Filler for structural bolt holes

[TpaRAF]

We are working on a bridge repair project, replacing rivets in deteriorated structural steel with high-strength bolts.

In some locations, the hole is several times the replacement bolt diametre. The concern when the bolts are torqued to provide a slip-critical connection, the scab plates (over the holes) will deform.

There does not seem to be any epoxy products specifically made for this application. The bolt force is about 40 kips (160kN), so a very high compressive strength is needed.

Any ideas on what processes or materials could be used to fill the annulus around the bolts?

Thanks in advance for your help! RAF

 

[bvanhiel]

HAZ = Heat Affected Zone

 

[magicme]

before you decide what to do, find out what happened in the Boston "Big Dig" project.... epoxy was used to hold bolts in, and they let go in short order, part of a tunnel collapsed and killed some people.

now there is much legal / political / engineering turmoil (not to mention the deaths!).

i have no idea what the cause of the failure was.

regards

magicme



------------------------------------
there's no place like gnome.

 

[ccw]

Heat affected zone problems are typically not an issue in structural steel. What kind of construction is this that uses steel not on the AWS D1.1 field weldable list?

 

[ccw]

"... have no idea what the cause of the failure was."

According to History Channel "Engineered Disasters" the epoxy had a "creep" failure in shear. At one time, after the failure, there were about 16 companies sueing one another over who was at ultimate fault for the failure. There is a great long thread on the "Big Dig" panel anchor failure over on "structural engineering". That is probably where this thread belongs also.

 

[minerk]

The more I've thought about this problem the more strange it seemed that Florida flat prohibits field welding. So out of curiosity I did a search...

http://www.dot.state.fl.us/structur...gnGuidelines/SDG5.11ConnectionsandSplices.htm

According to this field welding is discouraged, but NOT prohibited. This is clearly a case where field welding is necessary. Some work will need to be done to determine metallurgy and developing the best weld procedure, but it is definitely the best course of action.

 

[TpaRAF]

Thanks for the comments.

Minerk -- This particular jurisdiction of the DOT has had bad experience with field welding, and will generally reject repair plans calling for it. The real issue is having the government low bidder using the lowest paid welders he can get. Some of this work is overhead, the hardest welds to make. Weld certs only go so far.

Majicme, ccw -- One thing being considered in the Big Dig forensics is improper installation of the epoxy in an ... overhead use. Regardless of the quality of the method or material, it usually comes back to how well it can be installed or fabricated in the field

 

[surplusjohn]

how about a urethane bushing? compressable and very tough, many compounds are available for different durometers etc. seems to me you got to shape the filler, what ever it is.