Simulation Of Pedestrian Load And Response Of Long-span Floor Under Human-induced Vibration

With the development of lightweight and high-strength materials in the field of civil engineering,building structure is becoming more and more optimized,and the application of long-span floor in public construction is increasing.Long-span floor has the advantages of large span,light weight and high strength.The natural frequency of flexible structure is usually less than 3Hz,and it overlaps the step frequency,the phenomenon of resonance will happen.The excess vibration of long-span floor structures induced by pedestrian load will affect the comfort and safety.In this dissertation,the long-span floor structure is taken as the research object,and corresponding researches about the simulation of pedestrian walking load and the response analysis method of human-induced vibration are carried out.The main contents in this dissertation are as follows:1.The influence parameters of human-induced vibration responses are systematically studied.By means of finite element simulation and experimental research,the factors affecting the vibration response of steel-concrete composite model floor under single person load excitation are analyzed from human body characteristics and structural characteristics.In the analysis of human-induced vibration response under single person walking load,the weight of human body can be conserved as the mean weight of Chinese male,the step length can be conserved as 0.715 m,the damping ratio should be determined according to the relevant measured results and specifications.The numerical simulation results of pedestrian walking load model based on domestic tester are consistent with the measured results of human-induced vibration.2.The effects of population density on gait parameters are systematically analyzed,a random pedestrian load model based on population density is proposed.According to the relevant researches for the relation between walking speed and population density,this dissertation explains the causes and effects of the interaction among individuals.Based on the statistical results of actual observations,the change rule of step frequency and walking speed according to different population densities is determined.The results show that population density has a significant impact on walking speed and step frequency,the random pedestrian load model based on the population density can better reflect the interaction among individuals in the crowd.3.The human-induced vibration responses under crowd load excitation are systematically studied.A method of crowd load simulation for walking characteristic of Chinese people is established,and the accuracy of the crowd walking excitation is improved.Vibration response analysis method for large span floor structure under crowd load is established.Based on the actual model floor,human-induced vibration experiments are carried out.The results show that the calculated structural acceleration responses are consistent with the measured human-induced vibration responses,it can accurately simulate the vibration response of long-span structures.4.A vibration control scheme is proposed to control the vibration response under crowd load excitation.A set of tuned mass damping systems is arranged at the central point of the model floor to control the excessive human-induced vibration.The results show that the passive energy dissipation system has a good vibration reduction effect.By optimizing the damping system quality,damping ratio and frequency ratio,installing tuned mass damping systems in the appropriate position of long-span structure can effectively improve the vibration comfort.