This article describes the details of a case study on UHPC prestressed I-girders. Part I describes the material characterization of the used ultra-high performance concrete (UHPC), with an average compressive strength of 150 MPa and 1% fibre mix volume. The research program aimed at the determination of the flexural behaviour of two prestressed beams produced by the precast company Ergon from Belgium. The research includes an experimental phase and an analytical phase. The experimental phase focuses on determining the uniaxial compressive behaviour and the time dependent behaviour by completing tests on different specimens, the most relevant characteristics for the use of UHPC are being investigated (i.e. compressive strength, creep, shrinkage, stress-strain response and young modulus). The analytical phase of this research analyzes the results from the experimental phase and compares with standard EN 1992-1-1 recommendations (Eurocode 2). The full scale test results are compared with the standard Eurocode 2 predictions. In a next step, the test results on small scale specimens are used to correct and extrapolate Eurocode’s material laws, in order to provide a more accurate prediction of the flexural behaviour.
Belgian Building Research Institute – BBRI
2500 Lier, Belgium