Girder Deflection

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jbshoulder23
Girder Deflection

I cannot independently match the deflection results of the girder self wt. I match the moment and shear values. I can also match deflections for slab and other DC loads; therefore the E, I, and girder length is correct. Conspan is producing the same value I calculate. Is there a factor applied to this girder deflection to which I am unaware?

Rick Brice
Which girder self-weight

Which girder self-weight deflection?
Release, lifting, storage, transportation, erected?

Please post your file and more details about your hand checks.

There are factors that can be applied to deflections. They are defined in the Project Criteria. It depends on the publisher of the configuration you are using as to what the factors may be.

jbshoulder23
More information

I am checking the erected girder. I have the WSDOT configuration with a modified project criteria library. All deflection factors are set to 1.0.

I am calculating the maximum deflection at midspan using the deflection equation for a uniformly distributed load. [5wl^4/(384EI)].

I do not see how to attach a file on this interface?

Rick Brice
Girder Deflections

One common mistake is to use Ec rather than Eci when computing dead load deflection. Think of a girder that is always supported at the same distance from its ends through all stages of construction. The initial self-weight deflection is governed by the stiffness I*Eci. The deflection doesn't change just because Ec changes. That is, the deflection doesn't decrease because E increases.

Deflection calculations can be found in the Design Examples provided in the documentation. Here is a direct link. https://www.wsdot.wa.gov/eesc/bridge/software/Files/Examples/Design_Exam.... See section 6.4.2

jbshoulder23
Girder Deflection

Yes, I see. Thank you.

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