Effect of Design Ductility on the Progressive Collapse Potential of RC Frame Structures Designed to Eurocode 8

摘要

Progressive collapse is the cause of most structural failures around the world. The US General Service Administration (GSA) has presented guidelines for the assessment of the vulnerability of building structures to progressive collapse. It has been established in literature that the philosophy of ductility and redundancy used in seismic design is beneficial in resisting progressive collapse but not accounted for in these guidelines. The GSA methodology is particularly suited to seismic codes which allows for a constant member rotation but may be unsuitable to other codes that makes provision for ductility level. In this study, an investigation into the progressive collapse potential of RC framed structures designed to the seismic design code, EC 8, with varying design ground accelerations and ductility classes under different column loss scenarios was done. Based on the EC 8, a criteria for maximum plastic rotations and dynamic multiplies for progressive collapse analysis was proposed. These proposed criteria, together with the GSA criteria, were used to investigate the designed structures. The EC 8 criteria proved that buildings designed for higher ductilities yield at lower loads but undergo greater deformations and absorbs more energy to resist collapse. On the other hand, buildings designed for lower ductilities have higher yield loads but undergo lower deformations before collapse. Higher PGAs result in higher yield strengths but does not necessarily deformation capacity. This effect of ductility was not seen with the GSA criteria since a constant rotation capacity was recommended for all the buildings regardless of design ductility. It was also found that the removals of a corner column possess the greatest threat to progressive collapse on a building.