Dynamic Characteristics of a Tall Building Identified from Earthquake and Ambient Vibration Records

The paper presents the modal characteristics of a tall building in Bucharest (BRD-SG Tower) identified from earthquake and ambient vibration records. The building was built in the early 2000’s and has a reinforced concrete structure (inner shear wall tube and perimeter frames) with 3 underground stories, ground floor and 18 stories. The seismic instrumentation of the building consists of a seismic station with two triaxial acceleration sensors located at the top of the building (+69.6 m) and at the third basement (−9.3 m). The dynamic characteristics of the building are estimated from the seismic records from 23 earthquakes (with moment magnitudes M_W between 3.7 and 6.0) that occurred during the period 2004÷2010. The results obtained from the earthquake records are compared with those obtained from 35 ambient vibration records from the period 2003 ÷ 2010.