Study On The Mechanical Properties Of Unequal-limb L-ribbed Concrete-filled Steel Tube Columns Under Compression

In this paper,the limb length ratio 1.0,1.2,1.4,1.6,4 roots without ribs and 7 rib root with L-shaped steel-mix the axial compression test for composite structure column,through the experiment to observe the different segments without stiffener length ratio and damage of the specimens,analysis related to the bearing capacity of curve measured in experiment,combined with the finite element software ABAQUS simulation of 11 pillar of ranging from limb portfolio analysis,puts forward the range limb L ribbed steel pipe concrete column axial compression bearing capacity calculation method.The main research work of this paper is as follows:（1）To different limb length ratio and presence of stiffener to change parameters,design of 11 root limb L-shaped concrete-filled steel tube column,including 4 pillar of range for limb without ribs combination,7 root of stiffener number different limb composite column,compared to the damage form of specimens after test and the test measurement data,can be concluded that: with the increase of limb length ratio and setting stiffening rib,increasing axial compression bearing capacity of the specimens,but the bearing capacity of the growth rate declined;Compared with the specimen,the increase of limb length ratio improved the stiffness of the specimen,but had no obvious effect on its ductility,and the setting of stiffeners improved the ductility of the specimen.（2）Reference to domestic and foreign scholars on the rectangle and common L-shaped concrete filled steel tubular short column under axial compression is finite element modeling method,using the finite element software ABAQUS to 11 root without ribs and has a range of limb L-shaped concrete-filled steel tube column in axial compression process simulation,the simulation range of limbs and failure deformation of the bearing capacity of composite column curve and test results contrast,contrast the result of a good match to prove the validity of the modeling method.（3）The working mechanism of 11 unequal L-shaped columns in axial compression test was analyzed by using the validated modeling method of L-shaped composite columns.The analysis results show that the load of steel is greater than that of concrete in the axial compression process of unequal L-shaped CFST columns.With limb length ratio increases,the restriction in steel tube on concrete,steel tube long limb prone to local buckling,as a result of the existence of stiffening rib,longitudinal force wall is set stiffening rib change,local buckling of steel tube wall get effective slow,enhances the steel tube of the internal concrete constraints,improve the overall capacity of the specimens.（4）Based on the calculation method of axial compressive bearing capacity of ordinary L-shaped concrete-filled steel tubular composite columns,the improvement coefficient of concrete strength under the constraint of steel tube was modified,A formula for calculating the axial bearing capacity of L-ribbed CFST composite columns with unequal limbs is proposed by introducing the influence coefficient κ of the ratio of limb length to concrete strength...