Speaking

The use of Ultra-High-Performance Concrete (UHPC) has been gaining popularity for bridge applications in North America. UHPC has been used in both the construction of new bridges and retrofitting of existing bridges. This research introduces a novel retrofitting method for significantly damaged bridge piers that utilize Concrete-Filled Steel Tubes (CFSTs) in the plastic hinge zone. This research is an extension of the first phase of research, ITD Report 281 (2021), which experimentally and numerically validated the design of the connection.

In the first phase of the research, two bridge bents were subjected to quasi-static cyclic loading to drift ratios beyond Maximum Considered Earthquake (MCE). These same bridge piers are the specimens of interest in phase two. There are a total of four bridge piers evaluated and analyzed in this research: two precast and two cast-in-place (CIP).

After being severely damaged in the first phase of testing, each pier is re-aligned and retrofitted using the proposed UHPC jacketing technique and then re-subjected to extreme seismic loading. The design philosophy for the retrofit is to shift the plastic hinge above the damaged region of the column, thus re-instating capacity, stiffness and ductility of the piers. Through large-scale experimental testing, the proposed UHPC jacketing technique is validated. Experimental results from testing of the piers along with guidelines on retrofitting and construction techniques are presented.