Many factors contribute to the loads that affect the capacity requirements of your mezzanine. It is important to take these loads into consideration when approaching the mezzanine design.
Dead loads (anything permanent on the mezzanine, walls built on top, B-Deck and overlay, etc.) as well as live loads (racking on top of the mezzanine, pallet jacks, people standing and walking, etc.) needs to be taken into consideration when designing the mezzanine structure.
The decking or flooring of a mezzanine will vary by application but is generally composed of B-Deck underlayment and wood product finished floor, concrete or a heavy-duty steel grating. When designing a structural steel mezzanine, it is important to consider the application, as well as the equipment that will be used on top of the mezzanine. If pallet jacks are being used for example, a resin board overlay is ideal for a smooth rolling load.
Live loads are separated in two different categories: Uniformly Distributed Loads (UDL) and Point Loads. Refer to the drawings below for more information.
Live loads, dead loads, seismic loads, and climatic loads (for outdoor installations) must be taken into careful consideration when designing a structural mezzanine. These loads make up the vertical and horizontal forces that determine the bracing requirements necessary to develop the structural integrity of a mezzanine.
Vertical loads (i.e. live loads and dead loads) affect every aspect of the mezzanine structure. These are transferred from the decking to the joists, from the joists to the beams, from the beams to the columns, from the columns to the base plates, and from the base plates to the concrete. On their own, vertical loads can exert a tremendous amount of pressure on the mezzanine structure. Horizontal loads (i.e. seismic loads and climatic loads) are the external pressures applied at deck height that can force a mezzanine to move or sway back and forth. Braces are designed to transfer the horizontal loads to the base. The effectiveness of the braces is increased as the unbraced height is decreased.
Cogan structural steel mezzanines always include one of the following types of brace designs: knee-bracing, x-bracing, or structural knee-bracing. It is essential to consider the overall budget of your project in order to choose the proper brace design for your mezzanine.
To ensure the safety and longevity of your structure, it is always the sole responsibility of the client/owner to verify the area where the mezzanine is being installed and to provide proper anchor conditions. In situations where concrete depth is inadequate, it may be necessary to pour footings or to otherwise modify the slab. The responsibility of slab verification applies to both knee-brace and x-brace mezzanine designs. If you are looking for more favourable anchoring requirements, Cogan recommends an x-brace design.
Please keep in mind that calculations provided by Cogan are to serve as guidelines only. Cogan Engineers can only determine the number of anchor bolts required per column and the concrete depth necessary to develop the resistance of those anchors. Many variables may affect individual site conditions and therefore negate the calculations provided by Cogan Engineers. This is why Cogan cannot guarantee that the structural integrity of your installation site is sufficient to support the proposed anchoring requirements. Please keep in mind that Cogan is not responsible for certifying or analyzing the concrete slab capacity and integrity where the mezzanine columns are to be installed.