Exploring Our Industrial Heritage – The Hoover Dam (Part III)
(Continue reading from Part II)
The logistical requirements involved with the construction of the Hoover Dam were intense and the fact that the Hoover Dam supply team pulled-it-off at such a grand scale was pretty dam impressive! Not only did the team deliver massive quantities of materials to the dam site on-time to support the construction of the largest project of its time, they designed that supply chain to deliver project completion two-and-a-half years ahead of schedule!
The Concrete Production Plants
How were they able to get 4.5 million cubic yards of concrete to the construction site? Well, amazingly, they built three on-site plants to support concrete production.
The first plant was an aggregate plant only a few miles away. At this plant they received in railcars of sand and pebbles from a nearby dry creek bed in Arizona. At this aggregate plant, they separated the raw sand and cleaned and sorted stones by size. The aggregate and sand from this plant was then sent to the dam site concrete mixing plants by railcar. The aggregate which was processed at this plant represents 75% of the total mass of the Hoover Dam.
Additional to the aggregate plant, two concrete mixing plants were built specifically to support the Hoover Dam project. These plants were built at the bottom of the canyon and on the Nevada rim. The two plants were the largest and most sophisticated concrete production systems at the time. After mixing, nine crane-like cable systems delivered the concrete to the dam construction site and dumped the concrete into the forms. The total production from these plants equaled over 4.5 million cubic yards of concrete. This is enough concrete to make a 4 foot wide sidewalk around earth's entire equator!
The Steel Fabrication Plant
How did they deliver 4 miles of 30 foot diameter penstock to the dam site? Well, they didn't need to have it deliver it to far because they built a steel fabrication plant on the construction site. Imagine that! Instead of having materials delivered from afar, they built an entire factory on-site!
This steel fabrication plant was erected for the sole purpose of making large penstocks. Many of the penstocks were a full 30 foot in diameter. You see these penstocks (or pipe sections) were way to large to be transported over road or rail. So instead of being fabricated elsewhere, their only option was to ship thick steel plates from the east and complete the fabrication nearer to the dam. This required that they build a full fabrication plant on-site. All-in-all the hydro-power required 4 miles of piping.
This plant contained welding capabilities, giant lathes, planers and forming machines. Penstock sections weighed 150 tons or more. High-capacity trolleys and a crane system were used to place the penstocks sections into place. Then they could be joined together by workers who were assigned to work in the tunnels.
Building the Hydro-Electric Plant
The power generators weigh over 2000 tons each and there are 17 of these at the Hoover Dam. Each power station generates 95000 kilowatts per station. Each power station came on-line at different times. The timing of when a generator needed to be installed depended on the speed and growth of the westward expansion. Whenever more power was needed, more capacity was added to the Hoover Dam power plant. However, regardless of the timing, the logistically challenges remained.
Suppliers and machine shops across the US needed to support part fabrication and this was no small task! Remember, just one station requires 2000 tons of machined and fabricated parts. Once produced at various US plants, the parts had to be shipped to the Hoover Dam. This was done by using 60 full railcars. Once delivered the generators were assembled section by section and rigged into place.
Hoover Dam Logistics Summary
If you have ever worked in a supply chain, then you know some of the challenges that can occur. The more complex a supply chain is, the more frequent a system breakdown. It only takes one small component part to be delivered late and it can throw a monkey-wrench into the timing of a critical project. So the more complexity, the more supply chain challenges.
Considering the scale and complexity of the Hoover Dam, even by today's standards, it's no joke. Imagine again that supply chain leaders had no computers or MRP systems to use. They didn't even have formal lean principles and Kanbans to help them. Instead, they used long form math, determination and shear willpower to muscle through sourcing strategies and supply issues.
As you look at pictures of the Hoover Dam, it is easy to take all of the details for granted. We might say, "Wow, look at that dam, it is impressive!" And this is surely true. But when we really understanding the details and the history of the build, it adds a whole new level of Wowness!
(to be continued on 8/6...)
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