First released in IDEA StatiCa 24.0, this article was updated in version 25.1.
There are two types of bolt autodesign: Autodesign and Autodesign of bolts. Autodesign focuses on the 'first guess' (initial geometry), while Autodesign of bolts specifically refines the fastening layout for cost-efficiency. The new design is created based on the selected settings, which are further explained below. These features act as powerful assistants to speed up the engineering process, offering a solid design proposal ready for your final verification.
Autodesign
The Autodesign function serves as a rapid preliminary design tool. It allows you to quickly generate a valid connection geometry based on standard rules and the properties of the connected members.
The Autodesign function is prepared for these operations: End plate, Plate-to-plate, Splice, and Fin plate/Shear plate.
Autodesign can be called by one of the following:
- Right-clicking on the above-listed operation with bolts
- On top of the Operation properties
- Right-clicking on the Operation in the tree in the 3D scene and selecting Autodesign all. Here, you will autodesign not only bolts but also welds.
For End plate and Plate-to-plate operations, additional autodesign settings are available:
- Shear: Designs the plate and bolts for shear transfer (End plate operation only).
- Flush: Designs the plate flush with the beam's top and bottom flanges.
- Extended: Designs the plate to extend beyond the beam's top and bottom flanges.
The autodesign process is determined by the properties of the design members and specific global settings. The algorithm evaluates the following inputs:
- Cross-section & Material: The geometric and material parameters of the connected beam/column.
- Beam Resistance Setting: Uses the percentage defined in Project settings > Design – General (Default is 40%) to design the connection based on cross-section capacity. It applies shear resistance to webs and bending resistance to flanges.
- Detailing Rules: Respects the spacing and edge-distance rules located in the same settings.
- Max number of fin plate bolt rows: Respects the maximum limit of bolt rows defined in the (Default is 2).
When you run Autodesign, the function will automatically calculate and adjust the following parameters of the manufacturing operation to find a workable design:
- Plate properties: Thickness, dimensions (width/height), and offset
- Bolt properties: Total number of bolts and their specific positions
The function keeps the following parameters unchanged:
- Diameter and grade of bolts
- Material grade of the plates
Recommendation: For a sophisticated proposal that considers economy, efficiency, and optimal distribution, please use the Autodesign of bolts feature. Be aware that this function is specifically designed for the Fin plate and Splice and is limited to connections where bolts are subjected to shear forces only.
Autodesign of bolts
The Autodesign of bolts function is powered by machine learning, integrated with analytical formulas based on the design standards. This approach allows the tool to propose a solution that balances structural effectiveness with economy, resulting in an optimal bolt distribution.
The function Autodesign of bolts is ready for these operations: Fin plate and Splice, where bolts are primarily loaded in shear.
Autodesign of bolts can be called only after the calculation by:
- Right-clicking on the above-listed operation with bolts
The algorithm relies on the applied internal forces (N, Vz, My)—specifically considering the resulting shear forces on the bolts—and evaluates them against the following global settings:
- Rounding Rules: The positioning of the bolts is adjusted according to the rounding settings in Project > Preference > Application units - New entity rounding.
- Bolts: Target capacity utilization: This limit is defined in Project settings > Design – General > Autodesign (Default value is 0.9). The algorithm compares the real acting loads with this set value to find a solution that complies with the requirement. The specific value checked is the Utilization in shear (Uts).
- Detailing Rules: The algorithm respects the spacing and edge-distance rules located in Project settings > Design – General > Bolts detailing.
When you run Autodesign of bolts, the function will automatically calculate and adjust the following parameters of the Fin plate or Splice operation to find an optimized design:
- Bolt properties: Total number of bolts and the geometry of the bolt grid
- Plate properties: Dimensions (adjusted according to the new bolt grid) and thickness (partially adjusted to achieve the same bearing resistance as the connected element)
The function maintains the following parameters unchanged:
- Diameter and grade of bolts
- Material grade of the plates
Basic assumptions
- The Autodesign of bolt algorithm takes into consideration only forces and moments in the plane of the plate (N, Vz, My - generating only shear forces for the bolts) from the acting load effects in the model. Any tension forces occurring in the bolts (generated by other loads or prying) are not taken into consideration in the autodesign process.
- If the tension utilization is high (more than 30 % of total utilization), Autodesign of bolt could give inprecise results, and the user may receive a warning message. The autodesign of bolt is provided, but the results can be significantly influenced by tensile force in the bolts.
- Bolts in the operations have to be set with the bearing/shear interaction shear force type. Autodesign of the bolt is not performed if bolts are set as friction, and the user receives a warning message.
- The forces in bolts are not calculated correctly when the model is overloaded, and the analysis is completed with significant plastic deformation. Therefore, the Autodesign of the bolt is working with incorrect forces in the bolts and cannot give any correct result.
- Autodesign not support hollow cross-sections.
- If the selected cross-section is not suitable for placing the bolt grid according to geometrical requirements, you may also get a warning. For example, in cases with narrow flanges, it is impossible to comply with requirements for edge distances, distances from the wall, etc.
- The Autodesign and Autodesign of bolt is another tool that helps speed up the design process and make it more straightforward and automated while keeping safety and cost efficiency. Next to Weld sizing, the feature is the next step in the automated process of connection design.
It brings the simplification of the iteration process of finding the proper design of connections. The autodesign of bolts in shear takes into account the acting loads on simple connections. Instead of an iteration process, the user just calls this autodesign function, and the application finds the proper design.