The forces on the barrier in this study are usually characterized by a peak, which occurs immediately after the initial impact, on the order of 200 pounds per front foot of barrier and with a short duration on the order of 0.005 second. The impulse of the peak is usually a small percentage of the cumulative impulse up to the time of momentum reversal. After this short-duration peak, the force decreases exponentially until after an appreciable .part of the wave period — about one-sixth, depending on the wave steepness — when it rises again to a (second) maximum which occurs at the time of momentum reversal. This maximum in the force is approxi¬mately equal to the average force from the time of initial impact to the time of this maximum of rise (momentum reversal).
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