Monotonic and cyclic stress-strain models for confined concrete-masonry shear wall boundary elements: Fid-Bau Portal

Monotonic and cyclic stress-strain models for confined concrete-masonry shear wall boundary elements

AbdelRahman, Belal / Galal, Khaled

Highlights • Confined masonry boundary elements with different sections were tested under cyclic compression. • Boundary elements with different transverse confinement ratios were tested. • Monotonic and cyclic stress-strain models for confined boundary elements were developed. • The proposed model exhibited good agreement with the stress-strain envelope curve of tested specimens. • The proposed cyclic model showed significant conformity with the experimental results.

Abstract Simulation of the seismic response of fully grouted reinforced masonry shear walls (RMSWs) built with reinforced masonry boundary elements (RMBEs) necessitates reliable nonlinear models of their RMBEs. The axial monotonic and cyclic full stress-strain curves of RMBEs are essential for predicting the lateral cyclic response of RMSWs with boundary elements. Therefore, a reliable stress-strain constitutive model for the axial monotonic and cyclic behavior of RMBEs is required. The authors recently investigated the axial monotonic compressive behavior of unconfined and confined RMBEs built with different section configurations, vertical reinforcement arrangements, transverse confinement ratios, and different construction procedures. In the current study, the authors investigated the cyclic behavior of some RMBEs whose counterparts were previously tested under axial monotonic compression. In addition, more specimens with different confinement configurations and different grout strengths were tested. Comparisons of the test results showed that increasing the vertical reinforcement ratio increased the axial load carrying capacity of the tested RMBEs but decreased their strain ductility. In addition, using a low compressive strength grout significantly reduced the strain ductility of the RMBEs. Moreover, monotonic and cyclic stress-strain models for confined and unconfined concrete-masonry boundary elements subjected to axial compression loading were developed. The proposed models showed good-to-excellent agreement with the experimental results, predicting the stress-strain rising curve, stress drop, and postpeak behavior. Furthermore, unloading and reloading curves, strength degradations, and softening of reversal and reloading branches due to cyclic degradations were well captured by the proposed model.