Computational Framework for Fracture Simulation of Concrete Structures until Failure

Abstract

The need to predict the fractured behaviour of a structure with a high degree of certainty is becoming a significant problem in the construction industry, whether for designing new structures or for assessing and strengthening existing structures. Considerable advances in the construction industry – with the introduction of new materials and technologies and constant demand for safer, more cost-efficient, sustainable and bold designs – are overturning established design rules. It is becoming critical to bring new predictive tools to assure the safety and serviceability of these structures, and to accomplish the full potential of the new construction designs that are now becoming possible. This research developed a computational framework based on the discrete crack approach that can be efficiently used in engineering for the reliable simulation of the behaviour of concrete structures. The framework is built on an object-oriented finite element platform, specifically tailored to accommodate embedded strong discontinuities, and having tools to improve the simulation of discrete models, such as a non-iterative solution algorithm and a powerful direct sparse solver. Different new formulations are proposed for simulating and capturing crack propagation with embedded discontinuities, which: i) are based on local degrees of freedom, ii) are combined with embedded steel fibres, and iii) require minimum enhanced global degrees of freedom. Multiple case studies are performed for the validation of the new proposed techniques against important laboratory benchmark tests. The framework enables a close-to-reality prediction of the structural behaviour of plain, steel reinforced, and steel fibre reinforced concrete, with improved performance and without convergence issues in fracture simulations.