How to use Scage?
1 Introduction
Scage is a software dedicated to the structural analysis of reinforced concrete foundations and retaining walls.
In particular, it makes it possible to evaluate the internal equilibrium of piles and diaphragm walls in accordance with the Eurocode 2 (French and Belgian national annexes) and the French national application standard of Eurocode 7 (NF P 94-262 and NF P 94-282).
In the case of a pile type project, two types of studies are proposed:
- Preliminary design: it allows to decide on the diameter of the piles necessary to support one or several torsors and the rate of reinforcement necessary to be provided, and this for an infinite number of piles. It allows to estimate the maximum forces according to the forces applied at the head for each combination/situation considered.
- Detailed study: it allows the verification of one or more reinforcement cages for a set of internal force diagrams to be taken from a foundation or support equilibrium calculation. The calculation is performed phase by phase in simple, compound or biaxial bending, both at the ULS and at the SLS. The phases are grouped by envelope to facilitate the handling of the calculations to be performed.
In the case of diaphragm wall retaining walls, it allows the calculation of the required longitudinal steel sections at ULS and SLS as well as the required transverse steel sections at ULS from the results of the equilibrium calculation. The internal stresses of the diaphragm wall are considered as input data from a soil-structure interaction calculation (ISS calculation, e.g. obtained from K-Réa) taking into account the construction phase of the structure. The calculation is performed phase by phase in simple or compound bending, both at ULS and SLS. The phases are grouped by envelope to facilitate the handling of the calculations to be performed.
2 Pile projet
This type of project is used to design foundation and retaining wall piles.
2.1 Preliminary design
2.1.1 Project
- General information
It is possible to define the name of the project and the calculation section. This information will be used when printing the calculation report.
It is possible to work with the metric and imperial unit system.
- Definition of a calculation case
Within a Scage project, it is possible to store several independent calculations as “Cases”. The idea is to be able to define and compare several calculations carried out, which makes it possible to switch between them quickly. The interface also proposes a system of favourite cases to facilitate visual reference.
2.1.2 Materials
- Definition of materials
The concrete is characterised in terms of allowable stresses for each combination (the limitations required by NF P94-282 are also proposed). The inclination of the concrete rods must also be defined. Details of the calculations carried out are provided under the Details button, with indications as to the chapter and source paragraph of standard NF P94-282. The automatically calculated values are also customisable if the user wishes.
The steel is characterised by its characteristic resistance, the branch of its behaviour law (horizontal or inclined), its modulus of elasticity or Young’s modulus and its limit deformations accessible from Details.
- Behaviour laws
The behaviour laws are shown to scale for the ultimate limit states. The graphs are zoomable and can be exported to the clipboard.
- Partial coefficients
The partial coefficients on the concrete and steel strengths are to be defined for each design combination. The equivalence coefficient (ratio between the modulus of elasticity of steel and concrete) can also be set for the SLS combinations.
2.1.3 Preliminary design
This tab allows you to perform two types of calculations:
- Calculation of preliminary dimensions of piles
- Generation of interaction diagrams
The pile preliminary design calculation allows the user to decide on the minimum quantities to be provided per pile (diameter and minimum steel ratio) to take up a set of torsors (5 components: N, Mx, My, Vx and Vy) without the need to define a reinforcement cage.
The user can define :
- the list of diameters to be examined ;
- the range of longitudinal and transverse steel ratios to be examined
- the position of the centre of gravity of the reinforcement in relation to the edge of the concrete section;
- and the working stress of the steel at ELS.
The internal stresses can be derived from an equilibrium calculation (e.g. with Foxta or K-Réa) or automatically generated from the head forces using a wizard.
In addition, Scage offers a interaction diagram generator for a set of predefined diameters and longitudinal steel ratios at ULS and ELS.
2.2 Detailed design
2.2.0.1 Project
- General information
It is possible to define the name of the project and the calculation section. This information will be used when printing the calculation report.
It is possible to work with the metric and imperial unit system.
- Definition of a calculation case (scenario)
Within a Scage project, it is possible to store several independent calculations as “Cases”. The idea is to be able to define and compare several calculations carried out, which makes it possible to switch between them quickly. The interface also proposes a system of favourite cases to facilitate visual reference.
- Definition of the geometry
The section is considered circular, defined from a diameter of piles.
2.2.1 Materials
This tab is identical to the one described in Materials.
2.2.2 Phases/Envelopments
- Internal stresses
This tab is used to define the internal stresses to be considered in the verification of the reinforcement cage.
The internal forces of the wall must come from a soil-structure interaction (SSI) calculation, for example from a Foxta project, K-Réa or from an Excel file (find the model in the installation folder).
In the case of an import from Foxta, an import wizard allows to choose the source file of the SLS and ULS stresses as well as the choice of the variant to be considered for each calculation direction (X, Y, Z). In general, the Taspie module can be used to generate the normal force in Z and the Piecoef module to generate the X and Y loads. It is possible to use the loads from an SLS calculation to generate the ULS by defining the partial factor, usually equal to 1.35 (all loads are then multiplied by 1.35).
In the case of an import from K-Réa, it is necessary to choose a project for which the ULS calculation has been activated. The piles are assumed to be spaced at a certain center-to-center distance which must be defined in Scage in order to multiply the source stresses. In the case of a double wall project of K-Réa, it is possible to define which wall (1 or 2) should be imported.
In the case of an import from Excel, it is necessary to provide the SLS and ULS stresses. Indeed, they are necessary for the proper execution of the calculation. See details of the format of the Excel file to be provided in the dedicated document of the manual.
When importing, all phases are displayed in the list Unassigned phases. The user can then switch each phase into an envelope. It is also possible not to assign a phase to an envelope, which allows the liberty of not considering a phase in the calculation.
- Envelopes
As many envelopes as desired can be created.
An envelope can contain one or more calculation phases.
Scage allows you to simplify and reduce the number of calculation levels in order to simplify the calculation to be performed. This is achieved by choosing the maximum calculation step. This simplification preserves the extreme values of the internal force diagrams to keep continuity with the source diagrams.
According to Eurocode 2, it is necessary to apply an offset to the bending moment diagrams in order to guarantee the loading of the longitudinal bars over their anchorage length. The offset value can be entered by the user or automatically calculated by the interface.
If the source file is modified during the Scage calculation, it is also possible to import either all the phases again or only the stress values while keeping the same distribution of the phases within the envelopes.
- Internal forces
The internal forces are presented in two tabs: ULS (ultimate limit state) or SLS (serviceability limit state). The results can be displayed in graphical or tabular form.
The graphs are all titled and specify the unit of the displayed values, as well as the minimum and maximum values. They allow zooming, both on the internal region and on the axes, as well as export to the clipboard.
2.2.3 Steel sections
2.2.3.1 Phases/Envelopments
This tab allows you to define the reinforcement cage to be checked.
Each envelope is characterized by a situation at the ULS and at the SLS.
The bending mode to be considered can be defined for each calculation phase:
- Simple bending around X
- Simple bending around Y
- Compound bending around X
- Compound bending around Y
- Biaxial bending
- Biaxial compound bending
The working stress of the steel and the crack opening at SLS can be defined over the pile height by envelope.
2.2.3.2 Cage elements
This tab allows you to define the reinforcement cage on the basis of several cage elements.
The first sub-tab allows you to define :
- The maximum length of the longitudinal bars: this corresponds to the announced limit.
- The maximum length of the longitudinal bars: this corresponds to the limit announced by the reinforcement manufacturer, which guarantees that the bars entered in the elements will be acceptable.
- The minimum distance between the transverse zones: this is used to manage the spacing between the last frame of one element and the first of the next.
Then, each cage element is defined by :
- An altimetry: an upper level and a lower level of the element.
- A set of longitudinal bars positioned on the section of the pile and on the height of the cage element defined by an upper and lower level. A wizard is proposed to easily calculate the polar position of each bar, defined by a distance to the center of the section (\(r\)) and an angle (\(\alpha\)) to the vertical.
- A set of transverse zones positioned along the height of the cage element defined by a spacing, a number (1 or 2) and a hoop diameter.
All longitudinal bars or transverse zones can be duplicated to facilitate handling.
Throughout the input, all the steels are positioned on the height of the element in the Elevation map.
Once the cage is defined, the calculation can be started using the “Epsilon” button in the Results card.
2.2.4 Listing
This tab provides access to an overview of all steel bars arranged in the Steel Sections tab (#### Steel-Sections).
It allows you to know the number of bars per diameter, its total length and the total mass.
It also provides the steel to concrete ratio (kg/m³).
3 Diaphragm wall project
3.1 Steps to define a project
3.1.1 Project
- General information
It is possible to define the name of the project and the calculation section. This information will be included when printing the calculation report.
It is possible to work with both metric and imperial units.
- Defining a calculation case (scenario)
Within a Scage project, it is possible to store several independent calculations in the form of Cases or Scenarios. The idea being to be able to define and compare several calculations performed, which allows to switch between them quickly. The interface also provides a system of preferred cases.
- Definition of geometry
The section is considered rectangular, defined from a calculation width and wall thickness.
The imported internal forces per unit of length will be multiplied by the input calculation width.
3.1.2 Materials
- Definition of materials
Concrete is characterized in terms of allowable stresses for each combination (the limitations required by NF P94-282 are also proposed). The inclination of the concrete rods must also be defined. The details of the calculations performed are provided under the Details button, with indications as to the chapter and source paragraph of the NF P94-282 standard. Their values are automatically calculated and can also be customized if the user wishes.
Steel is characterized by its characteristic strength, the branch of its constitutive law (horizontal or inclined), its modulus of elasticity or Young’s modulus and its limit strains accessible from Details.
- Constitutive laws
The constitutive laws are represented to scale for the ultimate limit states. Graphics accept zoom and can be exported to the clipboard.
- Partial safety factors
The partial safety factors on the strength of concrete and steel have to be defined for each calculation combination. The coefficient of equivalence (ratio between the modulus of elasticity of steel and concrete) can also be set for SLS combinations.
3.1.3 Definition of phases and calculation envelopes
- Internal efforts
The internal forces of the wall must come from a soil-structure interaction calculation (ISS), for example from a K-Rea project or from an Excel file (find the model in the installation folder).
In the case of a K-Rea double wall project, it is possible to chose which wall (1 or 2) it should be imported.
In the case of an import from Excel, the solicitations must be provided to the SLS and ULS. Indeed, they are necessary for the proper functioning of the calculation.
When importing, all phases are displayed in the Unassigned Phases list. The user can then switch each phase into an envelope. It is also possible not to assign a phase to an envelope, which allows the freedom not to consider a phase in the calculation.
- Envelopes
It is possible to create as many envelopes as desired.
An envelope can contain one or more calculation phases.
Scage allows to simplify and reduce the number of calculation levels in order to simplify the calculation to be carried out. This is achieved by choosing the maximum calculation step. This simplification preserves the extreme values of the internal force diagrams to keep continuity with the source diagrams.
In accordance with Eurocode 2, it is necessary to apply an offset to the bending moment diagrams to ensure that the longitudinal bars are loaded over their anchorage length. The offset value can be entered by the user or calculated automatically by the interface.
If the source file is modified during the Scage calculation, it is also possible to either import all phases again or only the values of the requests while keeping the same phase distribution within the envelopes.
- Internal efforts
The internal forces are presented in the form of two tabs: ULS (ultimate limit state) or SLS (serviceability limit state). The results can be displayed in graphical or tabular form.
The graphs are all titled and specify the unit of values displayed, as well as the minimum and maximum values. They allow zooming, both on the internal region and on the axes, as well as exporting to the clipboard.
3.1.4 Required steel sections
This section provides the required longitudinal and transverse steel sections for each envelope defined above.
- Envelopes
The calculation of reinforced concrete requires the definition of the position of the centre of gravity of the longitudinal bars in relation to the corresponding concrete fibre. At this point, this value is considered constant over the entire height of the wall.
The value of the offset value of the bending moment curves is recalled and can be modified again. It is also possible to reload internal requests if the source file has changed in the meantime.
It is necessary to define the situation to be considered at the ULS and SLS for each envelope, as well as the allowable steel stress at the SLS for each side of the wall and according to the depth. This stress can be defined according to the required limit crack opening (the coefficient is adjustable in the Settings tab).
The user is free to request either a simple or compound bending calculation for each calculation phase, which will have an impact on the required steel sections and the stresses generated at the SLS.
- Required steel sections
The necessary steel cross-sectional diagrams are shown according to the previous choices. They are presented in graphical or tabular form, both of which can be exported to the clipboard.
In accordance with Eurocode 2, transverse steel are only to be designed at the ULS.
3.1.5 Detailed calculations
This section provides access to calculation details at any level of calculation.
- Steel design
The user can choose the target diagram as well as the envelope and combination. A simple click on a curve allows you to locate and display a new line in the Results table.
- Results
The Results table is filled with all available data.
If the SLS combination is Quasi-Permanent, the equivalent diameter must be entered so that the crack opening calculation can be performed (exact method).
Details of the intermediate calculation parameters are displayed under the strain/stress graphs and the geometric section.
3.2 ULS checks
Once the cage is defined, this section provides the following results specific to the chosen reinforcement sections:
- Allowable bending moment at the ULS: it is calculated at each level from the strain diagram of the section at each phase (the axial force is kept equal to that applied)
- Allowable shear force at the ULS: it corresponds to the maximum shear force that the section can support. The values are proposed in graphical and tabular form.
3.3 SLS checks
Once the cage is defined, this section provides the following results specific to the chosen reinforcement sections:
- Allowable bending moment: it is calculated at each level from the practical steel sections while respecting the admissible limit stresses in concrete and steel (the axial force is kept equal to that applied).
- Steel stress: they correspond to the stresses generated by the computational stresses on the useful steel sections.
- Concrete stress: they correspond to the stresses generated by the computational stresses on the concrete section.
- Crack opening (only available for quasi-permanent situation): values of crack openings obtained by the exact method at each level as a function of the practical longitudinal reinforcement section, the working stress of the steel, the equivalent diameter and the average spacing of the longitudinal bars.
3.4 Listing
This section summarizes all the steel bars placed in the cage by specifying their type, diameter, dimensions, mandrel required for bending, length and mass.
The average diameter, the total mass of the cage and the steel ratio (weight of steel relative to the volume of concrete) are also calculated.
4 Reinforced concrete calculator
This powerful calculation tool is proposed independently of the project carried out.
The objective is to allow the user to verify reinforced concrete calculations for a set of independent input data.
The calculation can be done for a circular section (piles) or for a rectangular section (diaphragm wall).
5 Printing the calculation report
Scage allows the printing of the report of the calculations performed while leaving the possibility to choose the content to be included. A dynamic print preview is provided on the interface.
The report can also be printed in PDF format, if a dedicated printer is available in the operating system.
