Innovative Application of Prefabs in Earthquake-Resistant Bridge Construction

Abstract

Abstract Pre-stressed concrete, widely known to be a prefabricated structure (Prefab in short) has long been accepted in statically loaded structures. Thus, we have seen the construction of pre-stressed concrete bridges, dams, pipelines, reservoirs and various structures including more recently atomic reactor pressure vessels. In recent years pre-stressed concrete has been specially used in seismic resistant structures. Just like any other new material, it will attract criticism and comment, sometimes by people who may not have had the opportunity of full investigation of the material in question. Furthermore, today engineers are more critical of any new material or technique and will seldom accept them unless conclusive evidence of their performance can be produced. More extensive use of precast concrete components, which are fabricated off-site and then connected on-site, could allow bridges, vulnerable to earthquakes, has to be constructed more frequently. The increased use of precast components in bridges also promises to increase work-zone safety and decrease environmental impacts for bridges that span waterways. Because precast systems contain connections, and connections are typically vulnerable to seismic loading, a qualitative evaluation of the expected seismic performance of each system is deemed necessary. Precast concrete substructure systems have received much less attention than have superstructure systems- both of buildings and bridges. The use of precast substructure components can provide significant time savings by eliminating the time needed to erect formwork, tie steel, and cure concrete in the substructure. The success of the system depends strongly on the connections, which must have good seismic resistance, have tolerances that allow easy assembly, and be suitable for rapid construction. This paper discusses precast concrete systems that have been used for rapid bridge construction, especially in the earthquake affected/prone area. The paper also identifies key features that are important for successful precast concrete system applications in bridge construction and repairing in high to medium seismic zones.