empirical correlation also compare well with a derivation of the mechanical model for the impact of a

rigid barge train on a rigid wall.

cal correlation are limited to an *F*m of less than 3.56 MN (800 kips). The designer should consult with

CECW-CE if the value of the maximum impact force exceeds 3.56 MN (800 kips). This limitation is

imposed because the equation does not account for the effects of lashing failures or deck buckling of the

corner plates under higher impact loads. The empirical correlation is defined as:

where

and

2*W*

where

2 = conversion factor from short tons to kips

g = 32.2 ft/sec2

service life is critical in the design of navigation structures. A method of defining load conditions due to

barge impacts needs to be defined on a basis equivalent with other loading conditions such as pool levels

or seismic events. To accomplish this, the use of the return period or an annual probability has been

adopted to design the structure to maintain a certain level of structural performance.

(1) The return periods for barge impact can be defined using the following three load condition

categories:

Usual These loads can be expected to occur frequently during the service life of a structure, and

no damage will occur to either the barge or wall. This typically corresponds to a 50 percent

chance of being exceeded in any given year.

Unusual These loads can be expected to occur infrequently during the service life of a structure,

and minor damage can occur to either the barge or wall. This damage is easily repairable without

loss of function for the structure or disruption of service to navigation traffic. This typically

corresponds to a 50 percent chance of being exceeded within a 100-year service life.

B-4