Development of guidelines for nonlinear finite element analyses of existing reinforced and pre-stressed beams

Øverli

et al. 2015

Structural Concrete

When performing non-linear finite element analyses during the design of large reinforced concrete structures, there is a need for a general, robust and stable solution strategy with a low modelling uncertainty which comprises choices regarding force equilibrium, kinematic compatibility and constitutive relations. In this paper, analyses of experiments with a range of structural forms, loading conditions, failure modes and concrete strengths show that an engineering solution strategy is able to produce results with good accuracy and low modelling uncertainty. The advice is to shift the attention from a detailed description of the postcracking behaviour of concrete to a rational description of the pre-cracking compressive behaviour for cases where large elements are used and the ultimate limit capacity is sought.

Section: Introductionmentioning

confidence: 99%

Solution strategy for non‐linear finite element analyses of large reinforced concrete structures

Engen

Øverli

et al. 2015

Structural Concrete

“…The embedded truss elements are used for rebar, assuming perfect bonding with concrete. The Hordijk model and the parabolic model are used to present the tensile and compressive behavior of concrete, respectively, and the rotating smeared crack model is adopted to indicate the crack initiation (Belletti, Damoni, & Hendriks, 2011). In this paper, 20-node quadratic solid elements are used.…”

Section: Appendix a Nonlinear Finite Element Analyses Of Strut-and-tie Modelsmentioning

confidence: 99%

Optimization‐based three‐dimensional strut‐and‐tie model generation for reinforced concrete

Xia

Langelaar

Computer aided Civil Eng

2020

Self Cite

Strut-and-tie modelling (STM) is an effective and widely used method to design disturbed regions (D-regions) of reinforced concrete structures. Among the various steps of STM, finding a suitable truss-analogy model is the most challenging part. Even for experienced engineers it is difficult to find representative models for complex D-regions, and this task is even harder for three-dimensional (3D) Dregions. To date, only a few 3D STM models have been proposed by researchers for several complex D-regions, which leaves practitioners with little guidance.In order to solve this problem, a method is proposed to automatically generate 3D optimization-based STM (3D-OPT-STM) models. The generation method comprises a compliance-based topology optimization process that generates optimized structural forms by maximizing stiffness, a topology extraction method, and a shape optimization method. In this study, three 3D-OPT-STM models are generated for typical 3D D-regions, and their performances are compared to manually created STM models. The generated 3D-OPT-STM models result in more economical designs. Moreover, geometrical and loading parameter studies demonstrate the applicability and robustness of the proposed method.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

“…Allaix et al, 11 Engen et al, 12 and Cervenka et al 13 all tested specific solution strategies, against, respectively, 14, 38, and 33 benchmarks, and thus quantified the within‐model uncertainties for the respective NLFEA approaches. Belletti et al, 14 , 15 Castaldo et al, 16 , 17 and Gino et al 18 tested in their studies up to 18 approaches, thus resulting in multiple within‐model uncertainties per study.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the resistance modeling uncertainty of 19 alternative 2D nonlinear finite element approaches benchmarked against 101 experiments on reinforced concrete beams

Putter

Rots

et al. 2022

Structural Concrete

Nineteen 2D nonlinear finite element analysis (NLFEA) solution strategies were benchmarked against a wide variety of 101 experiments on reinforced concrete beams failing in bending, flexural shear, or shear compression. The relatively high number of solution strategies was motivated by the conviction that choices for the constitutive models, the finite element kinematics and equilibrium settings will interact, and must therefore be tested in conjunction. Modeling uncertainty distribution parameters are presented for the 19 solution strategies, using all beams, and using beams with and without stirrups separately. The resulting statistics are discussed against the correctness of the simulated failure modes and failure loads, revealing that rotating crack models perform well for the relatively ductile failures in beams with stirrups, while fixed crack models perform better for the more brittle failures in beams without stirrups. The tailored solution strategies that predict failure modes correctly, imply a log‐normal distribution of the modeling uncertainty with relatively low coefficients of variation. The outlook is that these estimates of the statistical properties of the modeling uncertainties could serve as a basis within safety formats.