Temperature Load Parameters and Thermal Effects of a Long‐Span Concrete‐Filled Steel Tube Arch Bridge in Tibet

Abstract

Zangmu Bridge is a concrete‐filled steel tube (CFST) arch bridge along the Sichuan‐Tibet railway in Tibet, with a main span of 430 m. Owing to the unique temperature conditions in Tibet, there have been no large‐scale experimental studies on the thermal load design of CFST bridges in this area. Therefore, to determine the thermal load calculation parameters and thermal effects of Zangmu Bridge, a long‐term continuous field test was conducted to measure the temperature variations in a test arch with the same pipe diameter. The test results were then compared with current design specifications and relevant literature. Finally, the thermal effects in a CFST arch bridge were analysed using the finite element method. According to the results, the following recommendations were made: (1) the average temperature of concrete in the pipe after the formation of concrete strength should be used to calculate the closure temperature of CFST arch bridges in Tibet; however, the standard calculation formula was still applicable; (2) the daily average temperature in extreme weather should be taken as the maximum and minimum effective temperature; (3) we presented recommended values for the influence range and gradient temperature for a single large‐diameter pipe; and (4) a refined finite element model that included the arch base should be used to verify the temperature effects during bridge design.