Performance assessment of low–rise confined masonry structures for Earthquake induced ground motions

The performance of low-rise confined masonry (unreinforced masonry walls confined with horizontal and vertical lightly reinforced concrete elements) structures is assessed against earthquake induced site amplified strong ground motions using a probabilistic-based approach. This included analytical investigation of field representative structural models through a suite of natural accelerograms, for various hazard levels. The basic mechanical characteristics of structural material is obtained through experimental investigations recently carried out on masonry material, structural walls and reduced scale structural models, which are employed for the design, mathematical modeling and seismic analysis of confine masonry structures. The seismic performance of two case study (two storey) structure types is assessed for various scenario earthquakes with moderate to strong ground motions. The structures are designed and analyzed considering the existing building stock and new construction recommendations; both differ in provisioning of basic mechanical properties of building material for construction. The typical confinement of masonry walls can avoid the total structural collapse in most of the strong ground motions thereby minimizing the occupant's injuries, however the damages to structures in large earthquake events are significant. Besides the good behavior offered by confinement scheme, the role of construction material's mechanical properties in performance improvement is significant.