Blast Resistance of Steel Orthotropic Bridge Decks

Abstract

The main objectives of this study were to: (1) study the response of bridge decks to blast effects resulting from an explosion on the deck; and (2) develop efficient technologies and systems that can be used in design and construction of bridges to enable them to survive blast attacks without collapse. To understand the actual behavior of orthotropic decks subjected to blast loads, typical steel orthotropic decks used in long-span, cable-supported bridges were modeled using MSC/Dytran nonlinear finite-element analysis software, and the models were subjected to simulated explosions occurring on the deck. The parameters that varied in the analyses were the size of the explosive device in terms of equivalent TNT, the axial compressive force present in the deck, and the high-strain-rate mechanical properties of the material of the steel used in the orthotropic decks. Through dynamic analyses, the behavior of the orthotropic decks under blast loads was established and their failure modes were identified. Also, implementation of a new and effective blast-resistant technology, the “fuse system,” was simulated. In this system, to limit the effect of a blast to a localized area of the bridge and to prevent catastrophic progressive collapse of the span, special “fuses” (comparatively weaker structural elements) are placed between two deck segments.