Project: Atlanta CNN Center – Elevator Ramp Condition Survey
Client: Turner Properties, Inc.
Services Provided: Forensic and Non-Destructive Testing
NOVA completed an evaluation and oversight of the repairs of the four elevated ramps at the CNN Parking Deck in downtown Atlanta. NOVA performed chain drag soundings to determine the extent of the deterioration. Core samples were taken based on chain drag sounding test results and in areas where severe near surface delamination or cracking was noticed.
In two of the four subject ramps, the existing deck coating had reached the end of its service life, allowing water to penetrate through the deck coating and joints causing laminar cracking. Approximately 50-80% of the topping slabs were delaminated from the concrete structural slab, and compressive strength testing indicated relatively low strength semi-lightweight concrete was used. NOVA recommended a replacement slab with an air-entrained, reinforced, semi-light weight concrete with a low water to cement ratio. Saw cut joints were required to prevent shrinkage cracks, and with proper curing and a medium broom finish a deck coating was not required. In the remaining two ramps, less than 10% of the ramps were delaminated. Isolated full depth topping slab patch repairs and a new urethane heavy-duty deck coating was placed to extend the service life of these ramps. These ramps are now a beautiful example of concrete repair and protection of a structure designed for longevity.
This project was recognized by the ACI Georgia Chapter with the Outstanding Achievement Award, Restoration Category 2015.