Design of steel mezzanines and intermediate floors
More usable floor area inside the same warehouse or store.
Photo: DDES
A steel mezzanine adds a level inside a warehouse, store or plant. Its design sets beams, columns, deck, stairs and railings under the NSR-10 live loads (B.4.2), and checks that the existing structure and foundation can take it. DDES designs it and supports its erection.
- Code
- NSR-10, B.4 and Title F
- Service
- Structural design
- For
- Warehouses, stores, plants
What to have at hand
- Available area and height, and the location of existing columns.
- Use of the mezzanine: offices, storage or racking.
- Drawings of the warehouse or store, if they exist.
- Photos of the floor slab where the columns will sit.
How we solve it
- Definition of the live load under the NSR-10 (B.4.2) and of the deck system.
- Design of steel beams, columns, connections and bracing (Title F).
- Check of the floor slab and foundation under each column.
- Shop and erection drawings.
What load must a mezzanine carry?
The one for its use under NSR-10 Table B.4.2.1-1: a storage mezzanine carries much more load than an office one. Changing the use later without checking the design is one of the most common causes of deflection and failure.
Can it bear on the existing floor slab?
Only if the slab and the soil can take each column's concentrated load. If not, new footings are designed under the columns.
Technical notes
Occupancy groups: why a school or a clinic is designed stronger
The NSR-10 sorts buildings into four groups and raises the design forces by up to 50%.
Nonstructural elements: walls, facades and building systems in the NSR-10
What does not hold the building up must also be designed for earthquakes. And on the coast there is an exemption.
Geotechnical study: how many borings, and how deep, the NSR-10 requires
The building's category sets the minimum number of borings and their depth. Title H sets it out.
Frequently asked questions
Does a mezzanine need a permit?
A mezzanine adds built area and modifies the structure, so the curaduría urbana usually requires a permit with a signed structural design. Confirm it with your curaduría.
How long does erection take?
The steel is fabricated in a shop and erected quickly; the time depends on size and on the deck chosen.
Has DDES done mezzanines?
Yes. At Bodegas Centurión the works DDES followed included the warehouses' mezzanine.
Other situations
- Adding a second floorBefore adding a floor you need to know whether the house can carry it.
- Home structural retrofitSo an older structure resists what today's code requires.
- Crack assessmentNot every crack is serious, but every crack that grows needs to be studied.
- Warehouse designFrames, roof, floor slab and foundation, designed together.
- Retaining wallsFor basements, level changes and sloping lots.
- Tanks and poolsStructures that must not only stand but also not leak.
- Building permitWhich structural documents the curaduría asks for and who signs them.
Last updated:
Contact
Want a mezzanine?
Tell us the area, height and use. A DDES engineer replies.
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Photo: Julia Taubitz / Unsplash