Experimental Study On Inclined Brace With Respiratory Energy Dissipation For Steel Structure

With the development of energy dissipation damping technology,different types of energy dissipation components are widely used in seismic structures,However,there are still some problems in the practical application of steel braces.For example,the existing arrangement of steel braces often occupies and divides the indoor space,causing adverse effects on the use of the structure,and also causing difficulties in the installation,maintenance,damage and replacement of the bracing.If the braces are arranged on the outside of the structure,the brace’s influence on the indoor space and the trouble of installation and maintenance can be avoided.However,due to the exposure of the braces,additional internal forces will be generated in the braces because the action of external temperature,which will affect the normal use of the braces.For this reason,this paper studies a new type of energy dissipation brace,which composed of metal dampers and steel braces.By the way of arranging the intermediate metal damper out of the plane,the internal force generated which caused by the action of external temperature can be released through out-of-plane deformation,and when the structure bear the action of wind load and small earthquake,the energy dissipation inclined brace can provide lateral stiffness for the structure.under the action of large earthquake,through the shear deformation of intermediate metal damper,the inclined brace can consume a large amount of seismic energy and ensure the main structure safety.For the energy dissipation braces proposed in this paper,finite element analysis,scale model test and practical engineering application studies will be carried out at the same time to verify the above performance of energy dissipation braces.The main contents and achievements of this paper are as follows:1.Theoretical analysis of the breathing energy consumption brace.Firstly,introduce the construction form of respiratory energy dissipation brace and its mechanical properties,and then design the similar relationship to determine the size parameters and theoretical analysis model of the scale model.By using the finite element software ANSYS to simulate the temperature change and monotone loading of the scale model,study the force and deformation mechanism of the energy dissipation brace,to comprehensively judge its performance and provide reference for the follow-up experimental research.2.Determine the test scheme of energy consumption inclined brace,and carry out the heating and cooling tests.According to the results of theoretical analysis and finite element analysis,combined with the actual site conditions of the test,determine the test scheme;Designed and made the test specimens,and carry out the heating and cooling tests of the energy dissipation braces,and observe and measure the overall deformation process and stress and strain levels of the specimens under the action of temperature.the results show that the energy dissipation braces release the internal forces caused by temperature changes through out-ofplane deformation,and the temperature load causes lower stress level fluctuations in the braces,and has almost no effect on the main structure.3.The quasi-static test was carried out on the energy dissipation brace.The hysteretic curve of the specimen and the deformation test value of the metal shear damper are obtained by the low cyclic loading test,and measure the out-of-plane deformation value of the metal damper and the stress level of the other parts of the inclined brace except the metal damper at the same time.The results show that the hysteretic curve of the inclined brace with respiratory energy dissipation is full with no pinch,and the metal damper hardly produces out-of-plane deformation,which show that the braces has good energy dissipation capacity.Through the appropriate strength design,the other parts of the respiratory brace are still in the elastic state,which proves that the new type of respiratory energy dissipation brace has good energy dissipation stability.4.Study the practical engineering application of the energy dissipation brace.The damping design principle of energy dissipation braces is put forward,and the time history analysis of steel structures with energy dissipation braces or traditional central braces under frequent and rare earthquakes are carried out by using the structural analysis software YJK and Perform-3D.The comparative analysis results show that the energy dissipation braces can not only provide lateral stiffness for the structure,make the inter-story displacement angle and other indicators in line with the standard limits,but also can consume a large amount of seismic energy,reduce the damage of the main structure,and has a good actual energy dissipation effect compared with the traditional central braces.To sum up,the study of this paper shows that the new type of energy dissipation brace has simple structure and clear concept,and can be arranged on the outside of the structure to avoid adverse effects on the use of indoor space.At the same time,it has good thermal stress release capacity and excellent energy dissipation capacity,which can be widely used in the passive control of damping structures.