3-D pushover analysis of a collapsed reinforced concrete chimney

During the Izmit (Kocaeli) Earthquake of August 17, 1999, a 115 m high reinforced concrete chimney or heater stack, located at the Tüpras Refinery, collapsed. This stack was designed and constructed according to international standards and is representative of similar structures at refineries throughout the world, including those in earthquake-prone regions. This structure is of particular interest because several similar chimneys at the site survived the shock with only moderate damage. The particular distinction of this chimney appears to be an unusually larger rectangular opening, located about 13 of the height above the base, which appeared to be the region of collapse initiation.The main focus of the research is the dynamic response of the stack due to an earthquake motion recorded at a nearby site. A new 3-D pushover analysis procedure is proposed in this paper and the results will be compared with those of a nonlinear dynamic analysis.Results are presented that show the importance of the 3-D interaction effects in the dynamic response of the stack. The results also confirm that the stack could readily fail under the considered earthquake and are consistent with the debris pattern.