Research On Seismic Performance And Design Method Of Continuous Girder Bridge With High Piers Of Concrete Filled Steel Tubular Laced Column

Continuous Girder Bridge with High Piers of Concrete Filled Steel Tubular Laced Column is a new type of bridge with good bearing capacity,high stiffness,better ductility and energy dissipation capacity,beautiful shape and easy construction,which also are suited to span valley in intense seismic area for its light weight,in comparison with traditional reinforced concrete structures.At present,the aseismic research usually focus on dynamic characteristics of structure by real bridge,while there are few reports on seismic performance and analysis method of this new type structural parameters.Therefore,this paper taking Sichuan Ganhazi bridge as the engineering background,aim to study the seismic performance of Continuous Girder Curve and Straight Bridge with High Piers of Concrete Filled Steel Tubular Laced Column,seismic applicability of different design parameters based on Midas Civil software,and then simplified methods of seismic analysis method for practical engineering purpose is put forward under earthquake loading.(1)Analysis of the dynamic behavior of elastic and distribution of dynamic internal force of Continuous Girder Straight Bridge with High Piers of Concrete Filled Steel Tubular Laced Column with three-spans is studied.On the basis,the influence and application scope of structural parameters are researched fron conceptual parameters design under El earthquakes,which include rigidity ratio of beam-pier,girder depth-span ratio,beam width span ratio,axial compression ratio,seismic isolation device;parameters of column Include the pier height,longitudinal slope,steel ratio of longitudinal,yield strength of steel,strength of concrete and spacing of top longitudinal;connection parameters of lacing tubes covers arrangement type of lacing tube,diameter ratio of lacing tubes and longitudinal tubes,number of bracing element,vertical spacing of flat lacing tubes,make an optimization criteria of bridge structure designing,and the reasonable selection range of parameters design is suggested.The results show that conceptual parameters design(except girder depth-span ratio)are the most sensitive to the indexs of bending moment,axial force and displacement response value,followed by parameters of longitudinal,constructor argument of colum limb have a minimal impact.Optimum design of bridge was carried out on the base of numerical results,and calculation results indicated that seismic response of optimized model reduced greatly.(2)Using the same research methods,studies the influence law of seismic performance of Continuous Girder Curve Bridge with High Piers of Concrete Filled Steel Tubular Laced Column,adding curvature radius and seismic excitation angle.Meanwhile contrast the rule of design parameters with strait line bridges.It is found that not to neglected the bending-torsional coupling effect when radius of curvature less than 350m;the influence laws of girder moment,axial force and pier top displacement of seismic performance are basically similar between curve and straight bridges when radius of curvature greater than or equal to 350m,whereas the index of pier moment varies in different parameters design;both 0° and 90° are the most unfavorable conditions seismic excitation angle.Besides the optimized structure is quite effective as it can reduce the seismic response and improve seismic performance.(3)The response spectrum for Continuous Girder Straight Bridge with High Piers of Concrete Filled Steel Tubular Laced Column are analyzed by elasto-plastic seismic time-history analysis under major earthquake.Philosophizing about the force distribution of whole bridge,ductility,yield and damage process of the column pier.And seismic performance of six design parameters sensitibed to seismic response are analyzed,such as rigidity ratio of beam-pier,steel ratio of longitudinal,axial compression ratio and so on.The result indicate that Continuous Girder Bridge with High Piers of Concrete Filled Steel Tubular Laced Column has good advantages of seismic performance,high ductility;The ductile earthquake performance of pier present a different number of drops with rigidity ratio of beam-pier,pier height,axial compression ratio,beam width span ratio,steel ratio of longitudinal increase,and the seismic performance indexes can be improved to different extent after adding the seismic isolation device.Meanwhile contrast the response analysis of elasto-plastic and elasto of different design parameter models of Continuous Girder Bridge with High Piers of Concrete Filled Steel Tubular Laced Column are carried out.Borrowing from the aseismic design method of reinforced concrete bridge,which in JTG/T B02-01-2008?Guidelines for Seismic Design of Highway Bridge?,a simplified method for seismic analysis of Continuous Girder Bridge with High Piers of Concrete Filled Steel Tubular Laced Column is proposed basing on vibration period of bridge structure,and then verified through different seismic waves,fortification intensity,IDA.The results show good agreement between equivalent elastic and elasto-plastic methods.These research findings will provide theoretical basis for the seismic design of this kind of bridge,which can provide reference for the further improvement of seismic design codes of concrete filled steel tubular composite structure.