Students know how to run ETABS; engineers know how to do high rise design with ETABS as a process. The difference is the word process: an engineer does not begin by opening the software, and does not finish when the force tables appear.
This article sets out the eight steps a structural engineer at a design office works through for an ordinary reinforced concrete high-rise, with the deliverable each step must produce. Newcomers get the whole picture; people already doing the work get a checklist to measure against.
High rise design with ETABS pairs the two programs: ETABS for frames, walls, slabs and lateral loads, then SAFE for slabs and foundations. That is also the sequence of the Institute's ETABS – SAFE – SAP2000 high-rise design course. ETABS versus SAP2000, and when SAFE is used explains why this is the common pairing for buildings in Vietnam.
The process starts with the architecture, not the software
Before step 1 there is a task many beginners skip: read the architecture and decide the structural system.
The architectural drawings give the number of storeys, floor heights, the column grid the architect wants, the position of the lift and stair core, and the floors with different uses: basement, retail, apartments, plant, roof. They also show where the architecture is most demanding, such as long spans at the lobby, transfer floors and mezzanines.
From that the engineer chooses the system: frame, frame with shear walls, frame with core, or walls with core. Walls and cores are placed so that the centre of rigidity sits near the centre of mass. Then comes the slab type, beam-and-slab, flat slab or post-tensioned; preliminary wall thickness and column sizes from the accumulated load; and a foundation scheme to suit the ground investigation.
This is the part no software does for you, and the part that separates an engineer from someone pressing buttons. The deliverable is a structural scheme, meaning a typical framing plan and sections, plus a table of preliminary sizes, agreed by the lead engineer before any modelling starts.
Eight steps and what each must produce
| Step | What you do | Deliverable |
|---|---|---|
| 1. Set-up and geometry | Grids, levels, materials, sections; build columns, beams, walls, cores and slabs to the scheme; model a typical floor, copy it, then edit the floors that differ | Geometry matching the architecture, checked against plans and sections |
| 2. Supports and assumptions | Column and wall bases fixed or sprung to suit the foundation; rigid diaphragms; rigid end offsets; cracked-section stiffness modifiers; slab meshing | A one-page assumptions sheet, the most important document of the model |
| 3. Gravity loads | Finishes, wall loads, imposed loads by occupancy floor by floor; the mass source | A load table with sources; base reaction matching a hand check |
| 4. Modal analysis and model control | Run the modal analysis; read periods, mode shapes and participating mass; adjust wall layout and sections until the behaviour is sensible | Modal report: the first three modes not torsional, periods sensible for the height |
| 5. Lateral loads and combinations | Static and dynamic wind, seismic actions to the Vietnamese codes; load combinations; P-Delta where required | Roof drift, storey drift and the stability coefficient all checked |
| 6. Design of columns, walls and beams | Design columns, walls, cores and beams; check reinforcement ratios and seismic detailing; resizing sends you back to step 1 | Reinforcement schedules and the final member sizes |
| 7. Slabs and foundations in SAFE | Export loads from ETABS; design slabs by strips, check punching shear and long-term deflection; design the raft or pile caps | Slab reinforcement; pile reactions; raft or cap reinforcement |
| 8. Deliverables | Calculation report, structural drawings produced in Revit Structure or CAD, and clean model files | The structural design package submitted for appraisal |
In practice, high rise design with ETABS runs these eight steps two or three times round. A result at step 5 or 6 usually sends you back to step 1 to change sections or rearrange walls, and any change to the architectural plan restarts the whole thing.
What separates experienced engineers is organising the model so each loop takes a day rather than a week: naming storeys and sections systematically, keeping load cases clearly separated, and never editing element by element.
The Institute's 15-session course follows these same eight steps on a real building, so students meet the loops rather than a straight line.
Modal behaviour and drift: where packages get sent back
Steps 4 and 5 are where appraisers reject submissions, and where beginners are most likely to rush. Three checks are compulsory.
Modal behaviour. The fundamental period must be sensible for the height and the structural system, and there are estimating formulas to compare against. The first three modes should be two translational modes before any torsional one. The participating mass of the modes considered must meet the code requirement. If the first mode is torsional, the walls and core are badly placed, and the fix is the layout, not the numbers.
Roof drift and storey drift. Limits come from the design code as a proportion of height, checked against the wind and seismic combinations. A sudden jump in storey drift at one or two levels signals a soft storey, usually a tall retail floor or a transfer floor, and it has to be solved structurally.
Overall stability and second-order effects. For a tall building, check the stability coefficient and include P-Delta. Skip it and the column forces in the lower storeys come out short.
The results of these three checks, together with the total base reaction against a hand calculation, go into the calculation report before any member design. Appraisers read that section first, and a package missing it is usually returned before anyone looks at the reinforcement.
From ETABS to SAFE: slabs and foundations
Step 7 is where the two programs meet, and where the data transfer most often goes wrong.
Slabs. Export each floor, or the typical floor, from ETABS to SAFE with its loads and boundary conditions. In SAFE, set out design strips in both directions, calculate reinforcement strip by strip, and check punching shear at columns and walls. Check long-term deflection including cracking and creep, particularly for flat slabs and long spans.
Two mistakes recur: forgetting wall loads on the slab during the export, and using uncracked slab stiffness, which makes the calculated deflection smaller than reality.
Foundations. Export the column and wall base reactions from ETABS with the full set of combinations, then build the raft or pile caps in SAFE. The ground is modelled with springs from the subgrade modulus, piles as point springs using the pile stiffness from the ground investigation. Check maximum and minimum pile reactions, since piles must not go into tension beyond what is allowed, and check bearing pressure for a raft. Only then design the cap or raft reinforcement and check punching shear from the columns.
Foundation design in SAFE is the part most self-taught ETABS users have never done, because university projects usually stop at the frame. In an office, the foundation drives most of the substructure cost and is the part appraisers examine hardest.
The package has three parts
Step 8 is often dismissed as paperwork, but it is what the client and the appraiser actually receive.
- The calculation report. The structural system and analysis model; the assumptions sheet; materials; loads and combinations with sources. Then the modal, drift and stability results; member design results; slab and foundation design; and an appendix of software output, limited to what is needed.
- The structural drawings. Foundation plan, framing plan for each floor, member and reinforcement details, and bar schedules. More and more offices produce these in Revit Structure from the analysis model, which Revit Architecture, Structure or MEP? discusses.
- The model files. ETABS and SAFE files cleaned up, with trial load cases deleted and clear naming, together with the software version so the appraiser can re-run them.
Since 1 July 2026, Decree 217/2026/ND-CP has required building information modelling on new works of grade II and above, regardless of funding source. High-rise buildings almost always fall inside that scope, so the structural BIM model is now part of the package rather than an option. BIM regulations in Vietnam covers the scope in detail.
One rule the Institute's lecturers insist on: the calculation report must let someone else rebuild the model from the assumptions sheet and the load tables. A report that pastes software output without stating assumptions is a report nobody can check.
Frequently asked questions
How long does high-rise design in ETABS take?
For an ordinary building of 20 to 30 storeys with settled architecture, a fluent engineer needs roughly two to four weeks for the eight steps, not counting the loops when the architecture changes. Newcomers typically take twice that and need the lead engineer to check steps 2, 4 and 5.
Is SAP2000 required in this workflow?
No. SAP2000 is used for structures outside the building, such as steel roofs, unusual stairs and secondary structures, or when a particular analysis is needed. ETABS and SAFE together are enough for an ordinary high-rise.
Which step do beginners get wrong most often?
Step 2, the assumptions, and step 4, the modal analysis. An error at either makes everything afterwards wrong while the software reports no problem at all. An ETABS learning path for structural students lists the specific modelling mistakes.
Does foundation design in SAFE replace geotechnical software?
No. SAFE designs the structure of the foundation, meaning caps, rafts and reinforcement, using ground and pile stiffness taken from the ground investigation. Pile capacity, settlement and slope stability belong to the geotechnical calculation, done separately.
Can an ETABS model be exported to Revit Structure?
It can, and many offices work that way so the drawings follow the analysis model. But an analysis model and a documentation model serve different purposes, so the presentation side normally still has to be built rather than transferred once and left.