Technology At Work / A Periodic Series -- Hard Hats Set Sites On High Technology

It wasn't that long ago that crews at major construction sites used steel chains and tape measures to calculate distances.

"In cold weather (the steel chain) would shrink, and in hot weather expand, so you'd have to deduct or add depending on the temperature," recounts Bruce Church, a carpenter for 25 years.

No more imprecision.

Church and others working at the downtown block opposite the old Frederick & Nelson building have found an answer to doing the job right and doing it right the first time: technology. Now crews use electronics and light, with computer-based calculations, to get measurements about as precise as you could reasonably expect.

Amid the dusty air and rumble of earth movers at the site of what will become the Pacific Place building, technology is redefining how construction managers and workers do their jobs.

From using survey instruments that measure distances and angles electronically to sophisticated software that produces three-dimensional topographical maps, the construction industry worldwide has turned to high-tech gizmos to improve accuracy, boost communications and, most important, save time and money.

In the process, the job of workers - those who set columns, put hubs in the ground and mark off measurements to ensure that everything from duct work to utility lines fits together - has become easier and more exact.

"It's all about problem-solving," says Chris Heger, techno guru for Sellen Construction, the general contractor building the $175 million, five-story project with Lease Crutcher Lewis, directly east of what will be Nordstrom's new flagship store.

Now a hole 70 feet deep, the block bordered by Sixth and Seventh avenues, Pine Street and Olive Way will transform to below-grade parking for 1,200 vehicles, above which will sit 335,000 square feet of mixed retail and entertainment businesses, including an 11-screen, 3,200-seat theater complex.

The project entails removing roughly 200,000 cubic yards of dirt, the equivalent of a truck leaving the site every two minutes, every workday, for 10 straight weeks.

The labor of moving all that earth would be more difficult if technology had not cleared the way.

Neal Jorgenson, a carpenter for 34 years, uses what workers call a "gun" - an electronic instrument that shoots infrared beams to lock in locations - to measure distances for the massive hole.

"Before we'd have to set up a transit (a surveying instrument) on the edge of a hole and get down in a hole with 100-foot tapes and do a lot of physical measuring," he explains.

With the "gun," he says, "You hardly ever have to pull a tape measure out of your pocket. The instrument does all the work for you."

Known also as "total station instruments," the blender-size guns sit on tripods and come with their own software. They use infrared light waves to read distances and angles between points and are accurate to within one-sixteenth of an inch at 1,000 feet.

They're calibrated according to fixed coordinates, starting with "survey control monuments." They're spaced throughout the state, and you've probably seen them on some city streets: round metallic plates with numbers cast into them.

The guns work in tandem with hand-held reflector targets, placed according to blueprint data fed into specially programmed calculators. The targets reflect back the gun's beam to lock in a location for digging, filling or setting columns.

Sellen figures that the six guns in use at Pacific Place will have taken 10,000 shots by the time the project is over.

Jorgenson, 53, of Lake Stevens, says the new technology has been around for years among surveying outfits but is relatively new to construction. When his employer, Sellen, introduced it about four years ago, he wondered whether he could learn how to use it.

But he managed to pick up on it, "and now I get real excited standing behind that gun."

Satellites also speed things

Roger Caddel, an engineer with the state Department of Transportation, says the state likes the devices because they're safer, too. They allow workers to get off the road quicker, making them less vulnerable to highway traffic.

Caddel gets really excited, though, talking about another technology widely used in major construction projects - the global positioning system, or GPS. He used it this month to survey sites near Yakima as part of a Department of Transportation training program. To map rights of way for a new highway, the crew used a receiver and an antenna to communicate with at least four orbiting satellites.

Shooting for accuracy within a centimeter, the GPS-equipped crew stopped at each survey point for five minutes, covering 34 square miles in 7 1/2 hours.

"Surveying with the total-station instruments and with a five-man crew would take us close to two weeks" to cover the same territory, Caddel says.

For now, the state is renting the GPS equipment for $1,500 a week (purchase price is $120,000). It allows three men to accomplish in a week what would otherwise take five men six weeks. "That is amazing," he says.

Hand-held computers in the field

Another kind of time-saving technology - software that automates the production of daily work reports - is being used by CalTrans, California's transportation department.

Yader Bermudez, senior transportation engineer with CalTrans, says his crews use hand-held computers and a program called ePeg to prepare daily electronic work "diaries" of weather conditions, worker rosters, job equipment and observations. When field engineers return to the office, the information is transferred to another computer. The easily retrievable diaries are particularly useful when the state handles disputes with contractors.

The diaries also help the state keep track of costs by maintaining a running tabulation of work performed, seeing how close progress matches estimates and making payments accordingly. California started using ePeg a couple years ago to rebuild a bridge damaged by the 1989 Bay Area earthquake.

Bermudez believes the product, which along with hardware cost about $125,000, already has paid for itself in saved time.

Internet's global reach a plus

The construction industry has also taken to the Internet, notes Norbert Young, president of New York City-based Bovis Management Systems, a part of Bovis Construction Group, manager of more than $20 billion worth of construction around the world.

With the company's global operations, Young says, the Internet's reach is perfect, allowing for near-instantaneous exchange of documents and detailed drawings across continents.

Another Internet application: For a big shopping center Bovis is building in London, crews are experimenting with a video-conferencing program. The client, in Australia, can manipulate TV-type cameras mounted at the construction site in England.

Also, Bovis crews sometimes wear a camera rig mounted on a hard hat, allowing them to walk around the site, providing pictures and spoken words over the Internet.

New `4-D' drawings

Also exciting, he says, is the advent of "four-dimensional" drawings that add a time element. Designers, engineers and architects can then electronically "build" a structure in advance - and prevent some significant problems.

For example, 4-D technology could allow builders to know at the design stage that there won't be enough room for pipe to go where intended, or that a structural beam will end up in the way of something else.

"I used to think fax was magic," Young says.

Technology at Work is a periodic series in The Seattle Times that examines how technology affects professions, businesses and institutions.

Peter Lewis's phone message number is 464-3217. The e-mail address is: plew-new@seatimes.com