预应力混凝土斜箱梁桥多重耦合的静动力分析模型及其验证

Look for the appropriate longitudinal displacement function of shear lag for skewed box girder. Considering the shear lag and shear deformation effects, establish the static and dynamic multi-coupling models of flexure-torsion analysis for prestessed concrete box girder bridges. Considering the shear deformation effect, put forward the static and dynamic models of distortion analysis. Using the elastic mechanics method and numerical method, analyze the anti-distortion stiffnes in its own plane and anti-flexture stiffness in its out plane for skewed diaphrams, study the rational simplification of skewed diaphrams as the boundary conditions of restrainted torsion and distortion. Derive the transcendent equation about the vibrating frequency for the flexure-torsion vibration of skewed box girder bridge and the analytical method of vibrating frequencies to solve the determination of fundamental frequency for vehicle impact coefficient calculation. Analyze the mechanism of the creeping crawl phenomenon for skewed box girder bridge by using the distorting vibration. Discuss the influence of prestress on the shear lag of skewed box girder bridge. Based on the above studies, develop the computing program for multi-coupling analysis of skewed box grider bridge, verificate the suggested theories by using model tests and numerical analysis. Researching achievements can promote the formation and development of the multi-factors and multi-coupling computing theory, and reveal the pathogenic mechanism of the creeping crawl phenomenon caused by the distorting vibration.

寻找斜箱梁桥剪力滞纵向位移函数的合理形式；考虑剪力滞、剪切变形影响，建立预应力混凝土斜箱梁桥的弯曲- - -扭转多重耦合静动力分析模型；考虑剪切变形影响，建立畸变的静动力分析模型；利用《弹性力学》方法和数值方法，分析斜箱梁桥斜置横隔板自身平面内的抗畸变刚度和出平面的抗弯曲刚度，研究斜置横隔板作为斜箱梁桥约束扭转和畸变问题边界条件的合理简化形式；导出斜箱梁桥关于振动频率的弯曲- - -扭转振动的超越方程和解析方法，解决斜箱梁桥汽车冲击系数计算时的基频参数确定问题；开展畸变振动引起斜箱梁桥"蠕爬"现象的机理研究；探讨斜箱梁桥中预应力对剪力滞的影响。在上述研究的基础上，开发斜箱梁桥多重耦合分析程序，利用模型试验和数值方法，对提出的理论进行验证。项目成果将有助于斜箱梁桥多因素、多重耦合分析理论的形成和发展，揭示畸变振动导致斜箱梁桥"蠕爬现象"的致病机理。

利用Timoshenko梁理论，考虑剪切变形影响，建立了斜箱梁桥弯曲－剪切－扭转耦合静力分析模型，推导了单跨斜箱梁桥在集中竖向荷载、分布竖向荷载、集中弯矩、分布弯矩、集中扭矩和分布扭矩等多种常见荷载作用下的内力与变形计算公式，并对计算公式进行了实例和数值验证。经数值模拟，选择余弦函数作为斜箱梁桥剪力滞纵向位移函数，建立箱梁剪力滞分析方法。利用Timoshenko梁振动的修正理论和自由扭转振动理论，建立了斜箱梁桥弯－剪切－扭转耦合的振动方法，导出其动态刚度矩阵，结合斜支承边界条件，得到关于振动频率的超越方程和解析方法，解决了斜梁桥振动频率的计算问题，并利用时程分析方法研究斜箱梁桥冲击效应问题。对单跨斜箱梁桥进行数值分析和试验，研究多种斜交角条件下受集中力的应力和变形，检验斜箱梁桥的弯曲、剪切、扭转、剪力滞耦合的受力特征和相应的计算理论与计算模型。