Cf1 Design

DESIGN OF FOUNDATION F4 UNBRACED BAY ALLOW.N.S.B.C

=

ALLOW. N.S.B.C (SEISMIC CASE) ALLOW. N.S.B.C (WIND CASE) Unit Weight of Soil ALLOW. G.S.B.C ALLOW. G.S.B.C (SEISMIC CASE) ALLOW. G.S.B.C (WIND CASE) Increase in bearing capacity factor for Seis Load Increase in bearing capacity factor for Wind load

= = = = = = = =

150 kN/m2 187.5 187.5 18 204.0 241.5 241.5 1.25 1.25

kN/m2

Fck

kN/m2 kN/m3 kN/m2 kN/m2 kN/m2

Fy Clear Cover at Top Clear Cover at Bottom Height of pedestal Depth of foundation below FGL Lz Lx t P1x P1z Foundation CG P2x Load CG P2z

X 3.50

= = = = = = = = = = = = =

40 460 75 75 3.45 3.00 5.00 3.50 0.50 0.80 0.90 0.80 0.90

N/mm2 N/mm2 mm mm m m m m m (Thickness of Footing) m m m m

1.75 Lx =

FGL

3.50

0.80 1.75

ex

P1

0.80

P2

ez

0.90

Z

3.00 m

0.90 0.50

0.75

1.75 Lz =

Self Wt of Footing W1 Wt of soil above Fdn W2 Wt of pedestal W3 Total Wt.

m

0.75

1.75 5.00 = = = =

=(L X B-P1x X P1y - P2x X P2y)X(H-t)X18 =P1XXP1ZX(H-t)x25+P2XXP2ZX(H-t)x25

RCC Design

218.75 722.70 106.20 1047.65

kN kN kN kN (Self Wt. of Footing+Wt. of Surrounding Soil)

Design for 1m width of slab Design for maximum net soil pressure under the footing Load factor for concrete design =

57.5 KN/m 0.75

P1

P2 3.50

1.4

Design along longitudinal direction : Max. Cant Bm at face of column

=

16.2x(0.75-0.45)^2/2

Negative BM.at Center Factored Mu (+Ve) Factored Mu (-Ve) Foundation Depth D Effective Depth d Width B

= = = = = =

16.2x 3.5 ^2 /8 1.022 kNm 34.72 kNm 500 mm 417 mm 1000 mm

0.7

kNm

24.7

kNm

73.65 KN/m per m run 5.00 m

0.75

DESIGN OF FOUNDATION F4 UNBRACED BAY Mu = Mu/bd² = pt = Bottom Reinf.

1.022 kNm 0.006 N/mm² 0.100 %

Mu/bd2

% pt

Ast,mm2

0.006

0.130

542.1

Max S.F along Z axis

Mu = Mu/bd² = pt = Top reinforcement : Reqd. Dia of spacing rein bar mm 16 371

=16.2 x (0.75-0.9/2-0.417)x1

Max factored Shear Stress pt, provided As per BS 8110-1:1997,Table 3.8 Design along transverse direction : Effective Depth d Max BM at face of column =16.2 x (1.75-0.4)^2/2 Max Shear at distance d =16.2 x (1.75-0.8/2-0.403)x1 Mu/bd2 pt Reinf. Bottom Reinforcement Mu/bd2 0.127 Top Reinforcement Provide Minimum Steel = Provide Astprovided (Pt)prov. Max factored Shear Stress Allow. Shear Stress(Tc )

% pt 0.13

Ast,mm2 523.90

0.13 x 1000 x 403 /100 12 mm dia at

Ast Pro. mm2

pt,prov

Mu/bd2

150

1340.413

0.32

0.20

=

1.89 kN

= = =

0.01 N/mm² 0.32 % 0.42 N/mm²

= = = = =

Reqd. Dia of spacing rein bar mm 12 216 = 150

spacing provided

483.6 c/c

403 14.7 15.294 0.127 0.100 spacing provided

150 753.9822

spacing provided

Ast Pro. mm2

pt,prov

150

1340.413

0.32

OK

1.75

(Self Wt. of Footing+Wt. of Surrounding Soil) 57.5 Kn/m per m run 1.75

pt,prov 73.65 kN/m per m run 0.187

3.50

Punching shear perimeter (U1), (Refer figure 3.23, BS8110:1997)

OK =

0.05 N/mm2

=

0.36 N/mm2

OK

Refer Table 3.8 BS 8110-1:1997 Check for Punching Shear for U0 : For Punching Shear Critical Section is considered at '1.5d' from the face of column all around. Factored vertical load in column = 242 kN Perimeter of the critical section = 3400 mm Effective depth = 403 mm Factored Shear Stress

= 0.22 N/mm2 Shear Stress