轻轨载荷下对预应力混凝土桥梁的评估

轻轨载荷下对预应力混凝土桥梁的评估(中文8600字,英文6000字)
摘要：本文对轻轨载荷下预应力混凝土桥梁的评价进行了介绍，相对于传统重轨和高速列车载荷下的桥梁而言，轻轨载荷预应力混凝土桥梁具有显著的未开发性。这里选择了科罗拉多州丹佛市的四座桥梁来研究静态和动态响应，包括弯曲行为、客运量、统计特性、活载荷分布、自然频率和用户舒适度。为了补充就地调查结果，开发了三维有限元模型。测得的列车载荷随高斯分布在统计上是稳定的，当其平均运行速度从每小时 32.9 提高到 49.0 英里（53 至 78 千米）时，载荷会增加 10.8%。实际上随机的载客量也会平均增加 23.3% 的火车载荷。 现有的活载荷分布设计方法不同于从现场获得的设计方法，这对于内部梁尤为明显。实际使用的偏转控制标准也不适用。根据桥梁的偏转和频率，来评估轻轨系统（行人和乘客）的使用舒适度。获取和归纳统计特性，在制定设计指南时很有价值。

关键词：桥梁; 评估; 轻轨运输; 活载荷; 建模。

Evaluation of Prestressed Concrete Bridges under Light Rail Loading
Abstract:
This paper presents the evaluation of prestressed concrete bridges carrying light rail loading, which is significantly unexplored relative to bridges subjected to conventional heavy-haul and highspeed trains. Four bridges in Denver, CO, are selected to investigate static and dynamic responses, including flexural behavior, passenger occupancy, statistical properties, live load distributions, natural frequencies, and user comfort. Three-dimensional finite element models are developed to complement in-place findings. The measured train loadings are statistically stable along with Gaussian distributions and increase by 10.8% when their average operating speed rises from 32.9 to 49.0 mph (53 to 78 km/h). Passenger loading that is stochastic in nature also increases the train loading by 23.3%, on average. Existing design approaches for live load distributions deviate from those attained from the field, which is particularly noticeable for interior girders. Deflection control criteria used in practice are not applicable either. In accordance with the deflection and frequency of the bridges, the user comfort of light rail systems (pedestrians and passengers) is assessed. Statistical properties are acquired and characterized, which are valuable when developing design guidelines.
Keywords: bridge; evaluation; light rail transit; live load; modeling.