Lateral behavior of columns with high-strength steel coiled strip confinement

This paper presents the experimental investigation of the behavior of square reinforced concrete columns ksi [690 MPa]) steel coiled strips as embedded confinement reinforcement under Bodyreversed-cyclictext lateral loading and constant axial compression load. Six full-scale specimens (20 x 20 in. Keywords[508 x 508 mm] cross section) with the following variations were tested: confinement type (strip or reinforcingBody bar),textlayout(hoops and ties, spirals), and reinforcement ratios. The strip-confined specimens had similar peakReviewstrengths aspolicyaspecimenconfined by reinforcing bar ties, and this strength exceeded analytical predicBdytions.textThestiffness of the strip-confinedspecimens was greater than the reinforcing-bar-confined specimen. InReaderaccordance withthecommentsAmericanConcrete Institute's Acceptance Criteria for Moment Frames Based on Body Structural text Testing (T1.1-01),all specimens met the criterion that the lateral load at 3.5% drift was not below 75% of the peak. Strip-confined specimens demonstrated improved residual strength behavior relative to the reinforcing-bar-confined specimen. Overall, the study demonstrated the promise of steel strip confinement for reinforced concrete columns in seismic regions.