IDEA StatiCa Connection: A New Approach to Structural Design of All Steel Connections

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Bolts, welds, end plates, base plates, stiffeners, ribs, cleats, bolts with welded fin plates, beam to column connection, beam web to beam flange connection, gusset plates for bracings... These are only the few types of steel connections in the midst of many different types of connection elements. On top of these different connection elements, we also have different combinations of connection elements. This can result in complex checks, including nonlinear analysis checks. Yes, you can use the steel connections formulas in national codes to check basic steel connections, such as bolts or welds. However, for more complex steel connections, these checks are idealized and have limitations. How can different steel connection checks be made both accurately and effectively, and at the same time, comply with national codes?
 
IDEA StatiCa has this solution, the IDEA StatiCa Connection software. The team at IDEA StatiCa with the Faculty of Civil Engineering in Prague and the Faculty of Civil Engineering of Brno University of Technology developed a new method for design and analysis for steel connections, CBFEM (Component Based Finite Element Model). CBFEM makes up the basis of IDEA StatiCa Connection software. It still keeps the essence of the Component Method, which designs connections as systems of interconnected components. It still uses the Component Method for certain connections like bolts or welds since national codes comply with the Component Method. However, CBFEM improves the Component Method by including finite element analysis and nonlinear analysis to certain connection elements that require special attention to their nonlinear behavior. 
IDEA StatiCa Connection can:
1. Check for different customized steel connections
2. Display the steel connection’s FE model
3. Automatically generate FEM results
4. Calculate for stresses and strains of steel connections based on non-linear behaviour
5. Adhere to international codes, EN code and the AISC
 
In this post, we will go through an example of a steel connection, a simply supported beam to column connection, to test out how IDEA StatiCa Connection works.
 
Connection Geometry Input Function
 
You can input all your basic information that you use to calculate for steel connections, such as steel grade, your type of steel connection, which steel member is bearing, the geometry of the connection, the length of the connecting structural members, and end conditions. You can also choose or edit a predefined steel section in a diversified collection of standardized sections OR you can create your own. Predefined sections include:
1. Rolled sections (I sections, Channels, Angles, Rectangular and circular sections)
2. Welded sections
3. Cold-formed 

 
Load Effects Input Function
 
You can input any load reactions onto the connection.
Then, you can run the Equilibrium check, a handy tool in this load section. The Equilibrium check is based on equilibrium equations at the joints and checks to see if you have any unbalanced forces.
 
Joint design and manufacturing feature

You can choose additional connection elements to add to your connection type, such as stiffeners, end plates, bolts, gusset plates, member cuts, anchors, wideners to increase flanges or webs of members, ribs, openings and notches, splices, cleats, etc. After selecting your connection elements, you can input their structural properties. ​

For example, if you selected the stiffener or rib option, you can choose which member to add the stiffener/rib on, the position and the inclination of the stiffener or rib, its thickness and material, etc. There are other options, such as the typical fin plate. These can be connected to the flanges or webs of the steel members. You can define the fin plate’s material, thickness, whether the connection is bolted or welded, bolt and weld properties, and even whether there are notches or not. For welds, you choose whether the steel cross section is welded to a plate or the other connecting steel member, the number of welded edges, the type of welds (butt weld or fillet weld) or the throat thickness. If throat thickness is not inputted, the throat thickness is automatically determined according to the thickness of the connecting element ​

 
Plate Editor Feature

Another unique feature is the Plate Editor. Based off of realistic manufacturing plate conditions, you can edit your connecting or end plate to any geometry you want. You can offset any sides or all sides of the plate, have smooth circular rounding of the plate’s corners, have the plate chamfer, bevel, or arc cut, have holes and notches at specific places of the plate, etc. You can also use this function to visualize your bolt positions and change your positions to suit. Once you are finished with the setting out and dimensioning of the plate, you can then produce a drawing of the plate and bolt holes with dimensions and setting out, for manufacturing, design, or coordination purposes.

Calculator based on CBFEM

IDEA StatiCa Connection uses CBFEM to calculate all its connections. It provides comprehensive and diversified FEM checks for different connection types and for different failure modes. This Check function also helps you to cater for different efficiency levels of your analysis. Under the Code setup tab, you can do so by changing the number of analysis iterations.
 

After you set up and ran your analysis, IDEA StatiCa Connection shows whether all loads applied are used (okay state) or whether analysis has stopped (when applied load is more than the connection ultimate limit state capacity). ​

For each individual connection component, you can find your summary tables of design/capacity percentage based on specific load cases. ​​​

For plates, IDEA StatiCa Connection generates a summary table for individual connecting plates, including structural members’ flanges and webs. The table provides:

  • Maximum equivalence stress in plate
  • Maximum plastic strain in plate
  • Whether analysis of connecting plate is okay.

For bolts, the summary table shows:

  • Values of tension and shear forces applied
  • Max tension and shear
  • Max combined tension and shear
  • Whether the detailing is okay (edge distances, spacing, etc)
  • Whether analysis of bolts is okay

For welds, the summary table shows:

  • Stress in weld and stress perpendicular to weld throat
  • Shear stresses parallel and perpendicular to weld axis
  • Max stress capacity
  • Whether analysis of weld is okay

The program also shows a stress diagram for the connection so that you can see where the critical points of stress are.
There are various tools in the CBFEM ribbon that can aid analysis. The Strain Check feature shows a diagram of the relationship between the plastic strain and the plastic strain limit. The Buckling shape function shows the stress contour of the connection under the compressive stress of a selected load case.
 
Reporting Function

The Bill of Materials feature can generate summary tables of information and a section of the connection. The Bill of Materials can be used for shop drawings to clearly indicate to the supplier what the quantity and properties of bolts, plates, anchor, and other connection elements are needed for construction.

With the Report function, the software can generate a structural report with design equations used for the connection analysis. Depending on your needs, you can select whether you want a report with a single line of design results, a more detailed full page report, or an expansive detailed report with selected items from an all-inclusive list, such as geometry elements, cross-sectional pictures, strain check drawings, buckling analysis, etc. Idea StatiCa Connection also prepared commentaries on the theoretical background of the software, the advantages of CBFEM over the Components Method, its method of joint analysis check, and how the different connection elements are modelled (eg. Plates are modelled as plate/walls).

​All in all, IDEA StatiCa Connection is a ground breaking technology that can accurately and efficiently calculate for nearly all types of steel connections imaginable.

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