Study On Bridge Failure Mechanism Under Flood Wave-Current Coupled Stress

Bridge is the main form of road crossing rivers.Its appearance has made remarkable contributions to ensuring smooth road traffic and discharging flood.But it is precisely because of its role and location that it often happens collapse accidents.According to statistics,flood is one of the main causes of bridge damage,and the forms of damage are also varied.Flood is a common disaster in nature.More and more casualties and losses are urging us to strengthen the research and protection of flood.At present,the well-known flood control measures are generally divided into engineering measures and non-engineering measures.Among them,engineering measures refer to soil and water conservation,strengthening the construction and maintenance of water conservancy projects,setting up safe and effective flood control projects and optimizing canals and rivers.Non-engineering Measures refer to taking corresponding measures in advance through rainfall and mountain flood warning to achieve the purpose of preventing disasters in the future,studying the situation of various regions in China to make flood control planning in advance for disaster-prone areas,and improving the remedial measures after disasters.Up to now,there are many studies on the damage of bridges caused by floods at home and abroad,but there are few studies considering the effect of the coupling of current and wave on bridges,which makes the flood control measures imperfect.Therefore,in this paper,when studying the damage of bridge caused by flood,the coupling loads caused by flood,including hydrostatic,hydrodynamic and fluid-solid coupling,and the effects of various parameters such as water depth,velocity and wave height on the damage effect are taken into account.On the basis of the existing experiments,the following work has been done in this paper:(1)Firstly,the origin and characteristics of flood are consulted,and the characteristics of load caused by flood are studied.On the basis of previous experiments,the formulas of current load and wave load suitable for this paper are given,and the factors affecting them are analyzed.(2)Taking the deck reinforced concrete arch bridge as the research object,the finite element model is established,and the whole model and fluid-solid coupling method are adopted to simulate the load action of flood on the bridge by ANSYS.(3)By controlling the three parameters of water depth,velocity and wave height to change the load on the arch bridge,the influence of wave and current load on the stress and displacement distribution of the bridge is explored,and the mechanism of the coupling load is obtained.(4)Establish the reinforced structure model,replace the reinforced concrete material with rigid material,explore the dynamic response of the reinforced structure under the same working conditions,compare the stress and displacement changes of the two structures,and find out the weak area of the stressed structure,so as to provide the basis for flood control measures in practical projects.