钢-混凝土组合梁桥的截面弹性抗弯承载力计算方法研究

Research on Calculation Method of Elastic Bending Capacity for Steel-concrete Composite Beam Bridges

为探求一种钢-混凝土组合梁桥的弹性抗弯承载力计算方法,从弹性理论出发,通过对钢-混凝土组合梁自身构造特点和力学特性的分析与推导,总结、提炼现行行业标准和规范中计算方法的共性,选择满足各种规范要求的计算表达式;对相关参数进行定义,提出了一种简捷、实用的截面弹性抗弯承载力计算方法;给出了钢-混凝土组合梁简支梁桥和连续梁桥弹性抗弯承载力的2个计算示例,基于上述方法分别根据跨中正弯矩区段和中支点负弯矩区段的公式计算了其弹性抗弯承载力,并与其他规范中塑性抗弯承载力的计算结果进行了对比。结果表明:采用该公式计算钢-混凝土组合梁桥的截面弹性抗弯承载力的方法可行、结论可靠,能够用于公路桥梁的截面抗弯承载力计算;可以认为,同一组合梁的截面弹性抗弯承载力是截面承载能力的下限,而截面塑性抗弯承载力则是截面承载能力的上限。

To investigate a calculation method of elastic bending capacity for steel-concrete composite beam bridges,the commonalities on calculation method of relevant specifications were summarized and refined,and the calculation expressions that met the requirements of various specifications were chosen as well,based on the theory of elasticity,through the analysis and derivation of structural characteristics and mechanical properties of steel-concrete composite beams.The relevant parameters were defined,and a simple and practical calculation method of elastic bending capacity for steel-concrete composite beam bridges was proposed.Two calculation examples of steel-concrete simply supported beam bridge and continuous beam bridge were given to investigate on the elastic bending capacity.In terms of the above method,elastic bending capacity was calculated by the formula of the positive-moment region and the negative-moment region,and its results were compared with the results of plastic bending capacity calculated by other relevant specifications.The results show that the calculation method of elastic bending capacity for steel-concrete composite beam bridges is feasible and reliable,which can be used inthe calculation of cross-section bending capacity for highway bridges.It can be concluded that the elastic bending capacity of the same composite beam is the lower limit of the cross-section bending capacity,while the plastic bending capacity is the upper limit of the cross-section bending capacity.