Girder Replacement

[FM1]

Hi everyone,

i am working on replacement of only one of the prestressed girders of a multi girder 50 year old bridge!!

the new deck load is going to be less than the existing
the new deck concrete is as strong as the old girder concrete
The DILEMA:
to arrive at the same LiveLoad deflection
to TRY and minimize the or if possible eliminate creep in new girder so the interaction with thw existing in the long run wont be detrimental to the deck slab

How and what would you guys do and what else must be considered

suggestions are much appreciated

 

[eXCELman]

I hope I had understood your problem correctly.

I would not worry about the creep effects on the new girder if only one girder is to be replaced. It will actually be moving with the old deck in the case of live load effects.
That action might attract some additional forces to the deck slab in a way that deck might experience some higher transversal moments. Putting some addtional transverse steel to the deck would easily solve your problem. Creep calculations can also be done but would be time consuming.
And validity of these calculation are always questioned since creep is a dependent on many variables.

 

[FM1]

thanks

you sort of reinforced what I was thinking myself

thanks again