Bolhassani, Mohammad1 and Hamid, A. Ahmad2

1 Research fellow, Department of Civil Architectural and Environmental Engineering, Drexel University,Philadelphia, PA,
2 Professor, Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA,

Partially-grouted masonry structures traditionally have been built using single reinforced grouted vertical cells and horizontal bond beams. Special reinforced fully-grouted masonry walls in high
seismic design category have shown acceptable performance. However, this is not the case for ordinary reinforced partially-grouted masonry walls with grout spacing exceeding 4 ft (1.2 m) as
demonstrated by recent experimental studies. One simple proposed method to solve the low shear strength and limited displacement ductility of such walls is to simply fully grout the cells or limit their use to low seismic areas. Each of these two solutions has its own pros and cons as it was found and discussed in the literature. Alternative option proposed in this study is to reinforce
and grout two adjacent vertical cells and two courses of bond beams instead of one using the same amount of steel ratio. Seven full-scale partially-grouted masonry walls were built and tested as part of NSF/NEES project using conventional and proposed reinforcement details. Different parameters such as the effect of axial load, use of joint reinforcement and wall aspect ratio were investigated. Results demonstrated that the proposed new reinforcement detail resulted in a significant improvement of wall shear strength and deformation capacity.