or sky the natural imbalance will mean Vastu defect and result in bad effects.

- It is harmful to have a highly raised portion or ditches or deep areas in both these directions.

- It is also harmful if these areas have CUTS or huge extension of the plot.

Many of the Developers have expressed the opinion that these are normal problems faced by them. They treat these as a normal occurrence and part of the business. However one must understand that if these issues are resolved early on the problems get resolved on their own reducing the agony. It is thus imperative that we should go for Planning and Designing of the project according to Vastushastra and if certain natural Vastu defects still continue to be found in the plans, these can

be effectively resolved with Vastu Remedial Measures and success of the project is ensured.

Problem 4 starts on a positive note for that matter. The plot of land is in possession, plans have been sanctioned, the construction work has started, labor is available and financial status is impeccable. All this would mean that the construction speed should be healthy. However unforeseen obstacles such as reduction in the speed of work, stalling of work, unnecessary and heavy expenses, sabotage and accidents, non cooperation from contractors and others emerge.

Problem 5 speaks about the construction work being completed on schedule and project ready for sale. Marketing team is fully functional. The customers are arriving in numbers and still the spaces are remaining unsold. The response is very lukewarm.

The roots of both the above debacles lie in Vastu defects in North to East and South to West portions of the plot of land.

- The North East part should be as free as possible and also as light as possible. This must have become heavier.

- There must be CUTS created either in North East, South West or both.

- The North East must have become very heavy and South West very light.

- Underground water tank must have been placed in South West instead of North East.

- There must be a slope, cut or water in the South West.

- There would be a crematorium, Kabristan, Graveyard, Temple, Hospital, Railway, Bus stand or a Mall in North East or South West.

- The Entrance would be in South West.

As per Vastushastra South West provides stability and North East provides progress. However if there is a Vastu defect in either or both of them obstacles are definitely present in reducing the speed of work or in obstacles in sales.

In order to avoid these pitfalls, it is essential that we accept our own ancient Indian Vastushastra. If we go by the guiding principles laid down for excavation and construction here the work progresses with desired speed and results. If underground water storage is created in the North East of the project before start many of the obstacles are automatically taken care of and the financial inputs remain positive.

Other benefits of ancient Indian Vastushastra

- The work progresses without obstacles.- Easier to avoid the risks of delays, escalation of costs,

mental agony and losses.- The residents of the Complex also benefit with faster

development and progress.

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As on today we see a huge demand for Redevelopment due to the paucity of land, outdated and dilapidated buildings and the risky old structures. Redevelopment is a golden opportunity for the residents of these old buildings. Their residential accommodation could be made positive as per Vastu principles. The abodes they are in today might be less than 40 % positive which means that it is providing them benefits lesser than 40%. This means 40 % progress and 60 % regress and troubles. If the residents demand with a single voice for Vastu compliant buildings, all their homes could be made 80% positive without any expenditure. This means that they will be in for 80% fast progress and just 20% obstacles. With proper and justified Vastu remedial measures, the obstacles could be brought down to 0%.

In the Redevelopment it takes very long to cross all the hurdles due to the intricate human problems. In some cases the Vastu defects of the old plot of land itself causes hard feelings and tensions delaying positive results. If the Vastu defects of the plot of old land are taken care of with the help of Vastushastra the projects can take off smoothly.

A matter of fact needs to be mentioned here. Cities like Shanghai, Hong Kong and Singapore have today become symbols of what redevelopment can achieve in the World today. The Governments at these countries have used local architecture science Feng Shui for bringing in faster redevelopment. Although Feng Shui is part of the ancient Indian Vastushastra, one has to accept that we have not been able to propagate Vastushastra globally with necessary resolve.

On the Global level the importance of Green Building (LEEDS Rating) and its demand has been increasing. It can be understood that the concept has been accepted more because it has come from a foreign land. However we must say with pride that the guiding principles of Green Building design are exactly as per ancient Indian Vastushastra.

Apart from this all basic and infrastructure projects such as roads, energy projects, water reservoirs, construction of dams, new Town Planning Schemes including Agriculture could be benefitted effectively with Vastu analysis of land and the use of Vastushastra principles.

Ancient Indian Vastushastra has been a boon bestowed by India on to the World. By implementing the principles laid down in this science Maharashtra State can be a leader in terms of housing and development and can guide not only the Country but the entire World.

For further details:

Vasturaviraj

9869001719/022-67847600E-mail: [email protected]

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50 Years of Terre Armée

(Reinforced Earth) Technology- An Experience

It has been a proven fact observed that civil engineering does not provide enough opportunities in terms at technical innovation. In this historical back drop the innovation of

Terre Armee (Reinforced Earth) has revolutionized the civil engineering after the introduction of Reinforced Cement Concrete and Prestressed Concrete.

The concept of Terre Armee struck late Henri Vidal in the year of 1957 on beach of Ibiza, France. It took good six years for Vidal to complete his thesis “La Terre Armee” on soil reinforcement principle. He finally filed the patent on Terre Armme in 1963 and the patent was approved in 1964. It is, however, a lengthy experience when one considers the road it travelled till date. The first structure made of Reinforced Earth is now 49 years old.

Considering the growing global acceptance of the technology and reaching out to larger market segment, Terre Armee, France, decided to go international and formed Terre Armee International with the beginning of the operation in Canada, USA, Spain, Japan, in the 70’s and subsequently to other Asian markets. This needed a high-level team, indispensable in assuring users of complete services for the engineering and design elaboration of projects, for production and delivery of reinforcements and facing, analysis of foundation soils, and also for technical assistance in the course of construction. Terre Armee International started growing in leaps and bound.

Terre Armee International was formed to direct all of the research activities of the group, organize co-operation among different companies, distribute tasks according to need, means, and proficiencies and redistribute to all the countries of the world the totality of information and results.

Saikat ChatterjeeNational Manager – Business Development, Reinforced Earth India

Late Henry Vidal Terre Armée = composite material, with an artificial cohesion

The first structure constructed as early as 1964 in Pragnere in South of France made of metallic soil reinforcement. In the year at 1968 Henri Vidal formed La Terre Armee with Mr. Mauarire Darbon, one secretary and a draftsman. Since then, there was no looking back not only for Terre Armee as a company but also the acceptance of the new technology, globally. The road which has been travelled is first of all, the construction of more than thousands of structures since 1964 with million square meter of facing. Today, structures made of Terre Armee are completed and placed in service everyday somewhere in the world. The success of Terre Armee is indeed its worldwide acceptance and significant strength lying in the dynamism of its team, in its high technical level of engineering and construction services. Original Terre Armee concept

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During these years, 8 billion dollars have been invested in the research works for the development of Terre Armee Technology throughout the world.

1969 experienced the first Pure Bridge Abutment by Terre Armee mass in France, designed for heavy trucks. This application revolutionized the technology and construction became much easier and cost effective.

The patent for the ‘Cruciform’ Concrete Panels (Terra Class) was obtained in 1970. In the same year, the first subsidiary was formed in Canada and the creation of The Reinforced Earth Company in USA took place in 1971 followed by Tierra Armada in Spain in 1972. After North America and Europe, Asia was not far behind. In 1974, license for Terre Armee technology was given to a Japanese company to carry out the operation under the technical guidance of Terre Armee, France.

In 1974 it carried out a comparative behavior test between galvanized steel and stainless steel. The result showed excellent behavior by the stainless steel in comparison with galvanized steel.

In 1976 Terre Armee’s Madrid test station, adapted soil reinforcement with cross ridges/ ribs. This particular strip was named as High Adherence strips which roughly doubled the coefficient of friction between soil and soil reinforcement.

In 1979, French government officially approved the Terre Armee concept standardizing the following norms:

- Notion of minimum service life.- The principal of service probabilistic calculation.- Recommendation for the following up of structures.

Then Terre Armee International decided to diversify their activity through the use of precast arch system. And this was the beginning of a new chapter in the annals of Pre cast Arch solution. The Techspan pre-cast arch solution was a boon for construction Railway Over Bridge (ROB) Vehicular Under Passes (VUP), Hydraulic Bridges and others.

In a short span of time i.e. between 1976 to 1986 the Terre Armee International increased the surface of Terre Armee structure built every year from 1,00,000 m2 to 7,00,000 m2.

Mr. Henry Vidal reiterated “We should also mention as an example of a study distributed among several countries the research concerning the effect of earthquakes on Reinforced Earth, carried out first by French and American companies (with walls subjected to vibrations and explosion) and finally confirmed the excellent behaviour of all those structures which have actually been subjected to earth tremors (Japan and Northern Italy). This research has just been described in detail in a study about completed element in dynamic phase, thanks to the American programme.”

The time is past when a soil mechanics expert can claim that Terre Armee will not work. In reality the theory developed 50

Henry Vidal’s Thesis “La Terre Armee” and the First Terre Armee Structure in Pragnères (South of France)

High Adherence Soil Reinforcing Steel Strips

45m high Terre Armee Wall SeaTac Airport 3rd Runway, USA

Yandi Rapid Growth 5, Irone ore mine, Western Australia




years ago has been completely confirmed and it is worthy to note that with thousands of completed structures, there has not been a single mishap or accident resulting from the theoretical error concerning the design of Terre Armee.

Applications of Terre Armee at construction project

1. Retaining wall to support motor roads2. Retaining wall to support railroads or subways 3. Bridge Abutments4. Industrial structures5. Storage silos for heavy material6. Dams7. Marine structures8. Structures associated with Architecture

Since 1980s, Terre Armee became a global phenomenon in Civil Engineering Industry and the technology was not only acclaimed but proven, accepted and tested all over the world. It was the undisputed first choice for Mechanical Soil Stabilization activities.

Terre Armee in India

Terre Armee activities were launched in India during 1995, initially through a license agreement between Terre Armee International and an Indian company. This project initiative was

launched through an industry-academic platform with Indian Institute of Technology (IIT), New Delhi. In the year of 1996, the first Terre Armee project was executed for Arterial Expressway Corridor project in Jammu & Kashmir state of India.

In 2006, the license agreement was discontinued, and the business activities along with assets and human resources were transferred and Reinforced Earth India Private Limited became fully operational under the aegis of Terre Armee International, as a fully owned subsidiary of the parent group. Mr. Somnath Biswas who was already the General Manager in the licensee company, took over as the Managing Director of Reinforced Earth India, with a new challenge to drive a relatively young team of people to the next level of performance. Within short time span, Reinforced Earth has become a niche brand, providing specialized expertise and value engineering services to a dynamic and evolving, but competitive product driven market.

Over this period of organizational development, the main activities of the company have been Terre Armee walls and slopes, in-situ soil reinforcement techniques (TerraNail, TerraLink, Earth and Rock Anchors) and precast, pre-engineered concrete structures like TechSpan,TechCulvert,TechBox,TechAbutment (pure abutment and post tensioned slab) and TechWall.

Reinforced Earth India is committed to improve the environment protection of construction sites. It has a strong safety, health and risk prevention policy and dedicated towards a strong Corporate Social Responsibility.

The commercial approach of the company has been to work upstream in projects, providing value engineering services and positioning solutions before products. The portfolio is well diversified with different market segments, products and techniques/activity and territories (geography).

Conclusion

The worldwide acceptance and utilization of Terre Armee Technology make it one of the most significant civil engineering developments of the last five decades. Its fundamental concepts have been well documented based on continuous commitment to research and development, together with the experience gained in thousands of Terre Armee structures in service throughout the world.

Yet Terre Armee technology continues to evolve, and its applications to expand. And as we obtain new data from ongoing research studies, we can anticipate further innovations in design and materials. But only those changes which can be demonstrated through extensive testing and evaluation to be technically and economically justifiable will become standard practice in design and construction of Terre Armee structures.

Guru TeghBahadur Memorial, New Delhi

Navghar Flyover, Mumbai

january 2014 masterbuilder

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