TIMBER FLOOR VIBRATION

Reduce Timber Floor Vibration

Abstract

In the present work the change in natural frequencies, damping and mode shapes of a prefabricated timber floor element have been investigated when it was integrated into a building structure. The timber floor element was first subjected to modal testing in laboratory with ungrounded and simply supported boundary conditions, and then in situ at different stages of building construction. The first five natural frequencies, damping ratios and mode shapes of the floor element and the entire floor were extracted and analysed. It may be concluded that the major change in natural frequencies occur as the floor element is coupled to the adjacent elements and when partitions are built in the studied room, the largest effect is on those modes of vibration that largely are constrained in their movement. The dynamic response of structural timber flooring systems can cause vibrational serviceability problems in terms of discomfort experienced by the occupants. A unified method to control timber floor vibrations has not been established to-date. The vibration problem is manifold. The complexity and the limited amount of research with respect to timber floor vibrations have shown an urgent need for further investigations. This thesis has focused on the effects of structural and non-structural modifications on the dynamic performance of timber flooring systems by using experimental data from sixty-seven full-scale flooring systems for analytical investigations so as to identify structural configurations and vibration parameters, which are promising to further the design against disturbing vibrations. The construction of lighter and longer floor structures in recent years has resulted in an increasing incidence of floor vibration. For buildings where users or equipment are sensitive to movements, tight vibration criteria are appropriate. Buildings designed for more general purposes will not need to meet such strict criteria, but the need to correctly analyse and design for vibration is always more pressing when longer and lighter floor constructions are used.

 Rubber is used to reduce sound, noise, and absorb acoustical vibration.  Rubber or sponge rubber can be used for soundproofing and noise reduction and vibration control. These products work well in these applications because the physical properties of high density and regular consistency aid rubber in reducing the transfer of sound. Additionally,

The ideal vibration-proof measure would be to completely separate building frames from the frames of a viaduct, resulting in an image where a building floats under an elevated railway track. Constructing a building on layered rubber, which is used in earthquake-absorbing buildings, may be a realistic idea, but such rubber is designed to handle horizontal movement of earthquakes and has high rigidity in the vertical direction, resulting in transmission of vertical vibrations. And so, the idea of "suspending a building, and installing rubber cushions on the top and bottom of the suspension materials" was born so that seismic force can be reduced and vertical vibrations will not be transmitted. This idea also has the advantage of making implementation of the measure easy since vibration transmission is considered to enter the building from specific "points" ...