Numerical Investigation of Thermal Effects on Concrete Bridges: Insights from Frame and Shell Modeling

Bridges are essential structural components of transportation networks, and their performance is significantly influenced by temperature variations. Thermal expansion and contraction can induce stresses that affect structural stability, necessitating accurate modeling techniques for design and maintenance. This study investigates the thermal behavior of a three-span continuous box girder bridge using two different numerical modeling approaches: the Frame Element model and the Shell Element model. The research evaluates the effects of uniform temperature conditions (20°C) and a temperature gradient of ±5°C, focusing on bending moments, normal forces, and fiber stresses. Results indicate that the Shell Element model predicts bending moments and stresses 20-40% lower than the Frame Element model under uniform temperature conditions. However, when subjected to a temperature gradient of +5°C, variations in results increase, highlighting the Shell Element model’s sensitivity to localized stress distributions. The findings suggest that while the Shell Element model is more reliable for capturing detailed thermal effects, it may be more complicated and takes more time in analysis than the Frame Model. These insights contribute to the refinement of bridge design methodologies and maintenance strategies, ensuring the structural resilience of concrete bridges in diverse climatic conditions.