topic Re: Moment value in the Determination of longitudinal strain in Structural Bridge Design Forum

Moment value in the Determination of longitudinal strain

Anonymous — Wed, 10 Mar 2021 03:47:50 GMT

Hi,

I was examining the results for the Determination of longitudinal strain εx calculation and noticed the Factored moment does not match the applied moment in the beam. In the example below, the Factored moment result = 1016 kNm.

However, when you look at the applied load case, it shows a moment of

Would someone know how SBD calculates this moment? or am I missing something?

Regards,

Re: Moment value in the Determination of longitudinal strain

dave_geeves — Wed, 10 Mar 2021 12:41:35 GMT

Hi,

By means of trial and elimination I assume you are using AS5100 2017 Amd 1 standards (as opposed to Eurocode, AASHTO or British) and that you are carrying out shear calculations for a "design section" of a prestressed beam.

If this is the case, then I believe you problem is that on the analysis form you are selection both the load case and setting the "Capacity" to Mx (or other moment direction) so that the factored moment will be the capacity of the section rather than just the applied moment in your load case.

For the shear calculations to be fully meaningful it is important to set both the shear force and the associated moment in the load case and set the capacity to "*Not Used*" so that any shear reinforcement requirements are determined correctly.

Shear Analysis Form

I hope this has helped and has successfully answered your question, but if not, then please reply with a zipped up data file attached and a little more explanation.

Please mark my reply as a solution if it has solved your question so that others may benefit by searching for solutions. Thanks

Kind regards

Dave Geeves

Re: Moment value in the Determination of longitudinal strain

Anonymous — Wed, 10 Mar 2021 21:22:06 GMT

Thank you Dave! That worked.