Shake table test of a masonry building retrofitted with shotcrete

• Published in: Engineering structures 2020-09, Vol.219, p.110912, Article 110912
• Main Authors: Ghezelbash, Amirhossein, Beyer, Katrin, Dolatshahi, Kiarash M., Yekrangnia, Mohammad
• Format: Article
• Language: English
• Subjects: Adequacy; Buildings; Construction materials; Damaged buildings rehabilitation; Earthquake damage; Masonry; Rebar; Rehabilitation; Reinforcing steels; Retrofitting; Seismic response; Seismic retrofit; Shake table test; Shake table tests; Shotcrete; Sprayed concrete; URM buildings; Walls
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.110912

•Two shake table tests are conducted on 1:2 scale masonry specimen with scaled bricks.•The unreinforced building was tested, rehabilitated with shotcrete, and tested again.•Two walls were shotcreted from inside, and two from outside.•Different shotcrete connections were used and studied at the building corners.•The effect of the fixity of the vertical rebars into the foundation was investigated. This paper presents the results of a series of shake table tests carried out on a half-scale single-story unreinforced masonry building with asymmetric openings. First, the unretrofitted building is subjected to seven increasing stepsof bidirectional seismic excitation. The damaged building is then rehabilitated using steel mesh and shotcrete layer with two walls retrofitted from the exterior face and the other two from the interior face. Afterward, the shake table test is again conducted on the retrofitted specimen in nine increasing excitation levels. Three cases of interior-to-interior, interior-to-exterior, and exterior-to-exterior shotcrete connections are considered at the intersection of perpendicular walls, and for each case, the development of cracks is investigated. Moreover, the effects of fixity of the shotcrete vertical rebars in the foundation are investigated through releasing the rebar-foundation connection in the last three steps of the test on the rehabilitated specimen. The results indicate the adequacy of the retrofit method in creating a strong bond that leads to an acceptable composite action between the brick layer and shotcrete; though, concentrated cracks were observed at the connections of the perpendicular walls. Furthermore, the shotcrete layer has proven to be able to prevent further propagation of the previously developed cracks, which can provide a practical solution for rehabilitation of damaged masonry buildings.