Seismic Performance Parameters for Reinforced Concrete-Block Shear Wall Construction

The focus of the current study is to analyze previously reported test results to evaluate equivalent plastic hinge lengths for concrete-block shear walls and to extract related seismic performance parameters. Inelastic curvatures at the base of the walls are the main source of plastic deformation for flexurally dominated walls. With adequate estimation of the plastic hinge length and more realistic values for inelastic curvatures at the base of the wall, top wall displacement can be predicted more accurately. For the walls analyzed, measured compressive strains close to the base of the wall at maximum load were significantly higher than the strains specified by North American codes. The strains, although may not alter the wall strength, significantly affect the displacement ductility at maximum load. The analysis showed that the equivalent plastic hinge length varied between approximately 30 and 60% of the wall length at a drift of 1%. The product of the seismic force modification factors (for ductility and overstrength) varied between 3 and 6. The plastic hinge length and the seismic force modification factors were found to depend not only on the factors prescribed in North American codes but on the amount of vertical reinforcement and axial stress level as well. This study draws a road map for further research to facilitate better understanding and provide more realistic methods to predict the seismic performance of masonry shear wall construction.