桥梁冲击系数理论研究和应用进展

为推动桥梁冲击系数理论和应用研究的进一步深入开展，从计算方法、理论与数值模拟、现场试验与测试3个方面系统梳理国内外公路、城市和铁路桥梁工程领域冲击系数（或动力系数）的研究进展，并探讨其不足和发展趋势。计算方法方面，从桥梁冲击系数的定义出发，详细阐述典型国家最新规范冲击系数表达式；理论与数值模拟方面，分析了车辆参数、桥梁参数、桥面不平整度（或轨道不平顺）等对桥梁冲击系数的影响；现场试验与测试方面，分别综述了冲击系数的测试方法、数据处理手段及相关试验研究成果。研究表明：各国公路与铁路桥梁规范的冲击系数（动力系数）多由试验统计回归得到，但计算公式各不相同，公路桥梁冲击系数表达式较为简洁，铁路桥梁冲击系数计算公式较为复杂；有限元技术以及车-桥耦合振动理论的发展使得结构动力响应的数值模拟和求解更加精确化和高效化；中小跨径桥梁的整体冲击系数及大跨径桥梁中吊杆、拉索等局部构件的冲击系数是研究重点；影响冲击系数的各因素之间存在交叉影响，需要对不同结构、不同效应及不同截面的冲击系数进行现场试验测试和概率统计分析；设计规范中的冲击系数值不宜作为实际桥梁动力使用性能的直接评价指标；需要建立冲击系数试验分析技术的标准；非接触、抗干扰、高精度是今后冲击系数测试技术的发展方向。

State-of-the-art of Theory and Applications of Bridge Dynamic Load Allowance

To promote the theoretical development of bridge dynamic load allowance (DLA) and its application, a state-of-the-art review and the research progress of highway, municipal, and railway bridge DLA were summarized from three perspectives:calculation method, theoretical and numerical simulation analysis, field test study. The relevant shortcomings and development trends were also discussed. Bridge DLA calculation formulas in typical countries codes were elaborated according to the definition of DLA. In terms of theory and numerical simulation analysis, the effect of vehicle parameters, bridge parameters, deck roughness, track irregularity on DLA were analyzed. In the field test study, experimental methods, data processing methods, and DLA field test results were introduced. Results show that both highway bridge and railway DLA are derived by statistical regression analysis, but they have different provisions in different countries. In contrast, highway bridge DLA is relatively simple compared to railway bridge. The development of the finite element method and vehicle-bridge coupled vibration theory has made the numerical simulation of structural dynamic response more precise and efficient. Attention should be paid to the overall DLA of medium (or small) span bridges and the local DLA of long-span bridges, such as suspenders, cables, and other components. As several factors affect DLA and may be intertwined, it is necessary to conduct DLA field tests and statistical probability analysis of different structures, responses, and section positions. The DLA in the design code is not suitable for evaluating the dynamic performance of existing bridges. Moreover, a standard of the DLA field test and analysis technology must be established. Non-contact, anti-interference and high-precision DLA test technology are the most promising future development directions.