Repairs to the Citicorp building commenced immediately. The plan of action was to expose each bolted joint in the building by ripping away the flooring and walls around it, to cover each joint with a plywood 'house' in order to minimize any visible signs that things were awry with the building's structure, and to complete the repair welding at night when the tenants were not in the building, so as not to inconvenience them.
The pace of work was fast. Parts of the interior around the bolted joints were torn up at night and put back together in the morning. LeMessurier occupied himself with repair process calculations. Les Robertson calculated how to repair the joints, and, suspecting that other components of the building could be vulnerable, went about investigating the floors, columns, and braces for weakness.
The repair work was in full swing on the first of September, when a hurricane moving toward New York was detected. The news was met with alarm. The partial repairs -- along with the tuned mass damper -- greatly improved the building's strength, but no one wanted to see it tested. There was great relief when the hurricane moved out over the ocean.
Two weeks later, repairs had progressed to the point that, with no storms predicted, the elaborate evacuation plans could be scrapped. The next month, repairs were complete. Even if the tuned mass damper were to fail, a 700-year storm would not pose a threat to the Citicorp Center.
The engineering problem had been solved, and today the repaired building now exceeds even its originally intended safety factor.