Steel Beam and Column Design
This article describes how to use StatiCAD's steel beam and steel column design module. Calculations follow TBDY 2018 and ÇYTHYE (Turkish Design, Calculation and Construction Principles for Steel Structures — LRFD approach): for beams, flexure (including lateral–torsional buckling), shear, combined (interaction) effect and deflection; for columns, axial compression buckling and the combined effect of axial force plus biaxial bending. Member forces are taken from the program's own finite element solution, as envelope values together with the load combinations they belong to. For the formulas see Theoretical Basis of Steel Design, and for hand-calculation comparisons see Steel Structures Verification Studies.
Which editions? Steel structure calculations are available in the StatiCAD Ultimate edition.
Scope: The load-bearing capacity check is performed for hot-rolled I/H sections (IPE, IPN, HEA/HEB/HEM, HD/HL/HP). U, L, T, box and pipe sections can be assigned; they appear in the model and in the 3D view. The design of cold-formed sections (C, Z, Sigma, etc.) is performed in the Cold-Formed (Light-Gauge) Steel Structures module.
1. General workflow
- Model the building as usual (beams as horizontal bond beams, columns as vertical bond beams).
- Open the Properties window of the member that will be steel and assign the section from the Prefabricated Section Selection form using the Select Section button (Section 2). When the section is assigned, the steel material (S235, etc.) is also written to the member together with the section.
- In the same window, mark the member's design type as “Steel” (Section 3) and press OK.
- Run the analysis. Steel design checks are performed automatically at the end of the analysis.
- Obtain the report by ticking the Steel Member Reports group in the report selection tree (Section 6).
If a section is assigned to a member whose design type is not marked “Steel”, the member is included in the model with its steel section (weight, stiffness, 3D view) but does not enter the steel design check.
2. Prefabricated section library and section assignment
The Prefabricated Section Selection form is opened from the Select Section button in the beam (Bond Beam Properties) and column (Vertical Bond Beam Properties) windows.
| Form field | Function |
|---|---|
| Production Type | Rolled (default): hot-rolled sections. Cold Formed: cold-formed sections (light-gauge steel module). |
| Category | In Rolled mode: All / I-Wide Flange / Channel / Tee / Angle / Pipe / Tube. |
| Search box | Filters by name (e.g. “IPE 3”). |
| Preview | The selected section is drawn with its real geometry; the main dimensions and section properties are listed. |
| Material... | Steel grade selection (S235, S275, S355, etc.). If none is selected, the default steel grade is used. The material is assigned to the member together with the section. |
| Assign | Writes the section and material to the open member window; the section is also added to the project section library and the section image is generated for the reports. |
| User-Defined Section... | Switches to the user-defined section route instead of the prefabricated library. |
The same form can be opened from both the beam and the column; the assignment is made to the member from whose window it was opened. The assigned section is stored in the project library and travels with the file.
3. Selecting the design type
| Member | Window | Option |
|---|---|---|
| Beam | Bond Beam Properties → design type group | Steel (next to the Reinforced Concrete / Masonry / Timber options) |
| Column | Vertical Bond Beam Properties → design type group | Steel |
When the option is ticked and OK is pressed, the member's design type is saved as steel; at the end of the analysis these members enter the steel design check and the Steel Member Reports group becomes visible in the report tree.
4. Steel beam calculation
| Check | Code | Description |
|---|---|---|
| Flexure | ÇYTHYE Chapter 9 | Yielding, inelastic and elastic lateral–torsional buckling; the Lp and Lr limits are calculated and shown in the report. The governing limit state is stated in the report. |
| Shear | Chapter 10 | Vn = 0.6·Fy·Aw·Cv |
| Combined effect | Chapter 11 | Interaction check of flexure, axial force and shear |
| Deflection | Serviceability | Check f ≤ L/K; shown in the report with the line “Sehim f = ... ≤ L/K = ...” (Deflection f = ... ≤ L/K = ...). |
Laterally unbraced length Lb: If the lateral support (Le) fields in the member properties window are left automatic, the beam length is used; if a value is entered manually, that value is used. The moment distribution factor is taken on the safe side as Cb = 1.0.
Deflection limit K: It is defined per member, in the same place as the deflection K selection for timber beams (default K = 300; depending on the selection 200 / 150 / a manually entered value). Deflection is calculated from the service (unfactored G+Q or G+S) moment; for a cantilever beam the tip-load equivalent is used.
5. Steel column calculation
| Check | Code | Description |
|---|---|---|
| Axial compression | Chapter 8 | Flexural buckling about the x and y axes and, for doubly symmetric sections, torsional buckling; Fcr and φcPn (φc = 0.90) are obtained from the governing elastic buckling stress. The governing buckling mode is stated in the report. |
| Cross-section slenderness | Table 5.1A | Flange b/2tf and web hw/tw limits are checked. A member with a slender cross-section is explicitly marked “narin enkesit” (slender cross-section) in the report and is considered inadequate. |
| Slenderness ratio | ÇYTHYE recommendation | If KL/r > 200, a red “KL/r>200!” warning is shown in the report. |
| Combined effect | Chapter 11.3 | Axial compression + biaxial bending: Eq. 11.3a (Pr/Pc ≥ 0.2) or 11.3b; the equation used is stated in the report. |
Effective buckling length KL: By default the column length within the storey (storey height and bottom/top level differences) is used and K = 1.0 is assumed. A separate buckling length can be defined for each axis by entering values manually in the Le fields of the Vertical Bond Beam Properties window.
6. Load combinations
The calculation approach is LRFD (φb = φc = φv = 0.90). Demands are taken from the envelope of the ÇYTHYE LRFD combinations (1.4G; 1.2G + 1.6Q + 0.5S; 1.2G + 1.6S + 1.0Q; if wind is present 1.2G + 1.0Q + 0.5S + 1.6W and 0.9G + 1.6W) and of the program's seismic combinations (1.2G in earthquake, Q at least 1.0). These combinations do not change the project's load combination list; they are used only in steel design. The name of the combination that gives the envelope is shown next to the demand in the report.
The analysis warning line “Çelik kiriş/kolon tasarımında rüzgâr birleşimleri yok” (No wind combinations in steel beam/column design) indicates that no wind load case is defined in the project. The default (TBDY) combination list contains no wind; for wind to be included in the calculation, select the load cases and combinations defined in the Load Combinations tab.
7. Reports
After the analysis, the Steel Member Reports group appears in the report selection tree:
| Report | Content |
|---|---|
| Steel Beam Calculations | Storey by storey, one block per beam: section name; material (Fy); section properties (A, Ix, Wel, Wpl, ry); Lb, Cb, Lp, Lr; design moment (with the load combination giving the envelope), Mn, ratio and governing limit state; design shear, Vn and ratio; combined effect; deflection line; Result: Adequate / Inadequate |
| Steel Column Calculations | Section properties (A, Ix, Iy, rx, ry); KLx, KLy, largest KL/r (warning if needed); axial force (with its combination), φcPn, ratio and governing buckling mode; moments and capacities in both axes; interaction equation and its value; Result |
Checks that are satisfied are marked with a green UYGUN (OK), those that are not with a red X. Reports are produced in Turkish when the program language is Turkish, and in English in other languages.
8. 3D view
Beams and columns with an assigned section are drawn in the 3D window with their real cross-section geometry (I/H web–flange, box, pipe, cold-formed outline). Members without an assigned section appear as rectangular prisms. Section images are also added to the section tables in the reports.
9. Important notes
- The effective area method is not applied to slender-section columns in this edition; the program does not produce a capacity and explicitly flags the member. A result is never silently shown as “safe”.
- K = 1.0 is assumed for the column buckling length; for different support conditions enter the K·L value manually in the Le fields.
- The modulus of elasticity of the steel material is read from the material library; it does not matter whether it is defined in kg/cm² or MPa (the unit is recognised automatically).
- The seismic ductility cross-section requirements of TBDY Chapter 9, the column–beam capacity ratio and bracing members are outside the scope of this edition.
10. Frequently asked questions
The “Steel Member Reports” group does not appear in the report tree. The group appears if the project has at least one beam or column with the Steel design type marked, and after the analysis. Make sure the “Steel” option is ticked in the member's properties window and that the analysis has been re-run.
The report says “Profil katalogda bulunamadı” (Profile not found in the catalogue). The section name assigned to the member could not be found exactly in the prefabricated section library (for example, the section name was edited manually). Reassign the section from the Prefabricated Section Selection form.
The capacities came out much lower or higher than I expected. First compare the section properties line of the report (A, Ix, Wpl) with the section table; then look at the Lb and KL values — the lateral support or buckling length may have been entered manually. The consistency of the beam limit state (yielding / inelastic / elastic lateral–torsional buckling) with Lp and Lr can be seen in the report.
A steel beam or column looks rectangular in the 3D view. No section has been assigned to the member. Assign a section by following the steps in Section 2.
Can the same member have both steel and reinforced concrete checks? No; the design type is a single choice. The member enters the check of whichever type it is marked as.