SOLUTION ; Calculate, 



d 30.0 



= 0.031 



2 2 



gT 9.8 (10) 



H 3.0 



= 0.0031 



2 2 



gT 9.8 (10) 



From Figure 7-68, 



L. = 0.89 L = 0.89 I -^ ) T^ = 138.8 m (455.4 ft) 



From Figure 7-69, 



Tig = 0.52 H = 0.52(3.0) = 1.6 m (5.1 ft) 



From Figure 7-70, 



L = 1.01 L^ = 1.01 (138.8) = 140.2 m (459.9 ft) 



and from Figure 7-68, 



K = / (^ = -"^ = 0.46 

 i (z = 0) 



K^ = y^^= -'^ = 0.21 

 D (z = 0) 



Note the large decrease in forces with depth. The wave condition approaches 

 that of a deepwater wave. 



*************************************** 



For force calculations, an appropriate wave theory should be used to 

 calculate u and du/dt . Skjelbreia, et al. (1960) have prepared tables 

 based on Stokes' fifth-order wave theory. For a wide variety of given wave 

 conditions (i.e., water depth, wave period, and wave height) these tables may 

 be used to obtain the variation of f • and fp with time (values are given 

 for time intervals of 2TTt/T = 20° ) and position along the pile (values given 

 at intervals of 0.1 d) . Similar tables based on Dean's numerical stream- 

 function theory (Dean, 1965b) are published in Dean (1974). 



For structural design of a single vertical pile, it is often unnecessary 

 to know in detail the distribution of forces along the pile. Total horizontal 



7-110 



