Abstract:
The development of equations for a post-tensioning seismic retrofit design of URM walls is discussed and a summary of out-of-plane flexural testing is reported. A total of five (05) full scale unreinforced masonry (URM) walls, of which one was tested as-built and four were seismically retrofitted using post-tensioning, were structurally tested using an out-of-plane air bag rig. The out-of-plane loaded test walls had two different wall configurations that were representative of prevalent seismically deficient URM walls and were constructed using salvaged clay bricks and an ASTM type O mortar. Varying levels of post-tensioning were applied to the test walls using a single mechanically restrained sheathed and greased strand, inserted into a cavity at the centre of each test wall. Several aspects pertaining to the seismic behaviour of post-tensioned URM walls were investigated, including damage patterns, forcedisplacement behaviour, tendon stress variation, hysteretic energy dissipation, toughness, and initial stiffness. Finally, measured response was compared to calculated values and the proposed design equations were validated.