Foundation, Concrete and Earthquake Engineering

Steel Mezzanines

What should I look for and expect from my steel mezzanine project? I must clarify this article is written for the end user and is designed to give a better understanding of the product and how it is built, The intent is not to be a design source. You should understand the component sizes are governed by building codes and other requirements, the area where the steel mezzanine is placed (seismic zone) has a great impact on the member sizes and assembly methods. Some of the references that go into the selection of material and design are as follows; the most common and widely used building code today is IBC International Building Code, AISC Specifications for the design, Fabrication and erection of steel for buildings. AISC-SJI Standard Specifications for Open Web Steel Joist, Long span Steel Joist, and Deep Long Span Steel Joist.

Steel I Joist Beam and Column Mezzanine
ASTM A36 or A992/572 Grade 50 structural steel. ASTM A307 Carbon steel externally threaded standard fasteners. ASTM A325 High strength bolts for structural steel.

ASTM A365 Steel sheet, Zink coated (Galvanized) or zinc-iron alloy-coated (galvannealed) by the hot dip process. ASTM A500 Cold-Formed welded and seamlesscarbon steel hollow structural sections. ASTM A1011 Grade 50 specification for steel, sheet and strip, Carbon, Hot-Rolled structural quality. ASTM A1008Specification for steel, Cold-Rolled, Carbon, Structural. AWS D1.1 Structural welding code.
8" x 8"x 1/2" Base Plate with 4-1/2" Holes having Anchor Bolts
NAAMM Metal Bar- Grating manual. OSHA, Please note OSHA may be less than your building code requirements and could jeopardize your investment. Let's first consider the framing bottom and work our way up. You may or may not need footings some mezzanine manufactures have in house engineering departments that can assist you with the footing requirements but the majority doesn't. If you select a steel mezzanine manufacture that can address the issue or you use an independent engineering firm you should have the original slab drawings, or you may need a core sample to determine the composition of the slab.

The base plates should be a minimum 8" square x 1/2" Plate with a minimum of 4-1/2" holes for the anchor bolts. In most cases the base plates can be off set to accommodate other equipment, walls or pedestrian isles The minimum anchor bolt size should be ½" x5-1/2", The support columns can be I-Beam, square tube and some other material may be used by some manufactures however the square tube design is the most popular and I prefer to see a minimum of 5" square with a minimum 3/16" wall thickness, I like to see a top cap for the top of the column this reduces or eliminates the column from tearing from the fatigue of welding the column to beam connection.
Residential Steel Mezzanine
The joist may be I-Beam or open web joist or a combination of both this is usually determined by the span and loading. You would normally select open web joist for long spans to reduce cost.

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