Numerical And Experimental Studies On Vibration Serviceability Of Different Types Of Long-Span Floor

With the application of new building technology and new materials,multi-storey and long-span buildings with unique shapes and different shapes have made great progress.The long-span floor structure is prone to the characteristics of low frequency and low damping,and the problem of vibration serviceability is more prominent.At the same time,people’s demand for a better life is increasing,and the requirements for buildings are more inclined to use comfort.In order to study the mechanism of human-induced vibration response of long-span floor and solve the problem of vibration serviceability of long-span floor,this paper uses the combination of numerical simulation and field test to analyze the human-induced vibration response of prestressed concrete floor,and compares the vibration serviceability performance of prestressed concrete floor,well beam floor and steel-concrete composite floor.The vibration control method of long-span floor is studied.The main research work of this paper is as follows:(1)The field test of human-induced vibration of prestressed concrete floor is designed and completed.The results show that the measured first 6 natural frequencies of the floor are distributed from 8.30Hz to 13.28Hz,and the measured damping ratio is 0.03.The vibration response of the floor under human-induced load is mainly concentrated in the load excitation frequency and the natural frequency of the floor in the frequency domain.The floor vibration caused by mid span excitation is limited to the plates on both sides of the mid span short axis,and the dissipation varies greatly when the vibration is transmitted around along different paths.The influence laws of human-induced load scale,frequency,action position and type on floor vibration response are different.The peak acceleration limit of the floor dominated by rhythmic movement is recommended to be 0.4m/s~2.Foreign AISC,ISO and domestic JGJ/T 441-2019 standards have high reliability for floor serviceability evaluation.(2)The numerical simulation of human-induced vibration of prestressed concrete floor is carried out by using finite element analysis method.The results show that the applied prestress has little effect on the dynamic characteristics of the floor,and the beam shell model has high calculation accuracy and efficiency.The time history curves of walking force of different walking load models vary greatly,and the calculation results of vibration response are close;The time history curves of jumping force of different jumping load models are similar,and the vibration response results are quite different.The vibration response of the floor is affected by the excitation load frequency and its own fundamental frequency,and the degree of influence is related to the load type.Increasing the prestressed beam height,floor thickness and concrete strength grade can significantly improve the natural vibration frequency of the floor,and reducing the prestressed beam spacing,increasing the slab thickness and the additional dead load of the floor can significantly reduce the vibration response of the floor.(3)The vibration serviceability performance of different types of long-span floors is compared,the TMD damping design of steel-concrete composite floors is studied,and the research method of vibration serviceability of long-span floors is discussed.For new,under construction and existing buildings,it is recommended to use different research methods to analyze the floor vibration response.The research conditions should be divided into normal use conditions and extremely adverse conditions.The problem of floor vibration serviceability should be solved from the perspective of design and vibration source.