Investigations of Thermal Effects on Retrofitted Bosphorus Bridge: Comparison between Diagonal and Vertical Hanger Configurations

Abstract

Bosphorus Bridge which was constructed in 1973 recently has undergone a retrofitting process. In the process, original diagonal hanger configuration has changed into the vertical configuration. Literature includes numerous studies which address almost every aspect of the structural analysis of the diagonal case but lacks any study concerning the recent vertical configuration. In this study, an advanced 3D finite element model (FEM) of the complete bridge has been developed with intricate details. The model includes detailed structural components such as stiffeners with realistic 3D towers and also incorporates a frictional contact model for the cable saddle interaction – a unique feature among the model realm. Both diagonal and vertical configurations are taken into consideration with an automated script in the framework of a commercial FEM package. In order to demonstrate the effectiveness and usefulness of the model, we have opted to work on thermal effects on the bridge among various other possible research directions which can be tractable by the model such as vehicle interactions, forced vibrations, fatigue etc. We have studied the effects of homogeneous heating of the deck structure and various parts of the towers for both configurations. Variations on the stress distributions of the deck structure and cable forces are investigated. It is seen that diagonal configuration is more sensitive to the thermal effects and thus the related fatigue.