Experimental investigation of multihazard resistant bridge piers having concrete-filled steel tube under blast loading

This paper presents the development and experimental validation of a multizard bridge pier concept, i.e., a bridge pier system capable of providing an adequate level of protection against collapse under seismic and blast loading (but not acting simultaneously). A multicolumn pier-bent with concrete-filled steel tube (CFST) columns is the proposed concept, and the adequacy of this system is experimentally investigated under blast loading. This paper describes simplified blast analysis, multihazard design of bridge piers, and blast experimental program and results. Additionally, the results from the blast experiments are compared with the results from the simplified method of analysis considering an equivalent single degree of freedom system having an elastic-perfectly plastic behavior. It is found that prototype bridge CFST columns can be designed to provide both satisfactory seismic performance and adequate blast resistance. It is also shown that the CFST columns exhibited a ductile behavior under blast load in a series of tests at 14 scale. Maximum deformation of the columns could be calculated using simplified analysis considering a factor to account for the reduction of pressures on the circular column and determined from this experimental program.