Increasingly vibration criteria are required in building floor designs. Whether it is for comfort of occupants or the proper functioning of equipment, floor vibration criteria have become important in many designs. This paper explores different strategies to mitigate floor vibrations in common steel floor systems and discusses them in the context of three case studies. Strategies include the more traditional methods of stiffening and adding mass as well as other methods such as engaging multiple bays, splitting floors and adding tuned mass dampers. Two case studies look at situations where dancing or aerobics rooms were placed adjacent to office spaces and other sensitive areas. Stiffening and adding mass for such cases proved very costly and burdensome as beam sizes were unmanageably large. In one case, the floor was separated with a joint and for the other the floor was stiffened and tuned mass dampers were added. The third case study explores a situation where a piece of medical imaging equipment was desired to be located on an elevated floor with long span trusses. This situation required significant stiffening, addition of tuned mass dampers and a bridging truss to spread out vibration between bays. This increased the resonant frequencies of the floor system and added damping tuned to the resonance with the highest vibration amplitude. The former method placed the target resonance out of the reach of the lower harmonics caused by walking and the latter method lowered the peak velocity in the floor. This paper highlights how each method optimized performance to avoid resonance and reduce peak vibrations. Finally, the merits & disadvantages of each of these methods as well as the pros & cons of various computational tools used to assist in the design for vibration are discussed.
展开▼
