No Grout Base Plates

[mtm161]

I am looking for some text references or guidance for the design of base plates and anchor rods with open space between the plate bottom and the foundation. For this case, precast concrete posts are bolted to the plate with rods that extend out of the post bottom. The plate will then be bolted to the foundation and supported on the anchor rod nuts.

The posts are spaced 20 ft c-c and are up to 28 ft high. They support concrete noise barriers so as you can see the base moment is quite large due to the wind loading. Self-weight axial load is also considered.

Thanks

 

[JimParks]

MTM,

The method you are using sounds fine, right up till you don't fill the space between the base plate and foundation with grout after you've connected all the bolts and plumbed the posts.

Is there a reason you don't want to grout the space?

Jim

 

[mtm161]

Jim,
It would make the design much easier with a grouted plate, however our client has specified that grout will not be used to fill the space. I have seen these type of connections before but I cannot find any design example or text that deals with it.

Mark(mtm)

 

[wiktor]

Check this publication for quite extensive research and interesting approach used.
Your case is similar, but without the bearing pressure on the grout pad, just point loads from the bolts.

http://www.dot.state.ny.us/tech_serv/trdb/files/sr131.pdf