Behavior of post-tensioned dry-stack interlocking masonry walls under out of plane loading

Abstract

The researches done on wall construction to make it appropriate, easy, fast and cost effective have led to a promising technique known as “Dry-stack interlocking masonry system”. Nevertheless, there are several disadvantages attributed to using this system. One of the major drawbacks of this system is the low bending capacity that can be resisted by the interlocking keys alone. To overcome this problem grouting and reinforcing of the hollow block cells are required, which make the system a bit expensive. Additionally, the dry-stacked units had to settle down to balance uneven surfaces and notches, which may reduce strength and stiffness of the walls. One method that has been suggested to minimize this drawback is post-tensioning (PT) of these walls to eliminate grout and enhance the bending capacity.The objective of the current research is to investigate the behavior of PT dry-stacked interlocking masonry (DSIM) walls constructed using locally available masonry units and PT bars under out-of-plane loading. Some of the expected factors that could affect the performance of these systems are construction system, grouting effect, PT technique and restraining effect of PT bars. The test results demonstrated that PT-DSIM systems considered in the current study, under out-of-plane loading, behaved similar to the conventionally reinforced masonry walls. In addition, the proposed PT technique proved its efficiency for grouted walls. It can achieve a remarkable increase in the cracking load triple that of the ordinary reinforced walls and in addition to improving the durability and enhancing the appearance. Furthermore, ungrouted PT walls proved to be the most effective construction detail. Since, their specific strength (capacity/weight) ranges between 1.3 and 1.6 times that of grouted PT walls, in addition to taking the advantage of minimizing construction cost, time, and weight of the structure.