As Craig Poortinga of Walrite LLC Colorado Foundation Contractors waited for his crew to arrive to pour the third footing on a jobsite, he discovered the excavation was incorrect. In the past, this problem might have gone undetected, leading to lost time and profitability on the project. In the concrete industry, footing crews occasionally place a foundation, only to be called back to redo the work when layout and excavation problems are discovered later.
For this project, however, Poortinga, managing partner of the Loveland, Colo.-based concrete construction company, had a new tool that he put to good use—a Leica iCON robot 50 robotic total station. A total station is an electronic/optical instrument—basically an electronic theodolite or transit that is integrated with an electronic distance meter (EDM) to read slopes and distances from the instrument to a particular point. This instrument can be controlled by the operator from a distance by remote control.
“Finding errors before the whole crew is onsite resulted in a foundation not lost, and I was able to reroute the footing crew to pour somewhere else,” Poortinga says. “Total dollars savings for the company was $6,000, plus I charged the builder $400 for the time spent on layout so the excavator could come back and fix the job.”
A similar incident happened on another jobsite where two excavations were wrong because the survey crew from another company missed a detail. With the use of robotic total stations, the errors were discovered quickly. “I was able to allow the excavator a day to come and fix it with no loss to man-hours or production,” Poortinga says. If his crew had arrived onsite the day of the pour and the digs could not be fixed in time, the pours would have had to be delayed for a day with a loss of $4,500 on the smaller foundations, not to mention the challenges of being off schedule.
Without a total robotic station, a crew would typically be sent out to set the forms for the with tape measures and strings. “It’s generally around this time when we’d find a mistake in excavation or some other problem,” Poortinga says. “The guys would spend a good part of the day putting materials in the ground and then find out the footing wasn’t right so we wasted all that labor to get to that point. At $30 to $35 per hour pay plus insurance, with a three- or four-person crew, it adds up quickly.”
Mistakes are often made during the initial layout before excavation because “the math was done by the crew, not by a system.” Laying out with tape measures and strings leaves a lot of room for human error, Poortinga says.
He still finds mistakes using robotic total stations, but they are much easier to locate. “Ninety-nine percent of the time, it’s a mistake drawn on the plans by an engineer. If you look at the mistake category before we began using the robotic total stations, 99% were layout errors,” he says. “Very rarely do I even find mistakes now. Out of 100 foundations, I’ll find one mistake. However, when you’re running tape measures and strings, you make mistakes every day.”
This technology has also enabled Walrite to work in weather conditions that would have been challenging with the traditional tape measure and stringline method. “When you’re running a stringline 60- to 70 feet long with wind blowing 20 mph, you’re fighting the elements,” Poortinga says. “With total robotic stations, you can keep going forward unless it’s pouring rain. I just make sure the machine isn’t going to tip over, so the wind doesn’t affect our work.”
A more efficient pour
Using the robotic total station technology has made jobs much easier and more efficient because now the crew can just build and stake without the extra steps of a layout using multiple crew members. “We build with no need to take apart because after layout, we see things that don’t fit,” Poortinga says. “There are no strings to run or extra stakes to drive. Any errors in the form layout are fixed prior to the final square. It’s much easier to do at this point than later. There’s less labor in moving and adjusting walls to achieve square and it’s also easier on the equipment.”
Concrete work can be physically taxing on crew members. The robotic system eliminates much of the physical work by precisely laying out the project. “The crew can see it exactly the way it should be on the ground,” Poortinga says. “They can see which points they must build around. Envision holding a stick with a computer on it and walking around until it says zero-zero, marking it as a point, and then putting a nail in the ground. All you need to do is set up the machine and start walking around. It tells you where you have to go.”
This translates to time saved on the jobsite. On simpler jobs, Poortinga has reduced the time of three crew members by 30 minutes each. For custom homes, a total of six man-hours can be saved. “Add to that the ease of work and not having to tear apart and fix things, and we see a substantial savings,” Poortinga says.
A boon to business
Walrite was able to achieve its return on investment within two months of purchasing the robotic total station. The company is now on the profit side, saving about $300 to $400 per job in time, with an average of about a job per day. This adds up to a $1,500 to $2,000 in savings per week.
“It’s a daily savings for me,” Poortinga says. “I’m not only saving on those parts of the job they don’t need to do anymore, but I can have them focus on other parts of the job that make it better. Instead of having three guys together to do a layout, one guy can do that while the other guys focus on the details of the job, such as putting foundations together and making sure we aren’t missing the drops.”
Builders are noticing the technology. “When they see me come out with this equipment, I have received huge compliments and have heard some say, ‘I am so glad to see this,’” Poortinga says. “It gives them confidence about what I am doing and that with this technology I will be able to give them the best product possible.”
Builders and potential clients that point out Poortinga’s use of robotic total stations and indicate that they’d like to work with Walrite because it will assist with some challenging designs. An engineer who called him while working on very detailed, challenging project—a house with four 15-degree angle breaks. “He said, ‘Now that you have this machine, it will be no problem for you to be able to do this,’” Poortinga says. “They are calling me because they know they aren’t going to get a mistake call. Houses are becoming more complicated. People are looking for more in a home than it just being a square box. They are changing angles and bringing details into a house. This machine [robotic total stations] takes the fear out of some of these custom homes. Instead of taking days, a really complicated house can be laid out in two or three hours.”
Poortinga says if he sees a deficiency in his business or if there is something in which he is not confident, he wants to change it. “If I can beat it, I can be better in my business by taking that weakness and trying to overcome it,” Poortinga says. “The robotic total station takes away some of this weakness. It’s so much easier when doing a foundation to not have string all over the place. There are no tape measures, and we’re not constantly trying to get out of each other’s way.”
Tina Grady Barbaccia specializes in covering construction-related topics. For more information about Walrite LLC, e-mail email@example.com. To learn more about how to increase construction layout accuracy and efficiency, visit www.leica-geosystems.us/BIM.