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Re: FRP - Temp Reinf.

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I apologize for not responding sooner.  I have been out of town for a couple days unexpectedly and this is my first chance getting back on this project.

Tripp:

Yes, I need to use FRP bars because this project is in the Marshall Islands and their concrete mixes are highly corrosive for   steel reinforcement.  Plus, the quality of labor is far below what you will find here in the states.  Labor is the least expensive part of these projects.  Plus, the cost of the FRP is offset because the shipping costs are greatly reduced because of their lighter weight.

Gail & Scott:

I was not in any way trying to design this structure to meet ACI 318.  We initially designed some other structures out in the Marshall Islands before ACI 440 was even published, so one of our other engineers designed it based on working stress design and was somewhat cautious with it.  On that project, we only used #4 @ 16" o/c for temp control and didn't have any issues.  What I'm wondering is how they came up with the reinf. ratio for temp control.  Because when I did the calc, using ACI 318 eqn. 7.12.2.1 (c) and a 40 ksi bar, I end up with a ratio of 0.0027.  This is obviously larger than the prescribed 0.0020.  So, is this equation applicable when the adjusted (Es/Ef) yield strength is less than 60 ksi?  My other question is, are the values for 40 and 60 ksi steel from testing?

At 02:26 PM 7/21/2003, you wrote:

Just curious.  Do you really need to use FRP bars?  What's driving your decision to go that route?  Have you considered using galvanized or epoxy coated bars or cathodic protection?  Or maybe just plain bars with more cover or denser concrete?  Seems like FRP would be real expensive and hard to construct.  If I recall correctly, FRP bars can't be bent.  Could there be an easier solution?

Tripp Howard, P.E.


Tripp Howard


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