Bridges support important economic lifelines for cities throughout the U.S. As with other critical components of the infrastructure, they are vulnerable to a variety of threats, including from terrorist attacks. MCEER is investigating how technologies developed to prevent damage due to earthquakes can be adapted for protection against other threats.
One project currently underway is the development of a new design for bridge piers. The design, intended for use in small and medium-sized bridges, uses corrosion resistant steel tubes filled with concrete, but without reinforcing bars. The steel and concrete bind together, forming a composite structure, which provides the piers with superior strength and ductility. Additional structural shapes are imbedded in the concrete footing and pier cap to resist the large flexural forces that can develop at the base and top of the bridge piers.
The design was field tested this past summer at the U.S. Army Corps of Engineers Research Facility in Vicksburg, Mississippi. Two ¼-scale prototype bridge bents were subjected to blast forces similar to those corresponding to a credible terrorist threat for this kind of bridge. Following the testing, the piers showed permanent flexural deformations but they did not suffer any significant damage.
The bridge pier design is intended for use in the construction of new bridges, but future research will focus on development of retrofit variations for existing bridges. Detailed analysis is underway using data collected as part of this test program, to develop design recommendations and to calibrate and investigate the effectiveness of more advanced analytical models.
The design was developed by Michel Bruneau, professor in the Department of Civil, Structural and Environmental Engineering at the University at Buffalo. UB graduate student Shuichi Fujikara participated in the testing, and post-doctoral research associate Diego Lopez Garcia contributed to the research. The research is part of MCEER's Highway Project, funded by the Federal Highway Administration.