Seismic out-of-plane retrofit of URM walls using timber strong-backs

Inadequate seismic performance of unreinforced masonry (URM) buildings is frequently encountered in earthquake prone countries such as Italy and New Zealand consequently, effective economical retrofit strategies need to be adopted order guarantee safety the preservation URM building stock. The technique studied herein consisted connecting vertical timber elements (strong-backs), interior surface walls a using mechanical screws or bolts. framing typically non-structural support for inner wall lining its use, part retrofits, resulted being cost low impact solution. out-of-plane behaviour as-built retrofitted was investigated by conducting full scale static airbag tests. were subjected semi-cyclic loading through application uniformly distributed loads, inflated airbags simulate self-weight inertia force induced an earthquake. Five different specimens tested conditions, improvement capacity recorded performances configurations investigated. A simplified numerical model predict response strong-backs developed finite element software SAP2000. Its effectiveness validated means comparison between experimental results well sensitivity analysis on parameter variations, further considerations solution drawn.