Special Reports

Bridge neighbors cringe at cement plant

Six years ago, when Jack and JoAnne Sipperly bought their condo next to the Tacoma Narrows Bridge, they knew the place wasn't going to be exactly pastoral.

Their living room is just a few hundred yards from the Gig Harbor end of the bridge, and the traffic noise in their front yard often exceeds 70 decibels, roughly the same as a freight train at 100 feet.

On the other hand, the Sipperlys did not expect a concrete plant to spring up next door to them, either.

Over the past two months, Tacoma Narrows Constructors, the company building the new Narrows bridge, has transformed a 1.7-acre patch of scrub trees and blackberries across the street from the Sipperlys' gated community into a concrete production facility.

With extraordinary speed, the company has assembled a massive collection of hoppers, silos and conveyor belts. Starting next month, the plant will begin producing the thousands of cubic yards of concrete needed for the bridge project.

The concrete plant is so close to the Sipperlys, you could hit it by lobbing a rock from their front porch. For Sipperly and his neighbors, the idea of tons of gravel and cement crashing around inside steel drums, clattering conveyor belts and beeping trucks is dispiriting.

"There's no way to tell yet how loud it's going to be," said Jack Sipperly, 72, shouting to be heard above the roar of traffic. "We've got so much noise now, I'm not sure a little more is going to make a whole lot of difference."

Like many close neighbors of the bridge, the Sipperlys have watched nervously over the past two months as TNC and its subcontractors resculpted hillsides and mowed down trees in preparation for the new bridge.

But to some, the cement plant is more worrisome. Their concerns increased last month when many learned for the first time that the plant will operate not only in the daytime, but also occasionally at night, for two to five years.

Rick Lynde, 79, another close neighbor, has lived in the Narrows View condominiums for 10 years. He serves on the owners' board, representing the 44 residents on issues having to do with buildings and grounds.

Lynde says traffic noise increased dramatically when TNC removed stands of trees. But he thinks the noise from the concrete plant may be worse because it will be harder to ignore.

"The noise we're going to have is not the steady roar of the freeway but occasional rushes of noise," he said, "We'll hear it when the machine kicks on, and when trucks back up, there be a lot of dinging."

Lynde said he knows two owners who decided to put their places on the market and move away. But they are the exceptions, he said. Most residents are hunkering down and steeling themselves for the long haul.

For their part, the state Department of Transportation, TNC and Glacier Northwest, the subcontractor supplying the concrete for the project, are doing their best to make the plant as quiet as possible.

"Our whole thing is, we want to be a good neighbor," said Dave Siemering, Glacier's bridge project manager.



Quiet is as quiet does

Concrete is the critical ingredient in the bridge. At each end of the new span, the giant supporting cables will be anchored to buried concrete blocks the size of warehouses. The foundations supporting the two new bridge towers will be massive concrete pillars that drop 210 feet below the water surface. And, unlike the old bridge, the new 510-foot towers themselves will be made of reinforced concrete, which designers say is cheaper and stronger than steel alone.

When the new highway interchanges are included, the bridge project will use between 170,000 and 190,000 cubic yards of concrete, enough to lay down a 30-foot-wide highway from Tacoma to Seattle.

With that amount of concrete, putting the plant as close as possible to the construction site was "just flat efficiency," Siemering said.

From the new plant, trucks will have to haul the mixed concrete less than a quarter-mile along Stone Drive to a pumping station under the existing bridge. From there it will be pumped through a "slick line" suspended under the bridge deck and then out to the new caisson. Concrete for the Tacoma side of the bridge will be hauled across the Narrows and loaded into a similar pumping set-up there.

Aside from efficiency, there's also a timing issue, notes Ernie Mathis, TNC's quality-control manager. Construction specifications say concrete must be deposited within 90 minutes of mixing, he said, and having a shorter distance to the mixing plant will cut down on waste.

According to the manufacturer of the plant, neighbors concerned about noise are worrying too much.

"Believe it or not, there are not a lot of moving parts," said Jeff Bryan, vice president of Con-e-co, in Blair, Neb. "The noise is very minimal."

Bryan said the concrete mixer is so well-balanced it is powered by just two 75-horsepower electric motors, which are quiet compared to gas or diesel engines. The million-dollar plant, called a Lo-Pro 427, is "very aggressive," Bryan said. It is capable of turning cement, sand, aggregates and water into a finished batch of concrete in just 12 revolutions of the drum, he said, a process that takes about 60 seconds. The ingredients are mixed wet and don't fall very far, he added. "It's just sliding action. Noise is not usually an issue," he said.

Even so, TNC is installing 15-foot noise walls around portions of the plant to reduce the pain to neighbors, and Glacier has taken a number of other steps to reduce noise at the plant. It has lined gravel bins and hoppers with sound-deadening polyurethane, put mufflers on the cement supply pumps, and arranged the facility to minimize the beeping of backing equipment.

Recognizing that the plant may be noisier than state and county codes allow, the DOT applied for a noise variance from the Tacoma/Pierce County Health Department.

Because the bridge construction is regarded as an "essential service," the DOT can make just about all the noise it wants during the daytime, said David Delong, who works in the health department's community safety program.

But at night, the rules are tougher, restricting construction noise to certain levels based on the distance from the source.

"The variance has several aspects to it," Delong said. "They (DOT managers) were asked to put together a nighttime noise operations and communications plan. They're supposed to outline several different things they will be doing, including establishing a noise baseline and monitoring and a complaint response procedure."

The DOT promises that staff members will be on the site with noise monitors during nighttime work. They have also blanketed affected neighborhoods with informational mailings, held community meetings and established a 24-hour "hot line" (253-620-4440).

Lynde says he doesn't think many of his neighbors will complain.

"People are concerned, but resigned," he said. "I don't think anybody has suggested we ought to do anything about it. It's inevitable. I think there's a general feeling of, 'Let's just get it over with.'"

Sipperly agrees. "There's not a damn thing we can do about it, anyway," he said. "That's the bottom line."

Rob Carson: 253-597-8693

rob.carson@mail.tribnet.com

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