Numerical Modeling and Seismic Analysis of Tall Steel Buildings with Braced Frame Systems

The following paper presents the design and verification steps of tall steel frame structures with braced core, belt and outrigger trusses. The two case study structures refer to sky scrapers of 180m and 300m respectively, located in Istanbul, Turkey. The main objectives of this study are two: firstly designing the buildings through multilevel structural analysis, secondly to compare the results, in terms of seismic response, between response spectrum analysis (RSA) and nonlinear time history analysis (NLTHA). Such comparison has been made with the intention of investigating the relationship between the structure height and the accuracy of RSA predictions, considering that the latter approach tends to underestimate the influence of higher mode effects. In conclusion the capacity curves of the two structures, developed using incremental nonlinear dynamic analysis, are presented as an ulterior way to assess the seismic capacity of such type of high-rise structural systems.