Question
When trying to calculate the design in RF‑STEEL Surfaces, I receive Warning No. 1162 - Surface No. XX is of the type "Orthotropic" and cannot be designed. What does this warning mean?
Answer:
Orthotropic surfaces are non-linear and cannot be designed in the RF‑STEEL Surfaces add-on module. It is possible to get a full stress analysis in RFEM for orthotropic surfaces defined with the orthotropy type "Constant Thickness" and compared to limiting stresses manually. For all other orthotropy types, the program is not aware of the geometric properties for the surface at every FE mesh point that are needed to calculate stresses. An extensive and detailed FE model would need to be created. See FAQ 2468 for an example of this. Surface types need to be set to "Standard" to be designed in the add-on module. Author
Alex is responsible for customer training, technical support, and continued program development for the North American market.
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Plate girder is an economical choice for long spans construction. I-section steel plate girder typically has a deep web to maximize its shear capacity and flange separation, yet thin web to minimize the self-weight. Due to its large height-to-thickness (h/tw) ratio, transverse stiffeners may be required to stiffen the slender web.
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Understanding steel connection rigidity is crucial in structural design. Often, connections are treated as strictly pinned or rigid, but this can lead to uneconomical or even dangerous designs. Explore how Dlubal Software's RFEM and Steel Joints add-on help verify connection stiffness and moment resistance, ensuring safer and more economical designs.
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![KB 001761 | ...](/en/webimage/034236/3383734/Image_1.png?mw=512&hash=e291c1e4af5953551bde5d9d71f599f36ae2e3f7)
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- Numerous component types, such as base and end plates, web angles, fin plates, gusset plates, stiffeners, tapers, or ribs for easy input of typical connection situations
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- Graphical display of the connection geometry with dynamic updating during the input
- Wide range of cross-section shapes: I-sections, U-sections, angles, T-sections, hollow sections, built-up cross-sections and thin-walled sections
- Library in the Dlubal Center with a large number of program-side template connections, including user-defined templates
- Automatic adaptation of the connection geometry based on the relative arrangement of the components to each other – even in case of subsequent editing of the structural components
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In the ultimate configuration of the steel joint design, you have the option to modify the limit plastic strain for welds.
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The "Base Plate" component allows you to design base plate connections with cast-in anchors. In this case, plates, welds, anchorages, and steel-concrete interaction are analyzed.
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In the "Edit Section" dialog box, you can display the buckling shapes of the Finite Strip Method (FSM) as a 3D graphic.
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