Dynamic Response Analysis And Vibration Control Of Long-span Structures Under Jumping Loads

Since the beginning of the 21 st century,the development of human science and technology is changing with each passing day,the structural form in the field of civil engineering is increasingly optimized and the application of high-strength and lightweight materials is gradually being widely used.The development of long-span structures tends to have large span,light dead weight and low damping.This paper takes the long-span structure in the form of steel-concrete composite floor as the research object.The main research contents of this article are:(1)The simulation study of single-person jumping was carried out,and the changing law of the influencing factors of the structural dynamic response under the jumping load was deeply analyzed.The dynamic response analysis of the large-span structure under single-person jump is mainly carried out by the method of finite element simulation and theoretical research,the finite element model of the steel-concrete composite floor is established,and a jump load model suitable for mid-low frequency and mid-high frequency is proposed.The theoretical differential equation of floor acceleration response is derived.The results show that the structural acceleration caused by different load excitation methods has a small difference at low frequencies.When reaching structural resonance and high frequency,the structural acceleration caused by single ex-situ jump is greater than that of single-situ jump;numerical simulation of jumping load.It is recommended that the contact rate α be 0.45~0.70;when considering the accuracy of the load model,the time lag can’t be ignored;the value of the damping ratio should be determined according to the relevant specifications and field measurements.(2)Analysis of the influence of the jumping load excitation location factor on the dynamic response of long-span structures.The impact of different jump times on the peak acceleration of the structure is analyzed.It is recommended to take 10 load times for numerical calculation,which can effectively save time and ensure the accuracy of the results;analyze the single-point excitation generated by the jump load at different positions of the structure Influence of acceleration.It is found that when the excitation position is located at the secondary beam of the structure,the acceleration will be significantly reduced,and the acceleration when the excitation position is closer to the observation point will be significantly enhanced;find the unfavorable area where the second excitation point is located in the interval;the algebraic relationship between the acceleration peak generated by the synchronous excitation of the jumping load and the acceleration when the two points are loaded separately is about 0.7 times,and it can be known that the structure generates acceleration The location of the minimum.(3)In-depth study of the vibration response of long-span structures under crowd jumping load is established,and the method of dynamic response analysis of long-span structures under crowd jumping is established.And random crowd vibration response to structural vibration under jumping load.The calculation results show that the dynamic acceleration response of the structure under the jumping load of two certain people at 2.5 Hz exceeds the load comfort code limit,and the structure needs to be subjected to vibration damping control;The calculation results are in good agreement with each other;the difference between the structural vibration acceleration response under the deterministic crowd jumping load and the random crowd jumping load is 18.7%.(4)Vibration damping control analysis of the dynamic response of structures under deterministic crowd jumping load and random crowd jumping load is carried out.According to the dynamic characteristics of the structure and the characteristics of the jumping load,the influence of the thickness of the floor and the damping ratio on the vibration acceleration response of the structure under the jumping load of the crowd is analyzed.The analysis results show that the thickness of the building slab is generally effective in reducing the acceleration response of the structure under the crowd jump load,and appropriately increasing the structural damping ratio can effectively reduce the acceleration response of the structure under the crowd jump load.Based on the Tuned Mass Damper(TMD)vibration damping control mechanism and structural finite element model,single-group,2-group and 5-group TMD vibration-damping control schemes are designed and arranged.The effects of deterministic crowd jumping load,random crowd jumping load and the structural vibration control of TMD device under complex working conditions were analyzed.The analysis of the structure shows that the single-group TMD vibration-damping effect is not good,and the multi-group TMD vibration-damping system has a good vibration-damping effect.Optimizing the TMD device at the appropriate location of the structure can effectively improve the vibration-damping efficiency of the structure under crowd jumping load.