Seismic collapse resistance analysis of tall reinforced concrete chimney

The seismic collapse resistance capacity of a typical tall reinforced concrete (RC) chimney is studied within the probabilistic framework. On the basis of the incremental dynamic analysis (IDA), the lateral collapse fragility curves are derived and the collapse performance of the reference chimney is evaluated. In order to investigate the effects of soil-structure-interaction (SSI) on the collapse probability, a detailed integral soil-foundation-superstructure model is presented. The numerical study indicates that the collapse probability of the reference chimney is close to 0% and can meet the collapse resistance requirement under the 7-degree rarely-occurred earthquake with a peak ground acceleration (PGA) of 0.22 g. The median collapse capacity are PGA=2.16 g and 1.34 g for the cases with and without considering the SSI effects, and the corresponding structural collapse margin ratio (CMR) are 9.82 and 6.09, respectively. Even though the CMRs are generally large for both cases, the SSI reduces the collapse capacity of the RC chimney by 38%. It is suggested that the SSI effect should be considered in order to systematically evaluate the collapse performance of high RC chimney structures. The results obtained in this paper for the RC chimney are expected to be helpful for seismic risk assessment, seismic retrofit and could be used for performance-based design of RC chimney structures.