Design, construction and dynamic analysis of a laboratory-scale FRP composite footbridge.

Abstract

Pedestrian loading on flexible structures such as footbridges, grandstands and lightweight floors is an area, which is receiving significant attention from the research community of late. Of particular interest is the interaction between the pedestrian loading and the structural response of the loaded structure. This interest has been instigated by several noteworthy examples of high-profile structures, which have vibrated considerably under dynamic pedestrian loading under specific conditions. From a structural engineer’s perspective, recent developments in design and construction materials have led to lighter, longer spans than previously achieved, which may contribute to increased susceptibility to particular dynamic loads. Separately, fibre reinforced polymer (FRP) composites represent the greatest innovation in structural materials in the recent past. These materials offer advantages over traditional materials such as steel, concrete and timber, which include improved durability performance, flexibility of design, improved quality assurance in production, potential for use of recycled materials, etc. However, perhaps the most significant advantage for civil engineering structures is the increased strength to weight ratios offered in comparison to more traditional materials. These materials are growing in popularity in innovative structures and are gaining growing acceptance among designers internationally. One of the major barriers to increased use is the lack of design guidance on the use of these materials in load-bearing structures. The authors are currently researching pedestrian-induced loading on flexible structures and also the use of FRP materials in construction. This paper describes the amalgamation of these two discrete research interests by detailing the design and dynamic analysis of a laboratory-scale FRP composite footbridge. The bridge was specifically designed to have a natural frequency within the range excitable by human walking. It will be used to investigate the interaction between loads produced by walking and running pedestrians and the vibration of the structure which they are traversing.