EXPERIMENTAL TESTING OF SOLID BRICK MASONRY WALLS
In Bosnia and Herzegovina, many multi-story residential buildings built after the World War II have unreinforced unconfined masonry load-bearing walls which were proven vulnerable during strong earthquakes in the recent past. In order to study the seismic resistance of such walls, in-plane tests were carried out at the laboratory of the Faculty of Civil Engineering in Sarajevo. Four full-scale (233x241x25cm) and nine reduced-size specimens (100x100x25cm) made of solid clay brick and lime-cement mortar were subjected to cyclic shear and monotonic pushover loading program under constant vertical pressure. One-sided or two-sided reinforced concrete or mortar jacketing was applied to improve lateral resistance and displacement capacity. One way of strengthening was with the orthogonal position of reinforcement mesh Q196 and “new” type of connectors made of shaped Ø5 reinforcing bars. The connectors were placed vertically (9 pieces/m) and horizontally (4 pieces/m) in joints and grouted with high strength quick-hardening mortar. In the second type of strengthening, the mesh Q196 was inclined to 45° (135°) in order to follow the principal stress trajectories. Plain walls fail in shear with a typical cross-diagonal crack pattern. Jacketed walls exhibit rocking and significantly larger ductility compared to plain walls. Wallets were tested for compressive strength and elastic modulus of masonry and the results show significant variations.