Design GP Building for Pop.above 5000

DESIGN OF STRUCTURE

Construction of GP Building with population above 5000

Design Parametres:-

Unit weight of RCC = 25KN/cum

Concrete mix : M25

Steel : Fe415

Cover to Reinforcement : 25mm

Characteristic compressive strength of concrete = 25N/sqmm

Yield strength of steel = 415N/sqmm

Item

S1(End Panel)--Two

adjacent edges

discontinuous

S2(End Panel)--

Two adjacent

edges

discontinuous

S3(End Panel)-

-Two adjacent

edges

discontinuous

S4(End

Panel)--one

short edge

discontinuou

s

S5(Portico

slab)--Three

edges

discontinuou

s

Length of slab panel ly in m 3.51 3.51 5.64 3.51 2.06

Width of slab panel lx in m 3.51 2.93 2.93 2.13 1.83

ly/lx 1 1.2 1.92 1.65 1.13

Overall depth required in mm 110 92 92 67 57

Width of slab panel considered 'b' in

'm'

1.00 1.00 1.00 1.00 1.00

Depth provided 'D' in 'm' 0.115 0.115 0.115 0.115 0.1

Dia.of bars assumed 8mm 8mm 8mm 8mm 8mm

Dead load in KN/sqm 4.00 4.00 4.00 4.00 3.50

Live load in KN/sqm 2.50 2.50 2.50 2.50 2.50

Floor finishes in KN/sqm 1.00 1.00 1.00 1.00 1.00

Total Load in KN/sqm 7.50 7.50 7.50 7.50 7.00

Short span(-) moment coefficient at

continuous edge

0.047 0.060 0.089 0.089 0.067

Short span(-) moment at continuous

edge

4.34 3.86 5.73 3.03 1.57

Short span(+) moment coefficient at

mid span

0.035 0.045 0.067 0.067 0.050

Short span(+) moment at mid span 3.23 2.90 4.31 2.28 1.17

Long span(-) moment coefficient at

continuous edge

0.047 0.047 0.047 0.047 0.057

Long span(-) moment at continuous

edge

4.34 3.02 3.02 1.60 1.34

Long span(+) moment coefficient at

mid span

0.035 0.035 0.035 0.035 0.043

Long span(+) moment at mid span 3.23 2.25 2.25 1.19 1.01

Design Moment Me1(-)ve in KN-m 6.51 5.79 8.59 4.54 2.36

Effective depth for balanced section

in 'mm'

48.57 45.81 55.79 40.56 29.22

Effective depth provided 'd' in 'mm' 86 86 86 86 71

Actual depth of neutral axis 'xu' in

'mm'

8.79 7.78 11.78 6.04 3.77

Maximum depth of neutral axis 'xumax'

in 'mm'

41.28 41.28 41.28 41.28 34.08

Area of steel required Ast in 'mm2' 219.06 193.87 293.53 150.64 94

Main Steel provided at continuous

edge

8mm@150mm c/c 8mm@150mm c/c 8mm@150m

m c/c

8mm@150m

m c/c

8mm@200m

m c/c

Area of steel provided in mm2 334.93 334.93 334.93 334.93 251.2

Design Moment Me1(+)ve in KN-m 4.85 4.34 6.47 3.42 1.76


in 'mm'

41.91 39.67 48.4 35.19 25.24


'mm'

6.47 5.77 8.73 4.51 2.8

DESIGN OF TWO WAY SLAB:-

Slab panel Description


in 'mm'

41.28 41.28 41.28 41.28 34.08

Area of steel required Ast in 'mm2' 161.22 143.93 217.54 112.54 69.74

Main Steel provided at mid span 8mm@150mm c/c 8mm@150mm c/c 8mm@150m

m c/c

8mm@150m

m c/c

8mm@200m

m c/c


Design Moment Me1(-)ve in KN-

m(Long span)

6.51 4.54 4.54 2.40 2.00


in 'mm'

48.57 40.54 40.54 29.47 26.95


'mm'

8.79 6.04 6.04 3.15 3.2


in 'mm'

41.28 41.28 41.28 41.28 34.08

Area of steel required Ast in 'mm2' 219.06 150.53 150.53 78.41 79.7

Dist. Steel provided at continuous

edge

8mm@175mm c/c 8mm@175mm c/c 8mm@175m

m c/c

8mm@175m

m c/c

8mm@200m

m c/c


Dist.steel at mid span 8mm@175mm c/c 8mm@175mm c/c 8mm@175m

m c/c

8mm@175m

m c/c

8mm@200m

m c/c

Design Parametres:-

Concrete mix : M25

Steel : Fe415

Cover to Reinforcement : 40mm

Characteristic compressive strength of concrete = 25N/sqmm

Yield strength of steel = 415N/sqmm

Item

Piles--

P1(6,7,13,14)

Piles--

P2(2,3,5,8,9,10,11)

Piles--

P3(1,4,12,15)

Max.Load 'P' in KN 480 395.7 264.3

Dia.of pile proposed in 'mm' 450 375 300

No.of Under Reams proposed 2 2 2

Dia.of under reamed in 'm' 1.125 0.94 0.75

Depth of the pile proposed in 'm' 4.50 3.75 3.50

Bearing capacity of the pile in KN 617.4 396.9 264.6

Main Reinforcement 7-12mm 5-12mm 4-12mm

Stirrups 8mm@300 c/c 8mm@300 c/c 8mm@300 c/c

(Note:-The above design is as per clauses 6.3, 6.3.1, 6.6 and 8.3.2.2 of IS 2911(PartIII)-1973 duly

reducing bearing resistence by 25% for submerged condition)

DESIGN OF PILES

Design Parametres:-

Footing designation = F3

Concrete mix M25

Steel Fe415

Cover to Reinforcement 50mm

Safe Bearing Capacity(From soil Report)= 147.00KN/sqm

Unit weight of RCC = 25.0KN/cum

Width of Column b = 0.23m

Depth of Column d = 0.45m

Characteristic compressive strength of concrete = 25.00N/sqmm

Yield strength of steel = 415.00N/sqmm

Load calculations:-

Factored Load on the column from analysis = 493.00KN

493.00KN

Add self weight of the footing&Weight 73.950KN

of back fill (15%)

Total Load = 566.95KN

Ultimate Bearing Capacity of the soil qu = 1.5xSBC = 220.50KN/sqm

Size of the footing required:-

Area of the footing required = 2.57Sqm

Provide square footing of size 1.80mx1.80m,the area comes to 3.24Sqm

Width = 1.80m

Depth = 1.80m

The net ultimate bearing pressure acting on the footing due to direct load = 174.98KN/sqm

Design moment = 5.10KN-m

Section Modulus for the above section = (1/6)xbd2 = 0.97cum

Soil pressure due to moment = M/Z = 5.26KN/sqm

Max.Soil pressure = pu + mu = 180.24KN/sqm <220.50KN/sqm

Hence O.K

Min.Soil pressure = pu - mu = 169.72KN/sqm >0

Hence O.K

Hence,the design soil pressure = 180.24KN/sqm

Depth of the footing required:-

i)Bending moment criteria:-

The critical section for bending is at the face of the column.Hence,the

Maximum factored bending moment = Mu = 55.53KN-m

(Considering 1m width of footing)

DESIGN OF FOOTINGS(1,4,9,12)

Adopting Limit state method of design Mu = 0.138 fckbd2

The effective depth of footing required = d = [Mu/(0.138fckb)]0.5

= 126.87mm

Over all depth required assuming 12mm dia bars = = 182.87mm

However assume 350mm overall depth,then the effective depth comes to 294.00mm

The actual depth of neutral axis = 21.66mm

Area of steel required = 539.84sqmm

Assuming 12mm dia bars,the spacing comes to 209mm

Provide 12mm bars at a spacing of 175mm

Then the area of reinforcement provided = 645.94Sqm

Percentage of reinforcement provided = 0.22

ii)One way shear criteria:-

The critical section of one way shear is at a distance of 'd' from the face of the column

Hence,the factored design shear force VFd = 88.50KN

Nominal shear stress Tv = 0.301N/sqmm <2.8 N/sqmm

(As per Table 20 of 1S 456)

Hence,the section is safe from shear point of view

The percentage area of the tensile reinforcement provided = 0.220%

The design shear strength of concrete for the above steel percentage from

Table 19 of IS 456 is

0.339 N/sqmm Hence Vuc = 99.67KN

0.339 >0.301

Hence,no shear reinforcement is required.

iii)Two way shear criteria:-

The critical section for two-way shear is along the perphery of the square at a

distance d/2 from the face of the column

Hence perimetre of the preriphery b0 = 2536mm

Hence,the factored shear force VFd = qu(B2-AB

2)= 513.70KN

Nominal shear stress Tv = VFd/b0d = 0.69 N/sqmm

Permissible shear stress in concrete for two-way shear for M20 grade concrete

Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm

Hence,Tc' = 1.25 N/sqmm

1.12 >0.690

Hence,the section provided is safe from two-way shear point of view

iv)Check for transfer of bearing stress:-

Pu = 566.95KN

Compressive bearing resistance = 0.45 fck(A1/A2)1/2

.

For the column face A1/A2 = 1 and for the other face A1/A2 > 2 but should be taken as 2.

In any case, the column face governs.Force transferred to the base through column

at the interface = 1164.38KN >566.95KN

Hence O.K

There is no need to design separate dowel bars to tranfer the load to the base of the footing

Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


408.25KN


of back fill (15%)





Provide rectangular footing of size 1.65mx1.80m,the area comes to 2.97Sqm

Width = 1.65m

Depth = 1.80m






Hence O.K


Hence O.K


The maximum bending moment at the face of the column wrt the section along width ML = 49.75KN-m


The maximum bending moment at the face of the column wrt the section along length MB = 40.69KN-m



DESIGN OF RECTANGULAR FOOTINGS(7,8,9,10,11,13,14)



Maximum factored bending moment = ML = 49.75KN-m




= 120.08mm



Longitudinal direction:-

Calculation of reinforcement :-




Provide 12mm bars at a spacing of 175mm along width



Check for one way shear:-










0.369 >0.362


Transverse direction:-

Maximum factored bending moment = MB = 40.69KN-m


Over all depth provided = 300.00mm

Effective depth assuming 10mm dia bars 245.00mm




Reinforcement in central band = 0.96

Total reinforcement

Reinforcement to be provided in central band = 454.87sqmm

Reinforcement to be provided in each edge band = 10.34sqmm

However provide 10mm dia bars at a spacing of 150mm along length













0.335 >0.306







2)= 443.54KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.970



Pu = 469.49KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


283.50KN


of back fill (15%)






Width = 1.40m

Depth = 1.40m






Hence O.K


Hence O.K







DESIGN OF FOOTINGS(1,2,3,4,5,12,15)



= 93.20mm



















0.381 >0.353







2)= 311.80KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.950



Pu = 326.03KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


493.00KN


of back fill (15%)






Width = 2.10m

Depth = 2.10m






Hence O.K


Hence O.K










= 129.26mm



















0.339 >0.288







2)= 530.14KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.710



Pu = 566.95KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


408.25KN


of back fill (15%)






Width = 1.80m

Depth = 2.10m






Hence O.K


Hence O.K














= 126.58mm





















0.340 >0.278











Total reinforcement
















0.282 >0.210







2)= 443.61KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.730



Pu = 469.49KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


283.50KN


of back fill (15%)






Width = 1.60m

Depth = 1.60m






Hence O.K


Hence O.K










= 95.22mm



















0.347 >0.241







2)= 311.34KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.670



Pu = 326.03KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


493.00KN


of back fill (15%)






Width = 2.40m

Depth = 2.40m






Hence O.K


Hence O.K










= 131.04mm



















0.363 >0.271







2)= 540.49KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.720



Pu = 566.95KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


408.25KN


of back fill (15%)






Width = 1.80m

Depth = 2.60m






Hence O.K


Hence O.K














= 143.93mm





















0.363 >0.311











Total reinforcement
















0.302 >0.169







2)= 448.68KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.740



Pu = 469.49KN


.




Hence O.K


Design Parametres:-


Concrete mix M25

Steel Fe415








Load calculations:-


283.50KN


of back fill (15%)






Width = 1.80m

Depth = 1.80m






Hence O.K


Hence O.K










= 96.74mm



















0.367 >0.232







2)= 316.02KN



Tc' =ks . Tc

ks = (0.5+l/b)> 1

Hence ks = 1

Tc = 0.25(fck)1/2

= 1.25 N/sqmm


1.12 >0.680



Pu = 326.03KN


.




Hence O.K


Design GP Building for Pop.above 5000

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