Ambient Vibration Test and Retest of a Multistory Factory Building

Multistory industrial buildings have become prevalent in sectors such as electronics, machinery, pharmaceuticals, and textiles due to limited space in urban environment. There is usually a strict requirement of machine operation on the building vibration, so that it becomes relevant to quantify the structural dynamical characteristics, e.g., natural frequencies, damping ratios, and mode shapes. This paper presents a multisetup ambient vibration test and retest conducted in a multistory industrial building located in Haining, China, using eight triaxial accelerometers to cover 36 measurement locations in six setups during normal operations and shutdown condition. These tests followed a nearly identical test configuration with minor local discrepancies. To obtain the primary modal parameters of the structure, a Bayesian multisetup modal identification algorithm is adopted, followed with a detailed analysis of the results. Furthermore, the floor serviceability is investigated, primarily focusing on worker comfort. The study reveals several interesting phenomena, such as the impact of structural expansion joints and sensor synchronization on the identification results. This study serves as a demonstrative effort in examining the dynamic characteristics of multistory industrial buildings. It provides insight into evaluating the dynamic characteristics with limited sensors and abnormal identification results.