Perforated Hybrid Precast Shear Walls for Seismic Regions

This paper discusses the behavior of two 0.4-scale multi-panel hybrid precast concrete shear wall test specimens with large rectangular perforations (that is, openings) under combined lateral and gravity loading. The wall system used a combination of mild steel (to provide energy dissipation) and unbonded post-tensioning steel (to provide self-centering) for lateral resistance across horizontal joints. The paper compares the measured global and local behaviors of the walls with design and analytical predictions. The panel perforations, which varied in size between the two specimens, performed as expected and did not significantly affect the global behavior of the walls. One of the specimens satisfied the ACI ITG-5.1 performance validation criteria for "special" reinforced concrete shear walls, but the other specimen experienced full uplift at the base joint due to a greater contribution from the energy-dissipating mild steel to the total base moment resistance of the wall. These results are used to make recommendations for the seismic design and analysis of hybrid precast shear walls with large panel perforations.