Sheet1CRACK WIDTH CALCULATION (BS 8110)Reference:Moesley page
138-140Project:Location:Input:Characteristic strengths of
concretefcu =35N/mm2Characteristic strengths of steelfy
=460N/mm2Modulus of elasticity of steelEs =200kN/mm2Modulus of
elasticity of concrete (Refer Table 1.1)Ec =27kN/mm2Beam widthbb
=1000mmBeam heighthb =250mmNo. of tension Rebarnbar=8Diameter of
tension rebardbar=10mmArea of steelAs =628mm2Minimum cover to
tension reinfrocementcmin =50mmSide cover to corner tension
reinforcementcside=50mmDistance to centroid of tension
reinforcementd =195mmApplied Service MomentM =20kNmOutput:1. The
analysis of cracked section using half of the instanteneous value
of Ec to allow for creep effectEc =13.5kN/mm22. The neutral axis
position is given by 0.5 b x^2 + Es. As/ Ec x - Es.As.d/ Ec = 00.5
b =500.00Es. As/Ec =9308.42-Es.As.d/Ec =-1815142.42The neutral axis
positionx =51.66mm3. The stress in tension rebarfs = M/ ((d - x/3)
As ) =179.05N/mm24. Overall extension per unit length at depth y
below neutral axise1 = y/ (d-x) fs/ Es =0.0000062454yCheck maximum
crack width at 2 locations:Point 1: at the soffit corner of the
beamPoint 2: at equidistance between neutral axis and tension
reinforcementPointDist.
yacra'e1emwmax1198.3472.78250.000.00123873150.00051074310.091271.6785.34123.330.00044761620.00018455720.035Note:acr=
straight clear distance between rebar and pointa' = the distance
from compressive face to the point at which crack is calculatedbt=
the width of section at centroid of tensile steel5. Maximum crack
widthwmax =0.09mm
