Repeated Area-Load
Accumulator
Multiply a repeated tributary area by user-supplied permanent and imposed area loads, then optionally apply user-supplied weighting factors.
Who it's for: structural engineers summing tributary loads at schematic design or construction documents.
Bounded scope: this worksheet does not select loads, load combinations, reduction factors, standards, or structural members. A qualified structural engineer must establish all project criteria and perform the design.
Published benchmarks
Minimum uniformly distributed live loads from IBC 2021 Table 1607.1. Confirm against the edition adopted in your jurisdiction.
| Benchmark | Value | Unit | Edition | Scope | Source | |
|---|---|---|---|---|---|---|
| Residential, private rooms and corridors | 40 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Office | 50 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Corridors above first floor (office) | 80 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Assembly, fixed seats | 60 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Assembly, movable seats | 100 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Assembly, lobbies | 100 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Retail, first floor | 100 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Retail, upper floors | 75 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Storage, light | 125 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Storage, heavy | 250 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Roof, ordinary flat, pitched or curved (not occupiable) | 20 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) | |
| Roof, used for assembly | 100 | psf | IBC 2021 | Model code, US | IBC 2021 Table 1607.1 (Oregon OSSC 2022 viewer) |
Figures are as published on the linked page; check edition, scope and what the rate includes before using one.
Permanent contribution: —
Imposed contribution: —
The result carries the force unit implied by your area and area-load inputs. The calculator does not verify unit consistency.
How to use this calculator
The formula
Imposed contribution = tributary area × repeated levels × imposed area load.
Weighted total = permanent contribution × entered permanent factor + imposed contribution × entered imposed factor.
Worked example
When this estimate will be off
- No occupancy or load values are supplied; all project loads must be established independently.
- No standard, adopted edition, governing load combination, load reduction, or exceptional load case is selected.
- Repeated levels must share the same tributary area and entered loads; otherwise calculate levels separately.
- No member demand, strength, stability, deflection, connection, reinforcement, foundation, or adequacy check is performed.
Frequently asked questions
A common mistake: No occupancy or load values are supplied; all project loads must be established independently.
No. It performs arithmetic on values and factors you enter. It does not determine which loads, combinations, reductions, or standards govern.
No. The former preliminary column-sizing output was removed because the route lacked the information required for a member design.
Use one consistent unit system. If area is m² and area load is kN/m², the totals are kN. The worksheet does not detect mixed units.
Sources
- Declared arithmetic method — uses only the user-entered area, repeated levels, area loads, and factors
- Project structural criteria — must supply the loads, combinations, units, and applicability outside this worksheet
This free Structural Load Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.