Experimental study on the plastic hinge region of precast segmental bridge piers strengthened by CFRP

In this study, three precast segmental pier specimens with a scale ratio of 1:5 were fabricated, and the responses of these pier specimens were studied under cyclic loading. The first reinforced concrete pier specimen (Specimen 1) had no strengthening measures or initial damage; the second pier specimen (Specimen 2) was strengthened by carbon fiber reinforced polymer (CFRP) without initial damage; finally, the third pier specimen (Specimen 3) was first tested to moderate damage, then the damaged plastic hinge region repaired by CFRP was tested for the second time. It was observed that the drift ratio, horizontal load capacity, total cumulative energy dissipation and initial stiffness of Specimen 2 were increased by 75%, 0.71%, 115% and 8.23%, respectively, compared with Specimen 1. The same performances of Specimen 3 after repairing were improved by 25%, 0.64%, 47% and 4.29%, respectively, compared with Specimen 1. Therefore, CFRP can be used for pre-seismic strengthening and post-seismic repair of precast segmental piers, providing reference for engineering application. In addition, it was found that the damage was transferred out of the strengthened region due to the confinement effect of CFRP.