Dynamic Characteristics of Tall Buildings in Vancouver, Canada

This paper presents the results of a series of vibration tests conducted on tall reinforced concrete shear-wall buildings located in Downtown Vancouver, British Columbia, Canada. The buildings tested were the Sheraton Wall Centre, The City Tower building, The Heritage Court Tower and The Melville. Ambient vibration tests were performed on each building to obtain its dynamic characteristics. Overall vibration levels, mode shapes, modal frequencies and modal damping were determined. In addition, detailed ground measurements were taken on the Melville and the City Tower buildings to examine potential rocking behaviour and soil-structure interaction effects of the raft foundation. Interesting results of the study show that some lateral modes of vibration of the buildings include base rocking, even at low levels of vibration, and that modal coupling between the lower modes of vibration is significant. These findings indicate that the seismic response of these buildings during severe shaking may be different than that predicted during the design process.