Numerical simulation of the interconnection of high strength steel composite beams and UHPC concrete

Abstract

This article presents numerical analyses on composite beams made of high strength steel and Ultra High Performance Concrete (UHPC). Due to the high compressive strength of UHPC very slender structures with thin concrete elements are feasible. However, local stresses in the composite joints increase significantly due to the higher load capacity. For that, continuous shear connectors have been developed. Numerical simulations are explained to the study of composite beams related to the shear connection (springs). Details of UHPC are also presented. A composite beam with non-linear material properties was modelled. Beam-bending tests were simulated with ABAQUS to calibrate the numerical model. The numerical results agree relatively well with the test results, even after first crack initiation. In addition, a three dimensional model with volume elements for the steel and the concrete parts and non-linear spring elements for the shear connection were implemented. The results from performed push-out tests were used in the nonlinear model of the springs elements. The punctual application of the forces in the model due to the springs were the reason for tension peaks and on this account there was an earlier loss of stiffness compared to the beam test result. The ultimate load and the occurring slip were satisfactorily calculated.