In-plane shear behavior of masonry panels strengthened with ultra-high ductile concrete (UHDC)

Abstract

Ultra-high ductile concrete (UHDC), a new type of modified fiber reinforced concrete, exhibits superior strain-hardening and multi-cracking behaviors under tensile load. In order to study the effectiveness of UHDC layer strengthening on non-reinforced masonry structures, one un-strengthened panel as reference, one panel strengthened with high performance ferrocement laminate layer and six panels strengthened with UHDC layers by single side or double sides were tested under cyclic diagonal compression. The shear capacity, hysteresis behaviors, stiffness, and pseudo-ductility of all the panels were characterized and presented in this article. UHDC layer strengthening changed brittle failure mode of masonry panels into a much more ductile mode. The in-plane shear strength of the single- and double-side strengthened panels were 1.8 ∼ 2.4 and 4.2 ∼ 5.7 times higher than that of the un-strengthened one, respectively. The ductility, stiffness and energy dissipation of the masonry panels were obviously enhanced by UHDC layer strengthening. Additionally, the prediction based on the modified ACI 549 and JSCE 2008 algorithms agreed well with the experimental results. The present study demonstrated that applying UHDC layers, either on one or two faces to un-reinforced masonry wall, can significantly improve its seismic performance.