PT123X1 CH2 



TIME, SEC 



Figure 14. Typical maximum pressure record for Channel 2 



profiles exist for each of these records. These six instantaneous profiles 

 represent the six points in that particular record when a maximum value was 

 occurring on one of the transducers. For example. Plates 1, 2, and 3 depict 

 the six points in time when maximums were occurring during Test 45 (NE, swl 

 = +9.5, 50 percent gain). The plot labeled PT45 MAX CH2 Is an instantaneous 

 pressure profile at the point In time during Test 45 when the highest pressure 

 on Channel 2' was monitored. All other profile plates are labeled accordingly. 

 The pressure distributions indicate that maximum pressures at different wall 

 elevations rarely occur simultaneously, especially in the case of a nonvertl- 

 cal wall such as the stepped wall studied here, on which some wave energy is 

 dissipated through turbulence. Notably, the profiles often depict surge pres- 

 sures on channels other than the one experiencing a maximum. For example, 

 profiles labeled PTXXX MAX CHI represent the instant in time when the wave has 

 reached the last instrumented point on the face of the seawall. Therefore, 

 impact loads on the more seaward transducers occurred earlier, if at all, and 

 longer duration surge pressures are actually being measured at that point. It 

 should also be noted that the negative pressures Indicated on Plates 4 and 5 

 resulted from a mistaken zero offset before the test was performed. 



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