Full-scale tests of pipe sections with surface axial notches, repaired with a split sleeve
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Test objects:

pipe section Ø377×9 mm with axial surface notch (depth 4.8 mm), repaired with a split sleeve Ø381×8mm.

Test aim:

verification of the developed analytical limit load model of the defected pipe section, reinforced split sleeve.

 

 The problem of the exhaustion of the pipeline lifetime is due to the occurrence of various material defects and the change in the shape of the pipe. In case of the operator decision about the insufficient strength of the defected pipe section, improvement measures are used. The most widespread measure is the reinforcement of the pipe with welded sleeves. However, for submarine pipelines, the most practical method of repair are the split sleeves that can be easily mounted underwater.

  Such couplings can be divided into two groups:

  • Germetic sleeves - must withstand the nominal internal pressure with the same strength factors as the main pipe.

  • Sleeves with partially recovable bearing ability - have limited bearing ability, and when used, the joint work of the defected pipe and sleeve is taken into account.

 

   In the literature there is no information on the theory of the joint work of a defected pipe and sleeve. This hinders substantiation of the feasibility of their use, and as a result, restricts the use of more economical sleeves with partially recoverable bearing capacity, which are usually considered only as a temporary repair. However, if this type of repair leads to complete recovery and thus provides a given durability, then there should be no biases against its use as a permanent type of repair.

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