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The use of ductile concrete materials such as High Performance Fiber Reinforced Cementitious Composites (HPFRCCs) within plastic hinge regions of structural components has garnered research interest in order to improve the seismic resistance of reinforced concrete structures. While experimental and numerical results appear promising in reducing component damage and probability of system level collapse, accurate nonlinear analysis tools capable of capturing the influence of axial load well into a component’s inelastic regime is needed. In this study, a series of 180 high fidelity numerical simulations of HPFRCC beam–column elements are simulated and used to calibrate new plastic hinge length expressions for concentrated and distributed plasticity models for use in system level structural analysis. The numerical models cover a range of HPFRCC material properties, reinforcement ratios, shear span lengths, and axial load levels. The ability of the newly developed expressions to predict component inelastic rotations are subsequently compared to hinge length expressions in the literature and the inelastic rotations of 47 experimental components. The results of this study provide new insights into the effects of axial load on the plastic hinge behavior of HPFRCC components, significantly improves on the accuracy of past plastic hinge length expressions allowing for more accurate modeling of HPFRCC component responses and system level behavior.
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Experimental Characterization of Plastic Hinge Behavior from Flexure and Axial Effects
The unique mechanical properties of ultra-high performance concrete (UHPC) causes changes in failure modes and ductility in reinforced components. Numerous experiments have shown these materials, and others with similar ductile characteristics in tension, can improve the damage tolerance, strength, and ductility of members subjected to large deformations from seismic loading and similar extreme conditions. The use of these materials, however, has not been systematically studied to understand their application at a system-level performance and design procedures have been complicated due to their unconventional failure mechanism. This project aims to fill this gap by testing a targeted set of components subjected to combined effects of axial loads and bending with variations in axial load ratio and longitudinal reinforcement ratio. Additional experiments are planned to compare performance across other ductile concrete materials with variations in mechanical properties. The experimental results including load-deformation, reinforcement strain, concrete surface strain will be used to understand the parameters that have the highest influence on plastic hinge length and moment-rotation response which can ultimately help to validate analytical models against experiments based on these key parameters.
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- Award ID(s):
- 2141955
- PAR ID:
- 10432446
- Editor(s):
- Aaleti, Sriram; Okumus, Pinar
- Date Published:
- Journal Name:
- International Interactive Symposium on UHPC
- Volume:
- 3
- Issue:
- 1
- Page Range / eLocation ID:
- 77
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.21838/uhpc.16690
