Do-It-Yourself Plans For A Vertical Lift Draw Bridge

Thread Starter

Glenn Holland

Joined Dec 26, 2014
705
If you're retired, getting bored, and looking for an exciting year long project, try building your own vertical lift draw bridge.

CalTrans has posted the history of the former Commodore Schuyler Heim Bridge in Los Angeles Harbor along with a complete set of plans for its construction:

http://www.dot.ca.gov/d7/projects/docs/47/mitigation.php

Here are the actual engineering drawings and you'll need need to put in a $100 Million order from Home Depot. However, to save lots of time and money, I strongly suggest you go for just a scale model (like one that will fit in your den or family room). :)

http://www.dot.ca.gov/d7/projects/docs/47/As-Built Drawings PDFs.pdf
 

Reloadron

Joined Jan 15, 2015
6,137
Cleveland, Ohio with the Cuyahoga River winding through it has no shortage of bridges, many dating back to the 1800s which were engineering marvels of their day. Draw bridges, swing bridges and even bridges to bridge bridges we have them all. If anyone remembers the beginning of the Drew Carey TV show it showed some nice bridges. So here is some humor.

A classic historical bridge, while small is the Cleveland, West Third Street bridge. Built during 1939 to 1940 as part of the Cuyahoga River Streamlining Project. A lift bridge using counter weights and huge cables.

West 3 street bridge.png

Over the years the bridge had several "face lifts" and mechanical closures but this was a classic SNAFU;
"But the bridge had problems soon after its renovation. In 2005, the bridge towers were stripped of their paint in preparation to be fully painted, but Walsh only sandblasted and primed the towers because workers had to replace a concrete floor and girders at the top of each tower. On March 6, 2006, it was discovered that the lift cables were three feet too short, so the bridge could not be lowered to its lower position. The bridge opening on December 29 was delayed while awaiting installation of safety gates at each end of the span. It was then announced that the bridge would be closed on April 19 for 60 days for painting". :)

Ron
 

Thread Starter

Glenn Holland

Joined Dec 26, 2014
705
The bridges in the last two posts use winding drums mounted on the center of the truss to provide the lifting force and the counterweights have their own set of cables that run on idler sheaves at the top of each tower.

However the Schuyler Heim bridge uses "synchronized traction" in which the cable sheaves in each tower are driven by essentially huge clock motors that turn in opposite directions in order to keep the bridge level. I believe the video shows the operator's console with two dials that indicate the exact angular position of the sheaves.
 

nsaspook

Joined Aug 27, 2009
8,786
The bridges in the last two posts use winding drums mounted on the center of the truss to provide the lifting force and the counterweights have their own set of cables that run on idler sheaves at the top of each tower.

However the Schuyler Heim bridge uses "synchronized traction" in which the cable sheaves in each tower are driven by essentially huge clock motors that turn in opposite directions in order to keep the bridge level. I believe the video shows the operator's console with two dials that indicate the exact angular position of the sheaves.
Here you can see the counterweights moving during a steel bridge lift.

I-5 dual bridge lift.

Portland Hawthorn Bridge
 

Reloadron

Joined Jan 15, 2015
6,137
The bridges in the last two posts use winding drums mounted on the center of the truss to provide the lifting force and the counterweights have their own set of cables that run on idler sheaves at the top of each tower.

However the Schuyler Heim bridge uses "synchronized traction" in which the cable sheaves in each tower are driven by essentially huge clock motors that turn in opposite directions in order to keep the bridge level. I believe the video shows the operator's console with two dials that indicate the exact angular position of the sheaves.
They say for a ME (Mechanical Engineer) to tour all of these bridges in cities like Cleveland for example is like an artist touring the Louvre Museum. :) While boring compared to bridges that move and do things as I kid I watched The Verrazano-Narrows Bridge being built, I was 14 when it was completed in 1964. When it was completed it was the longest suspension bridge in the world. Today it ranks around #14. :)

Ron
 

Thread Starter

Glenn Holland

Joined Dec 26, 2014
705
Speaking of California historic bridges, I’m sure Glenn is familiar with the 4th street bridge in San Francisco. Rebuilt in 2006 for a cost of $34 million (original cost less than $90,000 in 1915). Complete with fake fibreglass counterweight. Read all about it:

https://m.sfgate.com/bayarea/matier...et-Bridge-is-up-a-creek-It-s-over-2514989.php

Enjoy.
I worked for the city's transit agency (the Muni Railway) and my shop maintained the train control system for the subway and the 3Rd Street Light Rail line on which the 4Th Street bridge is located.

In addition to cost over runs, the expansion joints aren't large enough to tolerate a prolonged temperature above 80 degrees and the bridge won't lower to be even with the pavement (or the rails which must be exactly even). After one incident of hot weather, the bridge was raised for a boat and lowered only to get hung up about 6 inches above the street. The Port of San Francisco was called and they brought in a fire boat to spray the bridge with water from the bay until it cooled and contracted enough to lower all the way.

It was an embarrassing case of not knowing Engineering 101-A: Steel expands when it gets hot!!! :p
 
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