EFFECT OF NEAR AND FAR FIELD RECORDS ON SEISMIC FRAGILITY OF INDUSTRIAL CHIMNEYS

As a critical component of industrial plants the acceptable seismic performance of chimneys during strong earthquakes is important. The structure has been studied by the previous researchers to investigate the nonlinear behavior during earthquakes, probabilistic seismic vulnerability and collapse mechanism (Wilson et al., 2003; Changdong Zhou et al., 2014; Huang et al., 2004). Openings in the structure have shown to increase the seismic vulnerability. Collapsing the 115 m high chimney in Tupras refinery during the 1999 Kocaeli earthquake, several researches was performed to investigate the seismic performance of this type of structures in earthquakes (Huang et al., 2004; Sezen and Whittaker, 2004). In this study, calculating the seismic fragility values, the effects of openings as well as the seismic source distance from the site will be studied on the nonlinear behavior and vulnerability of a RC chimney model. A finite element model was developed based on the specifications of the chimney in Tupras refinery provided by Huang et al. (2004). The external diameters of the structure are 10.3 m and 6.6 m in the lowest and highest level, respectively. The dimensions of the section of at the lowest and highest level of the structure as well as an elevation view are presented in Figure 1. 14 near-field and 14 far-field ground motion records were applied in the study to perform Incremental Dynamic Analysis (IDA). Four performance criteria were considered in order to estimate the fragility values as introduced in Table 2.

کلیدواژه ها:

Seismic fragility ، Fragility curves ، Reinforcement concrete chimney ، Far-field ground Motions ، Near-field ground motions