Dynamic Performance of Steel Lightweight Floors

Publisher Summary This chapter investigates the dynamic performance of steel lightweight floors. Cold-formed square hollow sections and rectangular hollow sections are used as piers, bearers, and joists. The dynamic performance of a floor at three different stages of construction is determined. The three stages are a standalone floor; a floor with wall frames and ceiling; and a floor with wall frames, ceiling, and roof loading. Three types of tests are performed at each stage: dynamic tests to determine natural frequencies, damping, and vibration modes; static tests to measure maximum deflection of the floor; and subjective tests to obtain human response to vibration. The tests demonstrate the change in the dynamic parameters, the maximum deflection, and the human response at different stages. The static deflection test shows no change in the deflection under 1 kN concentrated load. The damping for the first mode increases from 3.2% to 6.6%, and a similar increase for other modes is observed, as well. This could be explained by the absorption of some of the vibration energy by the wall and ceilings. The roof loading changes the first natural frequency and damping, and correspondingly there is change in the mean of human acceptability.