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

Xiao Guo,Shi Wang,Jielian Zheng,Tuo Shi,Nianchun Deng,Zheng Chen

doi:10.1155/2020/9710613

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.

Highlights

Concrete-filled steel tube (CFST) arch bridges have significant economic advantages at certain spans [1, 2]
E results obtained for closure temperature, effective temperature, and gradient temperature were compared with the Chinese standards and existing literature, resulting in a recommendation for the temperature calculation parameters that best represent the situation in Tibet. e recommended temperature parameters and the temperature parameters in the Chinese codes were used in a finite element model to calculate the temperature effect
The temperature parameters recommended in this study were obtained from actual test data; they are more applicable to engineering projects. erefore, when verifying the thermal effects in the design of CFST arch bridges, we suggest employing a refined finite element model (FEM) model that includes the arch base as well as the temperature parameters proposed in this study

Summary

Introduction

Concrete-filled steel tube (CFST) arch bridges have significant economic advantages at certain spans [1, 2]. E parameters required to calculate the design temperature load include the maximum effective temperature, minimum effective temperature, closure temperature, and gradient temperature. During the construction of a CFST arch bridge, the temperature field is affected by several factors. E China Technical Code for CFST Arch Bridges (GB 50923-2013) [5] (hereafter referred to as “Code 1”) and the China Highway Design Code for CFST Arch Bridges (JTGTD65-06-2015) [6] (hereafter referred to as “Code 2”) include specific provisions for the values of maximum and minimum effective temperature, closure temperature, and gradient temperature During the construction of a CFST arch bridge, the temperature field is affected by several factors. erefore, defining the calculation parameters under continuous and irregular temperature changes is a complex problem. e China Technical Code for CFST Arch Bridges (GB 50923-2013) [5] (hereafter referred to as “Code 1”) and the China Highway Design Code for CFST Arch Bridges (JTGTD65-06-2015) [6] (hereafter referred to as “Code 2”) include specific provisions for the values of maximum and minimum effective temperature, closure temperature, and gradient temperature

Methods

Results

Conclusion