AITC Technical Note 26

[akfed]

AITC Technical Note 26 was just brought to my attention

https://aitc-glulam.org/shopcart/details.asp?category=&item=TN-26

This note deals with Glued laminated beams fabricated before 1970. Apparently before 1970 the grading requirements for laminates were not as stringent as they are today resulting in an over stated Fb.

In the road system under my management I have a pre 1970 glulam bridge that has not undergone any changes in use or structural modifications since it’s construction. In light of this TN I'm putting a contract together to have the bridge professionally inspected.
My question is, if this report comes back with no defects noted what are my requirements for implementing this guidance? Utilizing the reduced Fb will resulting in having to post a very low load rating. Currently the bridge is rated to a HS-20 load.

Thanks in advance for any help/suggestions

 

[msquared48]

Why not take the monkey off your back, have the individual or firm inspecting the bridge put a load rating to it, making sure you inform them in writing of the reduced Fb situation. Make sure you detail all this in the contract. See what happens.

Mike McCann
MMC Engineering

 

[akfed]

thanks for the advise msquared. Generaly we do all of our inspections and load ratings in-house so I'm unfamiliar with the contracting aspects of load rating structures. If we do go the route you've suggested what would drive the ktr to give the bridge a higher load rating than would be suggested by the guidence in TN26?