Did you know you can use Consteel to run second-order and buckling analyses on specific parts or elements of your model by defining a Custom Portion for the portion of interest?

The workflow starts in the Portions Manager, where you can manually group structural members, frames, columns, beams, bracings into Custom Portions. These are fully user-defined and, importantly, only these custom portions can be directly used for analysis. This allows you to isolate exactly the structural subsystem you want to investigate, without being constrained by the full model.

Once a portion is defined, it can be selected in the Analysis Settings, where you can choose whether second-order and buckling analyses should be performed on the entire model or only on the selected portion. The solver will then consider only that subset of elements when assembling the stiffness matrix and evaluating stability behavior.

Running these analyses on specific portions has clear engineering advantages. Second-order effects and buckling phenomena are often governed by local structural behavior, such as a critical frame, a bracing system, or a column group, rather than the entire structure. By isolating these regions, you can:

• reduce computational effort and analysis time, especially for large models
• focus on the most critical load paths and instability mechanisms
• perform faster iterations during design refinement
• avoid unnecessary influence from non-relevant parts of the structure

This targeted approach leads to more efficient and controlled stability analysis, particularly when investigating sensitive or highly utilized structural components.

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

In this article, we aim to answer the question: Why are there two different procedures for exporting connections to IDEA StatiCa? Let’s explore the difference between using the Connection interface and Checkbot export.

IDEA StatiCa Connection 

In order to use the IDEA StatiCa Connection link, please make sure that the program is installed and that the folder location is specified in the IDEA StatiCa Interface ‘Options menu‘.

The conversion starts on the Structural Members tab, using the ‘Create Joint by Model‘ function. After selecting the appropriate intersection between members, a new window will appear.

If the ‘IDEA StatiCa Connection’ type is selected, the IDEA StatiCa application will launch automatically, and the selected connection will be transferred. 

Using this method and placing the joints into the Consteel model (possible in multiple positions with similar geometry), a direct connection is established between the two programs. This means that geometry (cross sections, materials) and internal forces (according to all combinations of locations where the joint is placed) are taken directly from Consteel.

IDEA StatiCa Checkbot

The IDEA StatiCa Checkbot export can be accessed from the ‘File menu’ by selecting it from the ‘Exports section’. Users must define a location where the entire model will be exported in .xml format. This file can later be imported into IDEA StatiCa Checkbot using the IOM (IDEA Open Model) import option.

The full 3D model is imported using this method, and all joints can be analyzed individually within the IDEA StatiCa. A list of all imported items will appear in IDEA, each marked with a status such as ‘Checked’ or ‘Not Checked’. The imported members can be visualized in 3D, along with the applied loads. 

The conversion supports materials, cross-sections, and load combination management. The internal forces resulting from the Consteel analysis for ULS combinations are available in IDEA StatiCa. This approach also ensures that the internal coordinate systems for all internal forces are preserved accurately. 

All connections present in the imported model can be exported to IDEA StatiCa Connection, where joint design is carried out. You can choose to export a single connection or select multiple connections and save them in one file, allowing you to design the connection or print reports for all modeled connections at once. 

Connections designed in Checkbot can only be considered in the global analysis phase in Consteel if the calculated stiffness is manually introduced at the release ends. 

When to choose the direct link to IDEA StatiCa Connection?

Use direct link IDEA StatiCa Connection when you want to jump directly to the connection design in IDEA. Since the joint can be placed in multiple locations within the Consteel model, all internal forces from all combinations and all positions where the joint is placed will be taken into account.

A key advantage is that if you’re still working on your 3D model and changes occur, there’s no need to regenerate the link, simply update and verify the changes directly in IDEA StatiCa.

When to use IDEA StatiCa Checkbot Export? 

Use Checkbot export when your structure contains many irregular or complex joints.For instance, if the bars in the connections do not intersect at a single point due to eccentricities or lack of space, you can merge them into one connection using Checkbot.

Conclusion

In summary, from the perspective of model updates and quicker access, using the direct connection via IDEA StatiCa Connection is generally the better choice, especially if the integrated Consteel Joint doesn’t provide enough flexibility for joint creation.

IDEA StatiCa Checkbot export offers significant advantages in terms of automated member recognition, possibility to merge joints, accurate assignment of internal forces, and efficient bulk joint analysis. It eliminates the need to manually verify force directions or coordinate systems, streamlining the workflow, especially for larger or more complex structures.

The main limitation of Checkbot export is that it establishes a one-way connection: every time the Consteel model changes, a new export is required in order to stay updated with the changes. Therefore, the choice between methods should depend on the nature of your project, if the model is expected to change frequently, the direct connection is more suitable. However, if you’re working with the final geometry and need to verify complex joints, the Checkbot export is the better option.

Did you know that Consteel provides a plugin to integrate structural modeling and analysis into your parametric Grasshopper definitions?

Download Pangolin from food4rhino.com or the Yak package manager of Rhino. You can also download it by logging in to our website. See Downloads/Plugins menu:

How will you possibly work in Pangolin? See the related videos on our YouTube channel, starting with the ‘Introducing Pangolin‘ video.

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

In Consteel, the calculation of cross sectional interaction resistance for Class 3 and 4 sections is executed with the modified Formula 6.2 of EN 1993-1-1 with the consideration of warping and altering signs of component resistances. Let’s see how…

Application of EN 1993-1-1 formula 6.2

For calculation of the resistance of a cross section subjected to combination of internal forces and bending moments, EN 1993-1-1 allows the usage -as a conservative approximation- a linear summation of the utilization ratios for each stress resultant, specified in formula 6.2.  

$$\frac{N_{Ed}}{N_{Rd}}+\frac{M_{y,Ed}}{M_{y,Rd}}+\frac{M_{z,Ed}}{M_{z,Rd}}\leq 1$$

As Consteel uses the 7DOF finite element and so it is capable of calulcating bimoment, an extended form of the formula is used for interaction resistance calculation to consider the additional effect.

$$\frac{N_{Ed}}{N_{Rd}}+\frac{M_{y,Ed}}{M_{y,Rd}}+\frac{M_{z,Ed}}{M_{z,Rd}}+\frac{B_{Ed}}{B_{Rd}}\leq 1$$

Formula 6.2 ignores the fact that not every component results the highest stress at the same critical point of the cross-section.

In order to moderate this conservatism of the formula, Consteel applies a modified method for class 3 and 4 sections. Instead of calculating the maximal ratio for every force component using the minimal section moduli (W), Consteel finds the most critical point of the cross-section first (based on the sum of different normal stress components) and calculates the component ratios using the W values determined for this critical point. Summation is done with considering the sign of the stresses caused by the components corresponding to the sign of the dominant stress in the critical point.

(For class 1 and 2 sections, the complex plastic stress distribution cannot be determined by the software. The Formula 6.2 is used with the extension of bimoments to calculate interaction resistance, but no modification with altering signs is applied)

Example

Let’s see an example for better explanation.

GATE

Did you know that you could use Consteel to calculate rotational stiffness for bolted column/beam moment bearing connections?

This capability is implemented through the Joint module, where connection behavior is evaluated in accordance with Eurocode EN 1993-1-8. The software does not treat joints as idealized (purely pinned or rigid), but allows the engineer to consider semi-rigid behavior by calculating the actual rotational stiffness based on connection components such as bolts, end plates, welds, and stiffeners.

In practical terms, the rotational stiffness is derived from the component method, where the stiffness contribution of each tension and compression component is taken into account. This enables a more realistic representation of the joint response, especially for moment-resisting beam-to-column connections where stiffness significantly influences global structural behavior.

Bolted connection

In this case, the connection exhibits relatively low rotational stiffness compared to a fully rigid joint. The flexibility is primarily governed by bolt deformation and end plate bending. Such connections are typically classified as semi-rigid and partial strength. They allow noticeable rotation under moment, which can be beneficial for redistribution of internal forces but must be considered in global analysis.

Bolted connection

This configuration shows a higher stiffness due to improved component arrangement, such as thicker end plates, larger bolt diameters, or additional stiffening. Although still semi-rigid, the connection provides significantly more resistance to rotation. This intermediate behavior often results in a more efficient structural system by balancing stiffness and material usage.

Welded connection

The welded joint behaves as a rigid connection with full strength. Rotational stiffness is high enough that joint deformation has negligible influence on the global structural response. In Consteel, this is reflected by a stiffness value approaching the rigid classification limit defined by the standard. Such connections are typically used where continuity and moment transfer must be ensured without significant rotation.

Using the Joint module, these behaviors can be modeled and evaluated through a structured workflow:

• Joint creation: Define the connection either manually or based on the global structural model using automatic recognition.
• Connection configuration: Assign geometry, cross-sections, bolt layouts, welds, and optional stiffeners.
• Loading definition: Apply either user-defined internal forces or import them directly from the global analysis.
• Analysis: The software evaluates moment resistance, shear resistance, and both initial and secant rotational stiffness using Eurocode-based procedures.
• Integration: The calculated stiffness can be applied back to the global model, enabling second-order effects and realistic force distribution.

Considering rotational stiffness leads to more accurate structural models. Instead of assuming ideal boundary conditions, the engineer can:

• Reduce conservatism in member design
• Capture redistribution effects in frames
• Optimize connection detailing
• Improve overall structural efficiency

This approach is particularly important in steel frames where joint flexibility can significantly affect deflections, internal forces, and stability.

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

Did you know that you could use Consteel to perform dual analysis with 7DOF beam and/or shell elements?

With two advanced features, Superbeam and Convert members to plates, you can choose the approach that best suits your project needs, whether you’re focused on modeling efficiency or detailed analysis.

The Superbeam function offers a smart, adaptive way to handle structural members. It enables you to model with the simplicity of standard 7DOF beam elements while allowing you to switch to a more detailed shell-based analysis for specific members whenever needed.

Once the structure is modeled using beam elements, you can select how each member is analyzed:

• Using the beam model, which applies Consteel’s proven 7DOF beam elements along with its comprehensive design tools.
• Or using a shell model, which is automatically generated for selected members. This shell model includes detailing features such as web cutouts and stiffeners, fully integrated into the global analysis model.

This dual approach is fully adaptive. You can continue modifying your model using beam elements and switch between analysis modes as required, offering both speed and precision within the same workflow.

For a complete overview of how to activate and manage Superbeam functionality, refer to the documentation:
Superbeam – Consteel Manual

When you need complete control over geometry and mesh, or when shell analysis alone is not sufficient, Consteel provides the Convert members to plates function. This tool allows you to manually transform selected members into actual plate elements, enabling detailed modeling from the start.

Unlike the automatic conversion used in Superbeam, this method performs a permanent, non-reversible transformation (though undo is available during the session). It supports a wide range of section types, including hot-rolled, cold-formed, and welded profiles.

The conversion process preserves and adapts existing connections, eccentricities, loads, and supports. Where needed, rigid bodies and constraint elements are added to maintain structural continuity. These constraints ensure proper transfer of deformations, including warping, between the new plate model and the rest of the structure.

This function is especially useful in cases where precision is critical, such as modeling joints, fabrication-specific details, or complex load interactions.

To learn more, see the full guide here:
Convert Members to Plates – Consteel Manual

Both Superbeam and Convert members to plates serve different purposes, depending on the level of detail and control required in your model:

Feature	Superbeam	Convert members to plates
Workflow	Beam modeling with optional shell analysis	Full plate modeling from the beginning
Conversion	Automatic and reversible	Manual and permanent
Suitable For	Flexibility in analysis, quick modeling	Full control, high-detail requirements
Supported Sections	Welded I and H profiles	Hot-rolled, cold-formed, and welded sections
Detailing Support	Cutouts and stiffeners (in shell analysis)	Full geometric detailing, including transitions
Design Integration	Integrated with beam-based design tools	Suitable for fabrication-level modeling

In Superbeam, constraint elements are generated automatically to connect converted shell elements to other members, such as bars. During member-to-shell conversion, these elements link the FE shell nodes to the rest of the model, ensuring accurate deformation transfer.

If the convert members to plate function is applied directly to beam elements, rigid bodies are created at their ends, which is useful for analyzing local behavior but does not transfer warping deformations. If the beam is first converted to a shell and then to plates, hinged rigid edges are placed along the plate boundaries. This arrangement, combined with constraint elements, transfers not only in-plane and out-of-plane deformations but also warping between the shell and the rest of the structure.

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

Did you know that you could use Consteel to design web-tapered members?

Tapered members are widely used in the economic design of steel-framed structures, such as industrial halls and warehouses, because they make it possible to save material while still ensuring structural strength and stability. With Consteel’s dedicated Tapered Member function, you can model, analyze, and verify these members efficiently, supporting both everyday engineering practice and advanced stability checks.

In Consteel, tapered members are line members with welded I or H, box, or cold-formed C sections. Hot-rolled and other macro sections cannot be tapered. Their section height can vary linearly along the member length, making them suitable for realistic structural modeling.

It is best to start with a section close to the smaller end of the taper. The start height (H1) applies at the beginning of the member, and the end height (H2) at the other end. If either value is less than half of the original section height, Consteel automatically resets it to 0.5 times the original. H1 and H2 can be swapped easily with the dedicated icon to reverse the taper direction.

The placement of a tapered member relative to the axis of the original beam is defined by beam eccentricity rules. Consteel offers three alignment options:

1. Centroid of the smaller section on the axis – the tapering develops outward from the end with the smaller height.
2. Centroid of the larger section on the axis – the bigger end of the member remains fixed to the original axis.
3. Centroid of the original section on the axis – one edge of the tapered member coincides with the original section, and the tapering starts from this position.

In analysis, Consteel creates tapered sections with the specified start and end heights and places them on the member’s reference line. Unless symmetric tapering is used, this placement is eccentric, which introduces additional effects. At frame joints, for example, extra moments from eccentric axial forces must be considered to maintain equilibrium.

Consteel handles these effects automatically, ensuring realistic results. Symmetric tapering keeps the analysis simpler, while eccentric tapering requires more attention. In all cases, global stability checks should complement sectional verifications to guarantee structural safety.

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

Did you know that you could use Consteel to determine the optimum number of shear connectors for composite beams?

In composite beam design, the required number of shear studs is not only a detailing issue but a direct part of the structural resistance mechanism. The modelling and design environment in Consteel allows this number to be determined in a rational and automated way, consistent with EN 1994-1-1:2010.

The process begins with the definition of a composite beam cross-section (Macro section). Two standard types are available: a solid slab composite beam and a profiled steel sheeting composite beam. The effective width is defined at input level, but the actual effective width used in analysis is calculated automatically based on span, geometry, and stud spacing assumptions. This ensures that the structural response is captured realistically, while maintaining simple input control for the user.

After defining the cross-section, the member is created and design parameters are assigned through object properties. These parameters govern key aspects of composite behaviour, including stud spacing, support conditions, and whether shear stud design is performed manually or automatically.

For shear connector design, Consteel applies a plastic distribution model. The governing section of the beam, typically corresponding to the maximum bending moment, is identified automatically. From this section, shear studs are distributed symmetrically along the beam length.

When automatic optimisation is selected, the software determines the minimum number of shear studs required to satisfy bending resistance. It then increases the number iteratively until the composite section achieves sufficient capacity. The resulting value represents the optimal number of shear connector positions for the given loading and geometry.

The key parameters used in this evaluation include:

• nopt: optimal number of shear stud positions in the governing region
• nact: actual number of stud positions applied
• sL, sR: spacing of studs on the left and right side of the critical section
• nmin: minimum required number of stud positions based on resistance

The ratio nact / nopt is used as a direct measure of utilisation of the shear connector system.

There is also the option to define the number of studs manually. In that case, Consteel distributes them uniformly along the member and checks compliance with detailing rules such as minimum and maximum spacing. This is typically useful when construction constraints or predefined detailing standards take priority.

Composite beam design itself is carried out according to EN 1994-1-1:2010. Plastic bending resistance is evaluated for Class 1 and 2 cross-sections, while shear, concrete flange crushing, and longitudinal shear are checked at critical sections. Shear buckling is treated according to EN 1993-1-5. Lateral-torsional buckling is not included in the current design scope.

For profiled sheeting, shear stud resistance is reduced depending on rib orientation, in line with Eurocode 4 rules.

Overall, the key point is that the number of shear connectors is no longer an assumed input. It is derived from structural demand through an automated and transparent process, which makes it easier to reach an efficient and consistent composite design without repeated manual iteration.

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

Did you know that you could use Consteel to determine automatically the second order moment effects for slender reinforced concrete columns?

Download the example model and try it!

Download model

If you haven’t tried Consteel yet, request a trial for free!

Try Consteel for free

When applying design rules in load combination filter, the most frequently used utilization type is Steel – Dominant results. What results are exactly considered by this option and what do corresponding limitations mean?

Introduction

There are four ways to apply load combination filter: based on limit states and load cases, manually, and by rules. Unlike the other three methods, filter by rules is only possible based on analysis and/or design results.

The most effective way to reduce the number of load combinations is definitely the use of design rules.

With design rules, load combinations can be selected based on utility ratios. Utilizations are available from several design checks, including dominant results and detailed verifications for steel elements, such as general elastic cross-section check, pure resistances, interactions, and global stability.

The meaning of the dominant check

The dominant check is not always the check which gives the maximal ratio but the one with the maximum RELEVANT ratio. Typical example: if plastic interaction formulas are valid, those results will be dominant over general elastic cross-section check results, although the latter are higher.

Steel – Dominant results

Steel – Dominant results option contains the utility ratio of the dominant check at every finite element node, in all load combinations. Meaning that there are as many utilization values as the number of load combinations calculated, in every FE node.

It is also important to understand the difference between the utilizations of Maximum of dominant results and Steel -Dominant results. Maximum of dominant results option contains the dominant utility ratio of the dominant load combination at every node, like an envelope of Steel-Dominant results. Meaning there is only one utilization value in every FE node. Also, it is the same as the dominant result table on Global checks tab.

When a rule is applied, the utilizations of the chosen utilization type are compared against the limitation. The load combinations which give the results that correspond to the limitation, are selected by the rule. Every FE node of the selected model portion is examined.

Limitations in case of Steel – Dominant results

• Maximum: to select the combinations which cause the maximum utilization at any node. It can be the same as Maximum of dominant results, except if there are combinations where the utilization is the same and it is maximal. In this case, here all the combinations are selected, while with Maximum of dominant results, there is always one maximum.
• More than % of maximum: to select the combinations as in ’Maximum’ plus those which cause utilization that is more than the given percentage of the maximum. E.g. at a certain point max utility ratio is 80%, Limitation= More than 90% of maximum. This rule will select all the load combinations which cause utility ratios between 0,9*80=72% and 80%.
• More than: to select the combinations which cause utilization more than the defined value at any point.

Let’s see an example of a simple 2D frame for better explanation. Right-side beam is in the portion for which three design rules were applied. Five points are selected for representation but of course all the nodes of the portion are examined against the rules’ limitations.

The utilizations of the five dedicated FE node in all 11 load combinations are shown on the below diagram. (To find all of these utilizations in the attached model, global checks must be calculated for the load combinations one-by-one.)

gate