Investigation of seismicperformance of viaducts considering traffic loadings and safety of moving whieles

本文采用三维动力响应分析方法，研究了高速公路桥梁、新干线高架桥和单轨桥梁在交通荷载作用下的地震反应，并考虑了高概率中地震发生时桥车列相互作用的影响。对公路桥梁和新干线列车车辆在地震作用下的运行稳定性进行了研究。为了实现本文的研究目的，将自卸车、新干线列车车厢和单轨列车车厢分别理想化为12自由度和15自由度的离散刚体系统。这些车辆和火车模型包含了地震期间与横向运动有关的运动，如摇摆和偏航运动。数值分析结果表明，重型车辆和火车的存在，同时也是动力系统，会影响桥梁的地震反应：车辆和火车的动力系统在地震时对桥梁起到了更大的阻尼作用。这一事实特别表明，包括单轨桥梁在内的现有铁路设计将火车视为额外质量，结果是保守的。还观察到，在公路桥梁上移动的车辆可能比静止的车辆更频繁地经历滑移。此外，在地震中，高架桥上的车辆比公路上的车辆更容易发生滑动。利用脱轨系数对新干线列车进行脱轨评价表明，脱轨系数随列车速度的增加而增大。对单轨列车的地震反应进行了研究，结果表明，先进桥梁的地震反应比传统单轨桥梁要大，这主要是由于结构体系的简化和主梁重量的增加。列车在先进桥梁上的动力响应比在传统桥梁上的动力响应更大。少

This study is intended to investigate the seismic response of highway bridges, Shinkansen viaducts and monorail bridges under traffic loads using three-dimensional dynamic response analysis, which even considers bridge-vehicle/train interaction subjected to moderate earthquakes occurring with high probability. The running stability of vehicles on highway bridges and Shinkansen train during earthquakes is also examined. To realize the purpose of this study, a dump truck and the car of train of Shinkansen and Monorail are respectively idealized as a discrete rigid multi-body system with 12 degrees of freedom (DOFs) and 15DOFs. Those vehicle and train models comprise the motions relating to the lateral direction, such as sway and yawing motions, during earthquakes.Observations through a numerical analysis demonstrate that the existence of heavy vehicles and trains, which are also dynamic system, can affect the seismic response of bridges: the dynamic system of vehicles and trains acts as … More a damper on the bridges during earthquakes. That fact especially shows that the existing railway design including monorail bridges, which considers a train as additional mass, yields a conservative result. It is also observed that moving vehicles on highway bridges may experience the slip more frequently in comparison with stationary vehicles. Moreover, during earthquakes vehicles on viaducts becomes easy to slip comparing with those on roadways. The derailment assessment of Shinalkansen train using the derailment coefficient clarifies that the derailment coefficient increases with increasing train speeds. Investigations for the seismic response of monorail trains reveal that the seismic responses of the advanced bridges are greater than those of the conventional monorail bridges because of the simplified structural system and increased girder weight that is attributable to composite girders of the advanced bridges. Moreover, the train on the advanced bridge shows greater dynamic response than that on the conventional bridge. Less