混凝土对称配筋梁的抗弯承载力分析与计算

针对混凝土双筋矩形梁在承载能力极限状态下可能出现的受拉纵筋应变超限问题,重新界定了其截面受压区的最小高度;根据混凝土双筋矩形梁抗弯承载力的计算理论,建立了混凝土对称配筋梁抗弯承载力计算的基本公式;对混凝土对称配筋梁的抗弯承载力进行相关计算,并提出了相应的实用计算方法。工程算例表明:对于混凝土对称配筋梁的抗弯承载力设计问题,应采用给出的实用计算方法进行相关计算,以确保安全;若按一般"双筋梁法"计算,则多数情况下结果偏于不安全,且最大误差可达10%以上。

Analysis and calculation for flexural capacity of symmetrically reinforced concrete beams

In order to deal with the problem that the strain of reinforcing bars in tension may be beyond the limit in the design of a doubly-reinforced concrete beam,the minimum depth of compression zone of its cross section was redefined.On the basis of computational theory for the flexural strength of doubly-reinforced concrete beams,the basic formulas for flexural strength of such beams were put forth.From the analysis of effect of depth of compression zone on stress of longitudinal reinforcement in compression,the corresponding practical method of computing the flexural strength of a symmetrically reinforced concrete beam was put forth.The example projects indicate that it is necessary to adopt the proposed method for the design of a symmetrically-reinforced concrete beam so as to ensure its safety.If traditional method was used,it would be unsafe in most cases,and the error could be more than 10% in the worst case.2 tabs,2 figs,9 refs.