| 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. A numerical
model of the retrofit method is also developed and analyzed for one of the precast specimens.
The numerical model is included to predict the performance UHPC jacketing method for CFSTs.
Keywords: Concrete Jacketing, Seismic Retrofit, Pipe Connection, Large-scale Testing,
Ultra-High-Performance Concrete, Numerical Modeling, Bridge Piers |