| Bucking-restrained brace(BRB)is a special kind of central brace,and composes of the core element,the external constraint element and the sliding mechanism element.It was fist invented and studied by the Indian engineer Shuhaibar.Then the different countries in the word have developed various forms about the BRB on the basis of its similar principle.What's more,it can overcome the weak point of the traditional brace that failed because of its complete bulking before its bearing-capacity has not yet reached its yield strength,while the bearing-capacity of the BRB can reach its yield strength even more.The BRB,therefore,can make full use of dissipating seismic energy of elastoplastic properties of the steel.As a result,it improves the seismic performance of structures.However,this kind of BRB has some unsatisfactory aspects.For example,the problem of the clearance reservation between the external confined rigid(or concrete outer cylinder)and the core stress components exist;no more accurate mathematical expressions can be used to calculate the dissipating seismic energy of the BRB that can be estimated according to the hysteresis curve measured by the test;in the working stage of the BRB,the relative slip between the outer steel tube and the core component can produce,which will have an adverse effect on the component;the whole device of the BRB require to be replaced when the core component fail.In this paper,a new shear type fully assembled bucking restrained brace(NSTBRB)can avoid these problems mentioned above effectively.The working mechanism of the NSTBRB is different from the traditional BRB.The traditional BRB mainly relies on the axis elastic-plastic deformation the core component produces under the action of the tension and compression dissipating the seismic energy,while the NSTBRB mainly relies on shear deformation the slotted steel plate of the core component produces dissipating the seismic energy.The NSTBRB is composed of the element and the outer confined element(outer sleeve steel pipe).The core element connects the eight-slotted sleeve steel plate with eight angle steel through high strength bolts.The outer sleeve steel pipe is divided into the same four parts instead of the whole part,and every part connects with the slotted sleeve steel plate of the core component through high strength bolts.When the NSTBRB is loading,the relative slip between the outer sleeve steel pipe and the core element isn't produce because the outer sleeve steel pipe and the core element become a whole.The outer sleeve steel pipe is not like the traditional BRB that prevent the core element from buckling,but bears the load.While the out of plane buckling is overcome by the slotted steel plate.In this paper,the slotted steel plate adopts low yield point steel,while the angle steel and outer sleeve steel pipe adopts the high strength steel.The main contents of this paper are as follows:(1)In this paper,the maximum aspect ratio of the small plate with the slab resistance buckling energy dissipation is deduced by theoretical analysis.When the small plate is deformed at the same time,the small plate has the bending moment deformation and the shear deformation.This paper holds that when the shear deformation of the small plate is greater than 80% of the total deformation,it belongs to the shear type.This paper deduces the aspect ratio of the small plate of the slab type energy dissipation plate supported by the shear buckling energy dissipation,which lays the foundation for the model design of this paper.(2)The finite element software is used to simulate and analyze the aspect ratio,the aspect ratio,the aspect ratio and the high thickness ratio of the small plate of the slotted energy consumption steel plate.,The overall size of the model and other parameters on the shear buckling buckling energy dissipation support mechanical properties and hysteresis curve of the impact.The simulation results show that the incremental percentage of the width of the small plate of the slit-consuming steel plate is approximately equal to the incremental percentage of the maximum bearing capacity of the model and the percentage increase in the energy dissipation capacity;the thickness of the small plate The incremental percentage of the value is approximately equal to the incremental percentage of the maximum bearing capacity of the model and the incremental percentage of the energy dissipation capacity.When the aspect ratio of the small plate of the slit and consumable steel plate changes at the same time as the high thickness ratio,Performance and energy consumption are better than those in the case of single factor changes.The percent increase in the maximum carrying capacity of the shear buckling energy dissipation and the percentage increase in energy dissipation is approximately the percentage of the overall dimension of the model And the relative stiffness of the jacketed steel pipe reaches a certain value.By increasing the thickness of the casing steel pipe,the bearing capacity curve and the hysteresis curve of the shear buckling energy dissipation are not affected.The change of the width value of the shear zone has no effect on the bearing capacity curve and the hysteresis curve of the shear buckling energy dissipation.The influence of the parameter variation of each group on its buckling characteristic value,The first ten order buckling eigenvalues of each model show the same rule,and the buckling eigenvalues of each group model show similar laws but different from other groups.(3)A controlled structure(using a steel frame structure with the shear-type buckling energy dissipation)installed by structural analysis software through a damping stack of a 12-story rigid frame structure with a transverse span of three spans,The elastic-plastic time-history analysis of unmanned structure(non-damper steel frame structure)under rare earthquakes is used to compare the deformation of the two rigid frame structures under four seismic waves(two days of artificial wave),the maximum interlayer displacement,The maximum interlayer displacement angle and the displacement of the top layer with time,so as to identify the energy dissipation performance of the new shear-type buckling energy dissipation.The results show that when the deformation of the building reaches a certain value,the shear buckling energy dissipation support can significantly reduce the interlaminar displacement,the interlayer displacement angle and the maximum displacement of the top layer,and improve the torsional effect of the structure.Dissipate the energy in the seismic input structure.In the rare earthquake can effectively protect the main structure from damage.In this paper,the hysteresis curves of the new type of shear-type fully-assembled buckling buckling energy dissipation are all very full and there is no pinching phenomenon.The influence of the parameters of the model on the mechanical properties and energy consumption performance of the model can provide design reference and estimation for the design of the shear buckling energy dissipation support.In the design,a standard component can be used to change the parameters of other models Estimate the maximum bearing capacity and energy consumption performance. |
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