Seismic Performance of Tall Buildings with Setbacks in Elevation

Structural irregularities could directly or indirectly cause the collapse or severe damage of complex tall buildings under strong earthquakes, which was verified again in 8.8-magnitude Chile Earthquake on 27 February 2010. This paper first introduced the damages of a tall building with setbacks in Chile Earthquake. Then, a 244.8-meter high super-tall building with setbacks was studied by the shaking table model test and the numerical analysis. It was concluded that, both experiment and analysis reflect the similar damage pattern of the building to that observedin Chile Earthquake. Although the practice of setbacks is popular in tall buildings, refined analysis of the stories below and above the setbacks is still needed. The stiffness and ductility of those stories should be carefully designed to control the serious damage or even prevent the collapse of the buildings.