| With the development of economy,the continuous updating of structural materials and construction technology,the large-span,lightweight,flexible and low damping structure becomes more and more popular.As a result,the issue of human induced vibration becomes increasingly serious and widespread concerned.The crowd which stay or walk on structure not only enlarge the mass of the structure and apply dynamic load,but also interact with the structure as the system with stiffness and damper.The study of human dynamic model parameters is a key factor to understand this couple effect in depth.And it is of great significance to analyze the dynamic characteristics and dynamic response of the structure under the action of the crowd and provide some guidance for the structural vibration control.In addition,the results of a number of long-span floor dynamic test show that the decorative surface not only increases the mass of structure,but also has some contribution to the stiffness of the structure.This discovery is very important for the study of the structural dynamic characteristics.Based on the existing research results at home and abroad,this paper studies the parameters of the single-degree-of-freedom vibration system model of the human body,and investigates the changes of the simplified model of the human body.Taking the Suzhou Industrial Park Stadium as the engineering background,through the vibration test and finite element analysis,this paper studies the vibration response of large-span floor structure under crowd load.In addition,the modal test of structures with different surface layers was carried out,and the influence was analyzed by using the finite element model.The main concerns and conclusions are as follows:1.Study on the parameters of simplified human body model.The identification tests of the human body vibration model of 30 individuals standing or sitting on the stationary floor and 5 individuals standing or sitting on the vibrating floor were carried out.Human stay on the structure is simulated as single degree of freedom dynamic model,the kinetic theory model of the two-degree-of-freedom coupling system is established and the dynamic differential equation is solved.The natural frequency and damping ratio of the individuals are obtained by modal test,5.12Hz and 36.76%for human stand,4.92Hz and 43.93%for human sit.And with increasing the vibration acceleration magnitude from Omm/s2 to 300mm/s2,the average frequency of human body modal in the normal standing posture decreases from 5.14Hz?4.85Hz,the average damping ratio increases from 38.71%?43.52%,and in the sitting situation,the average frequency is 4.96?4.57Hz,the average damping ratio is 41.13%?45.33%.2.A concrete experiment slab is designed and completed.Considering the actual floor boundary conditions,a 3 m × 6 m floor was designed to carry out the modal test.The Sap2000 finite element simulation was carried out on the test plate and the modal test was carried out.The base modal frequency was 17.900 Hz;3.The influence of building surface on the dynamic characteristics of the structure was analyzed.Three different surface(ceramic tile,terrazzo,marble)modal tests are carried out to analyze the effects of different surface layer on the structure frequency.And the results show that after laying the surface layer,the first frequency of the structure is reduced,but the second and third frequencies increase.The finite element software is carried out to simulate the influence of building surface layers and the results show that the building surface should be considered as an additional concrete layer,the quality of which is taken as the actual surface layer weight and thickness of the additional layer is recommended to take 29?31mm,then the results of the finite element calculation and the measured value can better fit.4.In-site test for a large span structure is carried out.The dynamic characteristics and the human-induced vibration response of the stadium structure of Suzhou Industrial Park Stadium were tested;the comparison between testing results and that of computing for original structure and human-structure joint system shows that the calculated results are less than those without considering the influence of the human-structure interaction.5.The human-induced response of large-span floor is analyzed.The finite element model is established for the Suzhou Industrial Park Stadium.The human-induced response of large-span structure is analyzed under three different types of loads and load considering human-structure interaction.The paper determine using 38 sets of fluid viscous damper energy dissipation systems in order to control the vertical vibration of the structure,the theoretical calculation shows that the effect of vibration response control is very obvious and satisfied the requirements of regulation. |
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