Sunday, October 30, 2011

Portfolio Update 2011

Imagine this: on average, over 110,000 cars and trucks cross the Fremont Bridge each day. Multiply that by 365 and that's a lot of annual traffic! Now consider this: the Fremont opened in 1973 with the original upper deck shouldering that load for the last 38 years -- is it any wonder that it needed to be resurfaced?
Stretching 175 feet above the Willamette River, the Fremont Bridge is a vital link for Interstate 405 which encircles downtown Portland, OR. I-405 is a heavily traveled loop that helps to ease congestion in and around the city center so construction activities affecting it must be scheduled to minimize the impact to motorists while ensuring the safety of the public and work crew. The Fremont upper deck paving project required full closures for 3 weekends (from 11 p.m. Friday to 5 a.m. Monday) and one weekend of partial closure -- it wasn't your average paving project!
The Fremont Bridge has an epoxy asphalt concrete surface -- it's the only bridge in Oregon with this type of pavement. After the project is finished, the upper deck will consist of 3 layers: a 1/2-inch-thick steel deck plate, 2 1/2 -inches of epoxy asphalt concrete, and 1 1/2-inches of conventional hot mix asphalt concrete. In total, more than 3,000 tons of epoxy asphalt and hot mix materials will be placed at a rate of 50 to 75 tons per hour. It's a time consuming and time sensitive process - and a demanding and interesting assignment to document too - so that's why I decided to present this photo essay as my Oregon Department of Transportation (ODOT) Portfolio Update for 2011.

Before the paving process can begin, all the old road surface must be removed. Chipping, grinding, scraping, tearing . . . all techniques need to be used to clear the bridge deck to bare steel. The hardest part had to be cleaning the big bolt heads . . . and there were about 56,000 of them!

Next, the deck is polished and primed by shot-blasting, or the rapid-fire bombardment of tiny steel shot against the deck surface to clean and rough it so materials will better adhere to it. Then the first epoxy bond coat is sprayed on the deck to coat the steel and prime it for the first lift of epoxy asphalt.

Two lifts of epoxy asphalt concrete were applied, the semi-permanent 2 1/2-inch-layer and the 1 1/2-inch-pavement protection layer which can be more easily maintained. And so the project flowed, from shoulder to shoulder, grinding, blasting, spraying, paving, rolling, spraying, paving, and rolling.

In the bitter evening cold (it really was!) and the debilitating midday heat, during shifts that lasted all day (and I mean 24 hours!) with sporadic meals and spotty sleep, I gained a new appreciation for our roadways and the people it takes to maintain them. So hats off to Kerr Contractors and their crew and all the others for a job well done -- I enjoyed working with you!

Special Bonus Feature
My good friend and ODOT videographer John Kazmierski covered this job from a unique perspective: on top of the arch of the Fremont Bridge! You can see his amazing time lapse video of the entire Fremont Bridge Paving Project here:
As Newsphotography:Exposed enters its 6th year of publication (I can't believe it's been 5 years already!), I want to thank you for your interest and support, but most of all, thanks for visiting!