Experimental And Design Study On A Novel Double Circular Steel Pipe Buckling-restrained Energy Dissipator

As one of important energy dissipation members,the buckling-restrained brace plays an important role in the structure.These roles are:(1)providing large flexural stiffness for the structure which is similar to common brace under wind-induced vibration and weak earthquake.(2)dissipating energy with plastic deformation to protect the main structure from damage when large earthquake comes.A new type of double circular steel pipe buckling-restrained energy dissipator is designed in this paper.It has great advantages in reducing self weight,balancing energy consumption performance of the centural pipe and realizing absolute machine processing and prefabrication.A series of research is carried out in order to study the aseismatic performance of the new type of double circular steel pipe buckling-restrained energy dissipator.The main research contents and achievements are as follows:(1)Numerical simulation analysis on aseismatic performance of the energy dissipator is carried out.The solid element C3D8 R in ABAQUS is used to simulate the energy dissipator.Then the selection of constitutive relation,mesh and the setting of contact and boundary conditions are discussed.Based on cyclic loading simulation,the effects of slenderness ratio and constraint strength on the hysteretic energy dissipation performance of the member are investigated.The results show that slenderness ratio has a certain effect on the energy dissipation of the member while the effect of constraint strength is not obvious when cumulative deformation is not taken into account.(2)Experiment study on the energy dissipator is conducted.Two groups of specimen were designed for slenderness ratio and constraint strength using Q235 and low cycle loading tests were carried out.The results show that the hysteresis curve of the test member is full and the damage occurrs at the bolt hole in the drawing stage which indicates that this part of the section is the most dangerous section of the member.The effect of slenderness ratio on members is shown when the slenderness ratio is small,the yield displacement increases with the increase of slenderness ratio,but when the slenderness ratio exceeds a certain limit,the yield displacement will decrease.In addition,the smaller slenderness ratio is,greater the number of cycles can be experienced and the greater cumulative plastic deformation can be borne.The effect of constraint strength is shown that the yield displacement tends to be smaller with the increase of the constraint strength while the yield force tends to become larger.(3)Working principle and design methods of the energy dissipator are discussed.Methods of determine parameters such as thickness of the debonding layer and size of cross section are proposed in the article.Theoretical analysis and discussion are carried on against instability problems which possibly appear in different parts of the double circular steel pipe buckling-restrained energy dissipator and construction measures are proposed to avoid these problems.The computational formulas of stiffness in elastic and plastic stages are given under lost and stability conditions of the calculation conditions are given with calculate assumptions.