Calibration of analytical models to assess wind-induced acceleration responses of tall buildings in serviceability level

Abstract

An accurate estimate of natural frequencies is essential to correctly predict wind-induced acceleration for serviceability checks in the design of tall buildings. In this study, finite element (FE) models for three tall reinforced concrete buildings were constructed using a popular PC-based finite element analysis program and calibrated to match their fundamental natural frequencies to actual values extracted from the acceleration measurements using the system identification technique. The modification of the FE models for calibration included: (i) consideration of the effect of beam-end-offsets, (ii) modeling of floor slabs instead of using ‘rigid diaphragm assumptions’, (iii) inclusion of major non-structural components such as plain concrete walls and cement brick walls, and (iv) higher elastic modulus of actual concrete than specified value. Natural frequency estimates from the calibrated FE models and the measurements showed remarkable agreement in all the buildings. Using the dynamic properties obtained from the calibrated FE models and the wind-tunnel test results, the acceleration response of one building during a typhoon was predicted and compared with the measured accelerations. Predicted accelerations during the typhoon also indicated a reasonable match with the measured values.