Abstract
The high cost of a large number of uniformly distributed and randomly oriented high-strength steel fibres
severely limits the applicability of ultra high performance fibre reinforced concrete (UHPFRC) to engineering
structures. In this study, two types of mesoscale modelling based optimization algorithms are proposed and
applied to optimize the fibre orientation and distribution in UHPFRC beams to reduce the total amount of steel
fibres. The first algorithm heuristically distributes fibres in regions with high tensile stresses only with their
orientations parallel to the principal tensile stresses, considering that the steel fibres contribute little to the
compressive strength but significantly to the tensile and flexural strength of UHPFRC beams. The second method
optimises the beams’ topology into strut-tie models using algorithms such as SIMP and BESO and then adds steel
fibres oriented longitudinally in the tensile ties. The load-carrying capacity and failure process of the optimised
beams are then simulated and assessed using a meso-scale finite element modelling approach recently developed
by the authors. Based on the results of steel-bar reinforced UHPFRC beams under 3 or 4-point bending, it was
found that the usage of steel fibres could be reduced by up to 60 %, and the amount of UHPC and cement could
be reduced by up to 50 %, respectively, without sacrificing the load-carrying capacities of the beams compared
with the beams with uniformly distributed and randomly oriented fibres.
severely limits the applicability of ultra high performance fibre reinforced concrete (UHPFRC) to engineering
structures. In this study, two types of mesoscale modelling based optimization algorithms are proposed and
applied to optimize the fibre orientation and distribution in UHPFRC beams to reduce the total amount of steel
fibres. The first algorithm heuristically distributes fibres in regions with high tensile stresses only with their
orientations parallel to the principal tensile stresses, considering that the steel fibres contribute little to the
compressive strength but significantly to the tensile and flexural strength of UHPFRC beams. The second method
optimises the beams’ topology into strut-tie models using algorithms such as SIMP and BESO and then adds steel
fibres oriented longitudinally in the tensile ties. The load-carrying capacity and failure process of the optimised
beams are then simulated and assessed using a meso-scale finite element modelling approach recently developed
by the authors. Based on the results of steel-bar reinforced UHPFRC beams under 3 or 4-point bending, it was
found that the usage of steel fibres could be reduced by up to 60 %, and the amount of UHPC and cement could
be reduced by up to 50 %, respectively, without sacrificing the load-carrying capacities of the beams compared
with the beams with uniformly distributed and randomly oriented fibres.
Original language | English |
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Article number | 107584 |
Journal | Structures |
Volume | 70 |
DOIs | |
Publication status | Published - 2024 |