includes the work boat, radio navigation system, acoustic subbottom profiles, magne- 

 tometer, echo sounder, side-scan sonar, and divers. The operational procedure of a specific 

 sonic cover survey is briefly described as an example of the application of the survey 

 methods, and recommendations are given for the requirements of a vessel to be used in such 

 a survey. 



179. PETRAUSKAS, C, "Discussion of Regression Model of Wave Forces on Ocean 

 Outfalls," (Proceedings Paper 7275, May 1970, by R. E. Johnson), Journal of the 

 Waterways, Harbors, and Coastal Engineering Division, May 1971, pp. 414—417. 



180. PLUNKETT, R., "Static Bending Stresses in Catenaries and Drill Strings," Journal of 

 Engineering for Industry, Vol. 89, No. 1, Feb. 1967, pp. 31-36. 



181. POSTLEWAITE, W. R., and LUDWIG, M., Method for Laying Submarine Pipe Lines, 

 Patent No. 3,266,256, Patent Office, Washington, D.C., 16 Aug. 1966. 



182. POWERS, J. T., "Stress Analysis of Offshore Pipelines During Installation," Offshore 

 Technology Conference, Paper No. OTC 1071, Vol. II, May 1968, pp. II9-II22. 



Keywords: Offshore pipeline. Stress analysis 



A computer-oriented finite-beam element, initial-value analysis method which may be 

 used to calculate stresses on an offshore pipeline during construction operations when the 

 pipeline is suspended between the ocean floor and a lay barge and stinger is described. 

 Applied tensions, external fluid pressures, depth variations in water currents, pipe stiffness 

 variations due to weakness of the weight coating at the field joints, and support buoys, if 

 used, are all considered in the theory. The method is general and can be applied to the 

 analysis of both two- and three-dimensional forces and deflections in the suspended part of 

 the pipeline under any support condition. Crosscurrents and lateral barge movements can be 

 considered. The use of the finite-element calculation procedure is described and several 

 examples of the calculations are included. The method is compared with other theories and 

 the advantages and hmitations are discussed. The basic equations of the method and their 

 derivations are given in the appendix. 



183. PROUDFIT, D. P., "Practical Selection of Material for Large Water Pipe," Transporta- 

 tion Engineering Journal, Vol. 95, No. TEl, Feb. 1969, pp. 203-212. 



Keywords: Material selection. Water pipes 



Proceedings paper discusses the factors that should be considered in selecting materials 

 for large water pipes greater than 30 inches in diameter. The materials considered are steel, 

 ductile-iron, and reinforced concrete. Steel and ductile-iron are considered as flexible pipes 

 and reinforced concrete as rigid pipe. Factors to be considered in the selection of a pipeline 

 include deflection limitations of pipe and coatings due to external loads and internal 



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