| Reinforced concrete double-column piers are widely used in highway bridges of small or medium span and urban viaducts.However,due to the weak deformation capacity of reinforced concrete structure,it is vulnerable to serious damage in earthquake,especially when the pier is low or the stirrup configuration is insufficient,the structure will undergo brittle failure.In order to solve the problem of reinforced concrete structure,a new type of steel-concrete composite structure is proposed,and the structure form is double-column pier.In this paper,the experimental research and theoretical analysis on the seismic performance of piers are carried out.The main research contents and conclusions are as follows:(1)In this paper,two tubed reinforced concrete double-column piers are designed and manufactured,and the test is carried out.Based on the test results,the failure mode,loaddisplacement curve and stress development of steel bar and steel tube of the double-column pier were studied.Then the bearing capacity,ductility and key seismic performance indexes of the structure are analyzed.Finally,the seismic performance of the pier is evaluated.(2)According to the size of the specimen,the finite element model of tubed reinforced concrete double-column pier is established.The accuracy of the model is verified by comparing the model and experimental results.Based on the correct model,the stress state of steel tube,steel bar and concrete is analyzed.Then,the influence of various parameters on the doublecolumn pier is explored.According to the results of parameter analysis,the design suggestions of tubed reinforced concrete double-column pier are put forward.(3)The fiber finite element model of tubed reinforced concrete double-column pier is established,and the hysteresis curve of the model is in good agreement with the experimental results.According to the correct modeling method,the influence of the tie beam on the structure is explored,and the design suggestions are put forward.It is suggested that the tie beams should be evenly arranged along the height of the pier,and the range of beam-column stiffness ratio and linear stiffness ratio is 0.5-1.0 and 0.42-0.84.(4)On the basis of test and numerical analysis,the force mechanism of double-column pier is discussed,the force analysis model is established,and the calculation formula of horizontal bearing capacity is put forward.The predicted results of the formula are in good agreement with the experimental results.At the same time,combined with the code,the structural measures are proposed. |
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