Resonance Analysis Of Municipal Bridges And Vehicles In The Congested State

With the rapid growth of motor vehicle ownership, traffic congestion in major citiesappeared frequently. The study found that car congestion in static loads will not cause directharm to the city bridge. However, under dynamic loads, the situation is quite different whenthe engine is idling vehicle congestion, that the engine speed is at600to800rev/min(frequency of10.0~13.3Hz) within this frequency in the ground much of the bridge in-band(1.23Hz~14Hz) range. Consider the engine idling vibration, the displacement and stresslevels of the bridge were increased significantly compared to static load. When car engineidling speed order is similar or same to the frequency of the bridge, the resonancephenomenon may occur. Combined with previous theoretical research power structure,access to city bridge traffic jam situation related statistics, selected a representative citybridge to expand research in this area.This paper selected a three-span continuous girder bridge in Shenzhen as an example,based on statistical analysis and vehicle bridge city urban vehicle traffic characteristicsconsisting of city bridges vehicle type, vehicle length, axle weight, wheelbase, vehicle pitchand other parameters investigation. Optional bus congestion load as the load model, the staticbus idling, dynamic loads and dynamic load amplitude of the engine caused by taking20%of the dead load. Due to the dynamic load effects of congestion and the engine has a lot ofthe initial phase, this article from the perspective of the most unfavorable load designedphase or anti-phase with seven kinds of traffic jams less favorable working conditions.Using ANSYS finite element model of the bridge simulation analysis, obtain thevibration characteristics of the bridge, and calculate the amplitude of seven kinds ofconditions at the bridge-the bridge frequency transient response relationship, as well as thethree most unfavorable conditions of traffic jams. Thus found that the role of a bridgetwo-way traffic jam adverse effects compared with one-way traffic jam, vertical bendingvibration coefficient greater than the torsional vibration dynamic load response. Finally,modify the bridge constraints resonance effect on traffic jams and simply supported beambridge continuous rigid frame bridge further study concluded that under the same traffic jamresonance, vibration effect simply supported beam bridge minimum; continuous rigid framebridge vertical bending vibration response than large continuous girder bridge, and torsionalvibration response of continuous beam bridge over small. For a small city known bridgespan, choose the form of simply supported beam structure is more conducive to reducing traffic jams caused by resonance bridge structure damage.