Wednesday, May 20, 2015

Three minutes of bridge lifts, seen from the bus while on the Hawthorne Bridge, heading west after work, May 20, 2010

I've decided to use larger photos today. Please let me know in a comment if they are too large for your computer, making them difficult to see or to load. I'm curious. Thanks!


Looking north at the Morrison Bridge, mid-bridge-lift, I wondered what large vessel had caused the lift and which direction was that vessel going, north which is down river, south which is up river--the Willamette River flows north. That brown shape to the right of the docked white boat with the blue trim is not what caused the bridge lift. Since the bridge is wide open, I'm guessing that the vessel is on its way to the Morrison Bridge. I took this photo at 5:20 p.m.

A bit about the Morrison Bridge: It is a bascule bridge which was completed in 1958, the third bridge at approximately the same site to carry that name.

The bridge is the largest mechanical device in Oregon. Thirty-six foot tall gears drive 940-ton counterweights located inside each of the piers. The 69 ft. clearance is sufficient for most river traffic, requiring bridge openings only about 30 times a month. It currently carries 50,000 vehicles daily in six lanes. The canted windows of the control towers give the distinctive look of air traffic control towers. The current bridge does not connect to Morrison Street at its west end because the second bridge was left in operation while the latest version was built.

Believe it or not, I've been on a tour of the Morrison Bridge which included walking down the steps inside the west-most pier and seeing those 36 foot tall gears and hearing the sound made by the movement of them and the 940-ton counterweights as the bridge is opened. Totally amazing experience!

By the way, the black, double-decker bridge north of the Morrison Bridge, partially visible in this photo, is the Steel Bridge (1912). Between it and the Morrison Bridge is the Burnside Bridge (1926), not very discernible at this perspective. Look closely along the square-shaped trusses which are a lighter brown color and around the height of those trees--they are part of the Burnside Bridge.

I can't tell from this angle if the Burnside Bridge has started to open, but from the traffic I can make out on it, I don't think it's opening yet. Maybe it won't have to, it all depends on the height of the vessel on the river--the bridge clearance when closed is 64 feet. A bit about the Burnside Bridge: The Burnside Bridge is a 1926-built bascule bridge. The lifting is normally controlled by the Hawthorne Bridge operator, but an operator staffs the west tower during high river levels. This bridge is part of my daily work commute, both morning and afternoon.

All of the black trusses and bridge decks belong to the Steel Bridge. A bit about the Steel Bridge: It is a through truss, double-deck vertical-lift bridge. Its lower deck carries railroad and bicycle/pedestrian traffic, while the upper deck carries road traffic (on the Pacific Highway West No. 1W, former Oregon Route 99W) and light rail (MAX), making the bridge one of the most multimodal in the world. It is the only double-deck bridge with independent lifts in the world and the second oldest vertical-lift bridge in North America, after the nearby Hawthorne Bridge. The bridge links the Rose Quarter and Lloyd District in the east to Old Town Chinatown neighborhood in the west.


My next thing to wonder about, how long would the bridge lift last for the Hawthorne Bridge (1910). It all depended upon the direction of the vessel--maybe whatever it was had already cleared the Hawthorne Bridge, no matter the direction it was moving. I took this photo looking through the bus windshield. Notice that dark-colored section of the bridge with the rust-colored handrail. There's one pedestrian walking east; those other folks are waiting to continue their westbound walk or bicycle ride.

A bit about the Hawthorne Bridge: It is the oldest operating vertical lift bridge in the United States. The 1,383-foot long Hawthorne Bridge is one of Portland’s busiest bridges, safely carrying approximately 30,000 vehicles and untold pedestrians and cyclists across the Willamette River. Vertical clearance for river traffic is limited and approximately 200 openings per month are required for this vertical lift bridge.

Like other vertical lift bridges, the Hawthorne Bridge uses a system of counterweights and cables to move the lift span straight up and down. The operating system is mostly original, but the electrical power and control systems—which were installed in 1975—were upgraded in 1999. Hawthorne’s counterweights each weigh 450 tons and are supported by the bridge’s two towers, which rise 165 feet above the bridge deck. The Hawthorne Bridge’s main span can be raised 110 feet to allow vessels to pass underneath. On average, an opening of the Hawthorne Bridge is 8 minutes long.


Looks like it's a tugboat causing these bridge lifts. Some of the letters are blocked by the bridge handrail, but I believe that I can read the name as Heidi L. Brusco. That's my best guess, and I did find that a towing vessel of that name has Seattle as its home port. As of right now, it's heading east on the Columbia River, bound for Cathlamet, Washington.


A few more folks have gathered to wait out the bridge lift. There's a curious person in the pickup truck in front of the bus.


Can you tell that the lifted bridge section has moved down quite a bit from the earlier photos? And even more commuters wait patiently. I took this photo at 5:23 p.m.Not too many minutes later, the bridge lift completed, we continued our westbound ride across the Willamette River.


William Kendall said...

It's quite an impressive bridge. The pics are fine on my computer, though by default anytime I open a link, the link goes to 125% and I have to shrink it down to 100%.

Randy said...

Amazing shots. Makes me really want to visit. said...

I moved to Portland Oregon in December 2014. I really enjoy your daily postings and find them educational as well.