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Validation of a non-linear hinge model for tensile behavior of UHPFRC using a Finite Element Model
Eduardo J. Mezquida-Alcaraz,Juan Navarro-Gregori,Juan Ángel López,Pedro Serna-Ros 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.23 No.1
Nowadays, the characterization of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) tensile behavior still remains a challenge for researchers. For this purpose, a simplified closed-form non-linear hinge model based on the Third Point Bending Test (ThirdPBT) was developed by the authors. This model has been used as the basis of a simplified inverse analysis methodology to derive the tensile material properties from load-deflection response obtained from ThirdPBT experimental tests. In this paper, a non-linear finite element model (FEM) is presented with the objective of validate the closedform non-linear hinge model. The state determination of the closed-form model is straightforward, which facilitates further inverse analysis methodologies to derive the tensile properties of UHPFRC. The accuracy of the closed-form non-linear hinge model is validated by a robust non-linear FEM analysis and a set of 15 Third-Point Bending tests with variable depths and a constant slenderness ratio of 4.5. The numerical validation shows excellent results in terms of load-deflection response, bending curvatures and average longitudinal strains when resorting to the discrete crack approach.
Mojtaba Farahi,Saeed Erfani 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.5
Numerical simulations are prevalently used to evaluate the seismic behaviour of structures. The accuracy of the simulation results depends directly on the accuracy of the modelling techniques employed to simulate the behaviour of individual structural members. An empirical modelling technique is employed in this paper to simulate the behaviour of column members under cyclic and seismic loading. Despite the common modelling techniques, this technique is capable of simulating two important aspects of the cyclic and seismic behaviour of columns simultaneously. The proposed fiber-based modelling technique captures explicitly the interaction between the bending moment and the axial force in columns, and the cyclic deterioration of the hysteretic behaviour of these members is implicitly taken into account. The fiber-based model is calibrated based on the cyclic behaviour of square hollow steel sections. The behaviour of several column archetypes is investigated under a dual cyclic loading protocol to develop a benchmark database before the calibration procedure. The dual loading protocol used in this study consists of both axial and lateral loading cycles with varying amplitudes. After the calibration procedure, a regression analysis is conducted to derive an equation for predicting a varying calibrated modelling parameter. Finally, several nonlinear time-history analyses are conducted on a 6-story steel special moment frame in order to investigate how the results of numerical simulations can be affected by employing the intended modelling technique for columns instead of other common modelling techniques.
한채훈,임영근,강병두,김재운 대한건축학회지회연합회 2008 대한건축학회지회연합회 학술발표대회논문집 Vol.2008 No.1
In the context of earthquake engineering, nonlinear response history analysis is an important tool to predict with reasonable accuracy the building response for varying levels of ground motion intensity. Ideally, the nonlinear response history analysis should faithfully simulate all significant modes of deformation and deterioration in the structure from the onset of damage up to collapse. However, given present analysis technologies and the practical constraints of design, it is usually not feasible and perhaps not warranted to directly simulate all significant nonlinear effects in analysis. Acceptance criteria for both individual components and the overall system must be tailored to the specific analysis capabilities for simulating nonlinear response. In this study, nonlinear response characteristics of the simple structure are examined with respect to three-nonlinear component models. The objective of this paper is to propose most appropriate nonlinear component models through a comparative analysis of top floor displacement and element force on the actual structure subjected to Elcentro earthquake.
Abdelhakim Zendaoui,A. Kadid,D. Yahiaoui 한국콘크리트학회 2016 International Journal of Concrete Structures and M Vol.10 No.4
This paper aims to provide guidelines for the numerical modeling of reinforced concrete (RC) frame elements in order to assess the seismic performance of structures. Several types of numerical models RC frame elements are available in nonlinear structural analysis packages. Since these numerical models are formulated based on different assumption and theories, the models accuracy, computing time, and applicability vary, which poses a great difficulty to practicing engineering and limits their confidence in the analysis resultants. In this study, the applicability of four representative numerical models of RC frame elements is evaluated through comparison with experimental results of four-storey bare frame available from European Laboratory for Structural Assessment. The accuracy of a numerical model is evaluated according to the top displacement, interstorey drift, Maximum storey shear, damage pattern and energy dissipation capacity of the frame structure. The results obtained allow a better understanding of the characteristics and potentialities of all procedures, helping the user to choose the best approach to perform nonlinear analysis.
Ultimate Analysis of Steel Structures Based on Fiber Hinge Model and Time-Varying Structure Theory
Yuhua Wang,Qi Wang,Jun Dong,Yang Peng 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.3
Oversize deformations and local damages may occur in steel structures due to inappropriate design, inadequacy of construction, improper uses and some other factors. Such damages could produce serious safety problems and shorten the service life of the structures. We proposed in this paper an effective and accurate method for analyzing the ultimate bearing capacity of steel framework based on the fiber hinge model and time-varying structure theory. A detailed study was conducted to investigate a cantilever column with I shaped cross section. The effects of cross section division and fiber hinge unit length on computation accuracy were investigated using SAP2000 finite element software. The proposed method was then applied to a real-life engineering problem, in which the steel structure of a mechanical building was gradually damaged under the action of uneven foundation settlement. The detailed information was obtained for the whole structural damage process as well as for the structural improvements after reinforcement. The results presented in this paper provided valuable information for strengthening of the damaged structures that are usually difficult to obtain in field detection, as well as the critical information for evaluating the structure conditions. In addition, the results in this paper could also provide useful information for safety assessment of new constructions.