The Cause Analysis Of Abnormal Vibration Jiantan River Bridge Double Line Bridge

Jiantan River Bridge and the double line bridge are hollow type catenary reinforced concrete box arch bridge.In dynamic test, the dynamic characteristics of the Jiantan river bridge, normal structure dynamic performance basic meet the requirements of bridge normal use, test vehicle impact across the bridge and double line bridge effect significantly, the measured(μ) maximum impact coefficient of 0.36(for 70.0 m span arch bridge, impact coefficient according to the old standard should not be considered, according to new standard value of 0.13), the largest vertical vibration acceleration peak peak of 1.431 m/s2, the horizontal vibration acceleration peak peak of 0.716 m/s2, biggest impact effect significantly, abnormal vibration phenomenon. Aiming at the phenomenon of abnormal vibration in this bridge has carried on the finite element numerical simulation analysis, to explore the related reason of abnormal vibration, the main research content has the following several aspects:First:first according to the Jiantan River Bridge of double line bridge design data to establish a finite element model, and by adjusting the material parameter correction model, the natural vibration characteristics of the model and the actual structure as far as possible close to, and based on this theoretical model to compute the arrow beach river bridge dynamic response of double line bridge, will impact coefficient calculated value with the arrow beach river bridge and its impact coefficient is analyzed by the comparison between double line bridge in order to explore the rationality of the model and the related factors of abnormal vibration.Secend:collecting 41 arch bridge’s dynamic test data, the structure of the natural frequency, impact coefficient, damping ratio and statistical parameters, in order to explore the main factors influencing the impact factor;In combination with the Jiantan River Bridge of double line bridge deck are the characteristics of the wavy groove, adopts frequency conversion for the space time frequency method, simulation of the bridge under the condition of uneven vehicle.the effect, in order to explore the Jiantan River Bridge of double line bridge is the main cause of abnormal vibration.Main conclusions are as follows:First:bridge deck is not smooth and the joint action of vehicle bridge coupling vibration of two factors are the decisive factors influencing the impact factor.Jiantan River Bridge of double line bridge bridge technique condition is bad, is an obvious wavy groove, get off at this condition the impact of the structure of the bridge bridge frequency coupling effect significantly, the two factors are combined arrow beach river bridge is one of the main reasons for abnormal vibration of double line bridge.Secend:the speed change on impact coefficient has a certain degree.From the Jiantan river bridge double line bridge of double line bridge in not considering the theoretical model calculation of bridge deck when uneven, impact coefficient is increased with the increase of the speed of the car, this part indicates that the speed of double line and Jiantan river bridge double line bridge bridge of abnormal vibration has certain relevance.Third:the influence of rise-span ratio on impact coefficient is has the certain regularity.Arch rise-span more hours, and its beam structure features tend to be more obvious, at the same time in the first two order frequencies tend to be close to vertical, such easy to cause the axle frequency coupling, so as to increase the impact effect.Statistical analysis results indicated that the Jiantan river bridge double line bridge of double line bridge rise-span ratio have a certain correlation with the abnormal vibration.