HomeMy WebLinkAboutWind Safety Calculations_42-INCH Formed Letter2/16/2021
To: Graphic Reseller
Wind load calculations are based on the following:
•A height (in.) of 41.71
•A wind speed (mph) of 150
•16 10-24 Al fasteners on a Formed letter.
•A Face mount
Area of failure examined:
The calculated points of failure are the tapped threads of the letter.
Safety factor calculation:
Wind load (lbs) =
Letter wind resistance strength (lbs) =490
Safety factor =
Not taken into consideration is the method of fastening letter studs to the building or
framework of the building. That is a field installation and must be calculated seperately
by a structural engineer familiar with the building materials.
In summary, a safety factor of 142 indicates that the mounted letters are 28.0 times
stronger than the wind load being applied to them. This safety factor exceeds the
recommended safety factor of 5 for structural applications.
Safety Factor is based upon using fastener quantity as listed above.
Calculation is based on using appropriate adhesive and/or anchors for installtion.
Best Regards,
Eliah Hauser
Gemini, Inc.
103 Mensing Way
Cannon Falls, MN 55009
157
3.1
Assumptions:
Conservative values are used whenever possible in calculating the safety factor to
increase the confidence of sending out proper fastener materials that will withstand
regional wind estimates. These conservative values include:
•Using shear strength even when force would be applied in tension. All
materials used for letters, plaques, and fasteners have weaker shear strengths
than tensile strengths.
•Calculations assume a full frontal force
•Screw strength is determined by area of the minor diameter or thread area
(whichever is smaller) times the shear strength (which is typically lower than
published screw strength data).
Calculations:
•Wind Load
(41.71^2 x 0.75 x 0.6)/144 x (0.00256 x (150 x 0.5)^2)*2 = 157 (lbs)
•Letter Strength
50460 x 0.017 x 16 = 490 (lbs)
•Safety Factor
490
157 =3.1