11/8/2023 0 Comments Metal roof decks![]() Inspection requirements are more time consuming also, when compared to many mechanical fasteners. Welding is a comparatively slower process and requires a higher level of skill.This may lead to needing a less dense fastening pattern for the deck, but there are pros-and-cons to be considered for each method. Generally, arc spot welded support connections are stronger and less flexible than mechanically connected support connections for both shear and uplift if the welding procedure is done properly. Welds, screws and PAF’s can be combined for instance, welds used for support connections and screws for sidelap connections, or in combination as part of a zoned steel deck diaphragm. These fasteners cannot be used for sidelap connections. Proper driving is ensured by following the manufacturer’s instructions, setting the power regulation on the installation tools, making trial fastenings and visual identification of the fastener head and washer conditions. The force used for driving the PAF is varied depending upon the steel strength and thickness. The driving process allows the fastener to penetrate the steel deck layer and fuses the fastener shank to the base steel supports. ![]() Power actuated fasteners (or PAF’s) look similar to short nails that are driven into the supporting structure using either pneumatic pressure or powder cartridges. Several manufacturers have developed “stand up” drilling equipment. Screws are installed using torque controlled drills which allow for proper installation without overdriving and stripping the screw. The drill points on these screws vary in length depending on the total thickness of the steel to be connected. Typically #10 screws are used for sidelap attachment, and larger #12 or #14 screws are used for support fasteners. Screws can be used for both fastening to supporting members and for fastening sidelaps. Per AWS D1.3 Structural Welding Code – Sheet Steel, arc spot welds can be made through multiple thicknesses of steel deck, as long as the total base metal (bare steel) thickness of the deck does not exceed 0.15 inches. This process requires a welder who is qualified to make these specific welds. The complete welding process usually requires 3 to 6 seconds, or perhaps longer on multiple deck thicknesses or thicker deck. When welding, it is essential that the finished weld penetrate into the supporting beam or joist, and that the puddle engage the deck on the weld perimeter. However, over the past 30 years, mechanical fasteners such as screws, power actuated fasteners, and proprietary sidelap crimping devices have proven to be viable alternatives. Traditionally, deck has been installed using welds for fastening to supports and button punches or welds for joining side-laps. What Choices Do I Have for Fastening Deck? Whether it is the performance of the product as a diaphragm to transfer wind or seismic forces, resisting wind uplift, acting as a concrete form, providing bracing to beams or joists, or providing a safe working platform during construction, proper fastening makes the deck do its job. Steel floor or roof deck is only as good as its fastening.
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