FRP/UHPFRC Composite Structural Systems for Elevated Rail Transit Structures

本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型梁。建议的单室箱梁使用纤维增强聚合物（FRP）和超高性能纤维增强混凝土（UHPFRC）作为协调。复合作用使每种材料能够减轻另一种材料的缺点，同时保持其自身的固有优势，从而使预制系统成为可能，该预制系统使用传统手段经济、容易和快速地建造，耐用，并且提供优于当前使用的结构系统的上级美学可能性。短期目标旨在填补验证拟议系统所需的以下知识空白：**1.开发并验证沿FRP和UHPFRC之间界面沿着传递剪力的可靠方法，以确保两种材料可在所有荷载水平下共同工作 **2。表征UHPFRC/FRP复合材料的抗疲劳性。由于列车的通过，轨道交通结构经受显著的应力循环。有必要确保复合材料不会因这些循环应力而发生显著的渐进损坏。** 3.表征UHPFRC/FRP复合材料的固有阻尼。轨道交通结构的设计必须最大限度地减少振动，以确保乘客的舒适性和车辆的正常运行。为了给设计提供充分的依据，需要对材料的固有阻尼进行适当的量化。** 4.为结构连续性开发关键结构细节，并在具有代表性的跨度和曲率范围内验证设计概念。**由于其重量轻，材料的有效消耗，以及相对于其他最近使用的结构系统的施工容易，拟议的梁提供了许多可能性，节省成本。其中最重要的包括制造和安装劳动力的显著减少，由于自重反应的减少以及由于其极轻的重量而降低的地震脆弱性，从而减少了桥墩和基础的尺寸和加固。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.