Static Test on Full Scale Rammed Earth Building with Mesh-Wrap Retrofitting Strategy

Abstract

This paper reports the experimental campaign for static tests performed on unreinforced (URE) and mesh retrofitted (RRE) full scale rammed earth building. Amongst varying building patterns of traditional rammed earth houses found in Bhutan, a two-storied building with a full solid wall (small openings) on the first floor and larger opening in the front facade of the second floor was chosen. The proposed mesh–wrap retrofitting of the walls involved the use of standard mild steel welded mesh as the main mesh, M–Mesh (Ø 1.8 mm and 34 mm c/c spacing) and light and galvanized welded mesh as a lapping mesh, L–Mesh (Ø 1.45 mm and 28 mm c/c spacing) provided at the corners and along the height of the walls. The static test loading protocol involved the displacement controlled loading with drift-control over the building. Cracks and damage observations were made at the storey drift ratios of: 1/2000, 1/1000, 1/750, 1/500 for URE building. The same URE building was retrofitted afterward and retested as RRE to storey drift ratios of: 1/2000, 1/1000, 1/750, 1/500, 1/250, 1/150, 1/100 and 1/75. The mesh retrofitting is found effective in both damage control as well as strength enhancement over the unreinforced one. The URE specimen showed a clear opening of shear and vertical cracks in the in-plane loaded walls near the openings and Jugshing holes. For the RRE specimen, cracks dispersed over a large region of the in–plane loaded walls. No delamination of mesh–wrap was observed, showing the effectiveness of the proposed technique. The RRE specimen showed enhancement in base shear by 2.5 times, ductility 2.3 times, and energy absorption 12 times the URE counterpart.

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