e m/(1+2.(a cr -c)/(h-x))ĬRACK_WIDTHS2.1ProjectSpreadsheets to BS 8110etcREINFORCEDĬONCRETE COUNCILClientAdvisory GroupMade byDatePageLocationGrid d = ' Z ' = d-(x/3) = Reinforcement stress ' fs ' = Ms/(As*Z) = N/mm 2 Concrete stress ' fc ' = (fs*As)/(0.5*b*x) = N/mm 2 Strain at soffit of concrete beam/slab ' e1 ' = (fs/Es)*(h-x)/(d-x) = Strain due to stiffening effect of concrete between cracks ' e 2 ' = e 2 = b.(h-x) 2 /(3.Es.As.(d-x)) for crack widths of 0.2 mm e 2 = 1.5.b.(h-x) 2 /(3.Es.As.(d-x)) for crack widths of 0.1 mm e 2 = Average strain for calculation of crack width ' e m '= e 1 - e 2 = Calculated crack width, ' w ' = 3.a cr. Project Spreadsheets to BS 8110etc REINFORCED CONCRETE COUNCIL Client Advisory Group Made by Date Page Location Grid line 1 RC 2 33 Crack Width Calculations to BS8110: 1997/ BS8007:1987 Checked Revision Job No v 2.1on CD © 1999-2003 BCA for RCC chg - R68 CRACK WIDTH CALCULATIONS - FLEXURE - INPUT fcu= 1000 mm 250 mm 200 mm 40 mm 150 mm 20 mm 80.14 mm 'acr ' is distance from the point considered to the surface of the nearest longitudin 69.0 KNm CALCULATIONS 13.5 200.0 14.81 0.010 85 mm 172 192 9.50 0.001375 Used n/a 0.000189 0.001186 CALCULATED CRACK WIDTH, 'w' = 0.19 mm Originated from RCC14.xls N/mm 2 fy = N/mm 2 Area of reinforcement ' As ' = mm 2 b = h = d = Minimum cover to tension reinforcement ' CO ' = Maxmum bar spacing ' S ' = Bar dia ' DIA ' = (S/2)^2+(CO+DIA/2)^2)^(1/2)-DIA/2) as default or enter other value = Applied service moment ' Ms '= moduli of elasticity of concrete ' Ec ' = (1/2)*(20+0.2*fcu) = KN/mm 2 moduli of elasticity of steel ' Es ' = KN/mm 2 Modular ratio ' a ' = (Es/Ec) = ' r ' = As/bd = depth to neutral axis, ' x ' = (- a.r +(( a.r ) 2 + 2.

Crack width calculation xls