Modeling and Analysis

Modeling of Steel Reinforced UHPC Beams Failure

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Abstract

Ultra-high performance concrete (UHPC) is a cementitious composite with compactly graded mix capable of attaining a very high compressive strength (around 150 MPa) as well as superior ductility when mixed with fiber reinforcements. Due to the complex composition of reinforced UHPC beams (cementitious matrix, fibers, and regular reinforcement), it is very challenging to predict its mechanical and damage behavior by developing empirical or semi-empirical prediction models. Therefore, the current study aims at employing a comprehensive computational model to predict the performance of reinforced UHPC beams with varying fiber contents while explaining the failure mode transitions from diagonal shear (without fibers) to flexural failure as fiber volume increases. The lattice discrete particle model with fibers (LDPM-F) is utilized in the cur-rent investigation to virtually probe into the reinforced UHPC beams to understand their failure characteristics. LDPM-F effectively accounts for concrete heterogeneity and intricate quasi-brittle features with mechanics of bond-slip for random fibers distribution. In the current scope of the study, LDPM-F is briefly reviewed and parameter identification assumptions are discussed to in-crease the robustness of the calibration. Results from an experimental program executed by other members of the same research group are simulated in this study. Experiments consisted of flexural testing of reinforced UHPC beams with varying fiber contents along with splitting, uniaxial compression and notched three-point bending tests of companion samples taken from the same batches from which the beams were cast. Calibration is performed using these companion specimens and the responses of beams are used for validation. Excellent agreement is observed in predicting the transition of failure modes and crack localization for different experimental test cases of reinforced UHPC beams. Moreover, this computational model enables virtual testing of the beams to explore the relative contributions of different load transfer mechanisms in the beam during failure showing the extent of fiber bridging, matrix damage and their interplay with reinforcement.

Keywords: Fiber crack bridging, Fiber-reinforcement interaction, Reinforced UHPC beams, LDPM-F

How to Cite:

Bhaduri, T. & Alnaggar, M., (2019) “Modeling of Steel Reinforced UHPC Beams Failure”, International Interactive Symposium on Ultra-High Performance Concrete 2(1). doi: https://doi.org/10.21838/uhpc.9732