From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001 From: prashantsinalkar Date: Tue, 10 Oct 2017 12:27:19 +0530 Subject: initial commit / add all books --- 3683/CH19/EX19.10/Ex19_10.sce | 52 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 3683/CH19/EX19.10/Ex19_10.sce (limited to '3683/CH19/EX19.10/Ex19_10.sce') diff --git a/3683/CH19/EX19.10/Ex19_10.sce b/3683/CH19/EX19.10/Ex19_10.sce new file mode 100644 index 000000000..92ebaeca3 --- /dev/null +++ b/3683/CH19/EX19.10/Ex19_10.sce @@ -0,0 +1,52 @@ +b=0.2//column width, in m +D=0.3//column depth, in m +fck=15//in MPa +fy=415//in MPa +P1=600//load on column, in kN +P2=0.05*P1//weight of footing, in kN +P=P1+P2//in kN +Pu=1.5*P//in kN +q=150//bearing capacity of soil, in kN/sq m +qu=2*q//ultimate bearing capacity of soil, in kN/sq m +A=Pu/qu//in sq m +L=sqrt(A)//assuming footing to be square, in m +L=1.8//round-off, in m +p=P1*1.5/L^2//soil pressure, in kN/sq m +p=277.8//round-off, in kN/sq m +bc=b/D +ks=0.5+bc//>1 +ks=1 +Tc=0.25*sqrt(fck)*10^3//in kN/sq m +Tv=Tc +//let d be the depth of footing in metres +//case I: consider greater width of shaded portion in Fig. 19.6 of textbook +d1=L*(L-b)/2*p/(Tc*L+L*p)//in m +//case II: refer Fig. 19.7 of textbook; we get a quadratic equation of the form e d^2 + f d + g = 0 +e=p+4*Tc +f=b*p+D*p+2*(b+D)*Tc +g=-(L^2-b*D)*p +d2=(-f+sqrt(f^2-4*e*g))/2/e//in m +d2=0.35//round-off, in m +//bending moment consideration, refer Fig. 19.8 of textbook +Mx=1*((L-b)/2)^2/2*p//in kN-m +My=1*((L-D)/2)^2/2*p//in kN-m +d3=sqrt(Mx*10^6/0.138/fck/10^3)//<350 mm, hence OK +//steel +//Xu=0.87*fy*Ast/0.36/fck/b = a*Ast +a=0.87*fy/0.36/fck/10^3 +//using Mu=0.87 fy Ast (d-0.416 Xu), we get a quadratic equation +p=0.87*fy*0.416*a +q=-0.87*fy*d2*10^3 +r=Mx*10^6 +Ast=(-q-sqrt(q^2-4*p*r))/2/p//in sq mm +Ast=L*Ast//steel required for full width of 1.8 m +//provide 12 mm dia bars +dia=12//in mm +n=Ast/0.785/dia^2//no. of 12 mm dia bars +n=12//round-off +Tbd=1.6//in MPa +Ld=dia*0.87*fy/4/Tbd//in mm +Ld=677//assume, in mm +//this length is available from the face of the column in both directions +D=d2*10^3+dia/2+100//in mm +mprintf("Summary of design:\nOverall depth of footing=%d mm\nCover=100 mm\nSteel-%d bars of 12 mm dia both ways",D,n) -- cgit