§ 7-5.704. Impact loads.

(a)

Types. For the purposes of these regulations, impact loads are those which result from floating debris and floatable objects or masses carried by flood waters striking against structures or parts thereof. These loads are of two (2) basic types: normal and special.

(1)

Normal impact loads. Normal impact loads are those which relate to isolated occurrences of logs or floatable objects of normally encountered sizes striking buildings or parts thereof.

(2)

Special impact loads. Special impact loads are those which relate to large conglomerates of floatable objects, such as an accumulation of floating debris, either striking or resting against a building or parts thereof.

(b)

Applicability. Impact loads shall be considered in the design of structures and parts thereof as stipulated below:

(1)

Normal impact loads. A concentrated load acting horizontally at the regulatory flood level or at any point below it, equal to the impact force, produced by a 1,000 pound mass traveling at the velocity of the flood water and acting on a one square foot surface of the structure.

(i)

Deceleration of the mass shall occur over 0.5 seconds;

(ii)

This load shall be applied to the structure in such a manner that stresses are maximized.

(2)

Special impact loads. Special impact loads shall be considered in the design of buildings, structures, or parts thereof. Unless a rational and detailed analysis is made and submitted for approval by the Director of Public Works, the intensity of load shall be taken as 100 pounds per foot acting horizontally over a one foot wide horizontal strip at the regulatory flood level or at any level below it. Where natural or artificial barriers exist which would effectively prevent these special impact loads from occurring, the loads may be ignored in the design.

(§ 1 (Exh. A), Ord. No. 1268, eff. April 20, 2017)