1 / 2022-02-02 14:04:57

3D Finite Element Analysis of Steel Fiber Reinforced Ultra-high Strength Concrete Beam-column Joints

FE analysis, Steel fibers, Tension stiffening, Ultra-high strength concrete

When steel fibers are added into a concrete mix, the tension stiffening effect of the resulting concrete, especially after cracking, is thought to be different from the one of normal concrete, as fibers between cracks can bear tensile forces. To investigate this effect on structural elements, pull-out tests of reinforcing bars from steel fiber reinforced and normal concretes were carried out to examine the tension stiffening properties at first. Subsequently, a 3D finite element (FE) analysis was conducted to verify softening characteristics of the both concretes. And then, a 3D FE analysis of the tested beam-column joints made of steel fiber reinforced and normal ultra-high strength concretes was conducted using a material model deduced from the previous FE analysis. The analytical results, in terms of the story shear force-story drift angle relationships and maximum story shear force, agreed well with the experimental data. The minimum principal stress distribution obtained from the 3D FE analysis also showed an expansion of the effective section of the diagonal compression strut in the joint of the steel fiber reinforced concrete specimen, in comparison to the specimen of normal concrete, which might explain the increase of the maximum strength when steel fibers were used.