Experimental study on vibration characteristics of poplar LVL orthogonal ribbed box floor

To study the vertical dynamic characteristics and the law of human-induced excitation response of poplar laminated veneer lumber (LVL) orthogonal ribbed box floor, six full-scale poplar LVL orthogonal ribbed box floors were tested by the modal test and the human-induced vibration test. Based on the peak acceleration and acceleration vibration level, the effects of the configurations of the box floor and the human-induced load conditions on the vibration response were analyzed. The results indicate that the box floor with the thickness of the oriented strand board (OSB) slab, the height of the rib beam, and the distance of the short rib beams of 18.3 mm, 285 mm, and 600 mm exhibits the largest first-order natural vibration frequency and damping ratio, as well as the best dynamic characteristics. The peak acceleration of box floors decreases with increasement of the OSB slab numbers and the height of rib beams, whereas it increases with increasement of the thickness of OSB slabs and the spacing of the shorter rib. The peak acceleration increases with increasement of the stride frequency and the number of people walking. When the stride frequency is the same, the peak acceleration of the box floor under the one-person jumping is larger than that of stepping in place or continuous walking. The calculating method for the first-order natural frequency and the peak acceleration of the box floor under one-person walking or jumping are carried out, and the calculated results agree well with the experimental results.