Study Of The Integral Stability For Homemade Rolled H-section Steel Beam

The integral stability capacity for homemade rolled H-section steel beam and the applicability of the design code (GB50017) are analyzed entirely in the paper. It gives a chance to master and popularize homemade rolled H-section steel.The modified CDC method, proposed by Prof. Li-Kaixi, is effective to solve the problem on inelastic integral stability capacity for steel beam with initial distortion and residual stresses. According to the method, the algorithm is put forward in the paper.Taking account of the simplified torsion moment of inertia, integral stability coefficient increase relatively 5% or 0.01~0.03 absolutely, only for narrow rolled H-section (HN) behind HN350×175, whose calculation length goes beyond the limit of 8 meters.The discrepancy of inelastic stability modified equation between the GB50017 code and the GBJ17-88 code is wee. The former result is not more 103.5% than the latter. Concerning inelastic stability modified equation, the GB50017 code is appropriate.As a result of the simplified torsion moment of inertia, integral stability coefficients based on the GB50017 code increase relatively 5% or 0.01~0.04 absolutely, only for HN behind HN400×150, whose calculation length goes beyond the limit of 8 meters, taking account of any load condition and any yield-point.It is indicated that the result, based on the GB50017 code, is appropriate during the elastic integral stability range and is conservative excessively during the inelastic integral stability range, for homemade rolled H-section steel beam. Integral stability capacity of rolled beam is more 10%~20% than welded beam. At the same time, the inelastic integral stability capacity of wild rolled H-section (HW) steel beam is more superior observably than HN steel beam.Based on the GB50017 code, the geometry control condition of integral stability capacity of homemade rolled H-section steel beam is conservative excessively and is modified accordingly. The suggestion is put forward that adopting the different geometry control condition between rolled H-section steel beam and general I-section steel beam.Simplified formulary of integral stability coefficient is conservative excessively for homemade rolled H-section steel beam, based on the GB50017 code. In the paper, simplified formulary is modified cautiously, with more sufficient accuracy and extensive availability.WP=6>The practical table is compiled that integral stability coefficient of homemade rolled H-section steel beam under constant moment.