A Huge Dam Challenge Apr 26, 2009
Completed in 1935, at 221 meters high and 379 meters across the top, the Hoover dam stands tall as an engineering marvel high above the Colorado river.
Building of the Dam took the brilliance of more than 200 engineers to pull off what many deemed as almost impossible. And it was the fortitude of more than 7000 dam workers that endured amazingly harsh conditions and extreme dangers from 1931 through to 1935 to complete the project almost two years ahead of schedule.
Imagine a 1.2 metre wide sidewalk around Earth at its equator. That’s how much concrete it took to complete the dam. The volume alone is impressive. Even more impressive is the fact that it would have taken around 100 years for that amount of concrete to cool and properly cure without engineering intervention.
The chemical heat generated by concrete setting was dissipated by embedding nearly 1000km of 25mm steel pipe through the interconnecting concrete blocks that circulated ice water. The onsite ammonia refrigeration plant that cooled the water was capable of creating a gigantic 450kg ice block every day.
Another equally innovative approach to an almost incomprehensible challenge was that before actual Hoover Dam construction could begin, the Colorado River had to be temporarily diverted around the dam construction site. At that time there were no roads into Black Canyon, so initially, dam workers and equipment had to be brought by boat. Over time, roads were built and catwalks were stretched across the river.
Carving the diversion tunnels was a slow,tedious process that exposed dam workers to immense danger from blasting, falling rocks and diesel gas fumes spewed by the trucks that carried out blasting debris. Compressed air was circulated into the tunnels through large pipes. However, despite the difficulties, the tunnels would be completed almost a year early.
The conditions were harsh on this difficult and daunting project, with 96 industrial fatalities during the dam’s construction. Many have speculated over whether bodies are buried in the dam. But given that the dam was built in interlocking blocks to which concrete was delivered in buckets (increasing the height of the block by no more than 15cm at a time), and with men called “puddlers” tromping around on the inside of the block between each layer to pack it down, we’ll leave it to you to decide whether it’s true (could you lose a body in 15cm of concrete?) or merely a “dam rumour”.