allow continuous data acquisition for an entire 30-inin run, yielding a more 

 comprehensive time-history of the overall pressure response at the expense of 

 clear resolution of shock pressures. 



Overall Results 



34. The primary objective of this evaluation of wave-induced pressures 

 was to identify the magnitudes and durations of both the shock and surge pres- 

 sures on a particular wall geometry. CENAO guidance stipulated that the most 

 important product of this effort would be a series of representative pressure 

 profiles describing some of the more severe conditions encountered. The im- 

 portance of identifying the occurrence of significant negative pressures was 

 also stressed. In conjunction with these objectives, the presentation of re- 

 sults is concentrated primarily on representative design conditions. Subjec- 

 tion of the seawall to spectral wave conditions resulted in the collection of 

 many less severe but more interesting pressure time-histories; however, de- 

 tailed analysis of these records is not documented herein. Maximum values 

 recorded on each gage for all runs are listed in Table D2 (Appendix D) . 



Shock Pressures 



35. For each combination of storm, swl, and percent gain, an initial 

 30-min run (simulating a 2.18-hr prototype) was performed during which the 

 wave train was closely observed and times of occurrence were recorded for the 

 more severe waves (in terms of impact on the seawall) . These observations al- 

 lowed scheduling of 1-min sampling intervals to coincide with the most proba- 

 ble times when maximum pressures would occur. 



36. Generally speaking, a 1-min test (simulating a 4.36-min prototype) 

 of a severe condition would provide three to four waves which induced distinct 

 shock pressure records. Most magnitudes of these most severe pressures were 

 in the 20- to 60-psi (prototype) range, although on two occasions pressures as 

 high as 117 psi were recorded. (Throughout the remainder of this text, all 

 values of pressure magnitudes and durations presented will correspond to pro- 

 totype.) Durations of the most severe shock pressures also varied but to a 

 much lesser extent. Pressures of 15 psi and more were normally characterized 

 by durations of less than 0.020 sec. Durations of the highest pressures 



30 



