Materials, design code and sections
Choose the design code, steel, concrete or timber, the grade, each member group's section and the slab and wall thickness in Struxt3D's Materials step.
The Materials step, titled What is it made of?, sets the design code, the material and grade, the section of every member group and the thickness of slabs and walls. Each template fills in sensible defaults, so you only change what you need. The model colours its members by group while you are on this step, with a legend under the view.
Design code
The first row picks the code family. It decides far more than the member checks: the load combinations, the floor live loads, the wind speed basis, the seismic spectrum and behaviour factors, the grades on offer and the section catalogue.
| Button | Standards | Steel sections offered |
|---|---|---|
| Eurocode | EN 1990, 1991, 1992, 1993, 1995, 1998 | IPE, HEB, CHS, SHS |
| AISC / ACI | ASCE 7, AISC 360, ACI 318 | W shapes, HSS |
| KDS | Korean Design Standards (KDS 41) | H-shapes, P- and □- tubes |
| CSA | NBCC, CSA S16, CSA A23.3 | Metric W shapes, HSS |
| NSCP 2015 | National Structural Code of the Philippines (adopts ACI 318 and AISC 360) | W shapes, HSS |
| AS/NZS | AS/NZS 1170, AS 4100, AS 3600 | UB, UC, CHS, SHS |
When you change code, the grade and any section that does not exist in the new code switch to the nearest valid choice. If the wind speed was still the old code's default, it changes to the new code's default too. The tutorials for each code — Eurocode, AISC/ACI, KDS, CSA, AS/NZS and NSCP 2015 — explain what each one sets.
You can also change the code later, in the Full interface's Design › Design settings…. A new code changes the loads and combinations, so changing it clears the results: run the analysis again.
Material and grade
Pick Steel, Concrete or Timber for the members, then a Grade. The grades depend on the code:
| Code | Steel | Concrete | Timber |
|---|---|---|---|
| Eurocode | S355, S275, S460 | C30/37, C25/30, C40/50 | GL24h, GL28h, GL32h |
| AISC / ACI | A992 Gr 50, A36, A572 Gr 65 | f′c 35, 28, 40 MPa | 24F-V4, 20F-V7 glulam |
| KDS | SM355, SS275, SHN355 | fck 27, 24, 30 MPa | Glulam 10S-30B, 8S-24B |
| CSA | 350W, 300W | f′c 35, 30, 40 MPa | 24f-E, 20f-E glulam |
| NSCP 2015 | A992 Gr 50, A36, A572 Gr 50 | f′c 28, 21, 35 MPa | 24F-V4, 20F-V7 glulam |
| AS/NZS | Grade 300, Grade 350 | N32, N25, N40 | GL13, GL10 |
Each grade carries its stiffness, density and strength: concrete's modulus comes from the code family's formula, and its density (2500 kg/m³) includes the reinforcement. Self-weight is worked out from the density and the section area, so you never enter it.
A few members keep their own material whatever you choose: cables and stays are always steel strands, and slabs and walls are concrete (in a concrete model, the chosen grade; otherwise the code's first concrete grade).
Sections
Members belong to groups — columns, beams, secondary beams, bracing, chords, hangers and so on, depending on the template. Each group used in the model has a row with its colour swatch, its name and a list of sections. Every member in a group shares the section.
The list depends on the material and the group's role:
- Steel columns get column shapes (HEB, W14, UC…), beams get beam shapes (IPE, W, UB…), bracing gets round hollow sections, chords get square and round hollow sections, and groups the template marks as tubes (poles, legs) get round tubes.
- Concrete and timber groups get rectangular sections sized for columns, beams or braces.
- Cables get strands from Ø20 to Ø100.
Lists run lightest first. You can also change a group's section later from any member's inspector in the workspace, or from a group's properties in the Full interface.
Slabs and walls
When the model has slabs, roofs, decks, walls or plates analysed as shells, a Slabs and walls section sets their thickness by kind — Floor slabs, Roof slab, Deck, Walls, Walls and plates — from 80 to 1500 mm in 10 mm steps. The defaults are 200 mm for floors and walls, 150 mm for roofs, 250 mm for decks and 300 mm for plates. Some templates set a thickness of their own (a raft, a retaining wall stem); those are changed in the Size step, and the note under the section says so.
Panels that only carry load — cladding, roof sheeting — are not structural and have no thickness: they pass their load to the members around them.
Size members for me
The switch at the bottom, Size members for me, is on by default. When you run the design, Struxt3D replaces each group's section with the lightest one that passes every check, including deflection. Your choice here is then the starting point. Turn it off to check the sections exactly as you set them.
The same switch appears as Size members automatically in the Full interface's Design menu and the design settings.
Next
Click Next: supports & loads — see Supports and loads.