Experimental Investigation of Blast Performance of Seismically Resistant Bridge Piers and Dynamic Analyses

Keywords: Blast performance.  Highway infrastructure.  Earthquake-resistant designs.  Bridges.  Piers.  Concrete-filled steel tube (CFST) columns.  Reinforced concrete (RC).  Ductility.  Steel jackets.  Retrofitting.  Seismic design codes.

Abstract: This report focuses on the protection of highway bridges against earthquake and blast hazards.  The results of a previously developed and experimentally validated multi-hazard bridge pier concept consisting of a multi-column pier bent with Concrete-Filled Steel Tube (CFST) columns are briefly presented (see MCEER-07-0005).  The performance of the CFST columns is compared to the blast resistance of ductile reinforced concrete (RC) columns and non-ductile RC columns retrofitted with steel jackets, detailed in accordance to current seismic design codes and practices.  This report describes the details of the design process and the experimental observations of the prototype bridge pier bent constructed using conventional and retrofitted seismic resistant RC columns.  The results from blast experiments are compared with results obtained using simplified analysis methods.  Nonlinear dynamic response history analyses are performed to simulate and better understand the behavior of CFST columns under blast loading.  The tests on conventional and steel jacket retrofitted seismic resistant RC columns demonstrated the non-ductile behavior of the RC columns under blast loading and that the columns failed in direct shear at their base.  Based on experimental and analytical observations, shape factors for the blast pressures acting on circular columns are established.