STUDY OF MULTIHAZARD ON URBAN HABITATS OF INDIA: A CASE STUDY OF AHMEDABAD CITY

Nilesh S. JhaDr. R. K. Gajjar

LITERATURE REVIEW “Applied multi risk mapping of natural disasters for impact

assessment” to develop a new approach to produce integrated multi risk maps to achieve more effective spatial planning procedures in areas prone to natural disasters in Europe by DSS.

Multi Hazard Mitigation Plan for Columbia County, covers each of the major hazards that pose risks. The objective of mitigation is to reduce negative impacts of Future Disasters on community.

“Disaster Prevention in Urban Environment” focuses on disaster prevention policy in Netherland, implementation issues and gaps and failure of local and national authorities’ preventative policies. Comparisons are also made with the implementation of Strategic Environmental Assessment.

“Multi Hazard risk assessment using GIS in urban areas: case study of Costa” is based on formulating a digitized map for city and its surrounding and based on historical information, a GIS database was generated which was used for mapping multi hazards.

LITERATURE REVIEW CONT’D. “Urban multi Hazard risk analysis using GIS and Remote

sensing: Case study of Kohima, Nagaland”, “presents a guideline for preparing a multi hazard map by GIS and Remote Sensing considering various building elements at risk and population at risk is calculated but limited to landslides, earthquakes and fire.

Management/Evaluation of Urban Disaster Risk by Norio Okada focuses on management. Research focuses on development of methodologies for evaluation of UDR and effective utilization of spatial GIS.

Promoting Safer Building Construction by V. Suresh lays emphasis on need for evolution of safer habitat which can respond and resist the loads, forces and effects due to natural disasters.

Risks influences and sustainable multi hazard design on built environment by Razvan Oprita. In this paper approach has been made for investigation of built environment affected by EQ, Flood, Wind and Fire.

LITERATURE REVIEW CONT’D. Quality of life, Sustainable Civil Infrastructure, and Sustaina

ble Development: Strategically Expanding Choice by Jamie Montague Fischer and Adjo Amekudzi reviews the role of QOL in civil infrastructure decision making.

Urban Runoff Mitigation by a Permeable Pavement System over Impermeable Soils by Elizabeth A. Fassman and Samuel Blackbourn suggests that Permeable pavements can mitigate conventional large design storm flows, but care must be taken during installation to ensure proper function.

Knowledge-Enabled Decision Support System for Routing Urban Utilities by H. M. Osman and T. E. El - Diraby presents a Web-based system for supporting the selection of the most suitable routes for buried urban utilities. The aim of the proposed system is to support (not make) decisions through a collaborative semi automated environment.

LITERATURE REVIEW CONT’D… Urban Hazard Mitigation: Creating Resilient Cities by David R.

Godschalk This research considers the relationship between resilience and terrorism, and discusses why resilience is important and how to apply its principles to physical and social elements of cities.

Built Environment Hazards in Urban Habitats by Farzad Naeim & Marshall Lew provides a basic understanding of major EQ performance issues of importance worldwide. This paper contributes to the critical understanding of issues and action to reduce the damage caused by them during future EQ.

Structural and Non structural seismic vulnerability assessment for schools & hospitals: case study in Central America and India by D. H. Long, M. I. Verbicaro, Y. Singh, JSR Prasad, D. Wong Diaz, M. Gutierrez has formulated a standardised questionnaire which allow a priority ranking and identification of most vulnerable features by advanced technology.

RESEARCH GAP In most of the developed and developing countries

research has been conducted on hazards planning and authorities take the effect of multi hazards for planning of urban habitats.

Till date we have been conducting research generally on a particular hazard in isolation but a hazard is always coupled with other systems failure which exacerbates the disaster. Eg. Bhuj EQ Utilities like power failure, communication failure etc.

Evacuation procedures and routes required in case of hazard for public buildings are not defined.

RESEARCH GAP CONT’D…. Urban hazard mitigation is not accounted for -

during the planning stage. e.g. Ahmedabad flash rains, Mumbai bomb blasts.

Earthquakes are followed by fires but its effect is not accounted during the planning stage of multi-storied buildings in India. This effect of multi-hazard leads to premature failures of multi-storied buildings.

Clear cut zoning guidelines are not formulated that identify areas and localities within urban habitats which may be subjected to hazards like faults, fire, flooding etc.

OBJECTIVE To study the effect of multi hazards i.e. earthquake and

fire on public multi-storied buildings and population affected in nearby locality due to multi-hazard.

Formulation of multi hazard maps using Geographic Information System (GIS)

To study the existing practice (planning, design and construction) followed by local body for earthquake and fire and formulate a check list for existing limitations and disparity in development for multi-storied buildings.

Formulation of guidelines for practicing engineers and formulating road map for setting safety standard for multi-storied buildings for hazards like earthquake and fire.

SCOPE Multi-storied public buildings of Ahmedabad city

are taken as case study and are mapped in GIS by finding locational details by GPS.

GIS maps for earthquake hazard are created for multi-storied buildings considering various parameters like soil profile, N – value, shear velocity (Vs), fault lines, lineaments, ground water table and zoning guidelines.

Fire hazard map for buildings are developed considering underground pipelines of water and gas, historic fire call record, household units, road networks, location of fire station and CNG stations, industrial estates and population details.

SCOPE CONT’D…. Effect of earthquake is studied on multi-storied buildings

and only those buildings that are vulnerable to earthquake are further analyzed for hazard of fire.

Mitigation strategies existing for the hazard of earthquake and fire specifically for multi-storied buildings are studied in developed countries like US and Europe.

Existing practices adopted by local authority like Municipal Corporation and urban authority for the hazard of earthquake and fire for buildings.

Study and comment on design features for earthquake resistance and fire safety measures of selected buildings.

RESEARCH QUESTION

Are the multi-storied buildings in India safe from the effect of multi-hazards such as earthquake and fire?

METHODOLOGY A primary survey has been conducted within the

city limits of Ahmedabad City wherein data is collected for desired parameters of Earthquake hazard.

Respective Maps for the hazard of earthquake is formulated in Geographical Information System (GIS) Environment.

Qualitative information is converted into quantitative data based on experience and consultation with professionals, academicians and experts of the subject and a table of values, is formulated.

METHODOLOGY CONT’D ….

Location details of the buildings under study are generated by GPS and fed in GIS.

Similar methodology as mentioned in steps 1 to 3 is adopted for generation of hazard map for fire.

The methodology adopted is not experimental and techniques adopted are both qualitative and quantitative.

METHODOLOGYCONT’D….

ABOUT AHMEDABAD CITY The city limit extents to the area of @ 464 sq.

km. The entire city is distributed into Six Zones for

Administration purpose which is further sub divided into various election wards based on population.

As of date, City is divided into 64 wards Total population within the city is @ 45.0 lac As per the records of AMC, there are as many

as 12.91 lac Residential Buildings and 3.96 lac Non Residential Buildings = 16.87 lac Total Bldgs.

City has @ 622 Govt. & Semi Govt. Buildings

From the tax bills of Corporation, 76 Government Multi-storied Buildings have been identified and is considered for study purpose

The exact location of these buildings along with the height above GL have been found by GPS.

Based on the parameters like;Geologic ProfileFault lines and LineamentsLand Use or Zoning Guidelines of AMC or AUDA

Soil ProfileN – ValueShear Value (Vs)Ground Water Table depth below the surface

And Depending on the severity of the above parameters on buildings during earthquake, some weightage is given

  Ranking

Parameters A = 20.0 B = 15.0 C = 10.0 D = 5.0

N - Value 1 - 8.0 8.1 - 15.015.1 - 22.0 > 22.0

Type of Soil CI/MI CL/ML SM SCGround Water Table (m) 1 - 8.0 8.1 - 12.0

12.1 - 18.0 > 18.0

Shear Velocity Vs (m/sec)

139.0 - 173.5

173.6 - 208.0

208.1 - 242.6 > 242.6

Land Use Regulation (AUDA Proposed Zoning)

Industrial Zone (General/Special)

Core Walled City / Central Business District

Residential Zone (1/2/3) Others

Distance Regulation for Faults (m)

Within 150.0 m Radius

Between 150.1 - 200.0 m

Between 200.1 - 225.0 m

> 225.0 m

Distance Regulation for Lineaments (m)

Within 50.0 m Radius

Between 50.1 - 75 m

Between 75.1 - 100.0 m

> 100.0 m

WhereA refers to Extremely High RiskB Refers to High RiskC Refers to Moderate RiskD Refers to Low Risk

DETAILS OF RISK RANKING CALCULATION

..\BISAG\EQ Mapping\Profile_.xls

Finally, Five BuildingsL. G. Hostel BlockBachat BhavanSales Tax Bhavan

Have been identified as Vulnerable to Earthquake based on the above parameters.

M. S. Building - Vastrapur (New) is also taken into consideration for calculation of Risk as it is newly constructed building with sensors and smoke detectors.

Apna Bazar located in the heart of city is also studied as population density is maximum in that locality.

DATA COLLECTED FOR EQ FOR SPECIFIC BUILDING

..\BISAG\Details of Bldg\Building Details.xlsx

FIRE Sources of Fire due to Earthquake

LPG cylindersCNG pipelinesPetrol PumpsChemical FactoriesPaper IndustriesElectric Short CircuitPower Stations/Substations

FIRE HAZARD MAP FORMULATION Historic data of last 7 years of the entire city

related to the events of fire. Gas pipe line details and network of the entire

city Locations of the nearest fire stations Population density of the area Location of the Industrial areas which are more

vulnerable (GIDC) Road Network Water pipeline distribution network Zoning regulations of AUDA

FIRE

Historic data has been collected from Ahmedabad Municipal Corporation (AMC) Fire Department.

Past 7 years data of Fire Call Data is sorted Ward wise (64) based on

the Address of Call and the outcome is ….

..\Fire\Fire Details Locality.xlsx

WATER PIPELINE DETAILS

Pipeline network of the entire Ahmedabad City has also been digitized for the possibility of liquefaction in case of EQ Hazard

AHMEDABAD CITY DIVIDED INTO SIX ZONES BY AMC

ZONING GUIDELINES WITHIN AHMEDABAD CITY

DISTRIBUTION NETWORK OF PNG OF ADANI WITHIN THE CITY

MAP OF AHMEDABAD CITY WITH GIDC LOCATIONS

ROAD NETWORK WITHIN AHMEDABAD CITY

WATER TRUNK MAIN PIPELINE NETWORK

DETAILS OF HOUSEHOLD UNITS AND POPULATION IN EACH WARD

..\Census 2011\Population Data Wardwise.xlsx

HOUSEHOLD UNITS WITHIN VARIOUS WARDS OF CITY

POPULATIONS DETAILS WITHIN EACH WARD OF AMC

HISTORIC DATA THAT REFERS TO FIRE CALLS WITHIN WARDS

MAP INDICATING ALL PARAMETERS MENTIONED ABOVE

MAP OF ONE OF THE SAMPLE BUILDING (APNA BAZAR)

RISK CALCULATION FOR VARIOUS PARAMETERS FOR FIRE

Parameters High Risk Moderate Risk Low Risk

Gas Pipe line Area & Water Trunk main Area ≥ 100% 99.9 % – 50 % < 50%Population ≥ 50000 49999 - 25000 < 25000Household ≥ 20000 19999 - 10000 < 10000Historical Incident data (Fire Call) ≥ 100 99 – 50 < 50River < 10% 10 % - 19.9 % ≥ 20%

Road ConnectivityApproach

Road Other District Road MDRFire Station ≥ 8.0 KM 4 – 7.9 KM < 4. 0 KM

GIDC / Major Industries

Bldg within GIDC Outskirts GIDC ≥ 1.0 KM from GIDC

       

TABLE SHOWING RISK ASSESSMENT AND RANKING

Sr. NoName

Total Area (ha) Gas

Water Pipe TotalPopln.

Historical calls

House

Water Body (River/Pond/Lake) %

Gas/Water Area %

Ward Area(Ha.)

Factor Distn.Pop_Dis HH_Dis

Rank

1

L.G Hospital Hostel Bullding 314 52 80 132 95000 100

22000 7 42 279 113 106918 24760 2

2

M.S Building 314 43 0 43 77000 150

14000 0 141265 25 19113 3475 5

3

Bachat Bhavan 314 0 66 66 60000 80

12000 17 21 209 150 90144 18029 3

4

Sales Tax Bhavan 314 48 51 99 50000 80

10000 21 32 716 44 21927 4385 4

5Apna Bazar 314 0 70 70

110340 78

13552 20 22 212 148 163428 20072

1

FIRE Further survey of those buildings that are

found vulnerable to EQ have also been conducted for hazard of Fire. (Building Specific)

For Fire Hazard; Height of Each Floor Approach to Road Distance of Building from Fire Station Distance between adjacent buildings Availability of open space No. of Exit in given Building Provision of fire safety Whether fire fighting equipment installed ? Provision of Pantry? Fuel used in Pantry Gas pipeline in vicinity Population likely to be affected No. of potential users of building

RISK ASSESSMENT BASED ON INTERNAL PARAMETERS (BUILDING SPECIFIC)

..\BISAG\Details of Bldg\Building Details.xlsx

CONCLUSION 622 Government buildings were identified in

Ahmedabad City through GPS out of which 76 multi-storied buildings were study building. Analysis of these study buildings based on various parameters considering earthquake as base hazard in GIS environment leads to 5 buildings vulnerable with risk ranking more than 60 % (Value 90 or more).

After generation of fire map in GIS based on related parameters and further analysis of these 5 sample buildings, population at risk is maximum (1.60 lacs) in the radius of 1 km for Apna Bazar (one of the sample building).

CONCLUSION CONT’D …. During the planning phase of multi-storied building for the

cases in which earthquake load is governing criteria as per codal provisions, as earthquakes are followed by fires, in case of multi-storied buildings load combination of earthquake and fire gives worst combination. This is not addressed in IS codes. This needs appropriate attention in design.

Multi-hazard map formulated for the city of Ahmedabad can be used by local authorities by mentioning latitude and longitude of the said location where the building is to be constructed, in GIS. Once this is done, all the discussed external parameters for the hazard of earthquake and fire can be assessed immediately. The related risk ranking can be calculated and population at risk can be known within 1 km radius buffer created. The procedure can be adopted for old and new buildings.

CONCLUSION

Newly constructed multi-storied public buildings are designed as earthquake resistant and further fire fighting equipment, smoke detectors and automatic devices such as sprinklers are also installed. However periodic checking/operation and services are lacking. In case of emergency, for the operation of fire fighting equipment and sprinklers, skilled and trained person is required hence basic equipment operation training should be given to the permanent users of the building. Mock drills should also be organised at regular intervals

THANK YOU

Questions????