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Computers and Concrete   Volume 20, Number 5, November 2017, pages 605-616
DOI: http://dx.doi.org/10.12989/cac.2017.20.5.605
 
An experimental and numerical study on temperature gradient and thermal stress of CFST truss girders under solar radiation
Guihan Peng, Shozo Nakamura, Xinqun Zhu, Qingxiong Wu and Hailiang Wang

 
Abstract     [Buy Article]
    Concrete filled steel tubular (CFST) composite girder is a new type of structures for bridge constructions. The existing design codes cannot be used to predict the thermal stress in the CFST truss girder structures under solar radiation. This study is to develop the temperature gradient curves for predicting thermal stress of the structure based on field and laboratory monitoring data. An in-field testing had been carried out on Ganhaizi Bridge for over two months. Thermal couples were installed at the cross section of the CFST truss girder and the continuous data was collected every 30 minutes. A typical temperature gradient mode was then extracted by comparing temperature distributions at different times. To further verify the temperature gradient mode and investigate the evolution of temperature fields, an outdoor experiment was conducted on a 1:8 scale bridge model, which was installed with both thermal couples and strain gauges. The main factors including solar radiation and ambient temperature on the different positions were studied. Laboratory results were consistent with that from the in-field data and temperature gradient curves were obtained from the in-field and laboratory data. The relationship between the strain difference at top and bottom surfaces of the concrete deck and its corresponding temperature change was also obtained and a method based on curve fitting was proposed to predict the thermal strain under elevated temperature. The thermal stress model for CFST composite girder was derived. By the proposed model, the thermal stress was obtained from the temperature gradient curves. The results using the proposed model were agreed well with that by finite element modelling.
 
Key Words
    temperature gradient; thermal stress; CFST composite girder; experimental study
 
Address
Guihan Peng:
1) School of Civil Engineering, Fuzhou University, Fuzhou, China
2) Department of Civil Engineering, Nagasaki University, Nagasaki, 852-8521, Japan
3) School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, NSW 2751, Australia
Shozo Nakamura: Department of Civil Engineering, Nagasaki University, Nagasaki, 852-8521, Japan
Xinqun Zhu: School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, NSW 2751, Australia
Qingxiong Wu: School of Civil Engineering, Fuzhou University, Fuzhou, China
Hailiang Wang: Tianjin Key Laboratory of Civil Structure Protection and Reinforcement, Tianjin Chengjian University, Tianjin 300384, China
 

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