Description
Using finite element (FE) analysis to model the nonlinear behavior of reinforced concrete can range from relatively simple, phenomenological approaches to highly complex, micromechanics-based models. The choice of approach depends on the desired accuracy, the scale of the analysis, expertise of the analyst, and computational resources. Plastic hinge models, typically used in pushover or nonlinear time-history analyses for global response prediction introduce basic nonlinearity for line-type elements but often fall short in numerous applications, including evaluating the performance or safety of structures; analyzing deep beams and disturbed regions; assessing distress in existing structures; and predicting crack patterns, crack widths, and deflections. In these cases, two-dimensional (2-D) or three-dimensional (3-D) continuum FE methods offer greater advantages. This guide focuses on nonlinear continuum FE methods, which introduce moderate to high levels of nonlinearity. Developed for practicing engineers, the guide aims to balance theory with practical applications, covering modeling approaches for key material aspects for cracked concrete (including mesh effects and regularization) and reinforcing steel (including stress-strain response, buckling, and bond slip), followed by practical guidance on continuum modeling of beams, columns, and beam-column joints.
Keywords:
assessment; bond slip; buckling; continuum; cracking; distress; finite element (FE); mesh; nonlinear; regularization.
Table of Contents
CHAPTER 1—INTRODUCTION AND SCOPE, p. 2
CHAPTER 2—NOTATION AND DEFINITIONS, p. 2
2.1—Notation, p. 2
2.2—Definitions, p. 5
CHAPTER 3—MODELING OF CONCRETE, p. 5
3.1—Representation of cracked concrete, p. 5
3.2—Modeling concrete in tension, p. 7
3.3—Modeling concrete in compression, p. 9
3.4—Spurious mesh size effects and regularization, p. 11
3.5—Modeling of shear stress transfer at the cracks, p. 14
CHAPTER 4—MODELING OF REINFORCING BARS, p. 16
4.1—Representation of reinforcing steel, p. 16
4.2—Stress-strain response modeling of reinforcing steel, p. 17
4.3—Modeling reinforcement buckling, p. 19
4.4—Accounting for bond slip, p. 19
4.5—Accounting for strain penetration, p. 22
CHAPTER 5—FINITE ELEMENT (FE) MODELING OF BEAMS, COLUMNS, AND JOINTS, p. 22
5.1—Introduction, p. 22
5.2—Verification and validation, p. 23
5.3—Geometry and element definition, p. 24
5.4—Material definition, p. 27
5.5—Loading and boundary condition definition, p. 28
5.6—Analysis parameters definition, p. 28
5.7—Modeling beams, p. 30
5.8—Modeling columns, p. 30
5.9—Modeling beam-column joints, p. 31
CHAPTER 6—SUMMARY, p. 32
CHAPTER 7—REFERENCES, p. 32
Authored documents, p. 33