Study on Lightweight Truss-type Composite Temporary Bridges for Disaster Relief

Study on Lightweight Truss-type Composite Temporary Bridges for Disaster Relief

Typhoons and earthquakes, which occur frequently in Taiwan, often lead to the washout or collapse of river bridges, subsequently causing traffic interruptions. When a bridge structure loses workability, constructing a temporary rescue bridge is effective for disaster relief. In this study, a truss-type composite temporary rescue bridge is proposed to improve the stiffness of longer span (50 m) bridges. A 50-m span asymmetric self-anchored truss-type cable-stayed bridge is designed and experimentally validated. The rapid assembly technology proposed for construction is validated via simulations. It is found that the assembly process improved worker safety during bridge construction and shortened the assembly duration. Two construction processes, namely the cantilever erection method and the incremental launching method, are compared to improve worker safety. The results of this study indicate that (1) the truss-type segmental composite bridge can improve the stiffness of a 50-m span temporary rescue bridge, thus meeting the required deflection-to-span ratio, (2) rapid assembly technology for bridge construction significantly improved worker safety and shortened assembly time of the temporary rescue bridge, (3) the incremental launching method had greater operational efficiency than the cantilever erection method, (4) the incremental launching method can avoid bridge construction over rivers, thus providing better worker safety, and (5) considering construction safety, the maximum allowable wind speed for construction should be set to maintain worker safety.