How to Reinforce an Existing Precast Double Tee?
How to Reinforce an Existing Precast Double Tee?
(OP)
I have an existing precast double tee floor that according to the shop drawings was only designed for 40 psf LL and 15 psf DL. The owner wants to hang a 1/2 ton hoist and rail to the underside of the precast tees. I expect the point load from the hoist to be around 1.6 kips.
How can I reinforce the existing double tee to support the new hoist load?
THANK YOU!!!
How can I reinforce the existing double tee to support the new hoist load?
THANK YOU!!!






RE: How to Reinforce an Existing Precast Double Tee?
Some thoughts:
Carbon Fiber
steel shapes attached to the sides of the stem
RE: How to Reinforce an Existing Precast Double Tee?
RE: How to Reinforce an Existing Precast Double Tee?
Don't forget two things.....
1. Attachment scheme of the reinforcement has to miss all existing cables/rebar.
2. Strain compatibility between reinforcement and concrete. Check both the elastic modulus and the secant modulus of the concrete. Supplier should be able to provide both values to you. If you have no supplier info, do the best you can with similar generalized data.
RE: How to Reinforce an Existing Precast Double Tee?
Dik
RE: How to Reinforce an Existing Precast Double Tee?
Peter Emmons book on Concrete Repair and Maintenance. It's a bit elementary but if you've not done this before it can be helpful.
NCHRP Publication 293 or 294 (can't remember right now) which is about strengthening bridge members. Of course there is a lot on both reinforced and prestressed members.
Lastly, for the newer FRP methods use ACI 440. You will note that ACI 440 will require a certain strength for the existing in order to use FRP and you will also note some healthy strength reduction factors for the FRP. For the time being that's what we have to work with until more engineers and appilcations yield more in-service data.
Please note that while some methods mentioned in the publications above, you can apply them to TTs with modifications.
Good Luck
Regards,

Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: How to Reinforce an Existing Precast Double Tee?