Prestressed bridge deck responses to blast loads

Bridges are critical to most transportation systems, especially in times of crisis; however, as highly visible and accessible structures, they are also potential targets for terrorist attacks. An understanding of the performance of bridges subjected to blast loads is of critical importance to prevent progressive collapse of such structures that could lead to a catastrophic loss of life. The current research focuses on investigating the behaviour of bridge decks under blast loads from various explosions. The bridge in this investigation is the Sheikh Saad Bridge in Wassit Province, Iraq, whose deck is made of simply supported spans with two types of prestressed concrete girders. Both spans were accurately modelled using the finite element software Abaqus/Explicit, and both concrete and steel mechanical material properties were modified to match the properties under high strain rate conditions of the blast analysis. The latest element deletion technique of the built-in Concrete Damaged Plasticity (CDP) model (available since Abaqus 2019) was used to provide a realistic simulation of concrete damage and spalling. The model was separately subjected to various explosive charges placed at different locations above or below the bridge deck in order to determine the influence of size and location of blast on the bridge superstructure, detailed results and the relevant conclusions are thus presented. Overall, the modelling managed to successfully simulate the blast load response and the cracking propagation within the damaged deck components.