Seismic and Durability Assessment of Externally Bonded FRP Retrofits in Reinforced Concrete Structures After 2018 Anchorage, AK Earthquake

Externally bonded fiber-reinforced polymer (EBFRP) composites are a cost-effective material used for repair and seismic retrofit of existing concrete structures. Even though EBFRP composites have been extensively utilized over the past 20 years as seismic retrofits, there are few data documenting their performance in a real shaking event or after long-term use on concrete structures. In this study, semi-destructive and non-destructive techniques were employed to evaluate the performance and durability of EBFRP-retrofitted buildings that had experienced the 2018 Cook Inlet Earthquake in Anchorage, AK. The performance of EBFRP was evaluated and documented through photographic evidence. Acoustic sounding, infrared thermography, and bond pull-off tests were utilized to evaluate the quality of bonding between the EBFRP and concrete. EBFRP samples were also collected from building interiors and exteriors for chemical and thermal analysis to evaluate the long-term effects of environmental exposure. Although environmental conditions were found to influence the bond quality between the EBFRP composite and concrete substrate, no major signs of earthquake damage to the building components retrofitted with EBFRP were noted. Materials characterization results demonstrated no evidence of polymer matrix degradation in exterior EBFRP samples.