Reducing human‐induced vibration of cross‐laminated timber floor - application of multi‐tuned mass damper system

As a vibration control technique, tuned mass damper (TMD) system has been shown to be effective in reducing the human‐induced vibration of a cross‐laminated timber (CLT) floor. However, the lightweight property of such a floor means there could be off‐tuning when its mass varies. This study therefore developed a steel‐based multi‐TMD (MTMD) system and a shape memory alloy (SMA)‐based MTMD system to reduce human‐induced vibration of the CLT floor. The superelastic SMA components can give the MTMD system more resilience and thus improve the robustness. Two 3‐TMD systems in different locations and 5‐TMD systems were designed to be effective within a certain bandwidth. The results show that SMA‐based 5‐TMDs are the most effective in reducing human‐induced vibration, for example, single‐person and two‐person slow walking, fast walking and running, as they can cover a wider frequency band. By contrast, the effectiveness of the steel‐based MTMD systems was unsatisfactory owing to permanent deformation of the steel components. When the loads on the CLT floor changed, the SMA‐based 5‐TMDs exhibited high robustness and were able to maintain the response at a low level. Test results show that a high‐frequency excitation could degrade the effectiveness of the MTMD, as this is beyond the effective bandwidth. Therefore, future investigations should focus on developing strategies to enlarge the bandwidth of the MTMD.