anchor type

[cvg]

seems everybody has an opinion on which type of anchor is best

epoxy threaded or unthreaded rod
vs
mechanical - undercut / cone and sleeve expansion

I'm looking for pros and cons of each type for:

tensile stress
shear stress
under water
in older concrete, cracked vs uncracked
installed in drilled hole (core drill vs percussion drill)
some vibration
cold water temperature

 

[spats]

I think you need to research it some yourself, so you can ask more specific questions... you're asking for a lot! Not many will be willing to write a dissertation on the subject.

 

[cvg]

ok, for starters
underwater installation
existing concrete
drilled holes, probably diamond cored
temporary, low tensile stress
reducing to no tensile stress and very low /occasional shear over the design life
1" carbon steel anchor

epoxy are more difficult to install underwater
temperatures are low

mechanical is easier to install underwater
but there is a "feeling they could come loose"

 

[Ron]

I would use a mechanical anchor (wedge type or similar) for your application. For added protection you can inject epoxy into the same hole, but engage the mechanical anchor before epoxy sets up so that the mechanical anchor has an opportunity to work. For most mechanical anchor holes, you can inject the epoxy after the anchor is in place, just displace all water in the hole.

I would not use a diamond coring bit to drill the hole. It makes the hole too smooth. Use a carbide bit.

Clean the hole, with or without epoxy. Use an anchor that is longer (more embedment) than your load will dictate.

 

[MiketheEngineer]

Call Hilti

 

[cvg]

Hilti will not guarantee epoxy below about 160 feet deep and water temperature is unknown. So they do not recommend epoxy.

 

[RFreund]

160 feet deep?
I think they are called plugs at that depth!

EIT

http://www.HowToEngineer.com

 

[cvg]

big dig failure was vertical epoxied anchors holding large concrete ceiling panels. purely in tension with no secondary support and they pulled out clean or otherwise failed due to many reasons:

inadequate cleaning of holes
incorrect epoxy
no epoxy
oil on the bolts
insufficient FS
cold temperatures
holes too large
epoxy not mixed properly
etc.

largely a failure due to inadequate design, construction and inspection...

 

[SAIL3]

given the option, I would use mechanical wedge anchors over epoxy because of all the variables during installation that can severely affect the effectiveness of the epoxy anchors....Ron recommended a sound engingineering decision to increase the embedment length from what is the design value, where possible...

 

[dik]

cvg... and the material used. The quick setting epoxy was not as originally specd, and had poor 'creep' qualities...

Dik