Nowadays few current studies on blast effects are executed with real bridge structures for economic and social reasons. This paper analyzes the blast loadings on concrete bridges and offers five characteristics: uncertainty, significant structural response, mechanic differences, rapid overpressure decay, and confinement effects. Then with the further study for blast loads fundamentals and real bridge inspection, the damage forms for concrete bridges under blast loadings have been obtained, i.e. localized damage are the main structural damages and fragmentation loads can be neglected when explosions detonated above deck. Furthermore, due to the collapse or fallen of the structural components or segments secondary damages, like collisions and restraining blocks destruction, must be kept an eye on.
A new rational peak overpressure formula about scale distance has been summarized by comparing differences of domestic and foreign scholars’ empirical formula. AUTODYN has been used to simulate the shock wave in the air by taking different mesh sizes. Comparing the numerical simulation results and empirical formula results, only when the scale distance is too small, two results about peak overpressure have certain deviation. But both results about positive pressure time are similar.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.