Temperature Effects on Strain Influence Lines and Dynamic Load Factors in a Steel-Truss Arch Railway Bridge Using Adaptive FIR Filtering

The dynamic strain response due to the passing trains is one of the most important indexes in the design and maintenance of long-span steel-truss arch railway bridges. The strain influence line (IL) and dynamic load factor (DLF) are used to characterize the vehicle-induced strain response of bridge members. Temperature effects on ILs and DLFs of strain response due to high-speed trains in various bridge structural members are investigated. An adaptive finite impulse response (FIR) filter is implemented to obtain the strain IL and DLF for the response of various structural members of the Dashengguan Yangtze River Bridge using data from strain sensors that are part of the bridge structural health monitoring (SHM) system. Relationships between the strain ILs and DLFs and temperature are obtained for various members. The analysis reveals that (1)the DLFs for the short hangers require further study; (2)the effect of temperature on the ILs of each member in the subject bridge can be described by polynomials; and (3)the DLFs of the majority of the structural members are not related to temperature. Recommendations to improve the design, maintenance, and long-term monitoring of steel-truss arch bridges are provided.