Study On Blasting Seismic Response Of Long Span Suspension Bridge

In recent years, applications of blasting in highway transportation construction spreadwidely. Frequent blasting met the project requirements and obtained enormous economicbenefits, but produced a series of harm at the same time. At present, according to the highspeed construction in China, land resources are becoming more and more valuable. And manyhighway erections, new road construction is likely to effect facilities near the highway, whichincludes the blasting construction disturbance. Although the design of blasting constructioncan be controlled, the blasting and blasting wave propagation through complex medium islikely to destruct adjacent structures. Therefore systematic study of blasting seismic wavecharacteristics, the action of blasting seismic wave, and the dynamic responses of highwaybridge structure, has very important meaning.Taking the highway suspension bridge as the research object, the blasting vibrationresponse is studied. Suspension bridge dynamic property and dynamic analysis method,research status was studied through the response spectrum analysis method and time historyanalysis method, to obtain a detailed action of blasting seismic wave and the dynamicresponse of suspension bridge. The main contents of this paper are as follow:1. Firstly, the blasting seismic wave characteristics, blasting seismic wave input, kineticdamping, soil structure dynamic interaction, traveling wave effect, more incentive problemand nonlinear problems of long span bridges were studied. The main influence factors ofblasting seismic response to long-span bridges are discussed. And the bridge seismic responseanalysis response spectrum method, bridge spatial nonlinear seismic response analysismethod, and the random seismic response analysis method for long span bridges wasintroduced and their advantages, disadvantages were pointed out respectively.2. The suspension bridge finite element modeling problem was undertook in detailedanalysis, through the reasonable selection of different finite element to simulate the structuralcomponent performance and establishment the correct structure finite element model. In thedynamic response spectrum analysis, the superposition method of vibration modeparticipation coefficient and mode combination methods (SRSS, CQC) are studiedrespectively, as well as effect of input dimension to the blasting vibration structural response.3. Inputting the measured blasting seismic waves curve, the suspension bridge structureon the consistent linear blasting seismic response was studied, and the calculation results by response spectrum method were compared. Using considering suspension bridge geometricalnonlinear properties finite element program through uniform excitation blasting nonlineartime-history analysis, the geometric nonlinearity on the blasting seismic response of structurewas studied.4. The Penzien model was used to establish finite element model to consider the pile-soil-structure interaction and compared with the base of pier consolidation model for modalanalysis. Considering traveling wave effect, local site effect, the method of time-historyanalysis was applied to analyze non uniform blasting seismic response of suspension bridgestructure.5. Based on actual engineering, influence of the adjacent blasting on long-spansuspension bridge anchorage system was studied. And the anchor span strand and anchoragedynamic response is calculated and compared with the measured values.