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Deflection and Design

Deflection and Design

When customers ask about fiberglass reinforced plastic (FRP) grating a question we’re commonly asked is “how strong is it?” compared to traditional materials. The answer is that FRP is very strong and can be used in virtually any situation metal or wood can. Despite FRP being extremely strong it is also more flexible than other materials, especially metal. This means deflection becomes a concern and in many cases is the primary factor to keep in mind as a designer considers the project. What happens when a span is too large is that the deflection factor increases so much that it makes the surface uncomfortable or unstable to walk on. In effect, the grating is storing energy from a footstep and releasing it like a spring. In the case that deflection is too high in the original design, the designer has essentially two choices.

Firstly, the designer can reduce the span distance, which will reduce the deflection and allow the original choice of grating to be used. If the span cannot be altered, a thicker grating profile can be selected in some cases. If the thicker grating cannot be selected; however, then the span distance simply must be reduced.

For a brochure with load tables for many common grating profiles click here.