#strengthening

What to do once a defect has been found — how to establish the cause before repairing the symptom, whether old steel can safely be welded at all, the four ways of dealing with a crack, and how to strengthen a member so the fix matches the way it was actually failing.

Most concrete repairs fail not because the material was poor but because nobody diagnosed what they were repairing. A patch placed in chloride-contaminated concrete drives the next failure at its own edge, and does it faster than the first one arrived.