Evo Design - structural engineering Calculation No. 001-RC BEAM INTERACTIVE ONLINE CALCULATION SHEET Project No. onlinestructuraldesign.com SAMPLE CALCULATION Project Title: Reinforced Concrete Beam - interactive design spreadsheet Calc. By Date Rev. MN 16.04.2014 0 Subject/Feature: Reinforced Concrete Beam - Bending Moment Capacity (ACI 318) Checked By Date Imperial Units spreadsheet CN 16.04.2014 Input Output Beam section dimensions Beam flexural strength Reinforcement Materials (steel, concrete) Beam bending moment capacity at ultimate limit state Beam section dimensions h = 32 in element depth b = 16 in element width (parameters that can not be modified in the demo version) Area = in2 RC Element Area Reinforcement cover in cover to the center of the bars d = in depth of bottom reinforcement (h- cover) Bar size # 3 4 5 6 7 8 9 10 11 14 18 no 3 4 5 6 7 8 9 10 11 14 18 no 3 4 5 6 7 8 9 10 11 14 18 mm n = 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 no of bars Area = nominal area As = in2 area of reinforcement in tension side rtens.reinf = % percentage of tension reinforcement per ACI 318 Section 10.9.1 Materias Concrete fc' = 2.5 3 3.5 4 5 6 7 8 9 10 ksi concrete characteristic cylinder strength Reinforcement type see reinforcement types here Grade 40 50 60 75 fy = ksi reinforcement yield strength As,min = [3*sqrt(fc')/fy]*bw*d but not less than 200*bw*d/fy minimum area of flexural reinforcement where sqrt(fc') is the square root of specified compressive strength of concrete in psi per ACI 318 Section 10.5.1 [3*sqrt(fc')/fy]*bw*d = in2 200*bw*d/fy = in2 As,min = in2 As As,min Section strength reduction factor per ACI 318-05 f = 0.90 For tension controlled sections Section 9.3 Values of f strength reduction factor References: ACI318-05 - Building code requirements for structural concrete Calculation No. CALCULATION SHEET Project No. onlinestructuraldesign.com Project Title: Calc. By Date Rev. Subject Ckd. By Date The relationship between concrete compressive stress and concrete strain is satisfied per ACI 318-05 by an equivalent rectangular concrete stress distribution defined by a 0.85*fc' uniform Sections 10.2.6 and 10.2.7 stress over an equivalent compression zone bounded by edges of the cross section and a straight line located parallel to the neutral axis at a distance a = b1*c from the fiber of maximum compressive strain. per ACI 318-05 Section 10.2.3 Maximum usable strain at extreme concrete compression fiber shall be assumed equal to 0.003; The relation between concrete compressive stress and concrete strain is assumed rectangular Section 10.2.7.1 0.85fc' value uniformly distributed over an equivalent compression zone bounded by edges of the cross section and a straigth line located parale to the neutral axis at a distance a = b1*c from the fiber of max. compression strain b1 = factor relating depth of equivalent per ACI 318-05 rectangular compressive stress block Section 10.2.7.3 to neutral axis depth between 2500 and 4000 psi b1 = 0.85, above 4000 b1 will be reduced lineary at a rate of 0.05 per 1000 psi but not lower than 0.65 a = b1 * c depth of equivalent rectangular Section 10.2.7.1 stress block Bending moment capacity - Stress and strain equilibrium for pure bending T = As * fy = kip C = T a = C / (0.85 * fc' * b) = in c = a / b1 = in fM = fAs*fy*(d-a/2) = kip-ft References: