钢梁稳定性再研究:国际上的试验研究和理论分析(2)

A RESTUDY ON STABILITY OF STEEL BEAMS: INTERNATIONAL TESTS AND THEORETICAL ANALYSES( Ⅱ)

介绍国际上对钢梁进行试验研究的试验数据以及理论分析,表明如下几个现象和结论:1)焊接梁的稳定系数低于热轧梁;2)焊接梁试验结果的离散性比热轧梁的大;3)早期热轧梁的试件较多,而且为了验证切线模量法,试件的制作和对中比较严格,试验结果偏高;后期随双非线性分析技术和手段的发展,相关试验结果下降;4)初弯曲对稳定系数影响巨大,无法采用残余应力来等效;5)截面的高宽比越大,稳定系数越小;6)荷载形式对稳定系数有不能忽略的影响;7)正则化长细比1.0处的试验结果中,热轧梁稳定系数的下限约为0.6,焊接梁约为0.5。

This paper is focused on the test results of steel beams available in the international literature and their numerical analyses of the inelastic lateral torsional instability. It was found ： 1 ） The stability factors for welded beams were smaller than those of the rolled beams; 2） the discreteness of the test results for welded beams was larger than that of the rolled beams; 3 ） early test results were mainly on rolled beams, and the results were higher than more recent tests, this was because some early tests were specifically conducted to check the tangent modulus approach to inelastic buckling of initially straight beams using specially prepared specimens; later the relevant test results were decreased due to the development of dual-non-linear analysis and means; 4） the unfavorable effect of initial out-of- plane deflection was great and could not be equivalently treated by residual stresses; 5）beams with higher height-to- width ratios of the cross section had smaller stability factors; 6） loading types had a non-negligible effect on the stability factors; 7） at point of normalized slenderness ratio being equal to 1.0 ; the lower limit of the stability factors was O. 6 and 0. 5 for rolled and welded beams respectively.