Rapid Strengthening of Masonry Structures Cracked in Earthquakes Using Fiber Composite Materials

Abstract

Many masonry structures have cracking problems after earthquake exposure. Rapid and reliable rehabilitation of such masonry structures is necessary for disaster relief purposes. To improve current methods for strengthening masonry structures with cracking problems using fiber-reinforced polymer, an investigation of the strengthening of a scaled five-story masonry structure built with concrete perforated bricks was conducted. The structure was initially tested on a shake table, from which its displacement, acceleration responses, and cracking were recorded. The partially damaged structure was subjected to rapid strengthening (in less than 3 days) using basaltic fiber-reinforced polymer (BFRP) because of its low elastic modulus and high strength (good compatibility with masonry substrate). The strengthening was carefully designed, and special anchorage measures were used on the first floor of the structure to ensure the strengthening effect of the externally bonded BFRP stripped sheets. The strengthened structure was then retested on the shake table to quantify the strengthening effect. By comparing the performance of the masonry structure during the two shake table tests, it was found that the externally bonded BFRP sheets worked well with the masonry structure, and the seismic performance of the masonry structure was improved significantly.