SEISMIC RESPONSE OF A 22-STOREY MONOLITHIC BUILDING BASED ON INSTRUMENTAL ACCELERATION RECORDS

Abstract

This study addresses the growing need for reliable seismic verification of high-rise monolithic reinforced concrete buildings in Almaty, Kazakhstan, where intensive vertical development is taking place in a high-hazard seismic environment. To improve the realism of structural response prediction, the building performance is evaluated using instrumental earthquake acceleration records and compared with the conventional response spectrum approach commonly applied in design practice. A 22-storey monolithic building is analyzed in the LIRA-SAPR environment by two independent procedures: (i) response spectrum analysis under the design spectrum and (ii) time-history analysis using selected three-component accelerograms representing strong ground motions (including recorded and artificial events). The comparison is performed for a representative structural element at the upper levels (a reinforced concrete wall along Axis 1/B at elevation 74.25 m), where higher-mode effects may be significant. The results indicate that peak lateral displacements are strongly record-dependent. For the El Centro (1940) input, time-history displacements are practically consistent with the spectrum-based estimates, whereas for the Kern County (1952), Baysorun (1990), and the artificial record, time-history responses are noticeably lower than those obtained by the response spectrum method, confirming the conservative nature of spectrum-based design. The observed discrepancies are primarily attributed to differences in frequency content and duration of ground motion. The findings support the combined use of response spectrum analysis for routine design and time-history analysis for enhanced verification of high-rise buildings, especially in regions with pronounced regional ground-motion features. The study also substantiates the value of engineering seismometric monitoring for refining local seismic inputs and improving assessment reliability.