Predicting and mitigating ground-borne vibration transmission to elevated floor structures

Abstract

Ground-borne vibration from road and rail sources is often a critical consideration for the functionality of research and healthcare facilities. Sensitive equipment can be isolated individually, but when improved vibration performance of the overall structure is required vibration must be mitigated before it enters the structure. To accomplish this, more comprehensive analysis methods must be considered. In the current case study a 12-storey hospital building containing microsurgical and surgical suites is under construction 15 m from a busy commuter and freight rail line. A neighbouring building located at a similar distance from the rail line was measured to have clearly perceptible vibration levels on elevated floors. In order to determine the vibration mitigation required for the new building, an extensive measurement plan was conducted to determine vertical and lateral soil propagation characteristics, a foundation model was constructed to determine soil-structure interaction properties and a finite element model of the building structure was constructed to determine vibration propagation to all floors in the building. The study shows how careful analysis and testing can lead to informed evaluation of various mitigation strategies to combat a very serious problem.