ᐅ Online structural calculation tools for concrete, timber, and steel

Does anyone know of a tool for home use, especially for concrete or masonry?

For wood and steel, I’m familiar with this Eurocode tool. I would like to compare whether, for example, a 12x12cm (5x5 inch) concrete post with reinforcement has the same load-bearing capacity as a corresponding 12x12cm (5x5 inch) wooden post.

I can help: No, they don’t have the same “support capacity” (and what do you mean by “support capacity” in your context?)

There are material properties, and these are fundamentally different. Compressive strength and buckling stiffness vary significantly here.
Additionally, for advanced (meaningful) calculations, you need specialized software that is generally used by professionals, and to my knowledge, it is rather expensive (around 5,000). Also, this is the reason there is the profession of a structural engineer, who guarantees with their signature that the design will hold up as calculated. Structural analysis was, in my opinion, one of the most difficult subjects in civil engineering studies. But I may be wrong, and there might be freeware available. However, you still need to know how to use it properly.

A lot of text, but in the end, I simply advise you not to perform life-critical calculations yourself.

By comparability, I meant whether I can use a 12×12cm (5×5 inch) concrete post or concrete pillar instead of a 12×12cm (5×5 inch) wooden post for the carport roof, for example. Or alternatively, if I can build suitable columns with shuttering blocks on which the roof beams would then rest.

A carport roof typically measures around 3x5 to 4x6 meters (10x16 to 13x20 feet), and it can be life-threatening if it collapses! Do not underestimate wind and snow loads. The weight of a 12x12 cm (5x5 inch) beam falling from 3 meters (10 feet) can easily seriously injure an adult, and even more so children. A basic understanding of structural engineering is essential. Posts alone are not enough; to ensure stability, you either need to fully clad the sides to create a shear wall effect or install a cross brace between the posts (for example, a diagonal brace). Are you familiar with Ivar from Ikea? They have a cross brace at the back to prevent the shelf from tipping sideways. Poorly built carports can fail in a similar way. In your case, sorry, it seems this understanding is lacking, so I won’t offer any building advice except perhaps to “use a kit,” which is type-tested.

To answer your question: concrete can bear much higher load capacities than wood. A 12 cm x 12 cm (5 inches x 5 inches) dimension is already oversized for wood.

There are tables available for calculation.

The specification with the 12cm (5 inches) wooden post comes from a carport kit that would be suitable for our snow load zone, but I can't use it because the dimensions are not optimal. I also don't want to modify or patch up the kit.

Therefore, I wanted to basically recreate the thing based on this, but with slightly modified measurements.