Preliminary Design and Analysis of a Smart Building Structural Dynamics Sensing System

Smart building technology is a growing area of research that uses integrated sensing systems in buildings to improve safety, comfort, and efficiency. Smart building structural dynamics sensing systems (SDSS) are a type of smart building system that measures the structural dynamics of a building via accelerometers and/or strain gauges to non-intrusively monitor the building and its occupants. Previous work in SDSS has deployed a single dynamic sensor type distributed throughout the building to monitor global building dynamics. Limited work has been done to utilize the SDSS for local building dynamics, such as occupant/building interaction, and a fully developed system that monitors both a building and its occupants using structural dynamics has not been developed. To bridge some of the gaps in the current literature, Tennessee Technological University (TTU) is developing an SDSS in the Ashraf Islam Engineering Building (AIEB), which has been designed as a comprehensive research platform containing multiple sensor types and both global and local sensor installations. In this work, an overview of the preliminary design and analysis of the SDSS in the AIEB is presented. A modal analysis of the structure is performed for the global SDSS to validate sensor selection and placement. Footstep and shock tests are performed to select accelerometers for floor vibration measurements in the local SDSS. The modal analysis indicated that the first three modes are sufficient to define the global seismic response of the structure. The range of the first three modal frequencies is 0.53–0.60 Hz, which is well below the 200 Hz frequency limit of the Endevco 773–2-R triaxial accelerometer selected for the global SDSS. The footstep and shock tests determined acceleration limits for the local SDSS, which are approximately 0.0035 − 25 g. Considering this acceleration range and prior literature, which shows that the majority of floor vibration frequency content is below 100 Hz but can extend up to 22 kHz, PCB J352B (ICP) and Endevco 7201-50-R (charge mode) sensors are chosen for the local SDSS. Both sensors have acceptable sensitivities and have frequency ranges of 1–15,000 Hz and 1–6000 Hz, respectively, which cover the majority of the frequency content in floor vibrations. Furthermore, the combination of ICP and charge mode sensors provides flexibility in the local SDSS measurement platform to enable a wide variety of future research.