Deflection Calculations

Ever wondered how long of a span you can run without any noticeable sagging? Which extrusion would be best? What about if you decide to hanging a sign from it or mount lighting on top? How much more will it sag then? AGAM has recently developed a formula to calculate the exact amount of deflection for each of its extrusions. No more approximations or educated guesswork is needed by you or your clients!

Based off the common physics equation for beam deflection, our formula works for every extrusion and allows you to input length, number of inline connectors, and load. The formula instantly outputs the maximum vertical deflection, or sag. See the following diagram for a visual description:

C:Usersahartappdatalocalautodeskautocad 2012 - englishr18

For example, a PH1005, our most popular horizontal extrusion, at 16 feet (4876.8mm) in the standard orientation and supporting 10 lbs. will deflect 1.877 inches (47.7mm). However, turning the same piece 90 degrees sideways will result in a deflection of 7.100 inches (180.3mm). This indicates that orientation of the extrusion matters greatly when calculating deflection. For comparison to the standard PH1005, a PH1035, a slightly shorter extrusion, would sag 3.657 inches (92.9mm), while a PH1003, a taller extrusion, would only sag 0.709 inches (18.0mm). See the chart below for comparison of each extrusion:

Extrusion Diagram_Hard Way

Deflection Chart_v3

This formula is extremely useful for many reasons. Not only does it give an exact measurement, but it allows you to choose the optimal extrusion for any given span and load. It helps us engineer a better solution and ensure that your design is structurally sound. No longer will you have to guess whether or not a larger extrusion is worth the additional cost to support your design. And not only does it work well for long spans, but this calculation is also very helpful for shorter bars with heavier loads, such as monitors.

When a span becomes long enough for deflection to become a concern, AGAM also specializes in manufacturing custom length truss. If your design involves heavier loads, this could be the most cost effective solution.

If you would like to calculate deflection for your design or would like to request an extrusion recommendation, please contact any of us here at AGAM and we will be glad to assist you.


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