Lateral Stability of Prestressed Beams during Handling

[jorton]

Does anyone know where I can find a copy of "Lateral Stability of Long Prestressed Concrete Beams, Parts 1 & 2" by R.F. Mast? I can only find it at the PCI website, but their website seems to have some issues that are preventing me from downloading it.

Also, I am looking for a copy of "Handling and Shipping of Long Span Bridge Beams" by George Laszlo and Richard Imper. I have an old tatered and illegible copy that has passed through the copier one too many times. Although it is referenced many times in other articles, I haven't been able to find a fresh copy of the actual document.

Many thanks for your help.

 

[shin25]

Get a copy of PCI bridge design handbook. They have some solved example of the lateral stability that you are talking about. This is based on RF Mast.

What is the size and length of your girder?

 

[jorton]

Thanks Shin52. I have a copy of the PCI Bridge Book, but it is a little more simplified than my situation. I have 150' 72"BT that are being picked by a single crane with no spreader beam (NOT my choice!). I've read a good bit of the work by Stratford (UK) and some work by Peart, but I would really like to read the documents they reference.

 

[shin25]

That's a really long beam for a 72" BT!!

I guess, you will have a crane with a very long boom to compensate for a steep sling angle?

 

[jorton]

Actually, I had not looked completely through the plans earlier. They are 160' 74"BT with 52-.6 strands. Sounds like wet spaghetti to me. Just the camber alone will lead to some stability problems. I'm still waiting for rigging details from the contractor.

 

[shin25]

jorton,

Quite not sure, what kind of limitation(s) PCI BDM approach has on the stability issue? And, why it will not be applicable for your situation? Can you please elaborate? I know that PCI BT has narrower top flange that PCEF BTs.

 

[jorton]

The PCI BDM appears to only account for vertical lifting strands. I suppose if the stability in the hanging condition is only based on lateral displacement due to an initial sweep plus additional effects due to self weight acting on the sweep, then the additional compressive forces due to pick angle will not affect the stability of the beam. This appears to be the logic behind most of the various calcs for the hanging condition; they assume rigid rotation of the body. The additional forces can then be considered when looking at the strength of the beam. However, when looking at it from a Euler buckling approach it seems that this loading condition is critical. This is why I was hoping to read some of the research behind the PCI manual. Also, some of the research out of the UK offers much more involved methods than the PCI method. I was hoping to see the difference between the two. Thanks again for your help.

 

[cooperDBM]

If you have the sixth edition of the PCI Handbook the Mast papers are included on the CD-ROM under chapter 5.

 

[jorton]

Thank you cooperDBM. I'll check it out. Does anybody know where I can find Laszlo and Imper?