DATA RESULTS, FLOATING BREAKWATER 

 PROTOTYPE TEST PROGRAM 



Laurie L. Broderick 



INTRODUCTION 



The monitoring program for the prototype test was conducted by the Civil 

 Engineering Department of the University of Washington under contract with the 

 US Army Corps of Engineers. The purpose of the monitoring program was to col- 

 lect data that would serve as a basis for establishing and evaluating the fun- 

 damental behavior of the two breakwater types under study. The University de- 

 signed a system to measure and record pertinent environmental and structural 

 variables that are involved in the design and mathematical modeling of the 

 test breakwaters and similar structures. The parameters that were measured 

 included incident and transmitted waves, wind speed and direction, anchor line 

 forces, stresses in the concrete units, relative float motion, rotational and 

 linear accelerations, pressure distribution on the concrete breakwater, water 

 and air temperatures, and tidal current data. 



"Off the shelf" transducers for measuring many of the parameters were not 

 available. A major effort was required to design and fabricate anchor force 

 load cells (Photograph I), wave measuring spar buoys, a relative motion sen- 

 sor (Photograph 2), pressure sensor housings, and embedment strain gages. By 

 the end of the monitoring program, approximately 60 transducers had been in- 

 stalled in and around the breakwater. Over 3 miles of underwater electrical 

 cable was required to feed signals to the data acquisition system that was 

 housed on the concrete breakwater (Photograph 3). Using large lead-acid bat- 

 teries for power, the system was completely self-contained. In addition to 

 the input transducers, the system included a microprocessor-controlled data 

 logger and special purpose signal conditioning electronics, which were de- 

 signed and built by the University (Photograph 4). The data acquisition 



125 



