1 files changed, 36 insertions, 0 deletions
diff --git a/3683/CH19/EX19.9/Ex19_9.sce b/3683/CH19/EX19.9/Ex19_9.sce
new file mode 100644
index 000000000..39a5c515b
--- /dev/null
+++ b/3683/CH19/EX19.9/Ex19_9.sce
@@ -0,0 +1,36 @@
+l=2.7+1//span, in m
+R=0.15//rise, in m
+t=0.27//tread, in m
+fck=15//in MPa
+fy=415//in MPa
+D=200//assume, in mm
+W1=D/10^3*25*sqrt(R^2+t^2)/t//slab load on plan, in kN/m
+W2=1/2*R*t*25/t//load of step per metre, in kN/m
+W3=3//live load, in kN/m
+W=W1+W2+W3//in kN/m
+Wu=1.5*W//in kN/m
+Mu=Wu*l^2/8//in kN-m
+d=sqrt(Mu*10^6/0.138/fck/10^3)//in mm
+d=115//round-off, in mm
+//assume 10 mm dia bars
+dia=10//in mm
+D=d+dia/2+25//< 200 mm, hence OK
+D=l*10^3/24//depth required for deflection, in mm
+D=155//round-off, in mm
+d=D-dia/2-25//in mm
+//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*d
+r=Mu*10^6
+Ast=(-q-sqrt(q^2-4*p*r))/2/p//in sq mm
+s1=1000*0.785*dia^2/Ast//spacing of 10 mm dia bars
+s1=110//round-off, in mm
+Ads=0.12/100*D*10^3//distribution steel, in sq mm
+//provide 8 mm dia bars
+s2=1000*0.785*8^2/Ads//in mm
+s2=270//round-off, in mm
+mprintf("Summary of design\nSlab thickness=%d mm\nCover = 25 mm\nMain steel = 10 mm dia bars @ %d mm c/c\nDistribution steel = 8 mm dia @ %d mm c/c",D,s1,s2)
+//answer in textbook for spacing of 10 mm dia bars is incorrect