Development of a lamella‐model to evaluate stresses caused by hot asphalt installation

On road‐bridges hot asphalt is installed to provide a level and waterproof surface. That wearing surface, however, needs occasional renewal. On a number of steel highway‐bridges it has been observed that after such asphalt‐renewal fatigue‐cracks have increasingly occurred at the welds of orthotropic bridge‐decks. The German Federal Highway Research Institute has assigned a research project to RWTH Aachen University to evaluate the response of steel‐bridges to time‐ and location‐dependent, nonlinear temperature profiles. Since FEM‐software with the needed level of detailing could not provide solutions for long large‐span bridges, a software‐based lamella‐model was developed. This model enables the partition of the bridge into rectangular beam‐lamella, precisely considers the nonlinear temperature and calculates the inner forces and displacements along the bridge. This paper presents the theoretical background of the lamella‐program as well as results calculated exemplary for a 742m‐long German highway‐bridge including validation with in situ temperature and strain measurements during asphalting.