FRP/UHPFRC Composite Structural Systems for Elevated Rail Transit Structures

这项研究的长期目标是开发一种适用于承载轻轨交通的高架结构的新型轻质梁。建议的单室箱梁采用纤维增强聚合物(FRP)和超高性能纤维混凝土(UHPFRC)复合作用。复合作用使每种材料能够在保持自身固有优势的同时减少彼此的缺点，使预制系统成为可能，这种预制系统经济、容易和快速地使用传统方法建造，经久耐用，并提供优于目前使用的结构系统的美学可能性。短期目标旨在填补以下知识空白，以验证所建议的系统：1.开发和验证沿FRP和UHPFRC之间的界面传递剪力的可靠方法，以确保两种材料在所有水平的载荷下都能共同工作2.表征UHPFRC/FRP复合材料的疲劳抗力。由于列车的通过，轨道交通结构会受到显著的应力循环。有必要确保复合材料不会由于这些循环应力而遭受显著的渐进损伤。3.研究了UHPFRC/FRP复合材料的内耗特性。轨道交通结构的设计必须使振动最小化，以保证乘客的舒适性，并确保车辆的正常运行。为了为设计提供充分的基础，需要对材料的固有阻尼进行适当的量化。4.开发关键的结构细节以确保结构的连续性，并在具有代表性的跨度和曲率范围内验证设计概念。与其他最近使用的结构系统相比，由于其重量轻、材料消耗高、施工容易，拟议的梁提供了许多节省成本的可能性。其中最重要的包括显著减少制造和安装的劳动力，由于减少了恒载反应，减小了桥墩和基础的尺寸和加固，以及由于其极轻的重量而降低了地震易损性。因此，拟议的研究有可能大大降低轻轨系统的资本成本，从而鼓励在加拿大各城市建立和扩大快速交通网络。

The long-term goal of the proposed research is to develop a new type of lightweight girder suitable for elevated structures carrying light rail transit. The proposed single-cell box girder uses fibre reinforced polymer (FRP) and ultra high-performance fibre reinforced concrete (UHPFRC) acting compositely. Composite action enables each material to mitigate shortcomings in the other while maintaining its own intrinsic advantages, making possible a prefabricated system that is economical, easy and fast to construct using conventional means, durable, and which offers aesthetic possibilities superior to structural systems currently used. The short-term goals seek to fill the following gaps in knowledge necessary to validate the proposed system: 1. Develop and validate a reliable means of transferring shear force along the interface between FRP and UHPFRC to ensure that both materials can work together at all levels of load 2. Characterize the fatigue resistance of the UHPFRC/FRP composite. Rail transit structures are subject to significant cycles of stress due to the passage of trains. It is necessary to ensure that the composite material will not undergo significant progressive damage due to these cyclic stresses. 3. Characterize the intrinsic damping of the UHPFRC/FRP composite. Rail transit structures must be designed to minimize vibrations, for the comfort of passengers and to ensure proper operation of vehicles. To provide an adequate basis for design, a proper quantification of the intrinsic damping of the material is required. 4. Develop critical structural details for structural continuity and validate the design concept over a representative range of spans and curvatures. Due to its light weight, efficient consumption of materials, and ease of construction relative to other recently used structural systems, the proposed girder offers many possibilities for cost savings. The most important of these include a significant reduction in labour for both fabrication and erection, reduction in the size and reinforcement of piers and foundations due both to reductions in dead load reaction as well as reduced seismic vulnerability due to its extreme light weight. The proposed research thus has the potential to bring about a significant reduction in the capital costs of light rail systems and thus to encourage the creation and expansion of rapid transit networks in Canadian cities.