Excavator on Bridge Deck for demo after Longitudinal Saw-cuts

[Deadblow]

Hello,

Today I got out on site to observe some bridge demolition procedures. It is a four span adjacent box beam bridge and we saw-cut longitudinally between each beam to cut the shear keys. Our demolition plan called for the crane to lift the beams from their bearings after the dowels were core-drilled. The site crew had a 70,000 lb excavator on the deck and was using that to lift one end of the beam free from the dowels. This took a considerable amount of effort and banging from the excavator and the entire deck was deflecting approximately 3"-6". Does AASHTO (or any other code) prohibit equipment from being on the deck after it has been cut longitudinally? I'm concerned for the safety of the workers but they say they do this all the time.

Thanks

 

[bridgebuster]

They do it all the time until they fracture the boxes. AASHTO does not have any prohibitions in this regard. Your analysis has to reflect how the contractor will do the work, or rather, the contractor has to do things as stipulated in your demo procedure. Is he following the approved procedure?

What do the DOT specs call for? On NYSDOT projects contractors have to submit detailed demo plans and calculations. The specs cite various provisions of OSHA and other codes.

Back to your case, if the contractor cut the keys the live load distribution is no longer following the AASHTO provisions.

 

[Deadblow]

The contractor is not following our approved demolition procedures. The problem is that this is a township road so there are no DOT inspectors present. After I expressed my concerns to the site crew, I also informed upper management of the risks.

 

[bridgebuster]

That's all you can do. CYA