1953 AASHO bridge specifications 1

[justhumm]

I'm working on an existing rating/rehab of a cast-in-place concrete T-beam bridge. For some reason, the shear ratings at one location along the span are coming up REALLY low using the latest aashto criteria, but the bridge beams look fine.

The bridge was built in 1958-ish and I would like to find out about the shear spacing criteria of the time.

I happened across this old post, but couldn't reply to it for some reason...same question...Does anyone know if the AASHO 1953 bridge specifications are readily available somewhere (online)?

[URL unfurl="true"]http://www.eng-tips.com/viewthread.cfm?qid=109274[/url]

 

[bridgebuster]

I'm not surprised the shear rating is failing; the allowable stress was lowered, I believe, considerably in the 70's. See attached page from the 1953 AASHTO, hopefully it's legible.

You would think AASHTO would put the old specs on line but they don't.

 

[justhumm]

Thanks for the response.

A few days ago, I stumbled across a paragraph from As per PennDOT Pub 15M (Design Manual, Part4 - "DM4"), 5.5.5.1: "If existing beams do not adequately rate for shear using the current LRFD shear criteria, the beams should be rated using the criteria used for the original design."

We ran the ratings using the AASHTO 1973 specs and the shear ratings were all above 1.0.

(they don't apply, since LRFD still governs for moments, but several of the 1973 moment ratings went below 1.0)

 

[bridgebuster]

Glad it worked out foy you.