Hole Edge Distance Requirement 1

[dozer]

As part of my job as a structural engineer I review vessel drawings to be sure they got the hole size and pattern right for anchor bolts. Recently I reviewed a drawing that had a 2.2" dia. hole that was only 1.8" from center of hole to edge of base plate. The vessel designer asked me if that was okay. I said not in the AISC steel design world it's not. You need at least 1.25 x nominal diameter of the bolt. Is there any ASME code requirement for bolt edge distance?

 

[nickelkid]

Design of Anchor Bolt for vertical vessels in Megyesy (Pressure Vessel Handbook), Table 1 indicates a nominal 1 x bolt size to edge. For a 2" bolt, 2" to the edge. . Moss (Pressure Vessel Design Handbook) provides a design procedure if validation is required.

 

[jtseng123]

you do not need to worry about the edge distance for the 'base ring" that contacts with foundation. The only edge distance to be worried is the top ring that the hold down taking place. There are many designs out there that the OD of the base ring is smaller than the OD of top ring.
Every company has their own standard how the edge distance shall be for the top ring ( we use bolt diameter + 1/2"). If no standard, then follow any vessel design handbook.
You shall ask that vessel designer if he is following any standard or handbook, and ask him to show you his basis.
Where is your vessel engineer? who shall take the whole responsibility, not designer who may not know many details. It is scary that a designer asking you that kind of question, that means he does not know what he is doing.

 

[doct9960]

dozer,

There are no ASME code requirements for anchor bolt edge distance at base plates.

The AISC minimum edge distance is for steel to steel connections. They don't apply to steel to concrete joints.

 

[doct9960]

Found this in the AISC website.

http://www.aisc.org/DynamicQuestion.aspx?Grpid=6&QueId=1832&ste=_Preview&id=2100&type=0

I believe the FAQ also applies to vessel base plates.

 

[dozer]

To clarify, the vessel is supported in a steel structure. It does not sit on a concrete foundation. From the responses, it appears to me then that AISC requirements do apply. Oh, by the way, the designer was asking me because he thought it seemed too small, which I agreed. The vessel engineer couldn't answer the question to either on of our satisfaction.