A multi-storey load takedown is the same single-column method repeated down a stack: compute the reactions at the roof, carry them down a level, add that floor’s load, and repeat to the foundation. Each support’s reaction at any level is everything above it, so the foundation reaction is the running total of every floor it carries. StructLoads does this across all supports and levels at once, and the rule below is what it is applying.
The top-down rule
You work a structural load takedown from the roof down because each reaction should already include everything carried from above. Start at the top, compute the column reactions from the roof, then treat those as point loads landing on the columns one level down, where they join that floor’s own tributary load. Repeat to the base. Working downward means you never revisit a level, which is why it is both natural and less error prone.
A worked three-storey column
Take an interior column on a six by five metre grid, tributary area 30 square metres, carrying three suspended floors at 4.5 kN per square metre dead and 3.0 kN per square metre live, plus a roof. That live value is the industry norm: SteelConstruction.info’s multi-storey office guidance gives 3 kN per square metre as the typical office imposed load, with up to 1 more for movable partitions and 0.7 for raised floors, ceilings and services, rising to 5 for speculative offices and storage.
| At the base of | Cumulative dead (kN) | Cumulative live (kN) |
|---|---|---|
| Level 3 | 249 | 90 |
| Level 2 | 384 | 180 |
| Level 1 | 519 | 270 |
Each row adds one floor’s 135 kN dead and 90 kN live to the running total. By the foundation the column holds 519 kN dead and 270 kN live, the same accumulation shown in full in a floor-by-floor worked example. Keep dead, live and roof in separate columns so the load factors can act on each.
Keep the load cases separate
A common multi-storey slip is to add dead and live into one number too early. If you accumulate a single combined total, you cannot apply the different load factors correctly at the end, and you lose the ability to reduce live load over the accumulated area. Carry dead, live and roof as separate running totals all the way down, then combine once at the level you are checking, following basic structural principles.
How transfers change the path
Not every column continues straight to the ground. Where an upper column lands on a transfer beam instead of a column below, its reaction jumps sideways: it becomes a point load on the transfer beam, which then splits it to the columns that support the beam. The accumulation rule is unchanged, but the path bends, and transfers concentrate a lot of load in one place, so they deserve extra care and usually a fuller analysis.
Live load reduction grows with height
The taller the stack, the larger the accumulated tributary area a lower column supports, and the more live load reduction the code may allow, because the full live load is unlikely on every floor at once. So a multi-storey takedown and live load reduction go together: the reduction is small near the top and largest at the base, as set out in ASCE 7 live load reduction.
Key takeaways: multi-storey takedown
Work top down, add each floor to a running total, and keep dead, live and roof separate until you combine. The foundation reaction is everything the support carries. Transfers redirect the path without changing the rule, and live load reduction grows toward the base. StructLoads accumulates all supports across all levels at once, as a preliminary figure a qualified engineer confirms, with full analysis for transfers and lateral loads.
Quick answers
How does a multi-storey load takedown work?
It works top down. Compute the reactions at the roof, carry them to the level below, add that floor’s own load, and repeat to the foundation. Each support’s reaction at a level is everything stacked above it, so the foundation reaction is the running total of every floor that support carries. Keep dead, live and roof separate so they can be factored correctly.
Do you start a load takedown at the top or bottom?
At the top. Starting at the roof and working down means each reaction already includes everything carried from above, so you never revisit a level. Working bottom up would require knowing the loads from above before you reach them, so top down is both natural and less error prone for a multi-storey stack.
How do transfer beams affect a multi-storey takedown?
A transfer beam carries a column that does not continue straight down, so the load jumps sideways onto the beam and then to the columns that support it. The accumulation rule is unchanged, but the load path bends: the upper column’s reaction becomes a point load on the transfer beam, which splits it to its own supports. Transfers concentrate load and deserve care.
When does simple floor stacking not work?
Simple vertical stacking assumes each column continues straight down. It does not work where columns are offset and land on transfer beams, where a level is a podium redistributing many columns, or where lateral loads add axial effects. There the path redirects and a frame analysis is needed. Use stacking for the regular gravity case and full analysis for transfers and lateral loads.