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Diffstat (limited to '3683/CH11/EX11.3/Ex11_3.sce')
-rw-r--r-- | 3683/CH11/EX11.3/Ex11_3.sce | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/3683/CH11/EX11.3/Ex11_3.sce b/3683/CH11/EX11.3/Ex11_3.sce new file mode 100644 index 000000000..13303fb88 --- /dev/null +++ b/3683/CH11/EX11.3/Ex11_3.sce @@ -0,0 +1,48 @@ +B=0.5//column diameter, in m
+fck=20//in MPa
+sigma_cbc=7//in MPa
+sigma_st=230//in MPa
+P1=1600//load on column, in kN
+P2=0.05*P1//weight of footing, in kN
+P=P1+P2//in kN
+q=300//bearing capacity of soil, in kN/sq m
+A=P/q//in sq m
+L=sqrt(A)//assuming footing to be square
+L=2.4//assume, in m
+p=P1/L^2//soil pressure, in kN/sq m
+p=278//assume, in kN/sq m
+bc=1
+ks=0.5+bc//>1
+ks=1
+Tc=0.16*sqrt(fck)*10^3//in kN/sq m
+Tv=Tc
+//let d be the depth of footing in metres
+//case I: refer Fig. 11.11 of textbook
+d1=L*(L-B)/2*p/(Tc*L+L*p)//in m
+//case II: refer Fig. 11.12 of textbook; we get a quadratic equation of the form e d^2 + f d + g = 0
+e=%pi/4*p+%pi*Tc
+f=2*%pi/4*B*p+%pi*B*Tc
+g=-(L^2-%pi/4*B^2)*p
+d2=(-f+sqrt(f^2-4*e*g))/2/e//in m
+d2=0.57//assume, in m
+d=max(d1,d2)//in m
+//bending moment consideration, refer Fig. 11.13 of textbook
+M=1*((L-B)/2)^2/2*p//in kN-m
+d3=sqrt(M*10^6/0.88/10^3)//<570 mm, hence OK
+z=0.9*d*10^3//lever arm, in mm
+Ast1=(M*10^6/sigma_st/z)//in sq mm
+Ast=L*Ast1//steel required for full width of 2.4 m
+//provide 20 mm dia bars
+dia=20//in mm
+n=Ast/0.785/dia^2//no. of 20 mm dia bars
+n=9//assume
+Tbd=1.12//in MPa
+Ld=dia*sigma_st/4/Tbd//in mm
+Ld=1030//assume, in mm
+c=50//side cover, in mm
+La=(L-B)/2*10^3-c//in mm
+//bend bar at right angle and provide length, l
+l=Ld-La//in mm
+D=d*10^3+dia/2+100//in mm
+mprintf("Summary of design:\nOverall depth of footing=%d mm\nCover:100 mm bottom; 50 mm side\nSteel:%d-20 mm dia bars both ways",D,n)
+//answer in textbook is incorrect
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