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I received this question from our maintenance staff.  It has to deal with bolt length on the back side of beam guard installation.  If MwRSF could provide input it would be appreciated.

I have reviewed the information provided below and am uncertain as to the direction of the question. Are you referring to the guardrail splice bolts or the guardrail post bolt? For connecting rail ends at a guardrail splice, standard guardrail bolts are used and are specified in AASHTO-AGC-ARTBA hardware guide. There should be no reason to cut or modify these bolts if ordered using the standard hardware. For placing rail and blockouts to posts, standard post bolts are also used to make this connection. These bolts have a specified thread length and should not require cutting or modification when the appropriate length is ordered. For rail to post attachment, the length of the threads extending out of the nut would not need to be limited to 0.5 in. or less for performance reasons. In rare circumstances, a unreasonable long rod could potentially contact the hazard face sooner than if the proper length bolt were used. However, I do not see this as being a big concern. If too long of a bolt were used, it would be difficult to use since the thread length is limited, thus not allowing the nut to be tightened. Are contractors trying to use non-standard bolts which require field modification in order to install the nut? If yes, I recommend that proper bolt length be used with standard guardrail bolts to avoid these field issues.