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 and live load calculator (free)
Need to turn floor build-ups and occupancy into dead and live loads fast? StructLoads is a free tool that computes them and carries them through a full load takedown.
Elena Marchetti··4 min
Load paths
Interior vs edge vs corner column loads
An interior column carries about twice an edge column and four times a corner. Here is why, the load ratios, and a worked comparison you can use as a sanity check.
Elena Marchetti··4 min
Codes & standards
LRFD vs ASD load combinations, explained
LRFD factors the loads up and the strength down; ASD keeps loads near service and limits the stress. Here is the difference, the ASCE 7 gravity sets, and a worked example.
Sam Rivera··4 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
Load paths
How to size a column from axial load
Once you have a column's factored axial load, a quick required-area estimate gives a trial size. Here is the preliminary method for steel and concrete, with worked numbers.
Elena Marchetti··4 min
Codes & standards
Factored loads vs service loads, explained
Service loads are the real, unfactored loads; factored loads are them multiplied by load factors for strength design. Here is the difference and when each is used.
Sam Rivera··4 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
Codes & standards
Partition load allowance explained
Movable partitions are covered by a load allowance rather than counted one by one. Here is what the allowance is, typical values, and when a partition is counted as dead load instead.
Sam Rivera··4 min
Fundamentals
Beam tributary width calculator (free)
Get a beam's tributary width and uniform line load without the sketch. StructLoads is a free tool that computes the strip each beam collects and turns it into a UDL.
Elena Marchetti··4 min