Designer's Comparison of ETABS-SAFE and STAAD.Pro

In the school of architecture, students are taken 7 different subjects of math to complicate things (not really). Simple load and reaction calculations were practised but not applied. Most of the time, architects based their size of the columns, beams, slab, footings, stairs and their reinforcements on someone else CD drawings. No one creates structural details from scratch, some base it from rule of thumb from Architect's Companion book or other references. After all, civil or structural engineers are the ones who checks if the design structural elements passes or not. If structural analysis software is available, why not try to use their specialised software?

To those who worry, I am not a civil or structural engineer so don't assume that everything written here is accurate.

It is relatively easy to use both structural analysis software. The main problem is usually the codes behind the software and the knowledge of the requirements of the structural code/law which is the National Structural Code of the Philippines (NSCP). The knowledge of International Building Code (IBC), American Concrete Institute (ACI 318) and Uniform Building Code-97 (IBC-97) is also recommended especially for loads. Most structures in the Philippine are reinforced concrete, few uses heavy steel, rarely for wooden structures. I personally never saw a new building without columns or beams which would be the balloon framing structures or similar. I only have experience in modeling typical RC structures with girders and tie beams on both software but not other complicated stuffs like structural steel with decking, trusses with more trusses, steel connections, RC stairs, suspension bridge and more which we expect a civil or structural engineers can do.


Introduction

CSi ETABS is another popular structural analysis software due to its ease of modeling and navigating analytical models. It has fairly good design and UI having less clutter. It can design RC column, beams and slabs but needs CSi SAFE for footing & slab design and CSiDetail for complete RC detailing.

Bentley STAAD.Pro is the most popular structural analysis software in the Philippines. V8i is the commonly used version. It has excellent reinforced concrete detailing as it can design RC footings, columns, beams, slab, wall reinforcements.

This comparison is only for RC buildings which is not everything of the software.


Modeling

ETABS is clearly winner at this one, it has column grids and stories which can make the modeling of the analytical model from scratch easier and much nicer to navigate as well. STAAD.Pro doesn't have it and click & drag navigation isn't always the best. Both can import DXF files though so modeling can be a less of problem.


Frame Assignment

STAAD.Pro is a more difficult to assign the frame sections since you can't setup custom names. ETABS can have custom names visible to the viewport unlike R1, R2, R3, etc in STAAD.Pro.


Load Assignment

STAAD.Pro is easier to assign and view the loads. Load cases are separated and the loads are somewhat on frame or plate applied. ETABS is much more difficult, I can't say much since I usually use shell uniform load.


Before Analysis

In STAAD.Pro, you have to apply code related specification separate to the analysis materials such as F'c of the concrete and F'y of the steel. You will have to manually define column or beams which is ridiculous. Only if you're not going to use RCDC though.

In ETABS, analysis are done first and then the strength of the materials are passed onto the code related automatically. For slabs, you'll need to add strips in order to see the number of reinforcements to be designed in the direction.


After Analysis

STAAD.Pro load analysis are great but ETABS one looks better due to automatic scaling and solid coloring. I can't say about the features.


RC Design

ETABS column and beam design is straight-forward. Numbers appear are the area of reinforcements needed. ETABS failures are mostly torsional ones and needs more reinforcements but less section than STAAD.Pro. For slab, you'll need to add strips (before analysis) and figure out the spacing by yourself. Applying UBC 97 seismic loads was somewhat confusing, some settings were greyed out while in STAAD.Pro doesn't. As for the footing, you'll need SAFE for that. I had great results by checking the foundation footings' soil pressure reactions, punching shear ratio and maximum rebar ratio.

STAAD.Pro can do the details of footing, column, beam, slabs easily, it is very detailed and fool-proof. Failures are also different from ETABS, it seems to be less conservative in compatibility torsion. Applying UBC 97 seismic loads were very transparent and produce accurate results expected in NSCP. The workflow is quite somewhat horrible though. RCDC is a separate software and can import once. Exporting the section size is possible back to the analytical model but separate RCDC import are needed again for consistency although settings can be imported from the saved RCDC file. This can be time consuming when the revisions comes or the building is too large enough but can also the same case with ETABS if we use SAFE, CSiDetail and more and more software.


Conclusion

ETABS-SAFE and STAAD.Pro are both powerful software, if they are utilised properly, they can help architects to size the sections of the structural elements in DD phase since the beam depth can affect the ceiling height and column size affecting the minimum clearances of the interior.

In my humble opinion, ETABS is better for architects since reinforcements or footings doesn't really matter much as the size of the columns and beams which could affect the functionality of the buildings. STAAD.Pro seems to be the first choice of structural engineers in the Philippines because of abundance of locally-produced tutorials which can be very helpful.

With all the destroyed buildings from the earthquakes in the Philippines in 2019, architects and engineers alike must design buildings with the thought that the buildings can still be habitable even after major earthquakes.


Tutorials


STAAD.Pro:

See John Paul Dela Rosa (XSTRUCTURES) YouTube channel for more Filipino-made STAAD.Pro tutorials. This is the link for the playlist which I found useful for beginners: Two storey reinforced concrete design per NSCP 2015.


ETABS:

It took me 2 hours to write this post. Updated with tutorials.