Models for FRP-wrapped rectangular RC columns with continuous or lap-spliced bars under cyclic lateral loading

A large database of cyclic tests on rectangular reinforced concrete (RC) columns wrapped with Fiber Reinforced Polymers (FRP) is used to develop or calibrate simple rules for the calculation of the column’s: (a) yield moment; (b) chord rotation at yielding; (c) secant stiffness to the yield point; (d) flexure-controlled ultimate chord rotation in cyclic loading and (e) cyclic shear resistance after plastic hinging. Two models are proposed for the ultimate chord rotation: the first one is based on a plastic hinge model which employs a plastic hinge length, the yield and the ultimate curvatures of the end section and the fixed-end-rotation due to slippage of bars from their anchorage zone beyond the column length; the other is an empirical extension of a previous model for rectangular RC columns without FRP-wrapping. The models cover seamlessly columns with vertical bars continuous or lap-spliced in the plastic hinge and FRP wrapping of the lap-splice region.