Worked examples, fundamentals and code notes for engineers and students running early load takedowns. Practical, transparent, and tied to how the tool actually works.
Tributary area is the single idea that turns a floor plan into column reactions. Here is the clean mental model, the midline method, and the cases where sketching it by hand quietly fails.
Turn a floor pressure into a uniform line load on a beam: multiply the tributary width by the load. Here is the method, beam self-weight, and the two-way equivalent UDL.
A slab loads a beam, and the beam passes that load to its end supports as reactions. Here is how to find them by statics, for uniform, triangular and trapezoidal loads.
Slab self-weight is thickness times density. Reinforced concrete is about 25 kN per cubic metre, so a 150 mm slab weighs about 3.75 kN per square metre. Here is how to get it right.
Floor live load depends on use, and codes set minimum values by occupancy. Here is a reference table for offices, homes, retail, storage and more, in kPa and psf.
A load takedown traces gravity loads from the slabs down to the foundation. Here are the five steps, a worked column, and the checks that catch errors.
The foundation reactions are where a takedown ends: the load each column and wall delivers to the ground. Here is how to read them and turn them into foundation design loads.
Spreadsheets are flexible and free but slow on geometry; software automates tributary areas and stacking. Here is an honest comparison and when each one wins.
A structural floor plan tells you the grid, the supports, the spans and the loads. Here is what each element means and what to extract for a load takedown.
Looking for a Tribby3d alternative for tributary areas and load takedown? StructLoads is a free, browser-based option. Here is an honest comparison of the two.
