Project

Spreadsheets to BS 8110etcAdvisory Group Grid line 1Crack Width Calculations to BS8110: 1997/ BS8007:1987Originated from RCC14.xls on CD 1999 BCA for RCC

REINFORCED CONCRETE COUNCILMade by Date Page

Client Location

RCChecked

22-Apr-2013Revision

33Job No

chg -

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R68

CRACK WIDTH CALCULATIONS - FLEXURE

INPUT fcu= fy= Area of reinforcement " As " = b= h= d= Minimum cover to tension reinforcement " CO " = Maxmum bar spacing " S " = Bar dia " DIA " = " acr " =(((S/2)^2+(CO+DIA/2)^2)^(1/2)-DIA/2) as default or enter other value = N/mm2 30 460 N/mm2 3270 mm2 1000 mm 700 mm 625 mm 50 mm 150 mm 25 mm 85.1 mm "acr " is distance from the point considered to the surface of the nearest longitudinal bar Applied service moment " Ms "= 360.0 KNm

CALCULATIONS moduli of elasticity of concrete " Ec" = (1/2)*(20+0.2*fcu) = moduli of elasticity of steel " Es " = Modular ratio " " = (Es/Ec) = " " = As/bd = depth to neutral axis, "x" = (-. +((.)2 + 2..)0.5.d = 13.0 200.0 15.38 0.005 205 KN/mm2 KN/mm2

mm

" Z " = d-(x/3) = 557 Reinforcement stress " fs " = Ms/(As*Z) = 198 N/mm2 Concrete stress " fc " = (fs*As)/(0.5*b*x) = 6.30 N/mm2 Strain at soffit of concrete beam/slab " 1 " = (fs/Es)*(h-x)/(d-x) = 0.001166 Strain due to stiffening effect of concrete between cracks " 2 " = 2 = b.(h-x)2/(3.Es.As.(d-x)) for crack widths of 0.2 mm Used 2 = 1.5.b.(h-x)2/(3.Es.As.(d-x)) for crack widths of 0.1 mm n/a 2 = 0.000297 Average strain for calculation of crack width " m "= 1-2 = 0.000869 Calculated crack width, " w " = 3.acr.m/(1+2.(acr-c)/(h-x)) CALCULATED CRACK WIDTH, 'w' = 0.19 mm

Notes

Disclaimer All advice or information from the British Cement Association and/or Reinforced Concrete Cou intended for those who will evaluate the significance and limitations of its contents and take responsibility for its use and application. No liability (including that for negligence) for any los resulting from such advice or information is accepted by the BCA, RCC or their subcontractors suppliers or advisors. Users should note that all BCA software and publications are subject to revision from time to time and should therefore ensure that they are in possession of the late version.

This spreadsheet should be used in compliance with the accompanying publication ' Spreadsh concrete design to BS 8110 & EC2' available from British Cement Association, Telford Avenue Crowthorne, Berkshire RG45 6YS. Status of spreadsheet Public release version. Revision history RCC14 Crack Width.xls

Date04-Aug-99

VersionRCC14 v0.1

ActionRenamed

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and/or Reinforced Concrete Council is itations of its contents and take ng that for negligence) for any loss BCA, RCC or their subcontractors, e and publications are subject to hey are in possession of the latest

ompanying publication ' Spreadsheets for ment Association, Telford Avenue,

Size (kB)81

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