Head of the project: Ing. Kraľovanec Jakub, PhD.

Research team: prof. Ing. Moravčík Martin, PhD., doc. Ing. Odrobiňák Jaroslav, PhD.

Duration: September  2020 – August 2021

As part of the research, four prestressed concrete beams will be examined to verify indirect methods for determining of prestressing force in specific time. In the case of two specimens, the prestressing force will be transferred into the concrete through the bond between concrete and prestressing steel. Another two specimens are designed with transfer only in bearings at the end anchorages. Prestressing will be provided by single prestressing strand LS 15,7 / 1860 MPa / 1660 MPa placed in duct of diameter 48 mm. First, based on general knowledge the specimens are designed in compliance with Eurocodes. To avoid the impact of shear stresses, four-point loading scheme is chosen for the test. For numerical analysis, a 2D finite element model with the assumption of nonlinear material behaviour will be used. The numerical analysis will be performed in ATENA software, Idea StatiCa and SCIA Engineer. Later, the results obtained in the laboratory will be compared to those of an analytical calculation. In order to quantify the residual prestress force theoretically, parameters influencing the prestress loses must be taken into account. Subsequently, the influence of the reduction of the stiffness due to cracking the concrete during the loading will be discussed. Finally, we intend to find the correlation between the width of cracks, deflections, strains and the decrease of prestressing force.