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FIBERGLASS GRATING LOAD/DEFLECTION INFORMATION

MANUFACTURING CONTROL LIMITS-  The load/deflection values given in this brochure are median values developed through a strict quality assurance program.  The manufacturing control limits on stiffness for all panels are plus or minus 7.5% of these median values.  This represents the tightest control on performance variation in the industry, based published data.

ULTIMATE CAPACITY-   Molded and pultruded grating product lines have been tested to their ultimate capacities.  Ultimate Capacity represents a complete and total failure of the grating and is presented to illustrate the reserve strength of the grating at a given span.   Ultimate capacities are not to be used for design;  functionality of the grating is limited to Maximum Recommended Load.

BARS PER FOOT OF WIDTH-   The preceding molded grating load tables were developed using 8 bars per foot of width for 1-1/2" square mesh grating and 12 bars per foot of width for rectangular mesh grating for uniform and concentrated loads.   Some manufacturers use 9 bars per foot of width and 13 bars per foot of width respectively.  This can overstate grating performance by as much as 12.5%.  When comparing the presented products to those using 9 or 13 bars, multiply the deflection reported in this catalog by 0.89 for square mesh products, and 0.92 for rectangular mesh products.

WALKING LOADS-    Walking loads, typically 50-65 PSF maximum or 250 lbs. concentrated point load, are recommended for pedestrian traffic.  Deflections for worker comfort are typically limited to the lesser of 3/8" or Clear Span divided by 125;  for a firmer feel, limit deflection to the lesser of 1/4" or Clear Span divided by 200.

STATIC LOADS-    The allowable loads in the tables are for Static Load Conditions at ambient temperatures only.  Allowable loads for impact or dynamic conditions should be a minimum of ONE-HALF the values shown.  Long term loads will result in added deflection due to creep in the material and will also require safety factors to insure acceptable performance.  For applications at elevated temperatures, consult Grating Pacific.  The designer is further referenced to ASCE Structural Plastics Design Manual.