Non-uniform temperature effect on concrete rectangular hollow bridge pier: Insights from long-term monitoring data

Non-uniform temperature action can cause cracks, damages, and other issues (or diseases) on bridges, which have serious impacts on the durability and even safety of bridges. At present, both domestic and international bridge design codes predominantly focus on addressing non-uniform temperature effects in relation to bridge decks and box girders. There has been comparatively less research and provision for addressing non-uniform temperature effects on bridge piers. In view of this, we conducted continuous temperature testing over a period of 212 days on the cross-section of the thin-walled hollow pier of Changjiahe Bridge. The aim was to systematically analyze the rectangular hollow pier non-uniform temperature field change rule. The results show that the depth of influence of day-to-day cyclic changes in air temperature and solar radiation is approximately 50 cm or less. The most unfavorable condition of positive temperature difference can easily occur when solar radiation is strong during continuous sunny days; the most unfavorable condition of negative temperature difference occurs when radiative cooling and strong cooling weather combine. A power function distribution curve of temperature difference along the direction of wall thickness is established, and the fitting accuracy is found to be higher than the commonly used exponential function curve. Subsequently, we introduced two methods to derive the maximum temperature difference of concrete rectangular hollow piers based on meteorological conditions. Method 1 involves obtaining the maximum daily difference of wall surface temperature difference using a regression formula, and then calculating the maximum positive temperature difference of wall surface according to the proportion of the maximum positive temperature difference of wall surface in the daily difference of wall surface temperature difference. Method 2 involves calculating the maximum positive temperature difference of wall surface over a period of time using a regression formula directly with the data of daily difference of air temperature. Through trial calculations during the observation period, the prediction accuracy of method 1 was found to be slightly better than that of method 2.