Working on a busy urban construction site, it’s a common observation that the cranes set the pace of the project. Managing hook time is key to productivity, and it’s been no different for Gilbane Building Co. as it provided construction management at-risk services for the new Virginia General Assembly building in Richmond, Va.
“The crane is the backbone of the project,” says Chris Whitley, Gilbane general superintendent on the General Assembly project. Due to staging limitations, the team had to settle on a single tower crane and a mobile crane for the duration of construction. The $181-million General Assembly project entails construction of a 400,000-sq-ft, 14-story building that also preserves the original 1912 facade of the old General Assembly. But this job has also served as a test bed for some new technologies Gilbane is evaluating, including the CraneView crane sensor package from Versatile.
Versatile’s below-the-hook crane sensor has been deployed on other projects before, but Gilbane’s use of it on the General Assembly is one of the first major projects to employ it from start to finish. And with nearly 3,600 tons of structural steel and 1,281 precast panels going into the building, that’s a lot of crane performance data to review.
“We started with Versatile in March of last year,” recalls Brett Thompson, Gilbane senior project manager. “We had the conversation one week and the next week it was on-site calibrated and ready to go.” Versatile’s CraneView features a load cell and a camera to record every crane pick, wirelessly uploading performance data to the cloud for regular analytics reports. “We were able to tailor our daily digests [from Versatile] to our needs,” says Thompson. The latest version of the CraneView sensor in use at the General Assembly comes with a Crosby StraightPoint load cell, as well as upgraded battery life that’s good for a month between battery swaps.
“It allows us to take this data and analyze it, so if for instance we are getting through one sequence faster or if another is lagging,” says Whitley, who has also been eager to share the crane data from CraneView with steel erector Mid Atlantic Steel Erectors and precast erector E.E. Marr Erectors. “Let’s say this contractor says they need the crane for two hours, but we see a report of only 30 minutes of active hook time,” he explains. “Is it worth the time of operator to do that?” Whitley also has an alert set up with CraneView so he will get a text if the crane is motionless for more than fifteen minutes. “That often leads to a phone call or me going out there to see what’s happening.”
In one instance, steel beams that usually were only on the crane for several minutes apiece were hanging on the hook for more than half-an-hour. And it was happening around the same spot on every floor. Whitley took the CraneView data to the steel erector, and discovered the problem. “We figured out this was a pretty precarious position, connecting to a two story column with an open stairwell, and it was hard for the erector to get at it,” he says.
They considered working with the city to get more traffic lanes closed so they could put in an additional aerial lift, but mapping the CraneView data against the construction schedule showed the limited access would only persist to the fourth floor. So the problem resolved itself, and took some pressure off the steel erector as they ran into those small delays, says Whitley.
But the data isn’t just to identify slowdowns, adds Thompson. “It was also [serves as] a confirmation of our original plans, that we were being efficient,” he says. “We’d have lot of weekly calls [with the project team] and the message was ‘you guys are crushing it, your crane utilization is really good.'”
“I had a bit of a different relationship with CraneView with the precast we erected overnight,” says Erin Holshouser, Gilbane project manager who oversaw the precast installation. “Right away for me it was a verification in the morning to see what was done.” On the first five levels of the building—the podium section—the team saw the most intricate precast segments installed at a rate of about six pieces a night, but that accelerated to about 12 or 15 per night as they moved into the tower section of floors 5 to 11. The precast pieces along the top of the building would be tricky as well, and slow the pace of installation. “In our planning, we said you will see this,” says Holshouser. “You won’t see a steady daily piece count—it’ll be slow to start then pick up and drop down. CraneView verified that to a tee.”
Structural steel erection has topped out on the General Assembly, and work continues on precast panel installation. But Thompson is already thinking bigger for CraneView. “We can use CraneView for verification and change management, but now we can start talking about money, about ROI.,” he says. Better utilization is fewer crane hours on site, which leads to savings, he notes.
And the data collected from the CraneView stays with Gilbane, better informing the company on how it’s executing on its projects, says Jason Pelkey, Gilbane’s chief information officer. I am always a zealot for data,” he says. “CraneView is collecting an enormous amount of data, and I feel as we get it into more jobs, we will be able to feed that into our predictions and plans for future jobs.”
While improving bidding and planning practices is important, Pelkey says another real benefit of collecting and analyzing this kind of data is in defusing some of the heated arguments that can break out on jobsites. “I can have empirical data to show that this way of doing it is more efficient, so even if we agree to disagree lets try it out and look at the data tomorrow,” he says, adding that he is currently exploring bringing Versatile’s CraneView to more Gilbane projects in the future.