Study On Seismic Behavior Of Reinforced Concrete Pier Bending Shear

Recent years,strong earthquakes happened frequently,and pier is the weak part of bridge,researchers has focused much attention on the seismic performance of bridge piers,the seismic theory is becoming more and more maturational,and the seismic analysis method is becoming more and more perfect.So far,many countries have formed it’s own systematic code for seismic design.Although there are special seismic design codes for highway and railway engineering in China,but with the rapid development of China’s transportation construction,there are some shortcomings and limitations in China’s seismic design code.At present,the study on the bearing capacity and the damage state of the pier column of the bending shear failure still needs to be calculated by the method of bending failure and shear failure.The bearing capacity of the ductility and the plastic hinge area of the pier column is greatly influenced by the axial force.the seismic behavior of piers under complex loading is studied as follows:(1)This paper summarizes the research status of seismic design of piers,seismic design ideas,methods and ductility seismic calculation methods of piers,so that to grasps the seismic design of piers comprehensively.(2)The contents of ductility design of seismic codes in various countries are compared and analyzed.Including the plastic hinge,plastic hinge shear bearing capacity calculation and structure characterization of ductility index and ductility calculation and other aspects of the comparison,pointed out the need to improve Chinese seismic code,the seismic ductility index and plastic hinge resistance comparison and analysis of the safety degree of the standard shear energy.(3)The influence factors of the failure mode of pier column are analyzed.The bending failure occurs mainly in the case of larger shear span,smaller axial pressure and reasonable reinforcement,and the shear failure occurs mainly in small shear span,larger axial pressure,larger reinforcement ratio and smaller stirrup rate.The influence factors of shear bearing capacity and displacement ductility coefficient of plastic hinge section are studied.The results show that the shear capacity of concrete increases with the increase of axial compression ratio,decreases with the increase of shear span ratio and decreases with the increase of displacement ductility coefficient,and decreases with the increase of axial compression ratio.The shear span ratio increases with the increase of stirrup ratio.The formula for calculating the cross section of the plastic hinge area and the calculation formula of displacement ductility coefficient are fitted.The comparison with the test results shows that the theoretical results are in good agreement with the experimental data,and the precision of the fitting formula is high,and it can be used for the calculation of the shear bearing capacity of the section of plastic hinge section.(4)In view of the similarities and differences between the highway seismic code and the railway seismic code,this paper compares and analyses the earthquake resistance of highway bridges and railway bridges through an engineering example.The results show that the method of determining the earthquake force adopted by the highway code and the railway code is different,and the seismic response of the structure is also different when the seismic checking calculation is carried out according to the different norms..Due to the limitation of the seismic understanding,the design of the early reinforced concrete pier has defects.The ultimate state of the pier designed according to the current standard is the flexural failure of the ductility and the seismic performance.