Concrete Beam Strengthening 4

[ali07]

We have a sitution where 60 ft span beam have to carry more live load and reinforcement becomes less than the required. I need to provide deficient reinforcement with steel plates anchored to soffit of the beam. How can i design the anchors? Beam is 24"x48" in X-sec.

 

[hokie66]

Thanks, apsix.

 

[ali07]

Guys cool down.

I'm in Canada, not able to reach the british standards.
Better refer something to Canadian Standards or US.

 

[hokie66]

Well, I am in Australia, and we have no such standard, so was grasping at straws. My access to the British information would be difficult also, so would appreciate it someone knows a more convenient source if it exists. If as yakpol says it has been done "many, many" times, someone must have some experience with bonding steel to concrete, whether bad or good experience.

 

[shin25]

I know some sika epoxies can create bond between steel and concrete, but, I will not be comfortable prescribing this for a situation that 'ali' is referring to.

 

[ali07]

Actually i need to learn how difference of strains at the point concerned are compatible with friction of epoxy to steel plate and epoxy to concrete. If there is a real uncertainity in analysis of bonding steel plate with concrete, there should be some simple solution for strengthening.

 

[LittleWheels]

ali07, perhaps you should check your facts. BA 30/94 is available online for free

http://www.standardsforhighways.co.uk/dmrb/vol3/section3/ba3094.pdf

 

[hokie66]

Thanks Dave for the reference. Looks like just what ali07 wanted, and I am interested also. But this procedure is far from a thing which you could entrust to just any contractor, so I think yakpol's argument that it is easier than external prestressing is not correct.

 

[yakpol]

hokie66,
I mean fibrewrap type of retrofit (passive)

http://www.geosyseng.com/0301fibrewrap.html,

not external prestressing.

 

[hokie66]

Yes, sorry, I got confused. But it seems to me that the steel bonding would be almost as specialised as the fibrewrap if the prodedures in the British Advice Note are followed rigorously.

 

[yakpol]

hokie,

Retrofit is about lots of money for just a little bit of capacity. Fibrewrap application becomes more popular since it improves bending and shear capacity as well. Call to the local representatives they will be happy to quote.