基于钢闸门设计规范屈服状态的面板弹塑性调整系数

Elastic-plastic adjusting coefficients of panel based on the yielding state in specification for design of steel gate

钢闸门面板在进入弹塑性阶段后,仍有很大的强度储备,规范中采用给容许应力乘以弹塑性调整系数来体现,但该值未准确反映面板长宽比和主(次)梁整体弯曲应力的影响。本文以规范中"将面板强度的容许应力提高到钢材的屈服极限"为极限状态,考虑面板长宽比及梁整体弯曲应力对弹塑性调整系数的影响,提出了更为合理的弹塑性调整系数表达式.研究结果表明:长宽比对弹塑性调整系数的影响最大可提高32%;梁整体弯曲应力对其影响很显著,梁整体弯曲应力越大,弹塑性调整系数越小;现行规范中采用固定不变的弹塑性调整系数,在梁整体弯曲应力较小时,是偏于保守的;在梁整体弯曲应力较大时,是偏于危险的。进一步分析了基于现行规范屈服极限状态的面板长边的超容许应力范围,评价了规范屈服极限状态的合理性。最后提出了基于此弹塑性调整系数的面板设计新方法,避免了繁琐的试算及偏差,对规范修订及钢闸门设计具有指导意义。

Experiment shows that a steel gate plate has a large strength stock after it reaches the elastic-plastic phase,which is embodied by an elastic-plastic adjusting coefficient in specification for design of steel gate.But the coefficient is not reasonable.In this article,based on the yield status of the specification—improving the allowable stress to the yield limit of steel,a more reasonable coefficient expression is presented which includes the effects of the plate length-width ratio and the whole bending stress of beams.The results indicate that the aspect ratio may increase the coefficient by 32% and the bending stress can effect the coefficient obviously,the more whole beam bending stress is,the smaller the coefficient becomes.The constant coefficient method adopted in the current specification has bias towards conservative at small bending stress,but toward dangerous at large bending stress.The yield area on the long edge of the panel under the yield state of the specification is analyzed to estimate the rationality of this method.A new design method of panel is suggested,which avoids the fussy tentative calculation in the current specification and provides a reference for revising standards.