Did you know that you could use Consteel to perform structural analysis at room and elevated temperatures as part of design process for fire resistance?

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Did you know that you could use Consteel to calculate the elastic critical moment of a member subject to arbitrary loading and boundary conditions?

Calculating the elastic critical moment can quickly become difficult when beams have tapering, unusual restraints, or complex loads. Consteel simplifies the process and gives a quick, accurate result for any situation.

The elastic critical moment for lateral-torsional buckling is the theoretical bending moment at which a beam, free to sway sideways and twist, becomes unstable and buckles elastically, before yielding, representing the absolute upper limit of elastic stability for beam bending. It depends on: cross-section stiffness properties (I_z, I_w), material (E, G), span / buckling length, restraint to lateral displacement and to warping at the restraints, and on the shape of the moment diagram (via factors C₁, C₂, C₃).

For doubly symmetric I- or H-sections with constant cross-section, uniform bending, and classical boundary conditions, the elastic critical moment M_cr can be calculated using the analytical formula:

However, for arbitrary support conditions and loading scenarios, the calculation becomes significantly more complex, and the classical formula is no longer applicable. In such cases, specialized software such as LTBeam or Consteel is required.

Let’s consider a tapered, welded I-section with pinned supports at both ends and two intermediate restraints, one at the bottom flange and one at the top flange. In addition to the uniform distributed load, a bending moment is applied at one end of the beam.

By performing a buckling analysis in the Analysis tab, the buckling shapes and the critical load factor (αcr​) can be obtained. The elastic critical bending moment of the beam can be then calculated by multiplying the critical load factor by the maximum bending moment.

Consteel uses seven-degree-of-freedom finite element that fully accounts for tapering effects, torsion, and warping, key components in accurately capturing the true 3D behaviour of steel members. The seventh degree of freedom represents cross-sectional warping, which becomes visible in the buckling shape as the flanges move out of the plane of the cross-section.

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Did you know that you could use Consteel to design simple supported, continuous and over-lapped purlins systems, considering shear and rotational stiffness of attached roof sheeting?

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Did you know that you could use Consteel to determine the critical temperature of a steel beam protected against fire with intumescent painting?

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Did you know that you could use Consteel to design a hot-rolled crane beam considering the effect of code-prescribed load eccentricities?

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Consteel offers a range of load combination filtering options, which can be applied based on limit states, load cases, and analysis and design results. By applying different series of filters, designers can streamline their workflow and reduce calculation time.

Filtering options

Filtering is realized through the Load combination set definition window.

Filtering by limit states and by load cases are handled together with the checkboxes under the Limit states and Load cases buttons.

The 3-state checkboxes affect each other as they are not only used for selection but also for indication of the content. They can be manually set only to checked or unchecked. The middle state only appears when other filters are applied.

Filtering by limit states or load cases does not require any calculation results.

Filter by rules, on the other hand,is based on the actual analysis and/or design results. Different types of rules can be applied one by one or at the same time to select the desired load combinations.

When a rule is applied, all the load combinations that are selected on the Load combination set definition dialog- either with filtering by limit states/load cases or checked in manually- are examined at every position the rule indicates. Load combinations that meet the rule’s criteria are selected (remain checked in), while those that do not, become unchecked.

• With analysis rules, load combinations can be selected based on deformations or internal forces at either every finite element node or only at the member ends. This last one is included specifically for connection design. Deformations are checked in SLS combinations, internal forces are checked in ULS combinations only.
• With buckling rules, those ULS load combinations can be selected which have the elastic critical load factor (first buckling eigenvalue) less than the given limit.
• With design rules, load combinations can be selected based on utility ratios checked in every finite element node of the chosen portion. Utilizations are available from several design checks: dominant results and detailed verifications for steel elements such as general elastic cross-section check, pure resistances, interactions and global stability. Only ULS combinations can be filtered with design rules.

Interaction of the different filter types

Filtering by limit states, load cases, and rules can be used together, with rules being applied only to load combinations that are checked in and have the necessary calculation results.

Let’s see an example.

It is a simple 2D frame model, with 27 load combinations of various limit states generated. Analysis and design results are calculated for all load combinations.

If applying design rule to select only those load combinations which result dominant utilization over 50%,

4 load combinations will be selected (Load combination set 1):

But if ULS Accidental limit state is turned off before applying the same 50% filter,  

only one load combination is selected (see Load combination set 2).

Application of multiple rules

Applying multiple rules together results in the sum of the lists that would have been created separately.

Warehouse building example for Overall Imperfection Method in Consteel

Watch our user guide about How to use the Overall Imperfection Method to learn more.

Example hall model for trying the smart link feautre in Consteel

Watch our user guide about How to use the smart link feature to learn more.

Example model for trying the smart link feature in Consteel

Watch our user guide about How to use the smart link feature to learn more.

Example model for calculate critical temperature in Consteel

Watch our user guide about How to use the critical temperature feature to learn more.