Axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls

This study investigates the axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls. Sixty walls were constructed and tested under axial compression. The variables include block type (unreinforced and coir fibre reinforced), grout condition (ungrouted and grouted), channel blocks, reinforcement type (steel bars and bamboo splints) and configuration (vertical and mesh type). The results show that addition of coir fibres significantly increase the axial load capacity and ductility of walls, regardless of all other variables considered. Grouting of masonry cores increases the load capacity of unrein-forced and fibre-reinforced walls (without bamboo/steel reinforcement), however slightly affecting the deflection capacity. The channel block had a detrimental effect on the load and deflection capacity of both unreinforced and reinforced walls. Bamboo/steel reinforced vertically significantly contributed to the axial load and deformability of walls, despite the presence or absence of channel blocks. Both bamboo and steel reinforced walls behaved in a similar manner; yet bamboo splints showing slightly lesser load and deflection capacity than steel. The axial load and deflection capacity of bamboo reinforced grouted walls are about 78.54% to 90.00% and 79.50% to 94.60% respectively as compared to steel reinforced counterparts. Bamboo/steel mesh reinforced walls with channel blocks exhibited better performance compared to corresponding specimens with only vertical reinforcement. However, the improvement was marginal, due to larger spacing between the horizontal reinforcement. Nevertheless, the presence of horizontal reinforcement greatly improved the failure behavior by restraining the buckling of vertical reinforcement. Overall, fibre and vertical steel reinforced grouted wall specimens without channel blocks (FSVRGMW) showed the best performance in terms of compressive strength. The design equations in MSJC-11 predicted the load capacity of unreinforced and reinforced masonry walls more conservatively. Finally, it can be stated that MSJC-11 recommendation of internally reinforced grouted walls must be treated as unreinforced walls, if no horizontal reinforcements was provided, is not reasonable.