Response parameters that control the service, safety and collapse performances of a 253 m tall concrete core wall building in Istanbul

Abstract

Seismic performance of a 253 m tall reinforced concrete core wall building constructed in Istanbul, designed according to performance-based seismic design principles, is assessed for determining the response parameters that control the serviceability, safety and collapse performance limit states. Serviceability performance is evaluated under the 50-year wind and 43-year earthquake whereas safety performance is assessed under the 2475-year earthquake. Collapse performance is elaborated through incremental dynamic analysis. Our study revealed that the service performance is controlled by the maximum interstory drift limits specified for wind loads, and safety performance is controlled by the flexural steel strain limits of coupling beams. Collapse occurs in two consecutive stages: flexural collapse of coupling beams, followed by crushing of concrete at critical shear wall segments. Collapse spectra are defined for these two collapse limit states. Collapse spectra can be extrapolated from the 2475-year maximum considered earthquake spectrum provided that the prevailing inelastic mechanisms are similar under the MCE and collapse ground motions. The building displays a significantly higher seismic performance at all performance levels, which is primarily attributed to the overstrength due to the limitation of axial stresses on vertical members under design earthquake load combination. The annual frequency of the mean earthquake ground motion that leads to incipient collapse is determined as 8·10−5, which is significantly lower than the annual frequency of 2475-year ground motions.