Shake-table test of flexural RC beams subjected to different levels of repair

Abstract

Typically, damaged reinforced concrete (RC) building components are fully repaired to achieve the highest performance recovery. However, this repair objective may not necessarily be essential to achieve building performance that satisfies design criteria and thus be unnecessarily costly and lengthy. In this research, a reasonable strategy of repair termed “partial repair” (in which only the heavily damaged areas of components are repaired) is investigated. Five identical RC flexural beam specimens were prepared and four of them were subjected to static loading to induce different levels of initial damage (three ‘moderately’ and one ‘heavily’ damaged). One moderately damaged and one heavily damaged specimen were fully repaired while one moderately damaged specimen was partially repaired (i.e., repaired only in the plastic hinge area). The three repaired specimens, the unrepaired specimen and the undamaged specimen were subjected to an identical series of gradually scaled dynamic excitations on a shake-table to quantify the differences in performance. Of the five specimens, the response displacement was the highest for the unrepaired specimen. The responses of the repaired specimens were marginally higher than that of the undamaged specimen; however, the difference between the fully repaired specimen and the partially repaired specimen was insignificant. Stiffness, strength and damping of the partially repaired specimen were also found to be similar to that of the fully repaired specimen, indicating that partial repair can be a reasonable strategy to achieve cost effective repairs.