Bolt holes do not line up exactly d

[QCJT]

Bolt holes do not line up exactly during erection and contractor is sometimes just enlarging the hole to be able to insert a bolt. They do not weld closed the unnecessary part of the hole, so you see a bolt in a large hole - they use a correct size of the washer of course and the bolt head is supported by the structural steel from three sides (only one side falls resting on the washer only). Is this a point of concern?

 

[hokie66]

Yes, it can be. Depends on which direction is enlarged, and to a lesser degree how the enlargement is made.

 

[QCJT]

Hokie66, thanks for your answer. Could you elaborate more on the direction please?

 

[hokie66]

If the bolts are in bearing, you don't want the bearing surfaces compromised.

 

[QCJT]

Ok. Thanks Hokie

 

[connectegr]

There are limitations on what is acceptable for reaming. As noted the direction of the adjustment and the type of connection can an issue. AISC (Is this an AISC project?) does not provide information for holes greater than given in RCSC. A tolerance of 1/32 is allowed. If the hole exceeds the maximum hole dimensions specified then it may be necessary to increase the bolt diameter accordingly.

If the erector is using a torch to modify the hole sizes, you can have many more problems.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[QCJT]

Connectegr, thanks. They are using a finger grinder for this purpose and this is basically ordinary carbon steel structure. The subject members aren't heavily loaded ones. This is not an AISC job. Which standard is the best to be consulted on this issue? What is RCSC?

 

[connectegr]

RCSC - Research Council on Structural Connections - develops the specification for structural bolting. You can download the specification at

http://www.boltcouncil.org

Some information about field modifications of bolted connection can be found on the AISC website or in AISC's Engineering and Quality Criteria for Steel Structures.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[rb1957]

i'd be concerned about opening a hole towards an edge.

FWIW, i wouldn't fill the hole with weld filler; i'd be more worried about the hole finish.

 

[TLHS]

Yeah, I'd watch the edge distance too. It's always a good idea to provide extra edge distance above the minimum so this doesn't become a problem. If they have to enlarge the hole a reasonable amount, you can repair it by making a plate washer with the right sized hold and welding that onto the original structure.

 

[QCJT]

rb1957 and TLHS thanks for your valuable comments. Connectegr, thanks - I'll check out that website.

 

[chicopee]

Structural steel, hmmm!! Here is one story about structural steel. Our company fabricated a tub girder with a sweep to specs, however, the designer contracted by the State used a program spitting out data which under-designed the tub girder. This information was not known at the time. This tub girder was all pre-assembled at our fabrication plant with no problem but when field erected, it rotated too much and to align the joints with the splice plates, the iron workers had to enlarge several holes. The State load tested the finished product( an "on ramp" to a major highway) OK, however, the life span of this ramp was diminished by about 40%.
So test your finish product before having it used by the owner and think about reducing its loading and life span.