We are an architectural design firm that specifies extensive amounts of shotcrete to mimic rockwork in our designs for large-scale animal exhibits. We often encounter differing views on the need for galvanized or coated reinforcing bar in our shotcrete work, especially when they are used as pool lining walls containing salt water. Can you tell us your opinion on whether galvanizing or coating of reinforcing bar is necessary if both integral and surface waterproofing are specified?

Shotcrete is a process of placing concrete. The need to use galvanized or any other type of reinforcing is, or should be, based on the needs of the project and the preference of the structural design engineer. For liquid-containing concrete structures, the designer may review ACI 350-06, “Code Requirements for Environmental Engineering Concrete Structures,” which has specific concrete material, cover, and reinforcing requirements for concrete exposed to a variety of chemical and saltwater exposures. (The aforementioned ACI Committee 350 publication may be purchased from the American Concrete Institute at www.concrete.org”.)