“What you gonna do when you get out of jail?…” part 346

Today’s videos go out to FotB Andrew, because.

“The Original Mackinac Bridge Story”, about the history and construction of the bridge.

Opened in 1957, the 26,372-foot-long (4.995 mi; 8.038 km) bridge (familiarly known as “Big Mac” and “Mighty Mac”) is the world’s 24th-longest main span and the longest suspension bridge between anchorages in the Western Hemisphere.

Bonus #1: because one bridge documentary isn’t enough. “Building the Mighty Mac”. This one is a little better quality, I believe.

To the best of my recollection, I have never been on the Mackinac Bridge. I wouldn’t mind making that drive someday, but the last time I was in Michigan, I wasn’t anywhere near the bridge.

Bonus #2: “Challenge at Glen Canyon”. Back in 1983, the Glen Canyon Dam had a problem. There’d been a heavier than expected snowfall that winter, which in turn led to more runoff as the snow melted. This in turn required the dam operators to open the spillways.

At the beginning of June, dam operators opened the gates on the left spillway, sending 10,000 cubic feet per second (280 m3/s), less than one-tenth of capacity, down the tunnel into the river below. After a few days, the entire dam suddenly began to shake violently. The spillway was closed down for inspections and workers discovered that the flow of water was causing cavitation – the explosive collapse of vacuum pockets in water moving at high speed – which was damaging the concrete lining and eroding the rock spillway tunnels from the upper ends of the diversion tunnels, which connect to the bottom of the reservoir. This was rapidly being destroyed by the cavitation and it was feared that a connection would be made to the bottom of Lake Powell, compromising the dam’s foundation and causing the dam to fail.

While some people might have enjoyed seeing the dam fail, it would have caused a lot of problems downstream. So the U.S. Bureau of Reclamation had to fix the spillway issue. But how?

2 Responses to ““What you gonna do when you get out of jail?…” part 346”

  1. tim kies says:

    When I was in high school, my parents were friends with a family who owned a resort in Michigan’s UP. We would spend weekends up there, several times a summer, fishing and swimming, and just hanging out.
    One of the friends from up there was a guy who at one time made his living painting the Mighty Mac Bridge. Walking the huge cables up and down. Of course, you never finish, you just start over.
    His name was Mike, and my dad’s friend, and Mike, my Dad and one of my older brothers took a big boat that they had, and went out on Lake Michigan, where Mike and my dads friend went scuba diving. My dad’s friend, Dave, was a pilot, and would fly about, finding old wrecked boats, and then scuba dive and pick over things like knobs and boards, to make tables, etc.
    Coming back, the weather had turned bad, my dad and brother were not too nervous, until Dave asked Mike to take over driving their boat, due to the horrible wave conditions.
    It is amazing when you get above the bridge, just how different the people are. Much like going down south, where the pace of life is slower.
    We also used to go to dumps at night, with bags of marshmallows, to feed the black bears that would come in to feed at dusk. Some people tried to get the bears too close to their cars, and ended up learning just how much damage a 150 pound black bear could do, with it’s tremendous strength and claws. Tearing the paint off down to almost cutting through the metal, prying off your side mirror, and just generally making a mess of things.
    They have shut down the dumps, long age, to chase the bears away from human contact, they were getting too tame, and a tame bear is a dead bear.

  2. The Real Kurt says:

    I’ve crossed the bridge 4 or 5 times, but not in the past 30 years.

    It was pretty awesome each time.

    Gad, I’m old…

    Kurt