| Structural system with special-shaped columns have been applied to engineering practice, special-shaped column can avoid that column prominents the wall.It can ment aesthetic requirement of people; It is convenient for furniture layout; It raises the rate of the Utilization of the space. Now special-shaped columns contains reinforced concrete pecial-shaped Columns, SRC special-shaped Columns and concrete filled steel tubular special-shaped column.Based on summaring the advantage and disadvantage of those pecial-shaped Columns, L-section steel tube column filled with steel-reinforced is presented in this paper.The axial load behavior of Composite L-section steel tube column filled with steel-reinforced concrete is tested by experiment and numerical simulation that provides the basis for research of other mechanical properties and provides the basis for preparing the relevant specification.Considering the steel-reinforced index and confining index of specimen,twelve composite L-section steel tube column filled with steel-reinforced and three Composite L-section steel tube column filled without steel-reinforced were experimentally investigated to study the axial load behavior of composite L-section steel tube column filled with steel-reinforced concrete. The failure modes of specimens, the load-deformation of the column relationship curves, ultimate bearing capacity of the column and the influences of steel-reinforced index and confining index on the axial load behavior of this column,are analyzed and test. Based on the conclusion of domestic and abroad codes, the formula for the compression bearing capacity of composite L-section steel tube column filled with steel-reinforced columns was deduced.In the whole loading process, deformation of the rectangular steel tube and U-steel tube of the test specimen is coordinate and there is not connection weld cracking phenomenon.The failure modes of specimens is locally convex drumming, because the built-in steel can effectively avoid the shear failure of concrete. Typical load-deformation of composite L-section steel tube column filled with steel-reinforced includes four part of the elastic work stage, elastic-plastic stage work, strengthen and steady decline phase. With the increase of distribution reinforcement index and the index of bone, ultimate bearing capacity of specimen has increased gradually,but the increasing rate of ultimate bearing capacity is not increasing. ultimate bearing capacity of the specimen with steel-reinforced is higher than the specimen without steel-reinforced.Based on the axial compression bearing capacity formula of SRC short columns and concrete filled steel tubular short column, the formula for the compression bearing capacity of composite L-section steel tube column filled with steel-reinforced colmms was deduced and the calculation results are close to experimental results. The test results indicated that,the encased steel-reinforce effectively delays or restrains the shear sliding crack in concrete and therefore the ductility of the columns is improved;Incresing stelel-reinforced index and confining index may improve the strength and plasticity.Finally, The formula can be valuable to the engineering design.Inorder to investigate the stability behavior of composite column,seventeen slender L-section steel tube columns filled with steel-reinforced were tested.The primary test pamaeters were slenderness ratios varing from14.7to50.3, steel-reinforced index varing from1.0～1.7and confining index varing from0.46～0.83. The failure modes of specimens, the load-deformation of the column relationship curves,load-deflection curve, ultimate bearing capacity of the column and the influences of steel-reinforced index and confining index on the axial load behavior of this column,are analyzed and test. Based on the conclusion of domestic and abroad codes, the formula for the stability ultimate bearing capacity of Composite L-section steel tube column filled with Steel-reinforced columns was deduced. Test results indicate that all specimens are not appearing obvious wound degree and deformation before getting the ultimate bearing capacity. The failure modes of specimens is locally convex drumming. Typical load-deformation of composite L-section steel tube column filled with steel-reinforced includes four part of the elastic work stage, elastic-plastic stage work, strengthen and steady decline phase. With different slenderness ratio, the fourth stage (steady decline stage) is reduced.with bone ratio and stirrup ratio and improving, ultimate bearing capacity increases. After the peak bearing capacity, the curve of all specimens are stable level and there is no sharp decline phenomenon in the larger longitudinal deformation. As slenderness ratio increasing, the ultimate bearing capacity is reducing and bearing capacity of the late isreducing slowly.Within the scope of slenderness ratio in article, before getting the ultimate bearing capacity,the deflection of specimens is smaller,and after getting the ultimate bearing, the deflection of specimens is bigger. The increasing direction of deflection is not a single direction.when the bearing capacity increases to a certain value, the increasing direction of deflection will change. Tability bearing capacity value of stable bearing capacity calculation formula is close to experimental results.The test specimens are simulated using large-scale finite element software ANSYS10.0. In the process of building model,this article considers the contact between steel tube and concrete, analyzes the cross section tress nephogram of the specimen and failure pattern. Results show that the numerical simulation results are in good agreement with the test results... |
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