straight stinger, an articulated stinger, or without a stinger, and with or without tension 

 applied at the lay barge. The weight of the pipe and coating and the buoyant and drag forces 

 are considered as static forces, although dynamic loads due to lay barge movements or 

 inertial forces may be introduced into the 'computation. The basic equations and procedure 

 of the analysis are given, along with examples illustrating the apphcation of the method. 



176. OVUNC, B., and MALLAREDDY H., "Stress Analysis of Offshore PipeUnes Under 

 Dynamic Loads," Offshore Technology Conference, Vol. I, Apr. 1971, 

 pp. I349-I356. 



Keywords: Offshore pipelines, Stress analysis 



A computer-oriented iterative method of analysis to determine the deformation and 

 stresses due to dynamic loads on a submarine pipeline suspended between the ocean floor 

 and the lay barge is discussed. A stiffness matrix method is used to solve the deformed shape 

 of the pipeUne under static loads, and a modal analysis is used for the dynamic loads. The 

 dynamic loads are applied to the statically deformed configuration of the pipeline, which is 

 modified to eUminate the terms due to rotations. The pipeline is assumed to consist of finite 

 elements, and the external loads on the members are lumped to tlie joints and expressed in 

 mass units. The natural frequency and modal shapes are determined from the equations of 

 motion for a multidegree, lumped mass system. The method is general and appUcable to any 

 dynamic loading condition. The procedure and equations of the analysis are given, and an 

 example of the application of the method is given for the dynamic loads of lay barge 

 displacements due to wave action. 



177. PEARCE, B. K., and KISHPAUGH, J. A., "Prediction of Pipelaying Equipment 

 Performance in Hostile Environments," Offshore Technology Conference, Vol. II, 

 Apr.-May 1973, pp. II455-II464. 



Keywords: Computer pipelaying model. Environment 



Conference paper discusses a computer model that simulates the process of laying 

 offshore pipelines from a lay barge. The computer model predicts probable installation costs 

 and time for completing the project, taking into account work interruptions due to weather, 

 equipment failures, and other factors such as pipe buckling and welding defects. The model 

 simulates pipelaying operations, weather generation, the generation of equipment failures, 

 and pipe-resupplying operations. The model was used to compare the performance of 

 flat-bottomed and small and large semisubmersible lay barges in the rough waters of the 

 northern North Sea and the Grand Banks of Canada. Comparisons of manual and automatic 

 pipe welding, and conventional and wide-truss .stingers were also made for these conditions, 

 using the computer model. 



178. PEEBLES, E. E., "Sonic Cover Survey of an Offshore PipeUne," Offshore Technology 

 Conference, Vol. II, Apr.-May 1973, pp. II295-n298. 



Keywords: Offshore pipeUnes, Survey methods 



The electronic and sonic survey methods that can be used to make cover surveys of 

 offshore pipelines are discussed. The equipment used in such a survey is described, which 



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