XIV. Beach Erosion Board Laboratory. 
(a) Wave Forces on Structures 
Analysis was continued on the wave force data obtained in the large 
wave tank on a vertical 12-inch diameter pile. A report presenting some 
of this data was prepared. in draft form. 
In connection with another study concerning transmission of wave 
energy over low-crested breakwaters, a small, though useful, amount of 
information was obtained on stability of rubble breakwaters under heavy 
overtopping conditions. 
(b) Wave Run-up. 
The joint distribution of wave height and wave period for a fully 
developed sea, as developed by Bretschneider's method, has been used to 
obtain the distribution of relative wave run-ups in a sea condition, and 
also the distribution of actual run-up. This latter distribution turns 
out to be essentially identical with that for wave height as developed by 
Puttz, Longuet-Higgins, and others (at least for conditions examined). As 
such, it appears that about 13% of the run-ups exceed the run-up of the 
significant wave, about 1% of run-ups will be 1.5 times (R/Hy,), and about 
1 in 1,000 will be about 2 times (R/Hy,). This analysis has Been made 
only for the case of relatively deep water fronting a structure (d/Ho > 3) 
and for a fully developed sea, though it may be extended to include normal 
generating areas. A report, " An Approximation of the Wave Run-up Fre- 
quency Distribution", by Thorndike Saville, Jr. was published in the 
Proceedings of the 8th Conference on Coastal Engineering, Council on 
Wave Research, Engineering Foundation (1963). 
A graphical method was developed for checking the design height of 
protective dunes for beach fills which are to be constructed along an 
existing shoreline. This design height is dependent on the maximum run-up 
which could be expected on the structure. The method involves computing 
a "critical profile'’ which, when plotted on transparent paper, can be 
overlayed on field profile plots to determine if run-up from expected 
waves will exceed the structure height. A report, "A Graphical Method for 
Checking the Design Height of Structures Subjected to Wave Run-up", by 
R. P. Savage was published in the Bulletin of the Beach Erosion Board, 
Volume 16, July 1962. 
Wave run-up testing was carried out at small scale on some stepped 
seawall designs, The tests reaffirmed previous conclusions that arti- 
ficial roughening of sloped seawalls by steps materially decreased wave 
run-up below that which would be expected on a smooth slope. Tests were 
made for both 1 on 2 and 1 on 3 slopes. Tests were made for vertical 
steps and also for a re-entrant type step. Essentially the same run-up 
was obtained for both types of step, although there is an indication that 
slightly lesser run-ups may occur with the re-entrant type step. This 
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