Missing Anchor Bolt Repair 1

[BubbaJ]

Despite the shop drawings indicating that only select columns could have the anchor bolts epoxied, the contractor left them out of all the pile cap pours, save one.

Unfortunately, with the tension and shear at the base of the columns, epoxy anchors will not work as a "replacement" for the cast-in-place anchors.

Does anyone have any "non-traditional" repair/replacement ideas for the missing cast-in-place anchor rods?

 

[msquared48]

This is way out of the box, but through-bolt the pile cap and attach galvanized washers/plates under the cap. Fill the excavated voids under the pilecap with concrete to protect the bolt ends. Don't know how this would marry up with the pile size and location though.

Mike McCann
MMC Engineering

 

[theonlynamenottaken]

Have you looked at undercut anchors? You can get more out of undercuts than you can out of adhesive anchors especially if the undercut's manufacturer provides an ACI 355.2 test report that includes installation sensitivity and kc values.

 

[SteelPE]

I'm with M^2, through bolting would be my first option. When they complain give them the option of ripping out the caps and repouring the cap. I can't stand it when they mess up the bolts with tension on them.

 

[BubbaJ]

Through bolting is not an option I had thought of, though I often do it for masonry applications. And yes, they would complain, the cap is 24" thick and this is an existing structure, they will have to cut out more floor to accomplish it.

If I try to use the existing base plates, my edge distances are not adequate for undercut anchors.

 

[SteelPE]

Is there anyway to get more dead load onto the column? How much tension are you looking at?

 

[msquared48]

Another wayout of the box concept - cap the whole pile cap with steel plate extended over the sides and after set bolt the verticl plate to the side of the cap. Weld the old base plate to the new plate cap.

Probably won't like that either...

Perhaps Ron could recommend a good epoxy to use to bond the plate to the concrete?

Mike McCann
MMC Engineering

 

[BubbaJ]

During the design I tried about 25 permutations of possible layouts.

Unfortunately, we are building over an existing structure, many obstacles and beam depth restrictions and very few convenient places for columns.

As a result, my braced frames (which are tall and somewhat narrow), on the end walls, have very little dead load in some instances.

I would have liked to have braced my frames in the opposite direction, where they would have had more dead load, but the Owner had some crazy requirement about keeping their doorways open.

One column has 62K Tension (LRFD) and 51K Shear.

 

[msquared48]

My final suggestion - shoot the contractor and bury him in one of the new pilecaps his replacement has to pour.

Mike McCann
MMC Engineering

 

[fegenbush]

In this case, I would stick with the "traditional" repair: Have contractor remove concrete and replace with the proper anchorage. If it was their error, they should be happy to do it to avoid further disruptions of the accounting variety.

 

[ztengguy]

Its too bad women dont run all construction companies, at least they read the directions (drawings in our case) on products!

 

[Robbiee]

I wonder if you have enough room to thicken the cap?. If yes, then thicken it to bury " the contractor"...no, the anchor bolts and provide epoxy dowels to transfer shear and tension between new and old concrete.

 

[BubbaJ]

We are close (about 4") to an existing interior concrete column (which has a lot of dead load on it). The contractor brought up the suggestion of tying our new column to the existing one. He also mentioned the existing concrete beam, which I quickly dismissed.

Tying to existing columns is not for the faint of heart, that is for sure.

I think he is grasping at straws.