continuous box girder 1

[Hafeezvr]

Iam designing 2 span continuos PSC box girder of 80 mt total length. Iam analyzing in the following sequence. Can anyone guide me whether procedure is right or i have to consider more factors.
1)Longitudinal anlysis by Elastic beam method using STAAD pro for calculating BM and SF.
2)Transverse analysis by 3d fram analysis using STAAD pro for calculation of BM and SF in Individual members.
4) Shear lag effect considered while calcluating ultimate strengths.

5)Shall i increase moments to take in to consideration torsional, warping and distortion effects.

regards
Hafeez

 

[tjhubo]

Maybe my reply here is a bit late. From the questions you raised, I guess you don't have a lot experience with this kind of structure, neither enough guidance from some experienced engineer.

Since PC Box Girder Bridge is a complicated structure, I strongly recommend you be very careful with any engineering judgment you will make.

1) and 2): Analysis can be done with any decent software. However, the key is not the software, but the way you build your model, run your analysis, and interpret the analysis results.

4) Shear lag needs to be considered in stress check.

5) Torsion will increase the shear stress in the section. Warping will increase the normal stress in the section. Distortion is insignificant in RC/PC box girder.

 

[Hafeezvr]

Thankyou tjhubo.
Is there any good book on concrete box girder analysis.Except proof checking i dont have any guidance here. if you don't mind can you give some more information. How to calulate warping forces.
Hafeez

 

[tjhubo]

I don't have a book by hand. I think if you want to look up something about warping force, any thin-walled structural mechanics book will talk about it.

 

[miecz]

PCI's Bridge Design Manual has good theory and design examples. I believe it's available online.