体外预应力连续组合梁预应力筋拉力计算方法及全过程受力分析

Analysis of prestressing load and whole mechanical process of externally prestressed continuous composite beams

对体外预应力钢-混凝土连续组合梁进行全过程受力分析时,需准确计算预应力筋的拉力,因此,对预应力组合梁中预应力增量及全过程受力分析的计算方法进行了研究。根据梁体自身在荷载作用下的变形条件,采用几何方法给出了各种布筋形式下体外预应力筋伸长量的计算方法;基于共轭梁法,并考虑连续组合梁内力重分布,采用迭代法得到了预应力连续组合梁的荷载-变形曲线和预应力筋拉力随荷载的变化规律,计算结果与模型试验及其它文献中的模型试验结果进行了对比,结果吻合良好。研究结果表明:体外预应力组合梁中预应力筋的荷载-拉力关系曲线反映出预应力筋经历了从弹性到塑性的发展过程。根据梁自身在荷载作用下的几何变形条件,得到任意加载时刻的预应力筋拉力,用于全过程受力分析。

In order to study the whole bending process of externally prestressed steel-concrete continuous composite beams,the prestressing load should be calculated accurately.The calculating method of the prestressing load and the whole bending process analysis were researched.According to the geometric deformation condition of the composite beams under load,the calculation method of the elongation length of external tendons of various layout was given firstly.Then,considering the changing law of bending moment redistribution coefficient with load,the load-deformation curve and law of prestressing increment with load were obtained using the principle of conjugate beam method and iteration method.The numerical results were compared with the model test results and results from other reference.The numerical results agreed well with the test results.Study results indicate that the load-prestressing load curve of externally prestressed composite beam is developed from elastic to plastic stage.Using the prestressing load developed from the geometric deformation condition the developement process with load can be more precisely reflected,the prestressing load under arbitrary loading condition can be obtained.