May 9, 2008

Today’s cutting-edge construction technology will become tomorrow’s essential technology

Construction Corner

Korky Koroluk

When you have 3,200 precast structural elements to be manufactured, transported and installed, and no lay-down yard in which to store them until needed, you’d better be able to keep track of them.

It’s not the sort of job an average contractor will ever undertake, but even on a smaller scale, contractors need to be able to keep track of the pieces of the jigsaw puzzle they’re building until they can be put in place.

Skanska USA Building Inc., the American arm of the Swedish-based international giant, is the design-builder leading construction of a new stadium being built in New Jersey’s Meadowlands area as a home for both the New York Giants and New York Jets of the National Football League.

Faced with the complexity of the billion-dollar project, plus a tight timeline that means having the project done and ready for the start of the 2010 NFL season, Skanska elected to use RFIDs, radio frequency identification tags, to keep track of things.

The elements are precast risers that will form the bowl of the stadium. Although sizes and shapes vary somewhat, they average about 44 feet by 10 feet and weigh about 45,000 pounds. As they are placed within the stadium’s structural frame they become seating risers.

Because the shapes vary somewhat, it’s not possible to substitute another riser if the one you want isn’t available.

The risers are being cast at four plants, all within four hours of the construction site. Each is tagged with a $2 RFID tag at that point, and the tag is read by a pen-sized reader at every stage from then on — from inspection and loading on to a truck to final placement.

Because there is no space to hold them on site, a just-in-time delivery system is used, which means for everything to go smoothly, every next-in-line piece must arrive in the right order, and roll under the hook right on cue.

Sounds somewhat complex when you’re doing it once. But it sounds even more complex when you realize that it has to happen 3,200 times, which is the problem Skanska had to deal with.

But there is a payoff. The company figures that it will gain at least 10 days on the schedule. The savings are expected to total about US$1 million.

This is obviously a system that’s only for the big players in the industry. While there was some off-the-shelf software used, there were also custom-written programs, and weeks of collaborative work.

The result is a system that uses RFIDs to capture tag numbers on individual pieces as they move from manufacture to placement, while at the same time creating a four-dimensional structural design and construction sequence model. The old method was a system of spreadsheets and colour-coded drawings which worked, but was slower and couldn’t provide the sequence modelling — the fourth dimension of time.

Consequently, several companies and products were brought into the design of the new system, which combines elements from Architectural Desktop and Navisworks from Autodesk, Primavera System’s P3 scheduling software, and supply-chain databases bringing together software from Vela Systems and Tekla Inc. The idea for all that came from another RFID-based management system Skanska developed for one of its projects in Finland.

Clearly, this is a one-off system that is far, far beyond the reach of the local contractor whose annual work might consist of three or four jobs totalling maybe $50 million. But it’s clear that the use of RFIDs in construction is one of the ways of the future.

As kinks are worked out, as software developers begin producing fully commercial products instead of prototypes that only the big firms can afford, we’ll find ever-smaller firms able to take advantage of the productivity gains things like RFID technology offer —gains we can’t afford to ignore.

Korky Koroluk is an Ottawa-based freelance writer. Send comments to editor@dailycommercialnews.com.

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