Monitoring And Analysis Of Constructing Continuous Girder Bridge Under Blast Vibration

As the continuous promotion and application of engineering blasting technology,the safety problem of blasting vibration for bridge structure has paid more and moreattention to the humans and government, especially the bridges is constructing, itssecurity goes without saying. The structure safety and bridge construction safety hasalways been a relatively new research topic. At present our country in the specificationhas no safety assessment methods for bridge structure under the effect of blastingvibration, therefore, this article’s research is very necessary.Firstly,this paper introduce the related knowledges of blasting seismic wave, andintroduces the national standard of blasting vibration safety assessment in detail, andlaid the foundation for the study of effect of blasting vibration.Second, the paper introduces the two basic method from theoretical basis whichanalysis dynamic response of structure,one is response spectrum analysis method,theother is the time-history analysis method.These help us analyze the problem in a reliableway.Then, equipment testing、 arrangement of blasting instruments have made simpleintroduction, and introduce analyze signals which we collect with the wavelet analysismethod, get the continuous girder bridge’s main vibration frequency band range from15.625～125Hz under blasting vibration,and we analyze the parameters which wecollected in detail, get the forced vibration attenuation effect of continuous girder bridgefrom substructure to the upper structure: the attenuation average coefficient undertriplexer’s is0.204、0.147、1.371in the construction stage and0.357、0.642、3.783inthe completed bridgephase.Furthermore, according to the basic information of the bridge, we established finiteelement model of entities. And analyze the model with dynamics analyze method,finally it is concluded dynamic response characteristics that the structure of this bridgeunder the action of blasting vibration. We give the continuous girder bridge’s upperstructure a anti-crack check,get the maximum stress1.045MPa on the concrete of edgeof the beam,is less than the multiple of0.7of the C50concrete’s values of axis tensilestrength standard,meet the anti-crack requirement and couldn’t cause the section’sdestruction. Finally, we contrastive analysis the datas which we monitored under blastingvibration and the control standards,we obtain that90percentage of the vibrationvelocity peak data and the whole frequency data in our control range,over80percentage frequency data in the range of20～50Hz.We provide a control standard ofcontinuous girder bridge under blasting vibration,in order to offer the foundation tomonitoring the blasting vibration on continuous girder bridge in the future.