Performance Analysis Of Reinforced Concrete Hollow Pier Based On Dynamic Test

Highway bridges are lifeline projects.Pier is an important part of bridge structure,and hollow section pier is more and more widely used in practical engineering.However,there are few studies on hollow piers at home and abroad,especially hollow piers with rectangular cross-section.Most of the existing research methods use quasi-static method,which ignores the influence of concrete strain rate on its performance and cannot accurately describe the response of the structure under earthquake.Therefore,it is necessary to conduct shaking table tests on reinforced concrete hollow rectangular piers,and then study the seismic response of reinforced concrete hollow rectangular piers under actual earthquake.The main contents of this paper are as follows:(1)Seven reinforced concrete hollow rectangular pier models with different stirrup ratio,reinforcement ratio and axial compression ratio were designed,manufactured,and shaking table tests were carried out.The failure phenomena and failure modes were studied.It was found that all pier specimens had through cracks,and the cracks were horizontal cracks,indicating that the specimens were bending yielding.After all the working conditions,the seven piers did not collapse and had good vertical bearing capacity.Damping ratio of each pier has little change,ranging from 0.02 to 0.064.(2)The experimental data are analyzed and processed to study the dynamic characteristics,acceleration response,displacement response,dynamic amplification coefficient,displacement ductility coefficient and energy dissipation of each specimen under different seismic intensity.The test results show that with the increase of input earthquake motion,the natural vibration period of each specimen increases and the displacement of pier top increases;the acceleration response of pier top increases with the increase of reinforcement ratio,decreases with the increase of axial compression ratio and stirrup ratio;and the energy dissipation of pier specimen increases with the increase of stirrup ratio and decreases with the increase of stirrup ratio.(3)The finite element numerical model of pier specimens is established by using finite element software ABAQUS,and the elastic-plastic time history analysis of seismic wave applied to pier specimens is carried out.By comparing the numerical simulation results of pier top acceleration and pier top velocity with the experimental results,it is found that the two time history curves coincide well,and the difference between acceleration extreme value and velocity extreme value is small,which verifies the feasibility of the finite element numerical model.The validity of the test results is also verified.