Research On Seismic Performance Of Double-Column Pier Bridges Arranged With Energy Consuming Tie-Beams

Double column pier viaduct is widely used with its unique advantages.When the pier height is high,reinforced concrete tie beams and other structural measures are often set between the pier columns to improve the overall stability of the pier.The existing earthquake damage shows that due to the improper setting of traditional reinforced concrete tie beam,the joint position of pier and tie beam will be cracked,and even the plastic hinge of pier will cause pier failure,which will bring great difficulties to the repair work of pier.In recent years,the structural system with replaceable members has become a new research direction in the field of earthquake resistance of engineering structures,and has been widely concerned by scholars and engineers of seismic engineering all over the world.The energy dissipation of the structure with replaceable members is mainly concentrated on the replaceable members.Therefore,in this dissertation,two new types of replaceable energy dissipation tie beams are proposed and applied to double column pier bridges,and their seismic performance is systematically studied.The main research contents and conclusions are as follows:(1)Based on the finite element software SAP2000,this paper analyzes the seismic performance of double column pier bridge with traditional reinforced concrete tie beam,and studies the influence of tie beam stiffness,tie beam number and capping beam on the seismic performance of double column pier bridge.The results show that: the development of plastic hinge at the bottom of double column pier is obvious,and shear failure is easy to occur;the hysteretic curve of reinforced concrete tie beam is full,and the bending moment and stress response at the end is large,so the tie beam is easy to be cracked and damaged under earthquake action;the stiffness of tie beam,the number of tie beams and the capping beam will affect the distribution of bending moment and rotation angle,the shear force at the bottom of pier and the dynamic response of displacement at the top of pier,and the development of plastic hinge is affected.(2)Two new types of energy dissipation tie beams are proposed.Based on SAP2000,the detailed analysis of parameters is carried out to verify the energy dissipation effect of the tie beam on the double column pier,and the ductility design of the double column pier is realized.The damping effect of the tie beam is compared with that of the traditional reinforced concrete tie beam.The results show that: the hysteretic curve of energy dissipation tie beam is full,which can replace the traditional reinforced concrete tie beam to play the role of energy dissipation,improve the stress of pier,restrain the development of plastic hinge of pier,and reduce the shear force at the bottom of pier and displacement response at the top of pier.(3)This paper makes a comparative study of the two kinds of energy dissipation type tie beam before and after the installation of the double pier rigid frame bridge.The results show that the X-type energy dissipation tie beam can improve the plastic hinge at the bottom of the pier,effectively reduce the bending moment,curvature and shear force at the bottom of the pier,and also reduce the longitudinal collision displacement of the pier top and main beam;The results show that the damping effect of the A-shaped energy dissipation tie beam arranged according to the first form is better than that of the second form.Both forms can reduce the bending moment and curvature of the plastic hinge at the bottom of the pier and the shear force at the bottom of the pier.Among them,the decrease of the response value of the lower time history is more obvious.