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2015FallShotcreteEMag

Nozzleman Knowledge Shotcrete Delivery System— A Football Perspective By Nathen Bent S march down the field and score as many they will try and run over the pump, or theconcrete mixer driver. Doing the best they can,upon us again. In football, the goal is to “ ET…HUT…HIKE.” Football season is nothing about your game plan of shotcrete: the points as possible. In shotcrete, the goal is to get operator. They will park in the neighbor’s the job done safely and go home to our friends driveway, who is already mad about the con- and families at the end of every day. Shotcrete struction. Adding water without permission for workers can be seriously injured, crippled, or any reason is a favorite game-changing play of possibly killed doing their job. I personally have your new teammate. The most consistent con- seen nozzlemen lifted well off the ground due to tribution of play is not paying attention and the pressures of a plugged hose. running the pump low or empty. Pumps must be kept full. Pumps that are not full are prone to Pregame Meeting produce “slugging” or uneven delivery to the Your shotcrete team could be playing together nozzleman. “Slugging” will tire the nozzleman for months, if not years. The team knows the quickly and with the interrupted delivery, the plan completely, versed on all safety practices nozzleman can get frustrated and lose focus. and procedures outlined by the company manual. Many times I have seen this occur; the irritated The nozzleman has years of experience, and the nozzleman turns to say something, and WHAM— finishers are the “best in the business.” But we the pump kicks in and throws the nozzleman off are continually inviting an “unknown celebrity” balance, possibly resulting in an injury. onto the team. Somebody who may know First and Goal Pumping low-slump concrete over distance can result in very high pumping pressures. One of the easiest ways to start lowering pressures is by the use of a slick line or rigid pipe instead of a rubber hose. Although it involves some calcula- tion and a great deal of clamps, it is effective and safe. The pipe is easy to clean and disassemble as you pump during the day, making washout at the end of the day safer as well. Some of the highest consistent pressures are right out of the reducers, where we see considerable hose whip close to the concrete pump operator and concrete mixer truck driver stations (refer to Fig. 1). A 90-degree elbow and two lengths of pipe greatly reduce pressure and increase operator safety. Offense A simple thrust chain installed to reduce pumping system surge is a safety must. Broken elbows and reducers at the rear of the pump, during pumping operations, can be deadly. The surging of the pumping process is easy to see, Fig. 1: A few pieces of metal pipe can greatly improve work station safety but the strain on the ends of the reducers and 34 Shotcrete • Fall 2015


2015FallShotcreteEMag
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