Award of Merit: Special Projects Category
Shotcrete Restoration of JEA Hyperbolic Cooling Tower Veil
Submitted by The Euclid Chemical Company
Florida Power & Light Company (FPL)/Jacksonville Energy Authority (JEA)
Existing Structures Engineering, Inc.
Cape Canaveral, Florida
Coastal Gunite Construction Company
Coastal Construction Products
The Euclid Chemical Company
The JEA Cooling Tower in Jacksonville, FL, is a cast-in-place, reinforced concrete tower 460 ft (140 m) tall with a diameter of 320 ft (98 m). Years of exposure to salt water from the Atlantic Ocean caused the concrete in the tower walls to deteriorate. Approximately 1080 panels on the lower quarter of the tower veil were in need of repair. Because of the size of the area to be repaired and for good bond strength, shotcrete was the application method of choice.
An engineering study was performed to identify, quantify, and chart unsound concrete. The engineer also designed a passive cathodic protection system to further extend the structure’s service life. The contractor used a hydrodemolition sled to remove delaminated and unsound concrete. Two shotcrete passes were used, the first pass to repair deep patches to the tower veil and the second pass to provide a topping to embedded cathodic protection zinc mesh.
The shotcrete specification called for concrete with a maximum resistivity of 15,000 ohm-cm to allow current flow for the cathodic protection system. A specially modified, prepackaged concrete repair material was used because of the special resistivity necessary for the project.
This shotcrete repair is truly unusual because of the methods, techniques, and unique shotcrete product used to perform the concrete restoration to the tower veil. Completing this project successfully, safely, and within budget created tremendous opportunities for applications of this specific technology on future concrete restoration projects.