Load paths
UDL on a beam from tributary area
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.
Sam Rivera··5 min
Tag
Tributary Area
15 posts tagged “Tributary Area”.
Workflow & tools
How to do a load takedown fast (and check it)
Speed in a load takedown comes from drawing once and checking smart. Here is the fast workflow and the three checks that catch most errors.
Elena Marchetti··4 min
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
Triangular and trapezoidal loads on beams
A two-way slab loads its beams with triangles and trapezoids set out by the 45-degree rule. Here is where the shapes come from, the equivalent UDL, and a worked example.
Sam Rivera··4 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
How to calculate tributary area for a wall
A wall collects a tributary strip, not an area like a column. Here is how to find its tributary width, turn it into a line load, and where the strip method applies.
Sam Rivera··5 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
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 loads transfer from a slab to beams
A slab hands its load to the beams that support it, as a uniform strip in one-way action or as triangles and trapezoids in two-way action. Here is how, with the load shapes.
Sam Rivera··5 min
Workflow & tools
Free tributary area calculator (online)
Need tributary areas without the sketch and spreadsheet? StructLoads is a free browser tool that computes them from a plan you draw, exactly and instantly.
Elena Marchetti··4 min
Fundamentals
Tributary area: edge column vs corner column
An edge column carries about half a bay; a corner column about a quarter. Here is why, with the geometry, the load ratios, and a worked comparison.
Sam Rivera··5 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
Codes & standards
ASCE 7 live load reduction, explained simply
A column carrying ten floors is not realistically loaded to the full design live load on every one at once. ASCE 7 lets you take credit for that. Here is the formula, the K_LL factors, and a worked reduction.
Sam Rivera··6 min