Flexural behaviour of CFST (Finite element analysis)

Abstract

To improve the shear transfer capacity in Concrete-Filled Steel-Tube (CFST) columns and beams, a novel system has recently been introduced with the application of the patent EP2305911B1 (upcCFST). It consists of steel crown-shaped protrusions created on the steel tube by punching, oriented toward the concrete core for acting as shear transfer elements. The new system’s influence on the bending effective properties of the composite section is evaluated experimentally in the research project STCC SIFECAT: IU68009746 funded by the European Regional Development Funds (ERDF) through the Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) - Generalitat de Catalunya. For the experimental part, 4-point monotonic bending tests have been performed to measure the bending deflections and the steel-concrete end-slip at the supports. The objective of this Bachelor Thesis is to develop and validate a parametric finite element simulation model capable of predicting the behavior of concrete filled steel tubes. The model developed aims to serve as new tool to the research initiative that investigates this novel technology. The model uses the software ANSYS Mechanical APDL and the simulation results are validated with the experimental data from 3 4 point bending tests of CFST samples, conducted at a previous stage of the research project, of which this investigation is a part of. The raw experimental data will be analyzed and contrasted with the simulation results generated by the model, which will be tuned and iteratively improved upon until validated for all empirically tested configurations. In addition, the empirical and simulation results will also be contrasted to a theoretical analysis, developed from the principles of strength of materials. Finally, the results from these theoretical, empirical and finite element results will shed light on possible improvements to the finite element model and the optimal future course of action for the research project.