Download or read book Rapid Repair of Severely Damaged RC Columns Under Combined Loading of Flexure, Shear, and Torsion with Externally Bonded CFRP written by Ruili He and published by . This book was released on 2014 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This research aimed to develop a technique to rapidly repair reinforced concrete (RC) bridge columns for emergency service restoration after severe earthquake damage has occurred. Experimental and analytical studies were conducted to study the performance and effectiveness of the proposed repair method. The experimental study included a series of 1/2-scale RC square bridge columns originally tested to failure under constant axial and increasing cyclic lateral loadings resulting in combined flexure, shear, and torsion with different torsional-to-flexural moment ratios. Using externally bonded carbon fiber reinforced polymer (CFRP) sheets, each column was repaired over a 3-day period and then retested under the same combined loading as the corresponding original column. Ruptured and/or buckled longitudinal reinforcing bars were not treated during the repair. A strength-based methodology was used to design the CFRP strengthening system to compensate for the strength loss due to the damage observed after the original test. Results indicated that the severely damaged columns were successfully repaired using the developed technique, with the exception of one column with fractured longitudinal reinforcing bars near the joint, which was only partially restored. The response of a prototype bridge structure was analyzed under earthquake loadings using OpenSees software considering different numbers and locations of repaired columns in the model. A technique was developed to model the response of the repaired column that accounted for the different damage and repair conditions along the column. The bridge models with one or more of the repaired columns were found to be capable of resisting the base shear and drift demand by the 40 ground motion records selected according to the target design spectrum, which confirmed the effectiveness of the repair"--Abstract, page iv.