【作者】 史奇彬；

【导师】 宋一凡；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 目前对于大跨径的复杂桥型冲击系数研究仍处于探索阶段,尤其是对刚构-连续梁组合体系桥梁冲击系数的研究较少。中外学者对冲击系数的研究大多仅限于单因素的影响分析。《公路桥涵设计通用规范》(JTG D60-2004)中冲击系数计算公式仅考虑结构基频惟一因素,并没有考虑车辆的动力性能及路面的不平整度等因素。因此,研究刚构-连续梁组合体系的冲击系数具有重要的理论意义与工程实用价值。本文以陕西某刚构-连续梁组合体系为依托工程,建立了4跨～6跨墩脚固结和桩土耦合作用六种主要桥梁分析模型,考虑3轴二系悬挂弹簧车辆模型,通过正交试验分析,对其展开了冲击系数的敏感性参数研究。共分为24种工况,考虑了车桥频率比、路面不平整度、车体质量、桥梁跨数、行车速度、车辆行驶方式、桥梁刚度、车辆阻尼比和下部结构计算模型这9个影响因素,给出了影响该桥主梁控制截面挠度、弯矩和主墩控制截面水平位移、弯矩冲击系数的敏感性参数及其最大值的参数组合。在此基础上,通过最大值参数组合工况的计算分析,绘制了该桥的冲击系数最大值包络曲线,给出了刚构-连续梁组合体系的冲击系数范围。分析表明,车辆行驶速度、桥梁结构频率和桥面不平度是该类桥梁冲击系数的主要影响因素。以路面不平整度为分项标准,车速和桥梁频率为自变量,通过回归分析,首次给出了针对A、B、C三种路面等级的刚构-连续梁组合体系主梁和主墩冲击系数近似计算公式,并用该公式与各国规范进行了对比分析。其研究结论可供该类桥梁的设计参考,也可为其他桥梁动力特性分析提供借鉴。更多还原

【Abstract】 Currently, the research about impact coefficient of complex long-span bridge is still in exploration stage, the research carried out for the composite structure of the rigid frame and continuous beam was especially less. Almost all the researches of impact coefficient at home and abroad are confined to single factor analysis. In the General Code for Design of Highway Bridges and Culverts (JTG D60-2004), the calculation formula of impact coefficient only considers the single factor of basic structure frequency without vehicle dynamic performance and pavement unevenness. Therefore, study on the impact coefficient of composite structure of the rigid frame and continuous beam has very important academic significance and practical value.This paper based on a composite structure of the rigid frame and continuous beam in Shaanxi province, building 6 different models from 4 spans to 6 spans, which contains the effects of pier-bottom consolidation and pile-earth coupling. In order to discuss the sensitivity parameters of impact coefficient, three axes two-line suspension vehicle model has been used and the analysis of the orthogonal experiment has employed. The calculation divided into 24 conditions, contains nine factors including the axle frequency ratio, pavement unevenness, body quality, bridge span number, driving speed, vehicle driving mode, bridge stiffness, damping ratio and the substructure calculation. The analysis shows the deflection of girder control section, bending moment and horizontal displacement of main piers control section, the bending moment impact coefficient parameter sensitivity and its maximum assembly parameter. Based on the above factors, the maximum impact coefficient curves are given and impact coefficient range of composite structure of the rigid frame and continuous beam has been provided according to the analysis results in the maximum parameters load combinations condition. The result shows that the vehicle speed, basic structure frequency and pavement unevenness are main influencing factors for the impact coefficient. In the article, pavement unevenness is considered to be the sub-item standard, speed and basic structure frequency is the argument. By means of regression analysis, the impact coefficient approximate formulas are given for the first time to direct at A, B and C three surface levels for the girder and main piers of the composite structure of the rigid frame and continuous beam, and the formula is compared with prescripts and standards of other countries to obtain its advantages and disadvantages.The research conclusions can be used for the design of the rigid frame and continuous beam, and also can be used as reference for dynamic analysis in other bridges.更多还原