Questions Abound Over Bridge Sinking -- Access Holes, Waste Water Left In Pontoons Criticized

CUTLINE: MIKE SIEGEL / SEATTLE TIMES: INSPECTOR PAM HARRIS CHECKS OUT HATCHES IN THIS PHOTO TAKEN IN AUGUST. THE HATCHES WERE INTENDED TO COVER HOLES CUT IN THE PONTOONS OF THE OLD I-90 BRIDGE, BUT THEY WERE NEVER INSTALLED.

Marine engineers say that virtually the only way to sink a floating bridge is to fill its pontoons with water.

So why was the old I-90 bridge left untended with a series of 6-foot-high holes cut in its side Saturday night, immediately after one of the heaviest single-day rainfalls in Seattle history? And why has water, which was routinely flushed off the bridge deck into the pontoons, been left to sit there until the bridge contractor was ordered to pump it out?

``It seems absurd,'' Ron Anderson, the Department of Transportation's Seattle-area administrator, said yesterday.

Neither Anderson nor anyone else knew precisely why the bridge collapsed in the relative calm of Sunday morning after a week of high winds and rains. Besides that, Army Corps of Engineers spokesman Dave Harris says the lake is at its lowest level in the winter to prevent wave damage from winter storms. The lake is controlled by a dam at the Hiram Chittenden locks. On Saturday night, Harris says, the level of the lake was, for the most part, controlled by letting water out of the dam.

Speculation and accusations yesterday focused on the cutouts that served as access hatches in the side of the bridge's pontoons and on the conduct of Traylor Bros. Inc., the Indiana-based construction company hired this year to renovate the bridge.

The bridge broke apart and sank as workers tried frantically to pump water out of its pontoons, which are essentially concrete boxes, hollow but for a web of walls within. Pontoons in the center of the bridge had been nearly dry when inspected by DOT engineers at 4 p.m. Saturday. The same pontoons were nearly submerged when the engineers arrived for work at 8 a.m. Sunday.

Where the water came from is a mystery. Only .03 of an inch of rain had fallen in the meantime, and winds were generally too light to cause high waves on the lake.

Not satisfied with the answers they found above the water yesterday, DOT officials planned to send divers down today searching for the cause of the collapse of the 50-year-old structure, which had been closed to traffic since last summer for a $35.6 million renovation.

Robert Sheppard, the DOT's project engineer, said divers would try to determine if the bridge structure had somehow broken before the pontoons filled with water. Other engineers doubted this possibility.

``If it sank, it got water in it. It's that simple,'' said another marine engineer not associated with the project.

Even Sheppard said the search for clues at the bottom of Lake Washington was a long shot.

``We don't understand how the water did it, so we're looking elsewhere. It's a process of elimination,'' he said.

State officials and records indicate that accumulating water in the pontoons has been a problem since Traylor Bros. began the renovation earlier this year.

Traylor routinely allowed water to accumulate in the pontoons beyond what were considered safe levels and had to be told to pump the water out by DOT inspectors. On at least one recent occasion, failure to pump the pontoons prompted the state to issue a stop-work order to Traylor until the water was removed. The company had been threatened with similar actions on several previous occasions, state engineers said.

Disputes between construction contractors and project owners are common. Most have to do with whether work was specified in the contract and who has to pay for work that was not.

As a prominent Seattle architect said recently: ``Construction is largely a matter of deciding who to blame.''

It is unusual, however, for such disputes to go to the point of a stop-work order, because neither side - contractor or owner - wants to delay a project.

As in this case, the contractor typically bids a lump sum, fixed price for the entire contract, and delays are costly. The owner is typically in a hurry to finish the project. Often, the owner will haggle about money and responsibility throughout a project but will seldom bring it to a halt.

According to correspondence between Traylor and the DOT, the company has resisted some state requirements for the pontoons because the company regards them as beyond the scope of the original contract. Specifically, the company objects to the way it has been required to dispose of water used to blast the old concrete roadway and sidewalks off the bridge.

State Department of Ecology officials have stipulated that all water used in the hydro-blasting operation be piped onto the bridge, rather than taken from the lake, and then piped off again. Traylor officials have argued in letters to the state that they originally intended to pump water out of the lake for hydro-blasting, use it, filter it, then let it drain back into the lake.

The DOE objected, saying the water would contaminate the lake with concrete dust and particles. Traylor was required to let the water drain into the pontoons, allow the concrete materials to settle out, then pump the water out to Metro sewer lines onshore.

Traylor has dragged its feet on emptying the pontoons the entire way, according to regular DOT inspection reports. A small depth of water - about 18 inches - inside the 10-foot high pontoons is considered harmless, but Traylor frequently exceeded this by one to several feet, inspection reports show.

Traylor officials declined to comment yesterday, and state officials refused to blame the company for sinking the bridge.

Others were not so slow to assess blame.

``The state of Washington is giving floating bridges a bad name,'' said Billy Hartz, a University of Washington civil-engineering professor. ``As soon as water gets in one point of a floating structure, it can destabilize the structure. They still don't fully appreciate that. Everything should have been watertight.''

Anderson of the Transportation Department said state investigators do not know yet what caused the pontoons to start filling with water.

``We are just starting in on our investigation. We want to keep good relations with the contractor. We don't want to start pointing fingers yet,'' Anderson said.

``When they left it Saturday night, it was floating and everything was fine. On Sunday morning at around 8 a.m., the center span was within one foot of being topped by the lake,'' he said. ``That means that those open hatches were under water, and that they were taking on water.''

Anderson said that, when the center span sank low enough to allow water in through the open hatchways, the bridge was doomed. The center span went down and dragged the others with it until they, too, sank one by one. Some of the pontoons broke in half on their way down, he said.

He said that, as far as he knew, the bridge pontoons were in the same condition last weekend that they had been in for months. That includes the fact that the hatches were open on the side of the bridge, and that various pontoons had been opened from above by the hydro-blasting.

``We've gone through some pretty severe weather over that period of time,'' he said. ``October had near-record rainfall.''

Anderson said he doubts that the pontoons were flooded by any rapid rise of the lake level that might have been caused by the flooding rivers and streams on Saturday night. He says the anchor cables are splayed out from the bridge at such a gradual angle, down to the bottom of the lake, that they won't prevent the bridge from rising with the water.

Anderson said the openings in the side of the bridge were supposed to be covered with doors at some point, but he doesn't know when that was supposed to be done.

``We are supposed to have watertight doors. Obviously it didn't happen,'' he said.

Once investigators are able to determine how water entered the pontoons, they will then have to figure how it was able to spread within them. The pontoons' interiors are cross-hatched with reinforced concrete walls that are supposed to be sealed with watertight doors.

The idea behind the watertight doors is to prevent a single open hatch from letting in enough water to fill an entire pontoon.

The doors have also been a source of contention between Traylor and the Department of Transportation. The design of the door seals was altered after the project began and the state began requiring the presence of an inspector when doors are installed. The DOT has complained that Traylor frequently has far too many doorways opened, waiting for installation. Traylor has complained that waiting for inspectors has forced it to reschedule work.

-- Times staff reporters Carlton Smith and Eric Nalder contributed to this report.

Bridge disasters

-- The Tacoma Narrows bridge, ``Galloping Gertie'': Nov. 7, 1940; windstorm causes the suspension bridge to twist, undulate, break apart and fall into the water. A newly designed bridge was opened Oct. 14, 1950.

-- Hood Canal Floating Bridge: Feb. 13, 1979; windstorm breaks up and sinks the span. Rebuilt at a cost of $130 million, it reopened Oct. 24, 1982.

-- West Seattle Bridge: June 11, 1978; a freighter damaged the north lift span, limiting vehicle traffic to the two-lane south span until the new high $150 million, six-lane West Seattle Bridge opened July 7, 1984.

-- Evergreen Point Floating Bridge: Dec. 22, 1989; a 44-year-old Seattle woman was killed when the midspan section accidentally raised during a mechanical test.