The frame in the middle carries a whole bay
Uprights are shared. Two adjacent bays of a run stand on the same frame between them, so that frame takes half the beam load of the bay on its left and half of the bay on its right. Add those halves and you get one entire bay. The frames at the two ends of the run take half a bay each, because there is nothing on their outboard side.
Check it the other way round and the arithmetic closes: a run of 6 bays has 7 frames, and two end frames at half a bay plus five interior frames at a full bay is 1 plus 5, which is 6 bays. The page prints that cross-check because it is the quickest way to see that the sharing is real and not a convention.
The defaults, worked through
Two pallets at 2,200 lb each is 4,400 lb on a beam pair, or 2,200 lb on each individual beam. Three beam levels give 13,200 lb of beam load in a bay. An interior frame carries all 13,200 lb of it, an end frame carries 6,600 lb, and each of the two columns in an interior frame carries 6,600 lb. On a 27.5 square inch baseplate that is 240 psi arriving at the slab, at four points per interior frame position.
The two pallets stored on the floor under the bottom beam add 4,400 lb per bay, and none of it touches the frame. That is why they are counted separately rather than folded into the total.
The bottom column segment is the loaded one and the exposed one
Load accumulates downward. The column segment above the top beam level carries one level; the segment between the floor and the first beam carries every level in the bay. On the defaults that bottom segment carries the full 13,200 lb on an interior frame, 6,600 lb per column.
That segment is also the one at fork height, at counterweight height, and at the height of every pallet that has ever been placed slightly wrong. The most loaded piece of steel in the run is the piece most likely to be hit, which is a coincidence of geometry and it is worth naming.
Two pallets is two point loads
Every number here assumes the load splits evenly — evenly across the beam pair, evenly between the two frames. Pallets are point loads sitting where the forks left them, and a heavy one pushed to one end of a level sends more than half of itself to the frame at that end. The arithmetic on this page is the average case, and the average case is not what the steel experiences on a bad day.
What this page will not do
It gives loads. It does not give capacities, and it will not tell you whether a beam or an upright is up to what you have just calculated. Beam capacity, upright capacity at a given beam spacing, deflection, bracing, baseplates and anchors are all in the configuration drawing and load chart written for your specific rack, and the load chart stops describing the rack the moment a beam level is moved. Putting the two numbers side by side is a job for the rack supplier and a qualified person.
Questions people ask
How much load does a pallet rack upright carry?
An interior frame carries a whole bay of beam load, because it takes half from the bay on each side. An end frame carries half a bay. With the page defaults — 2 pallets of 2,200 lb on each of 3 levels — that is 13,200 lb down an interior frame and 6,600 lb down an end frame, or 6,600 lb and 3,300 lb per column.
Is the load on a beam pair or on a single beam?
Rack load charts are normally written for a beam pair, which is the figure this page leads with. One beam of the pair takes half of it if the pallets sit evenly across both, which is the assumption and not always the reality. With the defaults, 4,400 lb on the pair and 2,200 lb on each beam.
Do pallets stored on the floor count against the rack?
No. Anything sitting on the slab under the bottom beam level goes straight into the floor and never touches the frame. The page counts them for the total in the run and keeps them out of the frame arithmetic, which is where they belong.
Which part of a rack upright is carrying the most?
The segment between the floor and the first beam level, because load accumulates downward and that segment is under every level in the bay. On the defaults it carries the full 13,200 lb of an interior frame. It is also the segment at fork and counterweight height, so the most loaded steel in the run is the steel most likely to get hit.
What pressure does a rack baseplate put on the slab?
The column load divided by the area of the plate that actually touches. With the defaults, 6,600 lb on a 27.5 square inch plate is 240 psi, at four points around each interior frame. Whether the slab and any anchoring are up to that is a question for the rack drawing and whoever owns the floor, not for this arithmetic.
Can this tell me if my racking is overloaded?
No, and it does not try. It gives loads. Beam and upright capacities live in the load chart written for your particular rack at your particular beam spacing, and that chart stops describing your rack as soon as a beam level is moved. Comparing a load against a rating belongs to the rack supplier and a qualified person, with the drawings in front of them.