{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 8:Slab Design Two Way Reinforced" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex8.1:pg-363" ] }, { "cell_type": "code", "execution_count": 7, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Summary of design\n", "Slab thickness= 100 mm\n", "Cover=15 mm\n", "Steel-\n", "(i)Short span = 10 mm dia @ 200 mm c/c\n", "(ii)Long span = 10 mm dia @ 210 mm c/c\n", "Alternate bars are bent up at l/7 from support in both directions\n" ] } ], "source": [ "import math\n", "lx=3.5 #in m\n", "ly=4 #in m\n", "sigma_cbc=5 #in MPa\n", "sigma_st=140 #in MPa\n", "D=lx*10**3.0/35 #in mm\n", "W1=(D/10**3)*25 #self-weight, in kN/m\n", "W2=1.5 #live load, in kN/m\n", "W=W1+W2 #in kN/m\n", "a=ly/lx\n", "Ax=0.078\n", "Ay=0.0602\n", "Mx=Ax*W*lx**2 #in kN-m\n", "My=Ay*W*lx**2 #in kN-m\n", "d=math.sqrt(Mx*10**6/0.87/10**3) #in mm\n", "d=70 #assume, in mm\n", " #assume 10 mm dia bars\n", "dia=10 #in mm\n", "D=d+dia/2+15 #<100 mm assumed value\n", "D=100 #in mm\n", "d=D-dia/2-15 #in mm\n", " #steel - short span\n", "z=0.87*d #in mm\n", "Ast=Mx*10**6/sigma_st/z #in sq mm\n", "s1=1000*0.785*dia**2/Ast #in mm\n", "s1=200 #assume, in mm\n", " #long span\n", "d=d-dia/2-dia/2 #in mm\n", "Ast=My*10**6/sigma_st/0.87/d #in sq mm\n", "s2=1000*0.785*dia**2/Ast #>3d = 210 mm\n", "s2=210 #assume, in mm\n", "print \"Summary of design\\nSlab thickness=\",D,\" mm\\nCover=15 mm\\nSteel-\\n(i)Short span = 10 mm dia @ \",s1,\" mm c/c\\n(ii)Long span = 10 mm dia @ \",s2,\" mm c/c\\nAlternate bars are bent up at l/7 from support in both directions\"\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex8.2:pg-364" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Summary of design\n", "Slab thickness= 100 mm\n", "Cover=15 mm\n", "Steel for both panels I and II-\n", "Main steel= 10 mm dia bars @ 765.561904762 mm c/c both ways. Alternate bars are bent up at supports.\n", "Torsion steel=(i) At corners, 6 mm dia bars @ 85 mm c/c both ways\n", "(ii) At continuous support, 6 mm dia bars @ 170 mm c/c both ways\n" ] } ], "source": [ "import math\n", "sigma_cbc=5 #in MPa\n", "sigma_st=230 #in MPa\n", "lx=3.75 #in m\n", "ly=4 #in m\n", "D=lx*10**3.0/40 #in mm\n", "D=100 #assume, in mm\n", "W1=(D/10**3)*25 #self-weight, in kN/m\n", "W2=0.5 #floor finish, in kN/m\n", "W3=2 #live load, in kN/m\n", "W=W1+W2+W3 #in kN/m\n", "a=ly/lx\n", "#panels I and III belong to case 8 and panel II belong to case 6\n", "#for panels I and III\n", "#at mid-span\n", "Ax=0.0483\n", "Ay=0.043\n", "Mx1=Ax*W*lx**2 #in kN-m\n", "My1=Ay*W*lx**2 #in kN-m\n", "#at support\n", "Ay=0.057\n", "Ms=Ay*W*lx**2 #in kN-m\n", "#for panel II\n", "#at mid-span\n", "Ax=0.0403\n", "Ay=0.035\n", "Mx2=Ax*W*lx**2 #in kN-m\n", "My2=Ay*W*lx**2 #in kN-m\n", " #at support\n", "Ay=0.045 #<0.057, hence not considered\n", "d=math.sqrt(Ms*10**6/0.65/10**3) #in mm\n", "d=80 #assume, in mm\n", "#assume 10 mm dia bars\n", "dia=10 #in mm\n", "D=d+dia/2+15\n", "#steel at centre\n", "#for panels I and III\n", "#short span\n", "z=0.9*d #in mm\n", "Ast=Mx1*10**6/sigma_st/z #in sq mm\n", "s1=1000*0.785*dia**2/Ast #>3d\n", "#long span\n", "Ast=My1*10**6/sigma_st/z #in sq mm\n", "s2=1000*0.785*dia**2/Ast #>3d\n", "#for panel II\n", "#short span\n", "Ast=Mx2*10**6/sigma_st/z #in sq mm\n", "s3=1000*0.785*dia**2/Ast #>3d\n", "#long span\n", "Ast=My2*10**6/sigma_st/z #in sq mm\n", "s3=1000*0.785*dia**2/Ast #>3d\n", "#steel at support\n", "Ast=Ms*10**6/sigma_st/z #in sq mm\n", "s4=1000*0.785*dia**2/Ast #>3d\n", "s=3*d #maximum spacing of bars in both directions as per IS 456, in mm\n", "Ast=1000*0.785*dia**2/s #in sq mm\n", "pt=Ast/10**3/d*100 #in %\n", "#steel for torsion, provide 6 mm dia bars\n", "#(i)at outer corner of slab\n", "At1=3.0/4*Ast #in sq mm\n", "l=lx/5 #in m\n", "s5=750*0.785*6**2/At1 #in mm\n", "s5=85 #assume, in mm\n", "#(ii)at continuous support\n", "At2=At1/2 #in sq mm\n", "s6=750*0.785*6**2/At2 #in mm\n", "s6=170 #assume, in mm\n", "print \"Summary of design\\nSlab thickness=\",D,\" mm\\nCover=15 mm\\nSteel for both panels I and II-\\nMain steel= 10 mm dia bars @ \",s1,\" mm c/c both ways. Alternate bars are bent up at supports.\\nTorsion steel=(i) At corners, 6 mm dia bars @ \",s5,\" mm c/c both ways\\n(ii) At continuous support, 6 mm dia bars @ \",s6,\" mm c/c both ways\"\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex8.3:pg-365" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Summary of design\n", "Slab thickness= 190 mm\n", "Cover=15 mm\n", "Steel:(A)Panels I, II, V and VI-\n", "1. Short span (lx=6 m)\n", "Mid-span - 10 mm dia bars @ 195 mm c/c. Alternate bars are bent up at supports at a distance lx/4 from centre of support\n", "Support - 10 mm dia @ 565 mm c/c\n", "2. Long span (ly=7 m)\n", "Mid-span - 10 mm dia bars @ 240 mm c/c. Alternate bars are bent up at supports at a distance ly/4 from centre of support\n", "Support - 10 mm dia @ 550 mm c/c\n", "(B)Panels III and IV-\n", "1. Short span (lx=6 m)\n", "Mid-span - 10 mm dia bars @ 235 mm c/c. Alternate bars are bent up at supports at a distance lx/4 from centre of support\n", "Support - 10 mm dia @ 775 mm c/c\n", "2. Long span (ly=7 m)\n", "Mid-span - 10 mm dia bars @ 300 mm c/c. Alternate bars are bent up at supports at a distance ly/4 from centre of support\n", "Support - 10 mm dia @ 550 mm c/c\n", "Torsion steel\n", "Outside corners- 6 mm dia bars @ 110 mm \n", "Continuous support- 6 mm dia bars @ 1 mm\n" ] } ], "source": [ "import math\n", "sigma_cbc=7 #in MPa\n", "sigma_st=275 #in MPa\n", "lx=6 #in m\n", "ly=7 #in m\n", "D=lx*10**3.0/35 #in mm\n", "D=180 #assume, in mm\n", "W1=(D/10**3)*25 #self-weight, in kN/m\n", "W2=0.5 #floor finish, in kN/m\n", "W3=1 #partitions, in kN/m\n", "W4=5 #live load, in kN/m\n", "W=W1+W2+W3+W4 #in kN/m\n", "a=ly/lx\n", "#panels I, II, V and VI belong to case 4 and panels III and IV belong to case 3\n", "#for panels I, II, V and VI\n", "#at mid-span\n", "Ax=0.043\n", "Ay=0.035\n", "Mxm1=Ax*W*lx**2 #in kN-m\n", "Mym1=Ay*W*lx**2 #in kN-m\n", "#at support\n", "Ax=0.058\n", "Ay=0.047\n", "Mxs1=Ax*W*lx**2 #in kN-m\n", "Mys1=Ay*W*lx**2 #in kN-m\n", "#for panels III and IV\n", "#at mid-span\n", "Ax=0.036\n", "Ay=0.028\n", "Mxm2=Ax*W*lx**2 #in kN-m\n", "Mym2=Ay*W*lx**2 #in kN-m\n", " #at support\n", "Ax=0.047\n", "Ay=0.037 #<0.047, hence will not be consdered\n", "Mxs2=Ax*W*lx**2 #in kN-m\n", "#check for depth\n", "M=max(Mxm1,Mym1,Mxs1,Mys1,Mxm2,Mym2,Mxs2) #in kN-m\n", "d=math.sqrt(M*10**6/0.81/10**3) #in mm\n", "d=170 #assume, in mm\n", "#assume 10 mm dia bars\n", "dia=10 #in mm\n", "D=d+dia/2+15 #>180 mm assumed value\n", "D=190 #in mm\n", "d=D-dia/2-15 #in mm\n", "#main steel-short span\n", "#for panels I, II, V and VI-at mid-span\n", "z=0.92*d #in mm\n", "Astm=Mxm1*10**6/sigma_st/z #in sq mm\n", "s1=1000*0.785*dia**2/Astm #in mm\n", "s1=195 #assume, in mm\n", "#at support\n", "Ast=Mxs1*10**6/sigma_st/z #in sq mm\n", "Astr=Ast-Astm #balance steel required at support, in sq mm\n", "s2=1000*0.785*dia**2/Astr #in mm\n", "s2=565 #assume, in mm\n", "#for panels III and IV-at mid-span\n", "Astm=Mxm2*10**6/sigma_st/z #in sq mm\n", "s3=1000*0.785*dia**2/Astm #in mm\n", "s3=235 #assume, in mm\n", "#at support\n", "Ast=Mxs2*10**6/sigma_st/z #in sq mm\n", "Astr=Ast-Astm #balance steel required at support, in sq mm\n", "s4=1000*0.785*dia**2/Astr #in mm\n", "s4=775 #assume, in mm\n", "#long span\n", "#at mid-span\n", "#for panels I, II, V and VI\n", "Astm1=Mym1*10**6/sigma_st/z #in sq mm\n", "s5=1000*0.785*dia**2/Astm1 #in mm\n", "s5=240 #assume, in mm\n", "#for panels III and IV\n", "Astm2=Mym2*10**6/sigma_st/z #in sq mm\n", "s6=1000*0.785*dia**2/Astm2 #in mm\n", "s6=300 #assume, in mm\n", "#at support\n", "#for panels I, II, V and VI\n", "Ast=Mys1*10**6/sigma_st/z #in sq mm\n", "Astr=Ast-Astm1/2-Astm2/2 #balance steel required at support, in sq mm\n", "s7=1000*0.785*dia**2/Astr #in mm\n", "s7=550 #assume, in mm\n", "#steel for torsion, provide 6 mm dia bars\n", "#(i)at outside corners of slab\n", "Ast=Mxm1*10**6/sigma_st/z #in sq mm\n", "At1=3/4.0*Ast #in sq mm\n", "l=lx/5 #in m\n", "s8=l*10**3*0.785*6**2/At1 #in mm\n", "s8=110 #assume, in mm\n", "#(ii)at continuous support\n", "At2=At1/2 #in sq mm\n", "s9=l*10**3*0.785*6**2/At2 #in mm\n", "s9=225 #assume, in mm\n", "print \"Summary of design\\nSlab thickness=\",D,\" mm\\nCover=15 mm\\nSteel:(A)Panels I, II, V and VI-\\n1. Short span (lx=6 m)\\nMid-span - 10 mm dia bars @ \",s1,\" mm c/c. Alternate bars are bent up at supports at a distance lx/4 from centre of support\\nSupport - 10 mm dia @ \",s2,\" mm c/c\\n2. Long span (ly=7 m)\\nMid-span - 10 mm dia bars @ \",s5,\" mm c/c. Alternate bars are bent up at supports at a distance ly/4 from centre of support\\nSupport - 10 mm dia @ \",s7,\" mm c/c\\n(B)Panels III and IV-\\n1. Short span (lx=6 m)\\nMid-span - 10 mm dia bars @ \",s3,\" mm c/c. Alternate bars are bent up at supports at a distance lx/4 from centre of support\\nSupport - 10 mm dia @ \",s4,\" mm c/c\\n2. Long span (ly=7 m)\\nMid-span - 10 mm dia bars @ \",s6,\" mm c/c. Alternate bars are bent up at supports at a distance ly/4 from centre of support\\nSupport - 10 mm dia @ \",s7,\" mm c/c\\nTorsion steel\\nOutside corners- 6 mm dia bars @ \",s8,\"mm \\nContinuous support- 6 mm dia bars @ \",l,\"mm\"\n", " #answer in textbook is incorrect\n" ] } ], "metadata": { "kernelspec": { "display_name": "Python 2", "language": "python", "name": "python2" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 2 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython2", "version": "2.7.11" } }, "nbformat": 4, "nbformat_minor": 0 }