Experimental Study On Human Induced Vibration Comfort Of Concrete Composite Slab

In this paper,the research on human induced vibration comfort of reinforced concrete composite slab with ribbed bottom panel（hereinafter referred to as composite slab）is systematically carried out.The human induced load models based on the force-measuring plate,vibration characteristics and vibration serviceability of this kind of composite plate,and vibration comfort evaluation index based on EEG were studied.（1）The single-step load-time history curves of 19 subjects under the excitation of walking and running were measured by the dynamometer test.The time history curve of the single-step load is expanded using Fourier series.The dynamic load factors,phase angles and single step load durations were counted after measuring and expressed by T_pusing the least square method.The calculation formula of the single-step load models under the excitation of walking and running were obtained.Based on the results of high-frequency video-recording technology,the time proportion of each action in the process of excitation was given.Thus,the continuous excitation load models under the excitation of walking and running were obtained using the time-history-expansion method.（2）The acceleration responses of four composite slabs spaning 7m（or 8m）with prestressing ratio of 0.53f_tpk(or 0.75f_tpk)under human induced loads（heel-drop,jumping,walking and running）were measured and recorded.The responses of only two composite slabs spaning 7m under construction loads were tested.The dynamic response parameters（peak acceleration and root-mean-square,i.e.,RMS acceleration,damping ratio and fundamental frequency）of the composite plate were analyzed.The threshold of the maximum RMS acceleration（maximum transient vibration value,i.e.,MTVV）were used to evaluate the vibration comfort of composite slab based on human comfort perception tests.（3）The finite element（FE）program SAP2000 was employed for analysis of the composite slab.The first two natural frequencies and corresponding modes of the the FE model were calculated and compared with those from measurements.The acceleration time-history responses at mid-span from FE model were compared with those from measurements,which verifies the correctness of the FE model and the proposed load models.The parameters that affect the dynamic response of the composite slab were analyzed,including the span and thickness of the composite plate,walking pace rate and body weight.（4）Based on the analysis of event-related potential（ERP）curve,it is found that there is a positive correlation between P2 peak value（or latency time）and RMS acceleration.By analyzing the rhythm of electroencephalogram（EEG）,it is found that there is a strong negative linear relationship between the proportion of θ（or α） rhythm and RMS acceleration.