IE DESIGN ASSIGNMENT

DESIGN OF EARTHQUAKE RESISATNT BUILDING

BY

JEETU RANA (roll no 39)

HEMANTH KUMAR (roll no 36)

ABSTRACT

          In this project work, an attempt has been made to plan and design a G+4 storied shopping complex building. This project work involves planning, analysis, designs, drawings and estimation of a typical multistoried building.

The salient features of the G+4 storied building are as given below the basement floor is 1.20m above the existing ground level. The shopping complex consists of G+4 floors with 3.60m ceiling height. The carpet area available in each floor is 1220sq.m.

This shopping complex having all facilities under one roof, designed with shops, Super market, Food court, Net point, Gym, Table tennis court, Coffee shop with ample car parking  etc, with very good water supply and sanitary arrangements.

           The planned five storey commercial building frame in modeled in STAAD Pro.Various load combinations are included in the frame analysis and the lateral loads are calculated by seismic coefficient method for the earthquake zone III with response reduction factor 3. The amount of concrete and steel required along with the total cost of the building is calculated.

          The structural design has been manually done. The estimate of the building is prepared on the basis of plinth area rate. Necessary structural drawings are enclosed at appropriate places. 

INTRODUCTION

1.1. SCOPE & IMPORTANCE:

                   Shopping and Entertainment is an important for each and every one. But they have short of time, so they need a shopping complex under one roof to save the valuable time.

1.2. LOCATION:                                                                                                                                                                                                                                                     

                   We have decided to choose the site for the construction of shopping complex at Vadapalani in Chennai city.

                   The site accommodates the following special feature.

Ø Land is available in the centre of city.

Ø The site is located in main road.

Ø 24 hour transportation facilities available.

3.2. ANALYSIS:

3.2.1. MATERIAL:

Grade of reinforcement            : Fe415

Grade of concrete                    : M25

Density of concrete                  : 2500Kg/m³

3.2.2. LOADING:

Dead load:

          Partition wall and other external walls, floor finish etc., as per the provisions of IS: 875-1987(part I)

Superimposed load:

          As per the provisions of IS: 875-1987(part II)

          For Commercial Buildings (AL)       =        4.00 KN/m²

Seismic load

Dead load + part of live load   =       DL+0.5LL

3.2.3. CODES:

           Concrete design                      :         IS: 456-2000

            Steel design                           :         IS: 800-1984

3.2.4. PARTIAL SAFETY FACTORS:

Load factors:

For dead load                                    =       1.50

For live load                                               =       1.50

The above partial safety factors are taken from IS: 456-2000

Material safety factor:

For reinforcement steel                     =       1.15

For concrete                                                =       1.50

3.2.5. LOAD CALCULATION:

Dead load:

At any floor level except ground floor (per m width)

Load from slab                        =       0.15 x 23.5       = 3.525 KN/m² (assuming 150mm thickness)

Partitions (G.F)                       =       0.23 x 4.20 x 20 =19.32 KN/m

Partitions (F.F TO F.F)           =       0.23 x 3.00 x 20 =13.80 KN/m

Partitions (Terrace floor)                  =       0.23 x 1.00 x 20 =4.60 KN/m

Floor finishes                          =       1.00 KN/m²

Floor finishes (Terrace floor)   =       2.00 KN/m²

B) Live load

For Commercial Buildings        =      4.00 KN/m²

C) Seismic load

Dead load + part of live load   =       DL+0.5LL

3.2.6. ANALYSIS ABOUT STAAD Pro:

  4.2. LIMIT STATE METHOD:

          Limit state of Design is a further improvement of ultimate load design in the limit state methods a structure is designed to with stand all loads like to act on it in the duration of its life span and also to satisfy the service requirements like deflection and limitation of crack width, limit means an acceptable limit, for the safety and serviceability requirements before anything can occur.

          The design provides a condition that the structure will not become unfit for use for which it is meant or in other words the structure will not reach a limit state.

          The entire limit state  that are relevant are considered in the design to ensure an adequate degree of safety and serviceability, the structure in general shall be designed on the basis of the most critical state and shall also be checked for other limit states.

4.2.1. LIMIT STATE OF COLLAPSE:

The design on limit state of collapse provides the necessary safety of the structure against partial or total collapse of the structure.

4.2.2. LIMIT STATE OF SERVICEABILITY:

          This limit state is introduced to prevent objectionable deflection and cracking.

4.2.3. CHARACTERISTICS STRENGTH OF CONCRETE:

Grade	M15	M20	M25	M30	M35	M40
Fck N/mm2	15	20	25	30	35	40

4.2.4. CHARACTERISTICS STRENGTH OF STEEL:

Grade	Fe250	Fe415	Fe500
fyN/mm2	250	415	500

4.2.5. CHARACTERISTIC LOADS:

           Characteristics load means the value of the load, which has a 95 percent probability of not being exceeded during the life of the structure.

Characteristics load is the weight of the structure itself. Characteristic live load and wind load are taken as per IS875-1964 characteristic seismic loads are taken as per 1873-1975.

4.2.6. OBJECTS OF LIMIT STATE DESIGN:

          The object of limit state design is the guarantee adequate safety consistent with economy against the structure being rendered unfit for service due to cracking, deflection, failure and such other cases. A limit sate corresponds to each of the states in which the structure becomes unfit.

5. DESIGN OF BEAM         

5.1. DESIGN OF BEAMS BY MANUAL (Beam No: 303):

Step - 1

Width of Beam     =       300 mm

Over all depth of Beam  =       600m

Thickness of slab, D_f     =       150mm

Breadth of web, b_w                        =       300mm

Concrete grade               =       M25

Steel grade                     =       F_e415

Step – 2: 

Bending moment and shear force

Negative moment @ interior support                   =      170.806 kNm

Positive moment @ centre of span              =       367.60 kNm

Maximum shear force at its support, V_u    =       224.952 kN

Limiting moment of Resistance

Mu_limit          =       0.138f_ck bd²

                                      =       0.138 x25x300x550²

Mu_limit          =       313.088 kNm

Mu _limit         <       Mu_max

Hence the section is designed for doubly reinforced.

Mu₂               =       367.60-313.088

=       54.512kN.m

A_st calculation:

                   Mu               =      0.87 f_y A_st d (1- (f_yA_st/f_ckbd))

313.088x10⁶         =       0.87 x 415 x A_st x 550 (1- (415 x

A_st / 25x300x550))

          313.088 x 10⁶           =       198577.5 A_st – 19.978 Ast²

                                A_st1              =       1965.19 mm²

Use 25mm dia bars

No of bars required        =       A_st / a_st = 1965.19 / ((π/4) x 25²)

                                      =       4.00   Say    4 nos

Main reinforcement (excess reinforcement Positive)

                             Mu1    =      0.87 fyA_st2(d-d’)

                   54.512x 10⁶ =       0.87 x 415 x A_st2 x (550-50)

                   54.512 x 10^{6 =}       180525 A_st2

                                A_st               =       301.97 mm²

No of bars required        =       A_st / a_st

=       301.96 / ((π/4) x 25²)

                                      =       0.62   Say    1 nos

Provide 5 nos of bars #25 at the Bottom tension face at centre of span section.

A_sc calculation:-

Main reinforcement (Negative)

                             M_u       =      f_sc A_sc (d-d’)

                   d’/d             =       50/550        =0.09

                   f_sc                           =            353.40N/m²

                   170.806x 10⁶ =     353.40 x A_sc x (550-50)

                                A_st               =       966.64 mm²

No of bars required        =       A_st / a_st =     966.64 / ((π/4) x 25²)

                                      =       1.97   Say    2 nos

Provide 2 Nos of bars #25 at the top tension face near support

6. DESIGN OF COLUMN  

6.1 GENERAL

                   From the STAAD Pro Analysis done we obtain the maximum positive moment, maximum negative moment and maximum shear force from these the beams are designed manually.

Maximum moments and shear forces

Beam  node   Env    Fx           Fy            Fz       Mx      My       Mz

                                kN          kN          kN      kNm    kNm       kNm

231       86                +ve    3513.2         94.90        100.4                  1.33   277.73 233.99

                      -ve   -63.88      -104.1       -114.8                 -1.32    -248.0     -253.11

                                          

6.2. DESIGN OF COLUMNS BY MANUAL (Beam No: 231):                           

Beam size                       =      450 x 450mm      

Concrete grade               =       M25

Steel grade                     =       F_e415

Factored load P_uz           =       2477.56kN

Factored Moment M_uz    =       11.747kN.m

         M_uy    =       262.42kN.m

Moments due to minimum eccentricity are less than the values given above

Reinforcement is distributed equally on four sides

As a first trail assume the reinforcement P = 3.75

                                      P/f_ck                        = 3.75/25 = 0.15

Uniaxial moment capacity of the section about XX and YY axis

Effective cover     d’      =       cover +dia of rod/2

                                      =       40+25/2 = 52.5mm

Effective depth      d       =       450-25-(25/2)

                             d        =       412.50mm

                             D       =       450mm

d’/D            =       52.5/450

=       0.1167

Check for d’/D 0.15 will be used

P_u/f_ck bd                =       2477.56 x 10³/ (25 x 450 x

                                                                    450)

                                                          =       0.49

Referring to chart45

M_u/ f_ck bd²              =       0.135

M_ux1 = M_uy1           =       0.135 x 25 x 450 x 450²

                                                          =       307.55kN.m

7. DESIGN OF FOUNDATION:

7.1 GENERAL

                   The outer Column footings are designed as Isolated footings where as the Inner column footings are designed as Combined footings. In these combined footings the two adjacent columns are combined in the Z axis direction. From the STAAD Pro  analysis done we obtain the Axial load for the designing of footing

7.2 Design of combined footing: - (Node No: 89 and 91)

Axial load P_u1       =       3900.68 say 4000kN

Axial load P_u2        =       3938.35 say 4000 kN

Bearing capacity of soil           =       250 kN/m²

To find length of footing

Taking moment about B,

4000 x 6.5 + 172 + 160           =       8000 X

                   X                =       3.29m

Taking AB                     =       0.75m                                                7.2.1plan

Total length up to CG from A =3.29m+0.75m

=4.04m

Length of footing                     =       2(m+n)

                                      =       2(0.75+3.29) = 8.08m

Length of projection CD                   =       0.83m

Taking 10% of total weight as self weight of foundation

Bearing area required              =       (8000+800) / 250

                                                          =       35.20 m²

Width of foundation                =       35.20 / 8.08

                                                          =       4.36 m say 4.50m

Footing Area                  =       8.08 x 4.50 = 36.36 m²

Net upward soil pressure                  =       8000 / 36.36

=       220.02kN/m²       

Net upward soil pressure                  <       safe bearing capacity

                             220.02 kN/m²       <       250 kN/m²

                   Hence safe.

Bearing area per meter length =       220.02 x 4.50

=       990.09kN/m²

To find Shear force,

SF @ A                =0

SF @ B left          =742.57kN

SF @ B right        =-3257.43kN

SF @ C left          =3178.15 kN

SF @ C right        =-821.85 kN

SF @ D                =       0                                   

To find shear force at Zero                       7.2.2.SFD &BMD

4000 – (0.75 x 990.09) – 990.09x = 0

                             X       =       3.29m

To find Longitudinal bending moment:-

Maximum hogging Bending moment,

M _max           =       990.09 x 4.04² / 2 – 4000x3.29– 172

                                      =       -5252.08 kNm

Max sagging Bending moment:-

At Support, B

M_x                        =       990.09 x 0.75 ²/ 2 -172 

=       106.46kN.m

At support C,

M_u                        =       990.09 x 0.83² / 2                   

=       341.04kN.m

Thickness of footing based on shear:-

The effective thickness of footing may be determined by considering that the shear is resisted without shear reinforcement as follows,

                             Vu_max =       ﺡ_c b.d

                             d        =       Vu_max / ﺡ_c b

For one way Shear:-

Vu_max = Max ultimate shear at the section at distance‘d’

    from the inner face of pedestal of column C2.

                             =3178.15 – 990.09d

                   b_o      =       B       =       4500mm

                   ﺡ_vu     =       shear strength of concrete in foundation slab

=       Ks which may taken as 1.0, and shear strength of concrete which may be taken as its minimum value of 0.25 N/mm²

                             =       0.25 N/mm²

dx1000       =       (3178.15 – 990.09d) x 1000 / (0.25 x 4500)

          1125000d   =       3178.15 x10³ – 990.09x10³ d

                   d        =       1.50 m       

=       1500mm. Say 1540mm

Over all depth      =       1600mm    

DESIGN FOR MOMENTS:-

The bottom reinforcement for transverse moments is placed below the bottom reinforcement for longitudinal moment. Distribution reinforcement in transverse direction.

                                      =       0.12% of gross sectional area

                                      =       (0.12 / 100) x1000 x 1300

                                      =       1560mm²                                          Provide 20mm # @ 200mmc/c

Use 20mm φ rods

                   Spacing       =       (314.15 / 1560) x 1000

                                      =       201.38mm say 200mm

1)     3d = 3 x 1240 = 3720mm

2)    And  mm300

Which ever is minimum

Provide 20mm #@200mmc/c

A_st Calculation:-

Longitudinal span moment:-

M_u    = 0.87 f_y A_st d (1- (f_yA_st/f_ck bd))

5252.08 x 10⁶ = 0.87 x 415 x A_st x 1240 (1- (415 x A_st / 25x4500x1240))

5252.08 x 10⁶ = 447702 A_st – 1.33 Ast²

                A_st     = 12171.28mm²

Provide min A_st

                             =       0.12% of gross sectional area

                             =       (0.12 / 100) x4500 x 1240       =6696mm²

A_st per meter length       =       (12171.28 / 4.5) =          2704.73mm²         /m     

Use 25 mm φ rods

                   Spacing       =       (490.57 / 2704.43) x 1000

                                      =       181.49 mm Say 180 mm c/c

Provide 25mm # @ 180mmc/c

Support moment:-

                             M_u      =      0.87 f_y A_st d (1- (f_yA_st/f_ckbd))

          341.04 x 10⁶              =       447702 A_st – 1.33 A_st²

                                                A_st     =       763.49 mm² < 6696 mm²

A_st per meter length       =       (6696 / 4.5) =1488mm²/m               

Use 20 mm φ rods

                   Spacing       =       (314 / 1488) x 1000

                                      =       211.13 mm Say 200 mm c/c

Provide 20mm # @ 200mmc/c

7.3. DESIGN OF ISOLATED FOOTING:-

DATA FOR DESIGN:

Axial load                                         =       1541.4kN say 1800kN

Moment, M_x                                                =       141.271 kN

Moment, M_z                                                =       -141.19kN

Safe bearing capacity of soil             =       250kN/m²  

Area required for foundation            =       1800 / 250

                                                          =       7.2m²

                Area required       =       LxB

                   BxB            =       7.2m²

                   B²               =       7.2m²

                   B                 =       2.68m

                   L                 =       2.68m

Length required              =       2.68 m                  7.2.

Breadth required            =       2.68 m                           7.3.1. Plan

Length provided            =       2.70 m

Breadth provided           =       2.70m

Original area                  =       2.70m x 2.70m

=       7.29 m²

Column size:-

Length                  =       0.45m

 Width                  =       0.45m        

Self weight of the footing:-

Unit weight of concrete                     =       25.00kN/m³

Depth below Ground level                =       2.40m

Depth of footing @ face of column   =       1.00m

Depth of footing @ Edge of footing  =       0.30m

Volume of footing:-

Volume of frusta of pyramids and concrete,

= (1.00 – 0.30) / 3 ((0.45 x 0.45) + (2.70x 2.70) +                      (0.45 x 0.45 x 2.70 x 2.70)

                             =1.559m³

Thickness of footing required against bending moments:-

Mu_max          =       Q_ubd²

431.52 x 10⁶=      0.138 x25x 2700x d²

          d        =       215.23mm Say 220mm          

          D       =       220+ 60        =     280mm

Upward soil pressure at B       =      203.86 + (203.06 – 289.98) / 2.7

 X (2.7 -1.125-0.45)

                                                 =      240.102kN/m²

M_ux = M_uy   =       P_nu L_x ((B-b) ²/ 8)

                                                =       240.102 x 2.7 x (2.7-0.45)² / 8

=       410.24kNm

Maximum Bending moment @ face of column = 410.24kNm

Thickness of footing required against bending moments:-

Mu_max          =       Q_ubd²

410.24 x 10⁶=      0.138x25x2700 xd²

d        =        (410.24 x 10⁶) / 0.138x25x2700

          =       209.85 mm say220mm

D       =       220 + 60    

=       280mm                                          7.3.2 one way shear plan

Check for Effective depth required against shear:-

The critical section of shear is taken at a distance of‘d’ from the pedestal

                   Vu _max         =Pu B ((L-a)/2) –d)

=252.56 x 2.70 x (2.70- 0.45) /2 –d)

                                      =681.912(1.125 –d)

Vu_max =767.15 – 681.91 d

The total shear stress induced at critical section is resisted by the shear stress, developed by concrete section,

                   ح_cu         =       Ks.   ح_c       

                   Ks     =       0.5 + βc

                             =       0.5 + (0.45 /0.45)

                             =       1.50 >1

                   Ks     =       1

                     ح_c       =       0.25 fck   

                    =       1.25N/mm²                 7.3.2 critical section plan

                    ح_cu       =       1x1.25

=       1.25N/mm²

ح_vu              =       (Vu_max/bd)            

                             ح_vu              =       (767.15 – 681.91d)/2700 x d

                               ح_vu               =             ح_cu

                                                1.25x10³     =       (767.15 – 681.91d)/2.70d

                                      d        =       0.189m

                                       d        =       189 mm 

                                      D       =       250mm

Check for Effective depth required against two way shear (or) punching shear. The critical section of two way shear is taken at a distance of d/2 around form the pedestal

Vu_max =      P_nu ((LxB – (a+d) (b+d))

=       252.56(2.70x2.70 –

          (0.45+d)(0.45+d))

=       252.56(7.088-d²-0.9d)        7.3.3 Two way shear plan  =       1719.27 – 218.30d – 252.56 d²

ﺡ_vu               =       (Vu_max)/(2(a+d)+2(b+d))d)      

                    =       1719.27 – 218.30d – 252.56 d²        /

                             (2(0.45+d) +2(0.45+d)) x d

1.25 x 10³ (1.8d + 4d²)   =       1719.27 – 218.30d – 252.56 d²

5252.56 d2 + 2468.30 d – 1719.21  =       0                                            

                                      d                 =       384mm say 390mm

                                      D                =       450mm                                    Provide maximum depth d        =       450mm                                   

Reinforcement along x direction:-

                   M_u                =      0.87 f_y A_std(1- (fyA_st/f_ck bd))

431.52 x 10⁶              =       0.87 x 415 x A_st x 390(1- (415 x

A_st / 25x2700x390))

                                                          A_st     =       3228.94mm²

Provide 20mm dia bars.

No of bar                       =       3228.94 / ((π /4) x 20²) 

                                      =       10.28 nos Say 11nos

CONCLUSION

Our project deals with planning, analysis and  design of shopping complex using STAAD Pro at Vadapalani, Chennai.

The shopping complex is designed with all necessary facilities such as shops, super markets, coffee shops, Food courts, offices, Escalators, Lifts etc., as per BIS specifications.

In this project, the Analysis of frame is done by stiffness matrix method using STAAD Pro. Software.

 Design of footings, columns, beams & slabs are done manually by limit state method as per IS456 – 2000, IS 1893-2002   and SP16.