Study the behavior of prestressed concrete deep beams using FEM simulations

Abstract

The objective of this master‘s thesis is to study and analyze the behavior of prestressed concrete deep beams and how prestressing changes the strut and tie model.

The method used for analyzing the behavior is finite element modeling in ATENA. The strut and tie models are developed by analyzing the principal tensile and compressive stresses for the different models at yield. The models are analyzed without prestressed reinforcement, with 25 MPa prestressed reinforcement and 100 MPa prestressed reinforcement. In order to analyze how different load patterns affect the principal stresses, this paper analyzes three different load patterns.

In total, two different models are analyzed, each containing three different load patterns. The models are analyzed without prestressed reinforcement, with 25 MPa and 100 MPa prestressing. The prestressed reinforcement is placed straight and curved. One of the models is also analyzed with two openings with three different placements of the openings.

The results show a decrease in the distance between the bottom of the deep beam and the tie when adding prestressed reinforcement. A proposed equation to calculate the distance from the bottom of the deep beam to the tie is included in this thesis. The equation takes both the height of the deep beam and the amount of prestressing into account. The equation is based on the results gathered in this thesis.