Research On Serviceability Evaluation Of Tall Buildings In Wind-induced Weak Vibration

With the development of light-weight and high-strength materials,tall buildings are becoming lighter and more flexible.The vibration response of the structure under the impact of wind load is more significant,which often makes people feel uncomfortable in the structure,and the problem of vibration serviceability is very prominent.Whether the calculation model is reasonable or not directly determines the correctness of the calculation results,so the study of reasonable calculation model is particularly critical.The traditional calculation model based on structural safety is established on the basis of strong ground motions.Generally,only the main bearing components of the structure are considered,while the non-bearing components are ignored.However,compared with strong ground motion,the structural deformation caused by weak vibration such as fluctuating wind,train vibration load and pedestrian load is limited.These non-bearing components participate in structural vibration at the same time,thus changing the stiffness,mass distribution and damping characteristics of the structural system.Therefore,it is unreasonable to apply the traditional structural safety-based calculation model to the calculation and analysis of weak vibration such as fluctuating wind.It is necessary to establish a structural calculation model which can reflect the real dynamic characteristics of the structure under load.In this paper,a sophisticated model and serviceability evaluation in weak vibration are studied based on a coastal tall building by combining field measurement with numerical simulation.The main work is as follows:(1)Explain the difference between strong vibration and weak vibration,analyze the difference in model simplification,and analyze the influencing factors of the sophisticated model.Considering the four model updating factors,i.e.infill wall,facing decoration,stairs and live load value,a general construction method of sophisticated calculation model of tall building structure under weak vibration is proposed.Taking a coastal tall building as an example,the correctness of the sophisticated calculation model is verified by comparing the measured results with the numerical simulation results,it is proved that the sophisticated model based on the above four factors is reasonable.(2)The basic theory of linear filtering method is introduced in detail,and based on AR model of linear filtering method,the 10-minute along-wind fluctuating wind speed time history at each height of the tall building is simulated,and the validity of the simulation is verified,it is considered that the simulated wind speed time history can be applied to the analysis of wind-induced response of structures.(3)The simulated along-wind fluctuating wind loads are loaded on the initial finite element model and the sophisticated calculation model respectively,and the dynamic analysis is carried out to obtain the acceleration response results,the difference of vibration response between the two models is analyzed.The sensitivity of the damping ratio and its influence on the vibration response is analyzed.Finally,making the damping ratio 0.02,and the wind-induced serviceability of the two models is evaluated by the relevant serviceability evaluation standards at home and abroad,which proves that the initial calculation model is not reasonable for serviceability evaluation.