VA LongBeach Retrofit

New Brace

This column & Isolator just needed a new brace

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Retrofit Brace

This column required retrofit. The majority of the project was retrofit.

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Retrofit Brace

This column required retrofit. Note the monocoat was removed to examine the old brace.

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New Brace Model

Design/Engineering model of new brace

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Failed pull test

Epoxy voids caused pull test failures.

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Failed pull test

Not enough epoxy was injected to coat threaded rod.

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Reason for failure

After injecting epoxy in to hole, the insertion of the rod pushed it out.

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Failed pull test

Failures were cored out to examine problem. We knew the epoxy was burping out before the pull tests.

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Failed pull test

Not enough epoxy stayed in place.

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Failed pull test

Epoxy was forced out as rod was placed.

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Failed pull test

Problem was clear.

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Failed pull test

Each failure occurred for same reason.

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Typical failed condition.

Each failed pull test was cored and examined.

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Failures laid out

After weeks of delay, Hilti engineers could not solve problem.

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Solution

I calculated the volume of epoxy required to coat rods.

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Solution

I calculated the volume of epoxy required to coat rods.

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Solution

Paper cone holding that volume was attached to rod.

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Solution

Clear tube emulates bore hole in concrete.

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Solution

Instructions were to insert rod with cone of epoxy into bore hole.

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Solution

As you feel top of hole begin to twist.

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Solution

Cone will crush and discharge epoxy.

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Solution

Displacing air as epoxy fills void.

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Solution

Twisting helps evenly distribute the epoxy.

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Solution

between the rod and concrete hole.

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Solution

As shown in these examples using the clear tube.

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Solution

The twisting motion combined with the insertion.

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Solution

Saturates the gap between the rod and cavity.

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Solution

displacing the air evenly.

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Solution

So we have a nice even coating.

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Solution

with no air gaps.

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Solution

or wasted epoxy as the correct volume of epoxy fills the cone.

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Solution

There were no more failures and we used the technique on hundreds of rods.

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Results

VA Hospital Operational & complient

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