Seismic Behaviour of Confined Autoclaved Aerated Concrete Masonry Buildings: a Shaking Table Study

The seismic behaviour of typical residential confined masonry buildings constructed with aerated autoclaved concrete (AAC) blocks has been investigated. Two three- and one four-storey models, constructed at 1 : 4 scale, have been tested by subjecting them to a simulated earthquake ground motion on a simple unidirectional seismic simulator. The floor plan of all models was the same, with symmetric distribution of walls along the shorter axis and slight asymmetry along the longer one. Lightweight prefabricated joists with AAC fillings without concrete topping represented the floor structures in the case of the three-storey model M1, whereas reinforced concrete slabs have been cast in the case of the three-storey model m² and four-story model m³. Bond beams have been provided at all floor levels and tie columns have been installed at all corners, wall intersections and along openings. The models have been instrumented with accelerometers and displacement transducers, placed in the middle and at the corners of the floor slabs at each floor level, and subjected to a series of excitations with increased intensity of motion in each successive test run. The acceleration record of the Montenegro earthquake of 1979 with peak ground acceleration of 0.43 g has been used to drive the simulator. Whereas models m² and m³ have been tested by subjecting them to seismic motion in the direction of the long axis, model M1 has been tested orthogonal to it. In all cases, typical shear type behaviour has been observed, with diagonally oriented cracks in the walls in the first story determining the failure mechanism. All models exhibited good seismic behaviour, with resistance and energy dissipation capacity exceeding the expected values. On the basis of test results, the correlation between the damage and storey drift at characteristic limit states has been analyzed and the values of typical design parameters, such as displacement capacity and structural behaviour factor, have been evaluated.