anchor bolt grout pocket casted in the wrong place

[Aakalim103]

We have a situation where anchor bolt grout pockets for a industrial silo are casted at the wrong location such that the whole bolt assembly is off set by a few degrees. The pockets were casted against a spiral steel pipe and were meant to be filled with epoxy non shrink grout after installation of bolts. The simple solution is to drill a new hole besides it, however, the new hole will intersect with the casted pocket at the edge, as shown in the attached figure. The contractor has indicated that they want to just drill the new holes and then grout the entire new cavity with the epoxy grout. However, my suggestion to the contractor will be to first fill the casted hole and then drill the new hole. Do you think this is necessary?

 

[dik]

I'd talk to the silo supplier. I don't think it would be an issue depending on the 'fill' material.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[RangeRock]

Drilling a new hole anywhere within the radial minimum spacing dimensioned area specified by the adhesive anchor manufacture will void manufacturer-provided load data values. The manufacturer-published values are counting on the homogenous properties/condition of the surrounding material and the existing drilled/ epoxied hole creates a unique non-homogenous condition (ie. adhesive forces btw/ epoxy and concrete.)

A better detail would be to either slot the silo base mounting hole such that the existing anchor can still be used as is. If this is not feasible... would recommend providing (2) new holes into the silo base assembly at the specified minimum spacing away from the existing hole to prevent interaction w/ the hole drilled in error.

Your anchoring layout and manufacturer directed minimum spacing will determine whether possible or not. If manufacturer doesn't specify minimum spacing, would take a look at ACI 318 Chapter 17 to determine your influence profiles.

 

[dik]

That's why you check with the silo supplier, first. It's not likey this is the first time they have encountered this problem.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JStephen]

The uplift design on tanks and silos is usually not too sensitive to shifting bolts on the circumference. If the silo is shop-fabricated with anchor chairs, or if there are a lot of other fittings that limit anchor movement, you may have a problem.

 

[dik]

Because it seems to be a proprietary system, he should review this with the equipment supplier, first.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik