Seismic performance testing of masonry-infilled frames retrofitted by fiber composite

An experimental program was conducted to study the effects of strengthening and repairing masonry-infilled reinforced concrete frames by fiber glass composite on their seismic resistance. As-built frame as well as those strengthened and repaired by external layers of fiber glass composite were examined to assess the relative seismic resistance due to the strengthening and repairing techniques. Full-scale reinforced concrete frames and full-scale hollow concrete blocks were used in the construction of the specimens to avoid the typical uncertainties associated with scaling the dimensions and properties of the materials. The observed behavior of the infilled frames is discussed on the basis of stiffness, strength, ductility, and modes of failure. The results indicated that the adopted strengthening and repairing techniques prevent the diagonal tension and shear failure of the infill. The nonlinear behavior of the masonry-infilled frames was also predicted using a nonlinear finite element analysis. The theoretical and experimental data showed close correlation for both the stiffness and strength of the specimens. Further corner crushing of the infill in the strengthened frames was observed as the failure mode in both the analytically-modeled and the experimentally-tested frames.