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2014WinShotcreteEMag

Shotcrete Corner American Shotcrete Association’s Board of Direction Position Paper #1 Shotcrete Contractor and Crew Qualifications S Shotcrete has been successfully used in substantial proj- contractor requirements will be best qualified to provide aa quality Shotcrete Contractor are then presented. Takentogether, a shotcrete team that meets or exceeds the crew andhotcreting is an efficient method for placing high-quality,durable concrete in a wide variety of concrete structures. ects for well over a century. As with cast-in-place concrete, the cost-effective, quality, and durable shotcrete application. quality of the shotcrete placement is dependent on the quality of the materials, proper mixing and transport, substrate/sub- Field Crew Duties and Qualifications grade preparation, the placing process, and protection until (based on input from ACI 506 Subcommittee developing final strength is reached. updates to 506R, “Guide to Shotcrete”) However, a comparison of the shotcrete process to the tra- ditional “form-and-cast” process shows significant differences. Composition and Crew Duties Specifically, when using the shotcrete process: The basic shotcrete crew may consist of a foreman, a noz- • Formwork is eliminated or substantially reduced; zleman, a finisher or rodman, an assistant nozzleman, a • It is necessary to identify the best shotcrete process (wet- or wireman, a gun or pump operator, a mixer operator (if needed), dry-mix) for the job; and laborers. • Special gunning equipment is required, including pumps, Depending on the size and complexity of the project, some guns, hoses, nozzles, and admixture/water pumps; duties may be combined by having one person performing more • Knowledge is required to safely use and maintain the shot- than one operation. For example, the foreman could also func- crete equipment; tion as the nozzleman; one person could perform as the rodman • A trained field crew that performs work totally unlike casting and finisher—also, an assistant can help the nozzleman by concrete in forms is required; pulling the hose and operating the air-lance/blowpipe; and, • Environmental conditions that are unsatisfactory for quality where needed, the gun or pump operator and mixer functions shotcreting must be identified; could be combined with proper equipment and one person could • The nozzleman must be well-versed in shooting techniques, perform the tasks. Larger, congested reinforced projects may including proper air, water, and mixture flow; require more than one nozzleman, air-lance operator, and sev- • The crew must be prepared to properly finish, protect, and eral finishers. Where several crews are operating, a foreman, cure freshly placed shotcrete; and superintendent, or engineer may be required. • Knowledge of quality-control procedures specific to shot- Shotcrete Foreman’s Duties—The foreman plans, directs, crete is required. organizes, and coordinates the work of each member of the Based on these factors, it is apparent that a contractor shotcrete crew to obtain a safe and successful application. This offering to place quality shotcrete must have specific knowl- includes safety of the work area and quality-control procedures. edge, equipment, training, and hands-on experience of the entire The foreman is responsible for the inspection and maintenance construction team—from company management through the of equipment and ordering and expediting delivery of materials. field crew—to truly be considered a Shotcrete Contractor. The foreman sets the pace of the work, maintains crew morale, ACI 506R-05, “Guide to Shotcrete,” is a great primer on ensures good housekeeping, and acts as a liaison to either the shotcrete design and application. ACI Committee 506, Shot- general supervisor or to the owner’s inspection team. The creting, is currently working on revisions to the “Guide to foreman is usually a veteran nozzleman, finisher/rodman, or Shotcrete” and in the latest drafts has developed an expanded pump/gun operator, and should be able to fill any of the posi- section covering shotcrete crew requirements. Those provisions tions if required. are summarized herein to help establish field crew qualifica- Nozzleman’s Duties—The nozzleman is a key person in a tions. The requirements for the contracting firm to be considered shotcrete operation and is responsible for applying the shotcrete 52 Shotcrete • Winter 2014


2014WinShotcreteEMag
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