Experimental Study On Fatigue Properties Of Parts Of Members Of Reinforced Concrete Rib Beam Bridge

Reinforced concrete simply supported t-shaped beam bridge is one of the main structural forms of the bridge.On the one hand,the deck slab is directly subjected to the wheel load,at the same time,the wheel load is diffused,and the load is transferred to the main beam.In addition,bridge deck and beam ribs together constitute T-shaped beam,which is an important part of the main beam.Bridge deck is an important local stress component in bridge.Whether it is damaged or not will directly affect the bearing capacity of the main beam and the comfort and safety of vehicle.Unfortunately,the design is only done according to static load,and its fatigue performance is not taken into account.In fact,with the development of economics,the proportion of heavy-duty vehicles is increasing.Under the repeated action of axle load,especially the axle load of heavy-duty vehicles,the damage of bridge deck will accumulate,and finally the bridge deck will be destroyed.Therefore,it is of great significance to study the fatigue performance of bridge deck in order to prolong the service life of bridge,ensure the safe operation of bridge and guide the anti-fatigue design of bridge deck in the future.In this paper,a certain amount of research on the fatigue properties of concrete reinforced bridges at home and abroad is evaluated.Based on the design drawings of 16m reinforced concrete standard T-shaped beam bridges,the static load and fatigue tests of double T-shaped beam pavement slab model on a scale of 1/4 are carried out.And in view of the damage theory of concrete and the damage model of steel bar,the fatigue performance of reinforced concrete pavement slab is studied.The main contents of the study are as follows:(1)To study the mechanical behavior and failure form of reinforced concrete T-shaped beam bridge under static load in order to research the reinforced concrete T-shaped beam bridge deck by using the double T-shaped beam dead load model.At the same time,the ultimate bearing capacity of the pavement is determined,which lays a certain foundation on the fatigue test of the pavement.(2)The fatigue test of double T-shaped beam pavement slab model is carried out to study the stress behavior and fatigue failure form and mechanism of reinforced concrete T-shaped beam bridge under constant amplitude fatigue load.(3)The damage parameters of concrete and steel bar are calculated,and the finite element models of pavement slabs under different working conditions are established by using the finite element analysis software abaqus.The influence of fatigue load level on the fatigue behavior of pavement slabs of reinforced concrete T-shaped beam bridge is studied.The main achievements of the paper are as follows:(1)Through the static load test,the force mechanism and failure mode of the lane slab of reinforced concrete T beam bridge under the static load are obtained.Under the static load,the loading behavior of the roadway slab is divided into three stages,and the ultimate failure pattern is punching shear fracture.The crack load of the roadway slab model is determined to be 26.71 kn,and the ultimate load is 72.6kn.(2)The mechanism and failure pattern of lane plate fatigue failure under constant amplitude fatigue load were found.(3)Based on the fatigue damage model of steel bar and concrete,the relationship between fatigue load level,the aspect ratio of roadway slab length and fatigue life is obtained by using ABAQUS fatigue analysis model.The research achievements of this paper can be used as a reference for the design of pavement slab of reinforced concrete T-shaped beam bridge.