Research on the influence of steel fiber content on the axial compressive behavior of self-compacting concrete-filled steel tubular columns

In order to improve the axial compression bearing capacity of concrete filled steel tubular columns, steel fibers were added into self-compacting concrete.Through orthogonal test, the influence of 3 groups of steel fiber content on the strength of self-compacting concrete is studied, and the basis for the steel fiber content of concrete filled steel tube is provided.The axial compression tests of steel fiber reinforced concrete filled steel tubular columns and ordinary steel fiber reinforced concrete filled steel tubular columns were carried out to study the influence of steel fiber on the axial compression properties of self-compacting concrete filled steel tubular columns.Based on ABAQUS, 26 groups of concrete-filled steel tubular column models with different steel fiber content are established.After the correctness of the model is verified according to the field test results, the influence of six groups of steel fiber content on its axial compression performance is analyzed, and the calculation formula of the axial compression bearing capacity of concrete-filled steel tubular column with different steel fiber content is established.The results show that 2 % steel fiber has a significant contribution to the strength growth of self-compacting concrete, and can increase the axial compression bearing capacity of self-compacting concrete filled steel tubular columns by about 4 %.The calculation formula considering the increase of steel fiber content to the strength of concrete filled steel tube is proposed, which is in good agreement with the test results.