FR 
The behaviour of reinforced concrete flexural structures is intrinsically non-linear and depends on cracking and the progressive plastification of sections.
Compared with earlier generation codes (BAEL), Eurocode 2 now benefits from the theoretical contributions required to take these phenomena into account, notably enabling the calculation-based treatment of concrete adaptation, the formation of plastic hinges, moment redistribution, as well as deformation compatibility issues.
Depending on the required level of analysis, the code also allows simplified, regulated methods based on linear-elastic analyses, possibly combined with predefined moment redistributions.
These various approaches provide the calculation framework with a certain versatility and give the engineer a degree of flexibility suited to the diversity of situations encountered in practice.
While simplified analysis methods (§5.4 to §5.6) are widely used in practice, the present study proposes to utilize non-linear methods (§5.7) on simple cases in order to progressively highlight the mechanisms underlying structural analysis according to EC2, and to provide additional insight into linear-elastic analyses and redistribution practices.
- Nicolas DUBREIL
- 20 mins
Identify the vocabulary and the sequential logic “structural analysis → design of cross-sections” to better read and understand the code.
This article deciphers the precise semantics used in EC2 — analysis, design, actions, effects, mean and characteristic values — and shows how these definitions structure the entire code.
It clarifies the two-step process (structural analysis followed by cross‑section design) and describes the different regulatory material behaviour laws associated with each step.
This conceptual basis then makes it possible to understand the boundaries between the models involved, and in particular to address the issue of deformation compatibility.
This topic constitutes the first part of a series dedicated to the flexural behaviour of reinforced concrete beams (1/4).
- Nicolas DUBREIL
- 11 mins
The material laws in EC2 vary between structural analysis and cross‑section design, incorporating different levels of physical complexity in the behaviour of concrete and steel depending on the objectives pursued.
This article details the different behaviour laws for concrete and steel, their distinct uses (structural analysis vs cross‑section design), and their limitations.
It explores how phenomena such as plastification, cracking, or even the tensile resistance of concrete are taken into account, and clarifies the safety factors and the possibilities for linearisation or other simplifications authorised by EC2 depending on the design step.
This topic is the second part of a series devoted to the flexural behaviour of reinforced concrete beams (2/4).
- Nicolas DUBREIL
- 14 mins
In hyperstatic structures, deformation compatibility dictates the exact distribution of moments — a challenge that the simplified EC2 methods only partially address.
This article explains how a hyperstatic structure possesses, for each load case, a unique exact solution determined by the actual deformability of its sections and supports.
It shows that internal forces depend closely on varying stiffness, reinforcement layout, progressive cracking and plastification, making the EC2 sequential approach sometimes insufficient.
It also explores the conditions for nonlinear analysis, enabling the limitations of the “structural analysis → cross‑section design” framework to be overcome.
This topic constitutes the third part of a series dedicated to the flexural behaviour of reinforced concrete beams (3/4).
- Nicolas DUBREIL
- 8 mins
Elastic structural analysis, limited redistribution, and plastic analysis. Study on an example, verification of ductility, and the limits of these models
This article presents the four structural analysis methods proposed by Eurocode 2 for continuous beams, and shows how simplified approaches (elastic, limited redistribution, plastic) deliberately bypass the pursuit of the exact solution.
It explains the mechanisms of hinge formation, the conditions for valid redistribution, the verification of plastic rotation capacity, and the biases of linear models when cracking and stiffness loss become predominant.
Finally, it highlights possible discrepancies between simplified analysis and actual behaviour, especially regarding deflection, second‑order effects, and redistribution at SLS.
This topic is the final part of our series dedicated to the flexural behaviour of reinforced concrete beams (4/4).
- Nicolas DUBREIL
- 13 mins
Analysis of a little‑known axial phenomenon: the elongation of simply‑bent RC beams under gravity loads, a direct consequence of reinforced‑concrete behaviour.
This article introduces the first axial effect observable in flexural reinforced‑concrete elements: the elongation of simply‑bent beams under gravity loads.
This phenomenon—often overlooked despite being non‑negligible—results directly from the fundamental behaviour of reinforced concrete, especially once cracking develops. Understanding it is essential before rigorously addressing the effects of thermal expansion and shrinkage.
It forms the first part of the series “Axial behaviour of flexural reinforced‑concrete elements” (1/4).
- Nicolas DUBREIL
- 6 mins
Thermo‑mechanical analysis of RC sections: constitutive laws, effects of thermal expansion and thermal gradients, and cases where EC2 requires their consideration.
This article examines the thermo‑mechanical behaviour of reinforced‑concrete members subjected to thermal expansion or thermal gradients, based on the assumptions of Eurocode 2.
It first analyses how the constitutive laws of concrete and steel are modified and how the mechanical diagrams of RC sections (strains, stresses, internal forces) evolve under thermal actions.
The article then reviews the regulatory situations in which thermal effects must be considered, illustrates the physical behaviour that can be observed, and presents the gravity/thermal concomitances that may become governing.
This is the second part of the series “Axial behaviour of flexural reinforced‑concrete elements” (2/4).
- Nicolas DUBREIL
- 8 mins
Analysis of concrete shrinkage, the induced self‑stresses, the differences with thermal effects, and the conditions for applying EC2 formula (7.21).
This article examines the mechanical behaviour of reinforced concrete subjected to shrinkage, highlighting the fundamental differences between shrinkage and thermal effects, and introducing the notion of self‑stresses that develop within the section.
It then analyses how the constitutive laws of concrete and steel are modified and how the mechanical diagrams of a reinforced‑concrete section (geometry, strains, stresses, internal forces) evolve under shrinkage.
Finally, the article clarifies the conditions under which Eurocode 2 formula (7.21)—used to estimate the curvature of a flexural member due to shrinkage—can be validly applied.
This contribution forms the third part of the series “Axial behaviour of flexural reinforced‑concrete elements” (3/4).
- Nicolas DUBREIL
- 9 mins
