Sprayed strain-hardening cement-based composite overlay for shear strengthening of unreinforced load-bearing masonry. Issue 5 (April 2019)

• Record Type: Journal Article
• Authors: van Zijl, Gideon PAG; de Beer, Leon
• Is Part Of: Advances in structural engineering. Volume 22:Issue 5(2019)
• Page Start: 1121
• Page End: 1135
• Publication Date: 2019-04
• Subjects: bonded overlay -- masonry -- strain-hardening cement-based composite -- shear resistance -- shotcrete; Structural engineering -- Periodicals; Construction, Technique de la; Structural engineering; Periodicals; 624.1
• DOI: 10.1177/1369433218807686
• Languages: English
• ISSNs: 1369-4332

Abstract

Strengthening of unreinforced masonry walls is realised by a bonded overlay of strain-hardening cement-based composite. In-plane shearing resistance is considered here, although out-of-plane resistance is also increased by the overlay. The strain-hardening cement-based composite mix is adjusted for sprayed application with low run-off and waste. Characterization of masonry joint shear-slip behaviour, interfacial response between the masonry substrate and the strain-hardening cement-based composite overlay and multiple cracking tensile response of the sprayed strain-hardening cement-based composite bond is described. Preferred failure of the composite by multiple cracking shearing in the strain-hardening cement-based composite overlay is achieved through structural mechanics–based design of the overlay. Drying shrinkage development and cracking due to restraint by the masonry substrate are reported. Finally, shear wall response is reported for single- and double-leaf masonry walls with a bonded strain-hardening cement-based composite overlay on one face only and compared with single- and double-leaf control masonry walls without overlays. An overlay of thickness similar to that of typical plaster rendering is shown to lead to significantly enhanced shearing response.