Since the collapse of the WTC towers in September 2001, concern about the protection of important military structures and government buildings against blast loading has increased significantly. Recently, increasing terrorist attacks on bridges have illustrated the vulnerabilities of this type of transportation infrastructure. Although some of the information on blast-resistant design for these simple structures could be applied to buildings, separate blast-resistant design principles must be developed separately for bridge infrastructures as their design principles and load-carrying mechanisms are very different from those of buildings. Therefore it is necessary to investigate the dynamic behavior of various bridge types under blast load effects....[ Read more ]

Since the collapse of the WTC towers in September 2001, concern about the protection of important military structures and government buildings against blast loading has increased significantly. Recently, increasing terrorist attacks on bridges have illustrated the vulnerabilities of this type of transportation infrastructure. Although some of the information on blast-resistant design for these simple structures could be applied to buildings, separate blast-resistant design principles must be developed separately for bridge infrastructures as their design principles and load-carrying mechanisms are very different from those of buildings. Therefore it is necessary to investigate the dynamic behavior of various bridge types under blast load effects.

Due to the cost and security constraints, it is impossible to obtain the whole structural response by testing a real bridge, so in recent years, a fully coupled fluid-structure interaction model was developed to simulate the blast wave propagation process and its interaction with the structures, and has become the most effective way to analyze blast loading effects. To solve the complicated computational algorithm and computer resource limitations involved in using this mode, a Multi-Euler domain method is proposed in this study using an explicit finite element method with high accuracy and efficiency.

This thesis focuses on the study of the performance of three modern reinforced concrete bridge types under blast loading: slab-on-girder bridge, box-girder bridge and long-span cable-stayed bridge. To obtain accurate non-linear behavior, detailed 3D finite element models were established. Parametric studies were also carried out in terms of the TNT charge weight and standoff distance to model different blast hazards. Both the critical bridge component and the global response were investigated to determine the critical location and charge weight, and provide a fundamental understanding of protection strategies. Based on the simulation results and observations, recommendations for bridge design against blast loads were also proposed.