Zelada: Bridges of the World, Zelada: Bridge Anatomy, A. J. Zelada, Morrison Birdge Portland Oregon

Welcome to Morrison Bridge in Portland, OR

Signing Waivers and Behavior agreements while on the property of Multnomah County. Below walking up the Esplanade to the bridge towers. We were briefed in the chain of command for disasters, the safety backups, the laws of the river versus the rules of the roads, and the grand view.

This page shows the shoulder of the Morrison Bridge in Portland Oregon. The bridge sits about 65 feet above the Willamette River and lifts its 4 million pound ramps with an electric motor and gear system. This simple design must have its origin with Leonardo DaVinci. Its simplicity is remarkable; it is silent as it lifts these ramparts to allow river traffic pass under this bridge.

 

The shoulder mechanics of lifting it arms up to the sky are in dark shrouds unseen by moving cars, bicycles and pedestrians above or by ships passing below the gears. The lighting is conflicting fluorescent greens and evening light blues and sunset reds. The garishness of the images is revealing of the form of metals. The images are small and speak of the visual magnitude similar to five blind humans describing a mammoth. I could find no corner to see the entire leveraged ramp.

 

Left & Below: light weight cement poured in the grating and awaiting the new polymer road surface.

Left: teeth with its precision

orthodonture of two ramps.

Below: the metal sinews and struts forming the erector set bones of the ramps.

This makes my shoulder hurt: the whole bridge ramp is turned by these two toothed gears.

We were less than 20 feet from these interlocked teeth moving very silently. No groaning. How jealous I am as putting 4 plates on the top kitchen shelf makes me groan 8 times as loud as this powered armature reaching its arms to the sky.

Bolts are frozen for insertion into the holes.

A special thanks to both

John Henderson and Mike Pullen both men of

great knowledge & passion

about our

Multnomah County bridges.

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