Study On The Influence Of Blasting Vibration For Long-span Suspension Bridge Anchor System

The underground structure vibration effects of long-span bridge caused by blasting vibration are important factors to affect the safety of bridge. Suspension bridge, because of its strong spanning capacity and high seismic performance, are becoming the first choice in long-span bridges. As its main underground structure, under the action of blasting seismic waves, the blasting vibration effect of the anchor is notable, which relates to the safety of the whole structure. However, there is little research papers for the blasting vibration effect of suspension bridges'anchor system. So, it is necessary for the choose of topic.First, this paper studies the formation of blasting quake waves and the rule of blasting quake wave attenuation, analyzes the difference of the blasting quake and earthquakes, the influencing factors of blasting quake effects and the influence of blasting quake wave on nearby building. Based on the summary of the existing related standard, points out the limitations of the existing structures of blasting vibration safety evaluation method, puts forward a reasonable blasting quake safety assessment method of bridge structure.Secondly, this paper introduced the development of blasting vibration theory, studies two kinds of structure dynamic response analysis method'fundamental principle which incloud the response spectrum analysis theory and the dynamic time-history analysis theory, and simple introduced the calculation methods of dynamic time-history analysis theory. Through deducing the analytical formulas of stay-cables static and dynamic characteristics, this paper analyses the influence of each parameters for cable characteristics, provide a theory basis for research in the dynamic response of anchor span strand under the action of blasting seismic.Finally,combined with an actual project, this paper come to some useful conclusions, through the simulation analysis for the dynamic response of long-span suspension bridges' anchor system which under the action of blasting seismic waves. And suggest a safe distance of anchor system for blasting vibration which caused on this project, proved the feasibility of safety assessment method about the blasting vibration.