[BS] 501.3.4 Expected Loads

Structures, or portions thereof, shall be designed and constructed taking into account expected loads, and combination of loads, associated with the event(s) magnitude(s) that would affect their performance, including, but not limited to:

1. Dead loads.
2. Live loads.
3. Impact loads.
4. Explosion loads.
5. Soil and hydrostatic pressure loads.

6. Flood loads (mean return period).

   • Small: 100 years
   • Medium: 500 years
   • Large: Determined on a site-specific basis
   • Very Large: Determined on a site-specific basis

7. Wind loads (mean return period).

   • Small: 50 years
   • Medium: 75 years
   • Large: 100 years
   • Very Large: 125 years
8. Windborne debris loads.

9. Snow loads (mean return period).

   • Small: 25 years
   • Medium: 30 years
   • Large: 50 years
   • Very Large: 100 years
10. Rain loads. See Table 501.3.4.

11. Earthquake loads (mean return period).

    • Small: 25 years
    • Medium: 72 years
    • Large: 475 years, but need not exceed two-thirds of the intensity of very large loads
    • Very Large: 2,475 years. At sites where the 2,475-year, 5-percent damped spectral response acceleration at a 0.3-second period exceeds 1.5 g and at a 1-second period exceeds 0.6 g, very large ground shaking demands need not exceed a 5-percent damped response spectrum that at each period is 150 percent of the median spectral response acceleration ordinate resulting from a characteristic earthquake on any known active fault in the region.

12. Ice loads, atmospheric icing (mean return period).

    • Small: 25 years
    • Medium: 50 years
    • Large: 100 years
    • Very Large: 200 years
13. Hail loads.
14. Thermal loads.