Out-of-plane performance of reinforced masonry walls with openings

The out-of-plane performance of partially grouted, reinforced concrete masonry walls subjected to simulated seismic loading is investigated. The three full-scale walls, with and without openings, were constructed from 190-mm-thick concrete blocks and were 9.0-m long and 2.4-m high with two 2.5-m-long return walls. A minimum quantity of reinforcement permitted by New Zealand Standard 4229 was used, and additional diagonal bars were added to the corners of the bond beam at the top of the wall. The test results show that the specimens exhibited a ductile behavior with a "pinched" shape of hysteresis response and that the ultimate out-of-plane capacities of the walls were considerably greater than the demands calculated using the current New Zealand masonry and concrete codes. The location and size of the openings influenced the load capacities significantly. Yield line theory gives a safe, conservative prediction of the out-of-plane capacity of partially grouted, reinforced masonry walls. Lateral deflection criteria are more important than force criteria in the out-of-plane design of walls.