A Survey Of Vibration-Reduction Control Of Long Cantilever Structure

In recent decade years,Beam String Structure(BSS)is a type of long-span prestressed space structure system.Strut bars bring upward component forces by stretching bar connecting arches and cables,and induce top chord to produce initial force and deformation contrary to those under external loads.Then initial force of top chord will reduce and the deformation of structure will decrease.There are definite researches at some aspects,special in complex long-span structure or two simple supported ends.But length cantilever structure study rarely directly applies to the principle of beam string structure of reasonable load and force flow,and how to effectively reduce end vertical displacement and root moment of length cantilever structure.These questions have become hot topics in engineering.Based on the above mention,the principle of Beam String Structure applies to cantilever structure,and a new cantilever spatial truss string structure(CSTSS)is established in this paper.In consideration of different pretension force,different strut height and arranging different number struts,this paper has carried out mechanical property analysis,free vibration characteristics analysis and time-history analysis of earthquake response.The results show that this cantilever roof structure has some advantages,such as concise shape,fluency and easy to construct;root hinge fully make use of mechanical property of space truss,and make structure force more reasonable,and avoid lower pillars to endure great moment;structure rods mainly endure axis force and few moment,this can fully avails material stiffness and effectively reduce vertical displacement and root moment of cantilever structure.Seismic hazard is one of natural hazard for mankind.Earthquake is paroxysmal and unpredictability,which can cause great personal injury and property loss. Long-span structures belong to flexibility system and have small damp ratio.So CSTSS may occur much more vibration and affect structure normal use and safety under dynamic loads,such as wind load and seismic force.Most of cities in our country are in earthquake regions.So it is great important to do earthquake resistance and vibration reduction in long-span structures.With the successful appliance of structural vibration control in multiple and high-rise and towering buildings,a lot of scholars,at home and abroad,have put attention to development potential of vibration control and have done relevant research on it.So far,however,the research has merely been in starting stage and has not formed systematic theory. This paper applies viscoelastic damper in CSTSS and discusses structure vibration reduction of cantilever roof structure with viscoelastic damper,and Analyzes structure seismic response between control structure and uncontrolled structure.The results show that viscoelastic damper can efficiently reduce seismic response in CSTSS.