Effect of temperature loading on the performance of a prestressed concrete bridge in Oklahoma: Probabilistic modelling

Spatial and temporal temperature variations in bridge structures due to changes in the surrounding climate cause bridge expansion which, if restrained, may induce secondary stresses in structures. Temperature effects have always been considered to be one of the most critical issues in the performance of traditional Prestressed Concrete (PC) bridges. In order to (1) develop an efficient temperature loading model for predicting bridge temperature-induced response; and (2) develop guidelines addressing the effects of temperature loading in reliability-based condition evaluation, numerical and analytical studies were conducted on a PC girder bridge in Oklahoma, USA. This paper focuses on the probabilistic modelling of temperature loading. Firstly, a heat transfer model was established using hourly input climate data to estimate the temperature distribution, and compared with monitoring counterparts for calibration. Secondly, the validated analytical model was employed to investigate the effects of thermal properties of concrete by a parametric analysis; Based on extreme environmental conditions from the 20-year climatic data and analytical results, probabilistic models of uniformly distributed temperature fields and temperature gradients were proposed, and the temperature loading value with a 75-year return period was determined and compared with recommended value in the AASHTO LRFD. The proposed temperature loading model can aid engineers in predicting the thermal behavior of PC bridges in Oklahoma, USA.