Human-induced Vibration Analysis And Serviceability Research Of Long-span Prestressed Secondary-beam Floor In Gymnasium

Compared with reinforced concrete floor, long-span prestressed secondary-beam floor has a lower stiffness out of plane and is more sensitive to the vertical vibration, especially when used in the gymnasium. As a fact that the reinforcement of vibration serviceability for existing bulidings generates huge costs, reasonable solution is to put the control of vibration serviceability into the stage of designing by analysis of human-induced vibration. Considering that the theories and analysis methods of human-induced vibration serviceability are still immature, and the stipulations in codes for design of vibration serviceability are coarse, the paper reviewed existing results of research on human-induced vibration serviceability, and made the human-induced vibration analysis and serviceability research of long-span prestressed secondary-beam floor in gymnasium by application of ANSYS and comparison with relevant measured results on a real construction, while totally 32 load cases in 4 kinds of movements were considered.Main work and achievements of the research are presented as below:(1)With the prestress effect realized with cooling method, the three-dimensional entity model of floor is established in ANSYS. By using the modal superposition method and considering the first six order mode, the simulation results are obtained while in good agreement with the test results, which verifys the reliability and accuracy of the analysis method of human-induced vibration and serviceability used in this long-span prestressed secondary-beam floor, and can supply reference for the further research of this kind of structure in modeling, loading and vibration analysis. Meanwhile, based on the analysis results associated with time-history and spectrum, the rationality of the load case choosing, the influence of human number and walking direction and the most dangerous activity are discussed.(2) With jumping, walking, running, mark time considered in various human-induced load models, the analysis of human-induced vibration is made. By the comparison with measurement results, proper ideas about the choice of human-induced load model are proposed. Based on the analysis of running mechanism, a new load model of running approximated with jumping is advised. Compared to traditional methods, this new model can mostly obtain the results corresponding to the measurement.(3)By the varying factor analysis based on finite element model, the influences of floor form, damping ratio, prestress value on human-induced vibration response and serviceability are respectively researched. With the results of analysis, it is proved that: 1) the box floor section has a pretty good effect on the improvement of vibration serviceability, and layout adjustment of floor should take the match of structural mass and rigidity into account. 2) damping ratio almost has no influence on the natural frequency of structure, but it has a obvious effect on the vibration response. 3) prestress value almost has no effect on the dynamic performance in vibration serviceability.(4)Based on the results of finite element analysis, standards of frequency limen, acceleration limen and annoyance rate model are respectively utilized to assess the human-induced vibration serviceability of the relevant construction. 1) As a result, it is proved that the vibration serviceability of the relevant construction can generally meet the request, while load cases of walking have enough safety stock but multiple jumping dangerous. 2) The control level of annoyance rate model can meet the request of relevant standards of norms, and is more serious as a comparison.The main innovation points are as follows:(1)The analysis method of human-induced vibration and influence factors of serviceability were studied in system.(2)According to the comparison between analysis and measurement, suggestions for the choice of load model for 4 kinds of movements were given, and a new load model for running which can meet request of the engineering application was proposed.(3)Different influences of box section and floor thickening were compared. The control level of annoyance rate model and standards of acceleration limen in relevant norms were discussed.