How should the joints of the bottom plates be located according to API 650?

• A. Evenly spread across the bottom
• B. Center above grillage members
• C. At random for ease of access
• D. No specific location required

Answer: (B)

The correct answer emphasizes the importance of proper joint placement in the construction of welded tanks for oil storage as specified by API 650. According to API 650, joints of the bottom plates should be located center above the grillage members. This practice ensures that the loads are evenly distributed and that the structural integrity of the tank is maintained. Placing the joints above the grillage members minimizes the risk of excessive stress concentration at the joint locations, which could lead to premature failure or deformation of the tank structure during service.

This specific alignment is crucial for maintaining the designed performance of the tank, as it allows for adequate support and minimizes potential weaknesses that could arise from poorly located joints. Proper joint placement also facilitates the ease of welding and contributes to the overall quality of the tank construction.

In contrast, evenly spreading the joints across the bottom would not take into account structural considerations, potentially leading to uneven load distribution. Locating joints at random or without specific guidelines could significantly undermine the structural integrity and safety of the tank. Therefore, adherence to the stipulation of positioning joints center above the grillage ensures compliance with best practices for tank construction as laid out in the API 650 standard.