In-plane seismic behavior of NSM strengthened adobe walls: Experimental evaluation of different reinforcements

Abstract

This study focuses on the seismic strengthening of adobe walls using different reinforcing materials using the near-surface-mounted (NSM) technique. The test specimens comprise five adobe wall panels. Out of these, four specimens are strengthened with the three different NSM reinforcing materials of ribbed steel bars, sand-coated glass fiber-reinforced polymer (GFRP) bars, and sand-coated reeds. The strengthening procedure involves insertion of the reinforcing materials into the horizontal and vertical grooves cut symmetrically on both sides of the panels. The in-plane performance of the wall specimens is assessed under an incremental cyclic loading regime at the presence of the vertical pre-compression stress of 0.3 MPa. The results are described in terms of lateral resistance, ultimate displacement, ductility, hysteretic energy, and stiffness degradation. The envelopes of the hysteretic load–displacement curves thus obtained are then used in the seismic evaluation of the test specimens. While the results confirm the efficacy of all the reinforcing materials, the NSM steel bars are shown to be superior in this regard but the sand-coated reeds to be inferior to the other materials. The superiority of steel bars is attributed to their higher strength and elastic modulus. Nonetheless, the improvement achieved with the sand-coated reeds is considered to be satisfactory as well, particularly from sustainability and affordability viewpoints.