预应力组合箱梁抗弯承载能力影响参数分析

Analysis of Influential Parameters of Bending Capacity of Prestressed Composite Box Beams

为对预应力组合箱梁的设计提供参考,利用简化塑性理论对完全剪力连接的预应力组合梁的抗弯承载力影响参数(混凝土和钢梁强度、预应力筋初始张拉力、预应力筋布筋形式、转向块数量)进行分析。分析结果表明:在截面尺寸受限制时,提高钢梁强度能够有效提高预应力组合梁的抗弯承载力;增加预应力筋的数量可较明显地提高梁体的抗弯承载力;预应力筋采用折线布筋形式时,可提高预应力初始张拉值,以提高预应力组合梁的弹性承载力;转向块布置数量越多,预应力增量越大,二次效应影响越小,预应力组合梁抗弯承载力越高。

To provide reference for the design of prestressed composite box beams,the simplified plastic theory was used to analyze the influential parameters（e.g.the strength of concrete and steel beams,initial tensioning forces of prestressing tendons,layout of the tendons and numbers of deviation blocks） of the completely shear connected prestressed composite box beams.The results of the analysis demonstrate that under the condition that the sectional dimensions are restricted,the improvement of the strength of the steel beams can effectively improve the bending capacity of the composite box beams and the increase of numbers the prestressing tendons can significantly increase the bending capacity as well.When the tendons are laid out in a drape way,the initial tensioning values of the tendons can be increased and consequently,the elastic bearing capacity of the beams will be increased.The more the numbers of the deviation blocks are,the greater the increment of the prestress,the less the influence of the secondary effect and the higher the bending capacity of the beams will be.