The partially fixed mast is a common configuration of reinforced concrete structures, which nevertheless remains poorly documented in the literature. Yet a partial fixity is a delicate assumption to handle.
This example offers a review of the data input process and the justification of such a calculation, according to the general EC2 method reduced to one critical section (MG1). It especially details various reminders and points of attention to monitor in order to successfully perform the design.
The end of the example shows the exact solution to the problem and the possible optimisation made possible by the integral general method (IGM).
- Nicolas DUBREIL
- 11 mins
This article presents the benefits of a nonlinear approach for the analysis of reinforced concrete line elements, intended to determine the unique solution of the mechanical problem — when it exists — by enforcing flexural and axial deformation compatibility at every point along the member.
Inspired by the General Method and fully covered by Eurocode 2, this approach, referred to as the “Integral General Method” or IGM, opens up possibilities for analysing and optimising many common situations, from slender columns to continuous members in combined bending and compression.
- Nicolas DUBREIL
- 11 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