INFLUENCE OF SEISMIC DETAILING ON THE PROGRESSIVE COLLAPSE OF STEEL MOMENT FRAMES

摘要

In previous decades, many steel moment frame buildings were built in seismic zones, when seismic codes were at its early stages of development, and as such, these structures were often designed solely to resist lateral wind loads without providing an overall ductile mechanism. On the contrary, the current seismic design criteria based on hierarchy of resistance allows enhancing the structural ductility and controlling the structural plastic behaviour. Therefore, seismic design criteria might be also beneficial to improve the structural robustness. In order to investigate this issue for steel Moment Resisting Frame (MRF) in the present paper a parametric study based on pushdown analysis and the Energy Balance Method is described and discussed. With this regard the following cases are examined: (i) MRF structures not designed for seismic actions, (ii) MRF structures designed for moderate seismic actions. The investigated parameters are (i) the number of storeys, (ii) the interstorey height, (iii) the span length, (iv) the building plan layout and (v) the column loss scenario. This study has enabled to quantify the effectiveness of seismic detailing in limiting the progressive collapse under column loss scenarios.