风-随机车流-桥梁系统气动干扰、精细分析和评价准则研究

The wind-random traffic flow-bridge system which references to multi-directional and multi-disciplinary cross is a time-dependent coupling vibration system under the action of multiple random excitations. In this study, the experimental technique and analytical method of determining vehicle steady and unsteady aerodynamic forces are firstly developed when vehicles overtake and meet under strong wind circumstance, and then aerodynamic interference characteristics of vehicle-bridge system can also be ascertained. Meanwhile, a fully functional wind-random traffic flow-bridge simulation analysis system is established with the research on loading method of wind load and vehicle load on steel truss stiffened beam cross-section and coupling mechanism as well as the establishment of vehicle-bridge system coupling vibration relationship under wind environment, which is the research foundation of dynamic visualization. According to the excitation characteristic and its own characteristic of vehicle-bridge system, probabilistic analysis of vehicle driving safety and comfort assessment method are established by adopting reliability theory and probability and statistics methods. Then the evaluation index of bridges in normal operation and extreme worst-case under combined action of wind and traffic load is respectively proposed with corresponding evaluation criteria set up. The proposed study will provide theoretical foundation for driving safety, driving comfort as well as structural safety analysis and evaluation of long-span river/sea crossing bridges and long-span steel truss suspension bridge across deep gorge. And it will also be important to promote scientific research level of stimulation analysis for bridge health monitoring system and other related study.

风-随机车流-桥梁系统是多重随机激励作用下的时变耦合振动系统，是多方向、多学科的交叉。本课题首先发展确定强风环境下超车和会车时的车辆定常及非定常气动荷载的实验技术和分析方法，探明超车和会车时的车桥系统气动干扰特性；通过风环境下汽车-桥梁系统耦合振动关系建立及耦合机理研究、钢桁加劲梁断面风荷载和车辆荷载加载方法研究，建立功能完善的风-随机车流-桥梁仿真分析系统，进而实现动态可视化；根据车桥系统输入激励特性和自身特性，采用概率统计方法和可靠度理论，建立车辆安全概率分析和舒适性评价方法，分别提出桥梁在风和交通荷载联合作用下正常运营和极端最不利情况下的评价指标，建立相应评价准则。通过本课题的研究将为强风环境下长大跨江跨海大桥以及山区跨越深切峡谷大跨钢桁架悬索桥的行车安全、驾驶舒适性以及结构安全分析和评价提供理论依据，还将对提升桥梁健康监测系统仿真分析及相关科学的研究水平具有极为重要的意义。

风-随机车流-桥梁系统是多重随机激励作用下的时变耦合振动系统，是多方向、多学科的交叉。采用风洞试验方法，获取考虑气动干扰的车辆气动力系数，探明了风-车-桥系统的气动干扰效应及机理，并输入多工况下的车辆气动力系数于已有风-车-桥系统，明确了气动干扰对车辆行车安全性和舒适性的影响；针对目前分析系统主要针对单主梁模型，不能实现风荷载精确加载方面的不足，提出了钢桁加劲梁断面风荷载等效加载和梁格法车桥耦合振动分析方法，并建立了大跨钢桁悬索桥风-车-桥分析系统，开展了风和随机车流对钢桁结构桥梁响应影响研究；基于微观交通流模型，对随机车流模拟进一步精细化，从微观交通流模拟和相对应全耦合风-微观交通流-桥梁数值分析框架两个角度对现有风-车-桥耦合振动系统进行精细化改进，并运用OpenGL函数库实现了风环境下随机车流动态过桥的可视化显示；采用斜风分解理论，建立了斜风-车-桥分析系统，并依据提出的行车安全性和舒适性评价指标和评价准则对多风偏角下的行车安全性和舒适性进行评价。本研究建立的分析系统，从气动干扰、风偏角、梁格法加载和微观交通流四个方面对风-车-桥系统进行了全面精细化，使得建立的风-车-桥系统进一步实现系统的高真实度模拟和系统响应的精确分析。