Cyclic testing of unreinforced masonry walls retrofitted with engineered cementitious composites

Abstract

The results of in-plane static cyclic lateral loading tests conducted on unreinforced masonry walls retrofitted with trowelling engineered cementitious composites (ECC) are presented in this paper. Six 1/2 scale testing specimens including unretrofitted and retrofitted walls were constructed. The first and second unretrofitted masonry walls were control specimens. The third and fourth walls were retrofitted applying ECC with strip type and the other two walls were retrofitted with ECC coatings. Every batch of tested walls was constructed with two different mortar strengths. The failure modes, lateral strength, ductility, stiffness, and the energy dissipation capacity of the tested walls were examined and compared. Furthermore, the experimental envelope curves were idealized and reasonable overstrength factors of the retrofitted walls were obtained. The results indicated that these retrofit techniques can effectively improve the lateral strength and the displacement ductility of unreinforced masonry (URM) walls, convert the brittle failure mode to a more ductile one, and provide an effective constraint for the walls, resulting in preserved integrity of the wall at large lateral displacements. Finally, the calculation methods for each retrofitting scheme were proposed to estimate the ultimate lateral strengths of ECC retrofitted masonry walls.