Project R-4146

Three-dimensional modeling of the end zones of prestressed concrete elements, stress distribution and crack propagation analysis. (Research)

The initiation of the pre-tension force in concrete construction elements is associated with a specific stress distribution along the length of the transfer zone and in the end zone of these elements. There already is a wide range of theoretical knowledge within this field but it does not always correspond to the practical experiences manufacturers observe within the range of products or applied procedures. The theoretical models which are used, are usually of a two-dimensional or linear nature. To accurately portray the correct stress distribution within theoretical models and to make a correct estimation of the behavior of the stress distribution and crack initiation and propagation within these structural elements, a three-dimensional model would have to be able to accurately display phenomena such as splitting, surface tensions and flange tension, and the influence of design parameters (e.g., geometry, bondage strength, prestressing, ...). The existing design methods are investigated and reported damage phenomena in prestressed concrete elements are mapped. The focus will then be placed on the modeling of the initiation of the prestressing force. The stress distribution, crack initiation, propagation, and the collapse of the material can be simulated using of the eXtended Finite Element Method (XFEM). This method allows cracks to be modeled independently of the chosen discretization used by the finite element model. The three dimensional models will be validated with empirical tests and/or documented damage reports, leading to design rules that can be used in the design of prestressed elements and a better and more economic use of reinforcement.

01 October 2012 - 30 September 2016