STEEL JACKET RETROFITTING OF REINFORCED-CONCRETE BRIDGE COLUMNS FOR ENHANCED SHEAR-STRENGTH .2. TEST-RESULTS AND COMPARISON WITH THEORY

In this, the second part of a two-part paper on assessment and retrofi t of bridge columns susceptible to shear failure, experimental results are pre sented from two test programs. The first involved tests of fo ur ''as-built'' circular columns expected to fail in shear, with a fur ther four columns retrofitted with steel jackets. The second involved three ''as-built'' and three jacketted rectangular columns. Variables included axial load level, strength of longitudinal reinforcement, and aspect patio as well as section shape. All ''as-built'' columns faile d in shear in a brittle fashion, or at low flexural ductility levels. Jacketted columns performed extremely well, with stable hysteresis loo ps being achieved to displacement ductility levels of mu(Delta) greate r than or equal to 8. Performance of ''as-built'' and retrofitted colu mns conformed to analytical models presented in the companion paper.