Blast-resistance performance of bridge jacking support subjected to up-deck blast load

The hydraulic synchronous jacking technology has been widely applied in bridge renovation and new bridge construction. As an important component of this technology, jacking support is widely used. In this study, the blast-resistance performance of bridge jacking support under up-deck explosion is studied through numerical simulation via LS-DYNA. The coupled effect of self-weight of bridge superstructure and TNT detonation is considered. The results show that the blast-resistance performance of jacking support is related to the standoff distance of TNT detonation and the local stiffness of the jacking support. The near-field explosion induces severe localized damage to the bridge superstructure and transverse jacking support, with buckling and permanent deformation observed due to high impulsive force. In contrast, far-field explosion leads to resonant vibration in longitudinal jacking support with low stiffness. Under the action of near-field explosion, the bridge upper deck around the centerline of the bridge is significantly flexural damaged. With the increase of scaled distance of TNT detonation, the upper deck around the bridge web plate is shear damaged, and the damage of bridge bottom slab is more severe. With the increase of standoff distance, the main control factor of jacking support deformation is changed from the standoff distance of TNT detonation to the low stiffness of the support component.