Manual, and which contains the calculations upon which all of the various beam tablesĪre based and the properties and strengths were calculated. Properties of the beam can be analyzed by calculation using the "Specificationsįor Structural Steel Buildings" which is part of the AISC Steel Construction Uniform Load" tables in the AISC Steel Construction Manual. An existing beamĬan be analyzed quite easily with the "Section Properties" and "Maximum The steps below are for the analysis of an existing beam. Refer to the IBC deflection limits table above for common deflection limits. Check the deflection of the beam and if it meets the serviceability and deflection requirements.
The beams shear strength, phiVn for LRFD or Vn/Omega for ASD.Ĥ. "Selection by Zx" tables and check the required shear strength, Vu versus Find the selected beam in the "Maximum Uniform Load" tables or the It means there is a more economical beam.ģ. The closest solid line will be the most economical beam. Choose a beam directly above and to the right of the point of intersection. Plot the intersection point of the required design moment with the unbraced Next find the unbraced length on the horizontalĪxis. Length", and find the required design moment on the vertical axis, Mn/Omegaįor ASD or phiMn for LRFD. Enter the tables for "W-shapes - Plots of Available Moment vs. Should also include the beam's own weight as part of the dead load.Ģ. Loading for LRFD or the unfactored loading for ASD the required design moment, MuĪnd the design shear, Vu are calculated. From the combination loading on the beam, either factored W-Section Beam Selection by Available Momentġ. Or equal to the unbraced length limit factor Lp. The uniform loading on the beam is for a beam with an unbraced length, Lb less than
Uniform loads are tabulatedįor each W- section for different span lengths in one foot intervals. If the loading on the beam is a uniform load, the W-section can be selected from W-Section Beam Selection by Uniform Load: *For steel structural members, the dead load shall be taken as zero. To calculate beam deflection can be used. Or the alternate method for simple-span beams and I-shaped members and channels The design shear strength, Vu calculated in step 1 above.Ħ. The shear strength of theīeam given in the chart, phiVn for LRFD or Vn/Omega for ASD, must equal or exceed Check the shear strength of the selected beam. Unbraced Length" chart by the method below.ĥ. Than Lp then the proper beam will need to be selected using the "Available Strength Mn, however if the design will have the beam braced at intervals greater Selected would require bracing less than or equal to Lp to achieve the required Check the unbraced length factors, Lp and Lr. Or Mn/Omega to insure it is equal to or greater than Mu.Ĥ. Check the flexural strength either phiMn for LRFD
Enter the "W-section Beam Selection by Zx" chart and find the beam Where Mu = Mn/Omega = FyZx, thus Zx = Mu/Fy.ģ. Where Mn/Omega = Mu and solve for the required plastic section modulus, Zx. For ASD set theĭesign moment equal to the Nominal Moment, Mn divided by the safety factor Omega Where Mu = phiMn = FyZx, thus Zx = Mu/Fy. Phi where phiMn = Mu and solve for the required plastic section modulus, Zx. The design moment equal to the nominal moment, Mn multiplied by the safety factor Calculate the required plastic section modulus of the beam. The design loading on the beam should also include the beam's own weight asĢ. Moment, Mu and the design shear, Vu are calculated. From the combination loading on the beam, eitherįactored loading for LRFD or the unfactored loading for ASD the required design The fastest and easiest way to design a steel beam is to use the beam selection Steel Beam Design Using The 14th Edition AISC Steel Construction Manual:ġ. All calculationsĬan be performed for Load Resistance Factor Design, LRFD or Allowable Strength Design, The 14th edition of the AISC Steel Construction Manual. This design guide and the corresponding calculations are based on
This design guide is intended to provide guidance for the safe and economical design