Seismic repair of deficient and code compliant bridge wall piers

• Published in: Engineering structures 2021-04, Vol.233, p.111595, Article 111595
• Main Authors: Kunwar, Bhaskar, McEntee, Vanessa, Pantelides, Chris P.
• Format: Article
• Language: English
• Subjects: Aspect ratio; Bearing strength; Bridge; Bridge loads; Bridge piers; Carrying capacity; Concrete; Concrete bridges; Concrete construction; Cyclic testing; Drift; Earthquake; Earthquakes; Energy dissipation; Fiber reinforced polymers; Hysteresis; Lap spliced bars; Load carrying capacity; Low carbon steels; Piers; Plastic properties; Plasticity; Reinforced concrete; Reinforcement; Reinforcing steels; Relocation; Repair; Retrofit; Seismic; Seismic activity; Steel; Stiffness; Wall pier
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.111595

•Tests carried out for as-built wall pier with deficient details and for modern code-compliant pier.•Seismic repair carried out for two half-scale wall piers with an aspect ratio of 4.0.•Repair of as-built and code-compliant wall piers with steel bars and FRP composites.•Repair of wall piers restored lateral force capacity and displacement ductility. Reinforced concrete bridge wall piers constructed using older codes perform inadequately during strong earthquakes; deficiencies include short reinforcement lap splices, insufficient steel reinforcement in the longitudinal and transverse direction and seismic detailing. A half-scale wall pier with an aspect ratio of 4.0 was constructed using as-built reinforcement details conforming to older bridge codes; a second pier with the same dimensions was constructed using modern code seismic reinforcement details. A total of four quasi-static cyclic tests were conducted about the weak axis of the wall piers: (i) as-built pier, (ii) modern code-compliant pier, (iii) repair of as-built pier using mild steel NSM bars, horizontal CFRP anchors and CFRP jackets, and (iv) repair of modern code-compliant pier using a CFRP shell and vertical headed steel bars for plastic hinge relocation. The repair method for the as-built pier increased initial stiffness by 50% and load-carrying capacity by 73% with similar hysteretic energy dissipation; the repaired as-built pier reached a 4.0% drift ratio before failure. The repair method for the modern code-compliant pier increased initial stiffness by 31%, load-carrying capacity by 15%, and hysteretic energy capacity by 55%; the repaired modern code-compliant pier reached a 6.0% drift ratio before failure.