Experimental Study on the Seismic Design and Retrofit of Bridge Columns Including Axial Load Effects

Keywords: Modeling. Control and Repairability of Damage (CARD). Retrofit, Control and Repairability of Damage (ReCARD). Seismic design. Retrofit. Replaceable fuse bars. Seismic displacement. Replaceable fuse bars. Sacrificial fuse bars. Non-ductile columns. Reinforced concrete bridge columns. Variable axial loads.

Abstract: This report details the development of retrofit procedures for reinforced concrete bridge columns and their connections. The report extends the Control and Repairability of Damage (CARD) column design philosophy for new structures that use replaceable fuse bars in the plastic hinge zone for the design of new structures (NCEER-97-0013). The work reported resulted in the development of a new philosophy, ReCARD (Retrofit, Control and Repairability of Damage) that uses the same fuse-bar concept adopted in CARD designs. Fuse-bars are spliced into existing non-ductile columns that have vulnerable hinge zone details. This type of retrofit permits relatively rapid and cost-effective repairs following a damaging earthquake. Both the CARD and ReCARD details are examined to verify that they have adequate fatigue life under realistic seismic loading, including the effects of variable axial loads that arise from a combination of the framing action of multiple column pier bents and vertical ground motions.