Human-induced Vibration Response Analysis Of Long-Span Structures Considering Human-structure Interaction

With the development of lightweight and high strength materials in the field of civil engineering,the design of building structures is becoming lighter and lighter.As a result,the fundamental frequency of the structure is easily close to the pedestrian step frequency,resulting in the problem of excessive vibration of the structure.Overvibration of structure under pedestrian load will affect the durability and safety of structure,as well as the comfort of pedestrian walking.In this paper,the long-span pedestrian overpass is taken as the research object,and the corresponding research is carried out around the modeling of random crowd model,the establishment of the vertical dynamic equation of random crowd-structure and the vibration reduction design under the uncertainty of structural modal parameters.The main contents of this paper include:1.The acceleration response and the change of modal parameters of the pedestrian overpass under the action of single person walking are analyzed in depth.Based on the simplified analysis of MF,MSD and MMSD models for single person,the coupled motion equation of pedestrian-bridge is established.The acceleration response and modal parameters of pedestrian overpasses under single person walking are analyzed.The differences of coupling equations under three simplified models are compared and studied.The effects of pedestrian dynamic parameters on structural responses are considered,including Human body mass,equivalent stiffness,equivalent damping and pedestrian walking force are the main factors.2.The simulation method of walking load based on pedestrian step size is deeply studied,and the randomness of walking crowd is analyzed,including the vertical coupling effect of pedestrian-structure,the difference between pedestrians and the randomness within individuals,the interaction between pedestrians and pedestrians and the synchronization rate of the walking movement of the crowd.The random crowdstructure coupling motion is established.The force equation,the discrete model and the centralized model of random population are proposed.3.Based on the proposed random crowd walking model,the instantaneous acceleration response,instantaneous frequency and instantaneous damping ratio of pedestrian overpasses with different modal mass and different fundamental frequencies are analyzed.4.The dynamic coupling equation of pedestrian-bridge-TMD is established,and the uncertainty of instantaneous damping ratio and instantaneous frequency of pedestrian overpass under random crowd walking is deeply studied.A vibration reduction strategy considering human-structure interaction under pedestrian walking is proposed,and the acceleration response of random walkers is studied.