batch 1

“DESIGN OF PREFABRICATED MODULAR HOUSING FOR DIFFERENT OCCUPANCIES AT

PANCHESHWAR POWER PLANT”

BY: • FEBA MARY THOMAS (1010910068)• HARSHAL RASTOGI (1010910079)• JITHESH DHARMADAS (1010910087)

PROJECT GUIDE

Dr. M. LAKSHMIPATHY

OBJECTIVE

• For the inhabitants (about 5327 households ) displaced due to the implementation of the Pancheshwar Power Project on Mahakali river; housing is required to rehabilitate them

NECESSITY• Pancheshwar Power Project is proposed as a

Nepal-India bi-national scheme on the Mahakali river with a capacity of 6720 MW. With its implementation, a total of 41,330 persons from 5327 households have been displaced for which rehabilitation works has to be completed by 2012-2013 but as for now the progress is too slow to reach the deadline.

• For faster construction and as an approach to affordable homes , we provide a solution to mass housing using precast members.

SCOPE• The project envisages selection of a

suitable plan as per modular coordination and use of building architecture for proper functioning and orientation of the building.

• The houses are proposed to be classified on the basis of income groups (i.e. High Income Group, Medium Income Group and Low Income Group) which will then decide the corresponding plan areas.

METHODOLOGY• Selection of a realistic site.• Suggestion of a suitable plan for mass housing with grid

dimensions.• Selection of type of precast structural system.• Collection of necessary data and code books as required

for the project.• Design of foundation as per soil specifications of the site.• Selection of type of connection to be employed.• Design of precast members- Beams, columns and slabs.• Installation of the members as per design plan.• Provision for grid wise extension of the designed plan.

MAJOR DESIGN EXPERIENCE

• Planning and layout of a residential building.• Grid wise distribution of plan.• Design of structural and non- structural precast

members.• Design of connections between individual

precast members.

REALISTIC DESIGN CONSTRAINTS

Manufacturing constraints:

The design of functional plan and construction technology shall ensure that the project can be implemented in the shortest possible time with acceptable quality.

Safety constraints:

The design of all joints between prefabricated components shall meet the accepted procedures

Social constraints:

The compulsion to provide housing for people belonging to different status in society within the shortest possible time due to mass displacement.

REFERENCE TO CODES AND STANDARDS

• IS 10297:1982

Code for practice for design and construction of floors and roof using precast reinforced/ prestressed concrete.

• IS 875 :1987 Part (1&2)

Design loads for buildings and structures(Dead load & Imposed load).

• IS 456 :2000

Design co-efficient, Limit state design method.

APPLICATION OF EARLIER COURSE WORK

MULTIDISCIPLINARY COMPONENT AND TEAMWORK

• This project involves in interacting with the government officials of the Pancheshwar Project for getting necessary data.

SOFTWARE USED• AutoCAD

CONCLUSION (expected)• The project would successfully complete

the design of modular houses using advanced technology and a solution to quicker construction with economic advantages.

• Completion of the project will finally help in gaining vital and practical implementations in accordance with safety and serviceability of the designed units.

FUTURE SCOPE OF THE PROJECT (tentative)

• The implementation of the project will be of a great help to the rising need of quicker construction and in the field of mass housing techniques.

• It will be a boon for the weaker sections of society where owning a house is still a common dream and the economic advantage of the project would be effectively implemented.

• Provisions for extension of plan for other suitability issues is also included for satisfying different functional needs.

Distribution of Households as per Income Groups

• As per rehabilitation works at Pancheshwar Power Project, we need a total of 5327 households, out of which we assume as per guidance in Planning Commission, Government of India:

• 20% belonging to HIG i.e. 1066 households.• 50% belonging to MIG i.e. 2664 households.• 30% belonging to LIG i.e. 1597 households.

Allocation of Area for each Household

• The rehabilitation site being Pithoragarh and an available area of 200 acres as per Rehabilitation Proposal of the Pancheshwar Power Project.

• We adopt the carpet area of households according to the specifications provided by Planning Commission, Government of India, as follows:

• HIG- 150m2 (1615sqft)• MIG- 90m2 (968sqft)• LIG- 60m2 (646sqft)

ARCHITECTURAL INPUTS

• Orientation according to the sun-diagram• Anthropometrics • Space standards • Functional Planning and Circulation

ORIENTATION

• The orientation of a house is done according to the sun-diagram as shown in Fig. 3.1

Fig. 3.1 The sun diagram

ANTHROPOMETRICS• The dimensions of the human body as shown in Fig. 3.2 and the sizes of the

furniture help in deciding the space required in the design of a room. The size of the sofa in the living room, dining room in the dining room, bed in the bedroom, stove and fridge in the kitchen, the closet in the bath etc. help to decide the size of the rooms with proper clearances provided between the furniture for easy movement.

Fig. 3.2 Anthropometrics

SPACE STANDARDS

• Space is a specific volume which provides for a specific form of human activity. The common factor in buildings and areas in the concept of space. An architectural space is man-made. The space must be technically efficient and aesthetically satisfying.

• Every space accommodates an activity or a function, which decides the area and volume required. The activities determine the furniture requirements for the space.

FUNCTIONAL PLANNING AND

CIRCULATION• The design of a building depends upon the

nature of the building. Every building has a special character of its own. The function of the building is to be ascertained first. Then different blocks or units are to be planned. The units are then joined together to form a whole building. The sizes of various units depends upon the number

CONCEPT OF MODULAR COORDINATION EMPLOYED IN THE

PROPORTIONING OF PLAN• Modular coordination is a dimensional coordination

employing the basic module or a multi-module. A Module is the unit of size used in dimensional coordination. A multi module is a module whose size is a selected multiple of the basic module.

• The purposes of modular coordination are:

1. To reduce the variety of component sizes produced

2. To allow the building designer greater flexibility in the arrangement of components.

• Rules related to the basic elements according to modular coordination :

1. Planning grid in both directions of the horizontal plan shall be 3M. The centre lines of load bearing walls should preferably coincide with grid lines.

2. Planning module in the vertical direction shall be 1M.

3. Preferred increments for sill heights, doors, windows and other fenestration shall be 1M.

4. In case of internal columns, the grid lines shall coincide with the centre lines of columns.

5. In case of external columns and columns near the lift and stair, the grid lines shall coincide with centre lines of the column in the topmost storeys.

MODULAR COORDINATION ADOPTED IN COMPONENTS

• FLOORING AND ROOFING SCHEME: Precast slabs or other precast structural flooring units:

1. Length- multiples of 1M

2. Width- multiples of 0.5M

3. Overall thickness- multiples of 0.1M• BEAMS:

1. Length- multiples of 1M.


3. Overall depth- multiples of 0.1M

• COLUMNS:

1. Height- multiples of 1M

2. Lateral dimensions- multiples of 0.1M• WALLS:

1. Thickness- multiples of 0.1M• LINTELS:



3. Depth- multiples of 0.1M• SUNSHADES:


2. Projection- multiples of 0.5M

CONCEPT OF MODULAR COORDINATION

• Modular coordination is a concept of coordination of dimension and space, in which buildings and components are dimensioned and positioned in a term of a basic unit or module, known as 1M.

• The principal objective of implementing Modular Coordination is to improve productivity in the building industry through industrialization.

TERMINOLOGY• Module: A unit of size used as an increment in

dimensional coordination.• Modular size: A size that is a multiple of the

basic module.• Modular grid: A rectangular coordinate reference

system in which the distance between the consecutive lines is the basic module or a multi module. The multi module may differ for each of the two dimensions of the grid.

• Multi module: A module whose size is a selected multiple of the basic module.

BENEFITS OF MODULAR COORDINATION

• To obtain maximum economy in the production of components.

• Simplifies site operations by rationalizing setting out, positioning and assembly of building components.

• Ensures dimensional coordination between installation (equipment, storage units, other fitted furniture, etc.) as well as with the rest of the building.

• To allow the building design a greater flexibility in the arrangement of components.

Finalized LIG PlanThe plan for LIG having a carpet area of 60m2. All dimensions are in m.

Finalized MIG Plan

The plan for MIG having a carpet area of 90m2. All dimensions are in m.

Finalized HIG PlanThe plan for HIG having a carpet area of 150m2. All dimensions are in m.

PLAN INCLUDING LIG, MIG, HIG

IDENTIFICATION OF STRUCTURAL ELEMENTS

• Masonry wall- A wall made from materials which have traditionally been cemented together with the use of mortar.

• Reinforced Concrete Columns- They are structural members designed to carry compressive loads, composed of concrete with an embedded steel cage to provide reinforcement.

• Reinforced Concrete Beam- A beam is a structural element that is capable of withstanding load primarily by developing bending stresses and resisting it.

• Reinforced Concrete Slab - A structural member whose thickness is small compared to its plan dimensions, spanning between beams, girders, or columns, walls etc.

DESIGN OF SLAB SPAN: 3m*5m

STEP 1: TO DETERMINE THE TYPE OF SLAB

Lx = 3m

Ly = 5m

fck = 20 N/mm2

fy = 415N/mm2

Ly/Lx = 1.667< 2 (TWO WAY SLAB)

End condition = Four edges discontinuous

STEP 2: EFFECTIVE DEPTH OF SLAB

Span/depth ratio = 28

Effective depth = 107.14mm

Provide effective depth of 120mm, effective cover of 20mm.

Over all depth is 140mm

STEP 3: LOADS

Self weight of Slab = 0.14X 1 X 25 = 3.5 KN/m2

Live Load (IS 875 Part-2; Pg: 09) = 2 KN/m2

Floor Finish = 1 KN/m2

Total load = 6.5KN/m2

Design Ultimate Load, Wu = 1.5 x 6.5

Wu = 9.75 KN/m2 say 10KN/m2

STEP 4: ULTIMATE DESIGN MOMENT & SHEAR

Refer IS456 – 2000; Pg: 91 Table 26

a) SHORT DIRECTION

M = αxWuLx2

No Negative Moment due to absence of continuous edges.

Positive at Mid Span

αx = 0.0945

M = 0.0945x 10 x 32

M = 8.505 kNm

b) LONG DIRECTION

No Negative Moment due to absence of continuous edges.

Positive at Mid – Span

αy = 0.056

M = 0.056 x 10 x 52

M= 14 kNm

STEP 5: CHECK FOR DEPTH

Mu.lim = 0.138 x fck x bd2

d = 71.22mm < 120mm, Hence chosen depth is safe.

STEP 6: REINFORCEMENT (short & long span)

Min. Ast = 168mm2

Positive at mid span

Mu = 0.87 fy Ast d

14 x 106 = 0.87 x 415 x Ast x 120

Ast = 323.13mm2

Spacing should least of the following

Spacing = 459.3mm say 460mm

3d = 3(120) =360mm

300mm

Ast(pro) =392.7 mm2

Provide 10mm diameter bars @ 200mm c/c as main steel.

Distribution steel

As per minimum steel,

Ast = 168mm2

Provide 8mm diameter bars @ 300mm c/c as distribution steel.

STEP 7: CHECK FOR SHEAR

Considering the short span unit width of slab.

Vu = 0.5 x Wu x L x = 0.5 x 10 x 3

Vu = 15kN

v = 0.107 N/mm2

Pt = 0.28 (Refer table 19, IS456-2000; Pg: 73)

τc = 0.39 N/mm2 >v (0.107N/mm2)

Hence Shear Safe

STEP 8: CHECK FOR DEFLECTION

Basic = 20 For pt = 0.28, (IS456-2000, Pg: 38)

kt = 1.2

Max > Actual

Basic x kt >21.42

20 x 1.2 > 21.42

24 > 21.42, Hence Deflection are Safe

STEP 9: CHECK FOR ERECTION STRESSES

Hooks are provided at 1m offset from edge in longer span and .5m offset from edge in shorter span, at all four corners of slab.

Load on slab due to erection= self weight of slab= 52.5kN/m

Check for dimensions:

Negative moment at the edge due to cantilever= 52.5x0.5x0.5/2=6.56kNm

Positive moment at mid span= 52.5x2x2/8=26.25kNm

Net excess moment= 19.69kNm

Mexcess = 0.138 x fck x bd2

d = 84.27mm < 120mm, Hence chosen depth is safe

Thus slab is safe for erection stresses too.

PLINTH BEAM DESIGN5m span

STEP 1: ADOPT A PRELIMINARY BREADTH AND DEPTH

d=L/20= 5000/20= 250mm

D=d+effective cover= 250+30= 280mm

b =150mm

STEP 2: LOAD CALCULATIONS

Self weight= .15*.28*25=1.05kN/m

Weight of brick masonry wall above plinth =.15*2.6*19= 7.41kN/m

Total Load= 8.46kN/m

Factored Load= 1.5*8.46=12.69~=13kN/m

STEP 3: MOMENT CALCULATIONS

Mu=Wu*leff*leff/30= 13*5*5/30= 10.83kNm

Mu,lim= .138fckbd2 =.138*20*150*250*250= 25.875kNm

Mu<Mu,lim Hence adopted dimensions are safe.

STEP 4: REINFORCEMENT DETAILS

Mu=0.87fyAstd(1-(Astfy/bdfck))

Ast=129.22mm2

Ast, minimum= (.85/fy)*b*D=(.85/415)*150*280=86.02mm2

Ast, cal>Ast, min

Adopt 10mm dia bars.

No.of bars= 129.22/78.5=2

Hence providing 3Y10 as tension steel.

STEP 5: DESIGN OF STIRRUPS

Shear force Vu=Wu*L/2= 13*5/2= 32.5kN

Nominal shear stress= Vu/bd= 32500/(150*250)=.87N/mm2

Permissible Shear Strength of concrete as per Table 19 IS 456 for M20 and Ast=235.5mm2 =.5N/mm2

Nominal shear stress> Permissible Shear Strength, stirrups are provided for Nominal shear stress= Permissible Shear Strength.

Vus=.87*fy*Asv*d/sv

32500=.87*415*Asv*250/300

Asv=108.01mm2

For a two legged 10 dia stirrup, 2*78.5=157mm2>Asv

Hence provide 2LY10@300c/c for shear reinforcements

STEP 6: CHECK FOR DEFLECTION

Basic = 20

For Pt = 0.628, (IS456-2000, Pg: 38)

Kt = 1.8

20 X 1.8 > 20

36 > 20

Hence Deflection is Safe.


Hooks are provided at 0.3m offset from both edges.

Load on beam due to erection= self weight of beam= 1.05kN/m



Positive moment at mid span= 1.05x4.4x4.4/8=2.541kNm


Moment adopted for design=10.83 kNm

Moment adopted for design> Net excess moment due to erection

Thus beam is safe for erection stresses too.

INTERIOR COLUMN DESIGNSTEP 1: LOAD CALCULATIONS

Load on column= 120 KN. Design constant a) Grade of concrete =M20 b) Grade of steel = Fe415. L = Unsupported length of the column in mm = 4650mm Design load Pu = 1.5 x120 =180 kN.

STEP 2: COLUMN DIMENSIONS

The cross-sectional dimensions required will depend on the percentage of reinforcement.

Assume percentage of comp. steel between 0.8 to 6% of gross c/s area

Assuming 1.0 percent reinforcement and referring to Chart 25 SP16 Design Aids,

Ag= 500cm2

Adopting square column, hence providing 250*250mm

STEP 3: TYPE OF COLUMN

Leff/b= 1*4650/250=18.6>12, hence long column.

STEP 4: ADDITIONAL MOMENT DUE TO BUCKLING IN LONG COLUMN

Max=May=(Pu*D/2000)*(Leff/D)2

=186000*250/2000*(1*4650/250)2 = 8.04kNm

Puz = 0.45fck Ac + 0.75fy As =751.40kN

Pu/Puz=.2, αn=1

Mux=Muy= 15.028kNm,

Interaction equation=.958 <1.0 as per SP16 Design Aids

STEP 3: LONGITUDINAL REINFORCEMENTSAsc = 1.0 % Ag= 625mm2 For = 12 No of Bar = N =5.52~=6∅

STEP 4: SHEAR REINFORCEMENTSa) Select diameter of lateral ties least of 6 mm or 1/4 diameter of the largest longitudinal bar not less than 16 mm diameter. Diameter of the lateral ties / link =8 mmb) Spacing of lateral ties / link Least of i) Least lateral dimension of column =250mm ii) Sixteen times the smallest dia. of bar = 16 x 12=192mm and iii) 300 mm Provide 8 mm dia. @ 150 C/c

STEP 7: SUMMARY OF DESIGN 1. Column size: 250x250 mm 2. Longitudinal Steel: 6Y123. Lateral Steel: 2LY8@150c/c


Hooks are provided at L/3m i.e. 1.55m offset from both edges.

Load on beam due to erection= self weight of column= 1.5625kN/m



Positive moment at mid span= 1.5625x2.325x2.325/8=1.05kNm


Mexcess = 0.138 x fck x bd2

d = 34.35mm < 170mm, Hence chosen depth is safe

Check for shear:

Vu = 0.5 x Wu x L = 0.5 x 1.5625 x 1.15

Vu = .898kN

v = 0.014 N/mm2

Pt = 1.0

(Refer table 19, IS456-2000; Pg: 73)

τc = 0.62 N/mm2 >v (0.014N/mm2)

Hence Shear Safe

Thus column is safe for erection stresses too.

FOOTINGData:

SBC of soil = 200 kPa

Unit weight of soil = 18 kNm3

Ø= 30°

Grade of concrete = M20

Steel bars used = Fe 415

Load from column = 258 kN

Step 1: Determination of depth of foundation:

Depth of foundation = qsΥs[1-sinØ1+sinØ]2

= 20018[1-sin301+sin30]2

= 1.3 m

Hence we have to excavate soil upto 1.3 m below ground level

Step 2: Determination of plan area:

Area = A = loadqs

= W+Wfqs

= 258+0.1×258200

= 1.419 m2

Step 3: Determination of width of foundation:

Assuming a square footing:

Width of the square footing = B = A = 1.419 = 1.19 m

Lets us assume the width of the footing = 1.2 m

Hence, we have to provide a square footing of size 1.2 m×1.2 m

Step 4: Determination of maximum bending moment:

Maximum bending moment = wa22

Where,

w= upward soil pressure in kNm

a= B2-b2

B= width of foundation = 1.2 m

B = width of column = 300 mm = 0.3 m

w = load from columnplan area×B

= [2581.22]×1.2

= 215 kNm

Ultimate bending moment = Mu = 1.5×215×.4522

= 32.65 kN-m

Step 5: Calculation of effective depth:

Mu=.36fckbd2k(1-.42k)

d=Mu.36fckbk1-.42k

d=32.65×106.36×20×1200×.48(1-.42×.48) = 99.305 mm

Hence, let us adopt a depth of 175 mm.

Step 6: Calculation of Ast:

Mu= .87fyAstd1-fyAstfckbd

32.65 × 106 = .87×415×Ast×1751-415Ast20×1200×175

From the above equation: Ast = 546.22 mm2

Ast,min= .0012×(b×D)

= .0012×(1200×230) = 331.2 mm2

Hence, Ast>Ast,min

Step 7: Check for one way shear:

For one way shear the critical section will take place at a distance, “d” from one face of column.

Upward shear force = V=upward soil pressure×area

= 1.5×2581.22×.275×1.2

= 88.68kN

Nominal shear stress = ƫv = Vbd

= 88.68×10001200×175

= .422 mPa

As per IS 456: 2000:

ƫv≤ k×ƫc

From IS 456: 2000, table number 19:

percentage of tension steel=p=100Astbd = .26

For,

p = .26 and fck= 20 mPa

ƫc= .36 mPa

k=1

Hence,

ƫv>(k×ƫc)

The depth chosen is not adequate as per one way shear criteria and the depth has to be redesigned.

1.5×2581.22×.275-d×1.2= .36×1.2×d

From the above equation; d = 274 mm

Adopting the depth to be 300 mm

Step 8: Check for two way shear/ punching shear:

The punching shear occurs at a distance of half of the effective depth from all the faces of column.

Fig. 7: Critical section for punching shear

Shear force = V = soil pressure ×area

= 215 [1.22-.2+.32]

= 255.85 kN

ƫv= Vbd

= 2558504×600×300

= .355 mPa

ƫc = .25fck= .25×20 = .64 mPa

ks=1

ƫv< ks×ƫc

Hence, the design is safe.

Step 9: Check for bearing stress:

Bearing stress = wcolAg

= 258×1033002

= 2.867 mPa

.45fckA1A2 = .45×20×2 = 12.47 mPa

=>2.867<12.47

Hence, the design is safe against bearing.

Step 10: Spacing of reinforcement:

Assuming 10 mm bars for main reinforcement, the spacing = s = .785×102×1200546.22 = 172 mm ≅ 150 mm

Hence, 10 mm dia Fe 415 bars will be provided @ 150 mm c/c distance as main reinforcement.

Spacing of transverse reinforcement:

Assuming 8 mm diameter bars, spacing = s = .785×64×1200.0012×356×1200 = 117.6 mm ≅ 100 mm

Hence, 8 mm dia Fe415 bars will be provided @ 100 mm c/c distance as transverse reinforcement.

JOINTS AND CONNECTIONS

• Connections are among the most essential parts in precast structures. Their performance relates to the structural limit states, as well as to manufacture, erection and maintenance of the structure itself. Proper design of connections is one major key to a successful prefabrication.

• The main purpose of the structural connections is to transfer forces between the precast concrete elements in order to obtain a structural interaction when the system is loaded.

• By the ability to transfer forces, the connections should secure the intended structural behavior of the superstructure and the precast subsystems that are integrated in it.

• This could for instance be to establish diaphragm action in precast floors and walls, or cantilever action in precast shafts. For this reason the structural connections should be regarded as essential and integrated parts of the structural system and they should be designed accordingly and with the same care as for the precast concrete elements. It is insufficient just to consider the connections as details for site erection.

• The advantages that normally are obtainable with prefabrication can be lost with an inappropriate design and detailing of the structural connections.

FLOOR TO BEAM CONNECTIONS

• Details of typical bearing of a floor unit over the precast beam are shown in Fig. 1 the stirrups of the precast beams are protruded and function as shear connectors

• The reinforcing bars of the in-situ screeding concrete are extended over the beam supports so as to ensure continuity.

Fig. 1 – Precast slab to beam joint

BEAM TO COLUMN CONNECTIONS

• The bracket support for the beam over the column is shown in Fig. 2.

• A tolerance of 2-3 cm is allowed at the seating of the beam over the bracket.

• A dowel bar inserted through the holes provided in the bracket and the beam ensures an effective connection between them.

• The top reinforcing bars of the precast beams are connected to thecolumn joint by welding. Since only a few number of bars are welded, it is assumed that the connection between the beam and the column is a rigid one at the serviceability stage, but behaves as a hinged one at the ultimate stage

Fig. 2 – Precast beam to column joint

FOUNDATIONS

• The foundations usually cast as in-situ isolated footings as the local soil conditions warrant.

• The bottom end of the precast column is connected to the foundation as shown in Fig. 3

Fig. 3 – In-situ footing to precast column connection

PRODUCTION AND ERECTION

• The method of production depends on the total number of prefabricated elements that are to be produced. The components may be produced either in a factory on mass scale or in casting yards located near the site and equipped with the necessary plant and machinery.

• For facilitating erection, lifting hooks are provided in the precast floors and beams. Erection eyes as given in Fig.4 provided in the structural elements help in lifting them during transportation and erection using temporary bracing.

• For transportation and erection purposes the hook placements adopted are shown in Fig. 5, Fig. 6 and Fig. 7.

Fig. 4 – Hook details

Fig. 5 – Hook placements for slab

Fig. 6 – Hook placements for beam

Fig. 7 – Hook placements for column

REFERENCES

• Various authors (2008), ‘Principles of Architecture’, Oxford University Press, New Delhi, Vol.7, pp. 154-167

• Nicholson Peter (2009), ‘Principles of Architecture: Comprising Fundamental Rules of the Art, with Their Application to Practice’, H. G. Bohn, Cambridge, Vol.6, pp. 38-42

• Venugopal M.S. (1981), Structural Engineering Research Centre, Madras, Vol.1, pp. 1-23

• Ramakrishna(1982), ‘Precast concrete- cost implications and future’ , SERC,

• Madras, Vol.1, pp.1-8• National Building Code of India(2005), Bureau of Indian Standards• Raju Krishna (2009), ‘Concrete technology’ Tata McGraw-Hill

Education, New Delh, Vol5, pp. 603-631

THANK YOU

batch 1

Documents

design plan

design of structural

design of connections

design loads

design of foundation

design of functional

design of modular houses

pancheshwar project