RENTON - A demolition project in Renton will shut down Rainier Avenue for five days during the massive Interstate 5 construction project.

Starting Friday, several lanes of the Interstate-90 interchange will be shut down for 19 days, and many fear the stretch of I-5 from Tacoma to Seattle could become a parking lot, especially during rush hour.

On Saturday, a contractor will begin tearing down an old railroad bridge over Renton's Rainier Avenue - a key alternate route for drivers trying to avoid I-5. The road will remain closed for five days until August 15th and a short detour will be set up using the streets Shattuck and Hardie. Rainier Avenue would have been a key alternate route for many drivers looking to avoid I-5.

The bridge construction is necessary to transport fuselages for the Boeing 737-900 from Wichita to the Renton Assembly plant. The 900 is too large for the present bridges.

That's understandable. Some of these bridges were built when Renton wasn't ahead of the curve, it was behind the cow.

On Shattuck Avenue, a placard calls the bridge a "four cow tunnel".

130 years after it was built, that old railroad bridge is being brought down by Scarsella Construction. But why all this work in the wake of the I-5 closure? Why will the bridge over Rainier Avenue be torn down Saturday, just as I-5 work begin?

When frustrated motorist see the contractor is doing, they may think:"It's Bob Scarsella who is screwing it up!"

But Scarsella says that's not so.

"Well, I'm not sure who's screwing it up. We're not here to screw anything up. We are here to get it done for the city and for the railroad," he said.

The potential five-day closure of Rainier Avenue is ominous. Rainier Avenue carries 44,000 cars a day.

Scarsella says he's going to see what can be done to speed up the demolition and says his goal is to finish by Monday night.

But why do it now at all?

One idea was to delay construction until all the I-5 work is done. But Renton said 'bad idea', since that would delay everything until the kids go back to school.

The state suggested around-the-clock work on Rainier Avenue over the weekend, but the Renton council again said "no."

"There were concerns expressed that the noise impact would just be too much for the neighborhood that surrounds the shopping area immediately next to the railroad bridges," said Peter Hahn of Renton Public Works.

The big question is: why was all the work scheduled for August?

The best guess for an answer: confusion.

Discussion on the Renton project began almost a year ago. It was noted then that August is considered the best month for work in a salmon-stream area.

Boeing says they were told that by the State Transportation Department. But, the state Fish and Wildlife Department told KOMO 4 News that only applies to in-river work. No one, the department says, asked for a clarification. And now it's too late. Boeing wants new bridges build by December.

For More Information:

Check our online traffic section for continuing coverage of the I-5 construction project, get your questions answered by KOMO traffic reporter Jenni Hogan, and check travel times, live cameras and more:

http://www.komotv.com/traffic