| The exposed steel column base joint has simple structure and convenient construction,and is widely used in low-and medium-rise steel structure buildings.Postearthquake investigation indicates that the traditional exposed column bases are prone to rupture of anchor rods and difficult to be repaired after an earthquake.This thesis proposes a new type of exposed column base that is easy to repair after an earthquake.The column base has a relatively large elastic stiffness under service-level earthquake,and the cover plates of the column base are designed to sustain plastic deformation under strong earthquakes to dissipate the seismic energy,while other Components remain elastic to improve the repairability after an earthquake.The main content of this article is as follows:Firstly,the experiment and theoretical research of the energy-dissipating cover are carried out,and a reasonable and efficient cover structure is selected for the energydissipating column base joint of the new replaceable cover.In this thesis,a total of 2 sets of energy-dissipating covers were designed,and each set included 3 different forms of 6cover specimens.Among them,the Type I cover was designed with a conventional structure,and the Type II cover was designed with a special-shaped structure.The structural design parameters are mainly Stiffener position,bolt hole spacing and number of bolts.Through the repeated loading test of the cover plate,the load-displacement curves of six kinds of cover plates were obtained,and the initial stiffness,ultimate capacity and energy dissipation area of the six kinds of curves were compared,and a better structural design of the cover plate was determined,which was carried out according to the EC3 standard method A theoretical study of the energy-dissipating cover was carried out and compared with the experimental values.At the same time,the numerical simulation of the energy-dissipating cover plate was carried out by using ABAQUS,and the accuracy of the numerical simulation was verified by comparing with the test curve and failure form,and the optimization of the cover plate flange and the laying of stiffeners were carried out through finite element simulation.It is concluded from this that:(1)The bolt spacing has a great influence on the bearing capacity and stiffness of the energy-dissipating cover;(2)The rational design of stiffeners can significantly improve the stiffness and bearing capacity;(3)The rational optimization design of finite elements can be used in On the basis of maintaining the strength and stiffness of the cover plate,the material consumption can be saved;(4)The yield bearing capacity and initial stiffness of the energy-dissipating cover plate are analyzed by using the EC3 component method,and the accurate prediction range of the initial stiffness is explained by using the dimensionless stiffness ratio.Then,the stiffness,bearing capacity and energy dissipation capacity of the new column base joint with replaceable energy-dissipating cover plate are studied,and compared with the traditional exposed column base joint.Numerical simulation is used to predict the quasi-static reciprocating loading bending moment-angle curves of the new type of column base joint and the traditional exposed type of column base joint,and the parameters of the curves are analyzed,and the functional advantages of the new type of column base joint are demonstrated.The yield bearing capacity of the new column base joint is analyzed by plastic hinge theory,and the bending stiffness of the new column base joint is analyzed by EC3 component method.ABAQUS is used to analyze the parameters of the mechanical properties of the new column base joint,mainly including four aspects:the thickness of the cover plate,the thickness of the stiffener laid flat,the strength of the cover plate material and the vertical stiffener.The research results show that:(1)the stiffness,bearing capacity and energy dissipation capacity of the new column base joint are better;(2)the stiffener is more efficient when placed horizontally than vertically;(3)the yield bearing capacity error of the column base joint can be analyzed by plastic hinge control,using the EC3 component method to predict the bending stiffness of the column base joint has an applicable range,and the stiffness ratio is used to illustrate the applicable range;(4)The thickness of the cover plate and the strength of the cover plate material have a great influence on the column base joint,and the vertical height of the stiffener is too high will waste material. |
PDF Full Text Request