TSA was approached by an Owner with a few issues in a concrete parking structure. They wanted to change out a cooling tower, but had no idea of the load capacity of the structure that was supporting the existing cooling tower since they didn't have the original structural drawings. They also noticed distress at a wall panel and double tee joint. The wall distress was caused by thermal loads that exceeded the concrete capacity because the anchors that were located too close to the panel edges. The double tee distress was related to an expansion joint that was added after construction even though the location was never intended to be an expansion joint.
Establishing the existing reinforcement size and configuration of the double tee-beam stems was of extreme importance. TSA had X-ray images taken, which revealed the number and location of tendons, which facilitated estimation of existing load capacity. TSA then designed a cooling tower support structure to minimize the structural impact of the proposed loads.
To deal with the edge distance problem, TSA designed a custom connection that reduced the capacity of the steel plate by creating an hour-glass shape . This design ensured that the steel would be the first to fail, thereby averting the more costly repairs of further concrete damage. The distress in the double tee flange was addressed by placing a plate that was anchored to the double tee flanges away from the edges to restore the integrity of the flange connections.
