Study On Human Induced Vibration And MTMD Control For Long-Span Floor

Because of the need of large space,large span floor structure has been widely used in public buildings such as conference center,gymnasium,high-speed railway station and museum.Due to the use of new high-strength lightweight materials,large span floor structure has the characteristics of light,low frequency and low damping,and the fundamental frequency of the structure will inevitably fall into the human walking frequency range.This structure will produce excessive vibration under human activities,affecting the normal use of the structure or even cause accidents,namely vibration comfort.For long-span floor structure,it is necessary to obtain the most unfavorable load response of the structure to evaluate the comfort of the structure,and then to judge whether the structure is comfortable.We need to take control measures to reduce vibration when there is a problem of comfort.When the floor has vibration comfort problem,it is difficult and not economical to change the form of structure,at this time through the installation of the control device is a relatively easy and economical way to achieve.Compared with single TMD,MTMD has become a research hotspot in the field of floor vibration control because of its advantages such as high control intensity and wide frequency band.Therefore,it is of great practical value to carry out the study on the vibration analysis and MTMD vibration control of long-span floor structures.At present,the study on the effect of control load and MTMD control scheme of this kind of structure is not perfect.In this paper,considering the interaction and the characteristics of pedestrian movement,the crowd induced response characteristics and the vertical interaction between human and structure under different density are analyzed.The research work of this paper is as follows:1.Study on walking load.The ASMD model II is established considering the interaction of structure and frequency sub harmonic component.The model is verified by experiments,which the individual experiments were performed on the two pedestrian bridge structures with different natural frequencies,respectively.2.Study on response characteristics of population structure coupling system.Using the ASMD model II,the coupling equation of population structure is established.Monte Carlo simulation was used to simulate the random load of the crowd.Considering the characteristics of crowd walking,the relationship between the population response and the crowd density was analyzed,and the suggested value of the most unfavorable load is given.3.Study on MTMD vibration control for large span floor.The control performance of different MTMD control schemes(control intensity,bandwidth and de harmonic effect)is analyzed,and a reasonable 4-TMD control scheme is recommended.The design method of frequency parameter readjustment is put forward according to the frequency detuning effect of frequency variation.The strength and reliability of the control system are verified by numerical examples.