2. High-strength nonweldable materials can be utilized, as no welding is 

 required in this vessel. To a large extent, the use of high-strength materials 

 can compensate for the need for additional wall thickness to accommodate 

 stress concentrations around shear pins. 



3. Individual segments can be transported by common commercial carriers 

 without any trouble. 



4. At the erection site only the hoists associated with the pressure vessel 

 test facility need be employed in the assembly of the vessel. 



5. The assembly of the vessel can take place after the test facility building 

 has been completed, since individual segments can easily pass through the 

 doors of the facility. Because of this, the overall construction time of the 

 facility may be reduced, as the vessel does not have to be fabricated and 

 installed before the building can be built. 



Undesirable Features 



1 . This construction concept is very new and a very extensive R&D program 

 will have to be conducted to develop safe design and fabrication techniques. 



2. This vessel will probably require 5 to 1 times as much steel as a multilayer 

 vessel of same material because of the stress concentrations in modules and 

 due to extra material needed for a yoke or tie-rod end-closure restraint system. 



3. Machining of modules for a segmented vessel will require at least 100 times 

 more machine shop time than for a multilayer vessel. 



4. The assembly time of such a vessel in situ is longer than for welding a multi- 

 layer vessel in the shop, or in situ. 



Conclusion. The construction of pressure vessels by the segmented 

 modular method is a new concept that has not been extensively applied. If 

 practive proves it successful, it will mean a breakthrough in the technology of 

 fabricating large, high-pressure metallic vessels. 



Recommendation. The segmented vessel construction concept is not 

 recommended for immediate consideration in the construction of large pres- 

 sure vessels because of complete absence of design or experimental data. 

 However, a study should be immediately initiated to explore this vessel concept. 



Prestressed Concrete 



The possibility of using prestressed concrete as material for constructing 

 a deep-sea-pressure simulation vessel appears attractive and competitive with 

 other fabrication methods. Prestressed concrete is quite commonly used for 



50 



