A finite element model was developed to simulate the crane induced vibration on the floor of high-tech factories, in which the mesh include beam, plate, spring-damper, and moving wheel elements. The finite element results were first compared with the experimental measurements in good agreement. The parametric studies were then performed to study the vibration behavior of high-tech factories due to the effects of rail irregularities, slab depth, and crane speed. The rail irregularities induce the vibration of the crane and slab at their natural frequencies, and both rail irregularities and the crane acceleration induce the crane rotation in its natural frequency, so that smoothing the wheel and rail should be the first priority to decrease slab vibration. The crane speed is another important issue to influence slab vibration, which decreases with the reduction of the crane speed clearly from the parametric study. Thus, decreasing the crane speed to reduce slab vibration is an alternative, and experiments are caused to find the optimal crane speed and acceleration. The crane induced vibration is the relatively largest and smallest at the column location and beam center, respectively. Therefore, increasing the slab and beam depth to decrease the slab vibration induced by the moving crane is an additional option.

In this work, an appropriate rail pad is proposed to reduce the vibration induced by moving cranes near the source location in high-tech buildings. Using a simple two-degrees-of-freedom model and laboratory experiments, we found that a low-cost rubber pad is effective to reduce crane-induced vibration. A number of finite element analyses with the full model are then performed for a high-tech factory and a moving crane. The results show that a decrease in the stiffness of the rail pad can decrease crane-induced vibration, and it is obvious that the proposed low-stiffness rubber rail pad with significant damping is an appropriate material to reduce crane-induced vibration by as much as five dB. In addition, the displacement field using the rubber pad is still much smaller than 2 mm, which is the working requirement for moving cranes.

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