预弯组合梁截面抗弯承载力计算方法的再研究

Restudy of calculation method of cross-section bending capacity for preflex composite beams

为简化现行标准中预弯组合梁抗弯承载力计算方法,基于塑性理论,对塑性抗弯承载力计算方法进行推导,并从安全性出发,最终提出了一种预弯组合梁的抗弯承载力简化计算方法。采用该简化计算方法、现行标准的弹塑性计算方法及塑性计算方法分别对7根试验梁的抗弯承载力进行计算,采用通用有限元软件Abaqus对预弯组合梁进行非线性有限元分析,并将计算结果与试验实测值进行对比,验证所提出的抗弯承载力简化计算方法的准确性。结果表明:采用所提出的简化方法与弹塑性方法计算得到的7根试验梁承载力差值均低于2%;计算值略小于试验实测值和有限元模拟值,且吻合较好,可满足实际工程计算精度及安全性的需要。所提出的抗弯承载力简化计算方法较现有标准方法及塑性方法有所简化,能用于预弯预应力组合梁截面抗弯承载力计算,在此研究基础上,给出了采用该方法计算预弯组合简支梁桥承载力计算示例,可供实际工程参考。

To simplify the calculation method of bending capacity for preflexed composite beams in current standard, the calculation method of plastic bending capacity was deduced based on the theory of plasticity, and a simplified calculation method of bending capacity for preflexed composite beams was put forward from the aspect of security. The bending capacity of seven experimental beams was calculated by the simplified calculation method, the elastoplastic calculation method in the standard, and a deduced calculation plastic method. Nonlinear finite element analysis was carried out on the preflex beams by the general finite element analysis software Abaqus, and the calculated results were compared with measured results to verify the accuracy of the proposed calculation method. Results show that the differences between the results calculated by the proposed method and those by the elastoplastic method were less than 2% for the seven experimental beams. The calculated values were slightly smaller than the measured and simulated values and showed good agreement, which could satisfy the requirements of calculation accuracy and safety in practical projects. The proposed simplified calculation method of bending capacity was simpler than the method in existing standards and the plastic method, which could be used in the calculation of cross-section bending capacity for preflex beam bridges. Based on the research results, an example of preflex simply supported beam bridge calculated by the proposed method was given, which could provide reference for practical projects.