Load paths
How to do a structural load takedown (step by step)
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.
Elena Marchetti··5 min
Tag
Concept Design
12 posts tagged “Concept Design”.
Fundamentals
One-way vs two-way slabs: which tributary model to use
Whether a slab spans one way or two changes how load reaches the beams, and what shape the tributary areas take. Here is how to tell them apart and when the distinction actually changes your numbers.
Sam Rivera··6 min
Fundamentals
The 45-degree rule for tributary area
The 45-degree rule sets tributary boundaries by bisecting the angles between supports. Here is what it is, how it relates to the midline method, and when it applies.
Sam Rivera··4 min
Fundamentals
Tributary width for a beam, explained
A beam's tributary width is half the spacing to the parallel member on each side. Multiply it by the floor load for the uniform load on the beam. Here is the method with numbers.
Sam Rivera··4 min
Fundamentals
What is a load path in a building?
A load path is the continuous route a load follows to the ground. Here is what it means, the gravity and lateral paths, and why continuity and redundancy matter.
Elena Marchetti··4 min
Fundamentals
Tributary area on an L-shaped floor
The re-entrant corner of an L-shaped floor is where hand tributary sketches drift. Here is why, how clipping to the outline fixes it, and the area-balance check that proves it.
Sam Rivera··5 min
Load paths
Gravity load path: slab to foundation
Follow one gravity load from the slab through the beam, column and footing to the soil. Here is each handoff in the load path and why tracing it prevents errors.
Elena Marchetti··5 min
Fundamentals
How tributary areas actually work (and where hand methods go wrong)
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.
Elena Marchetti··7 min
Fundamentals
Tributary area vs influence area
Tributary area is the floor that loads a member; influence area is the larger area whose load affects it. Here is the difference, the K_LL factor, and why it drives live load reduction.
Sam Rivera··4 min
Fundamentals
How to calculate tributary area for a column
A column's tributary area is the floor region nearest to it. Here is the half-bay method, the interior, edge and corner cases, and a worked example.
Sam Rivera··5 min
Load paths
Load takedown, floor by floor: a worked example
A column reaction is just every floor above it, added up in the right order. Here is a full three-storey gravity takedown worked by hand, from slab pressures to a factored foundation load.
Elena Marchetti··8 min
Fundamentals
Dead load vs live load, explained
Dead load is the permanent weight of the structure; live load is the movable weight it carries. Here is the difference, typical values, and how each is factored.
Elena Marchetti··4 min