Concrete Wonders - Engineering Marvels of History
Moderator: K. A. Pital
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Cycloneman
- Padawan Learner
- Posts: 155
- Joined: 2007-09-13 09:02pm
Maybe it's different on different browsers, but on mine it's your long lines of images. Try adding some spaces or something between multiple images. The biggest offender comes right after "Construction progress in photos (clickable for large panoramas):" and (not coincidentally) reaches all the way to the far right side of the page.
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K. A. Pital
- Glamorous Commie
- Posts: 20813
- Joined: 2003-02-26 11:39am
- Location: Elysium
Done! 
Should be easy to watch on 1024 monitors now (well, sans the Duchess picture - I'll ask her to resize it)
Should be easy to watch on 1024 monitors now (well, sans the Duchess picture - I'll ask her to resize it)Lì ci sono chiese, macerie, moschee e questure, lì frontiere, prezzi inaccessibile e freddure
Lì paludi, minacce, cecchini coi fucili, documenti, file notturne e clandestini
Qui incontri, lotte, passi sincronizzati, colori, capannelli non autorizzati,
Uccelli migratori, reti, informazioni, piazze di Tutti i like pazze di passioni...
...La tranquillità è importante ma la libertà è tutto!
Lì paludi, minacce, cecchini coi fucili, documenti, file notturne e clandestini
Qui incontri, lotte, passi sincronizzati, colori, capannelli non autorizzati,
Uccelli migratori, reti, informazioni, piazze di Tutti i like pazze di passioni...
...La tranquillità è importante ma la libertà è tutto!
Assalti Frontali
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starslayer
- Jedi Knight
- Posts: 731
- Joined: 2008-04-04 08:40pm
- Location: Columbus, OH
Issue #4. Hoover Dam.
The most recognizable and famous American dam, Hoover sits in Black Canyon on the border of Arizona and Nevada. It holds back the part of the Colorado River, which starts in the Rocky Mountains and flows down to northern Mexico; it has had so many dams built across it that it no longer reaches the Sea of Cortez.
The Colorado River is ~1,470 mi (~2,330 km) long, starts at ~9-10,000 ft. (~2700 m), has a ~240,000 mi2 (~629,000 km2) watershed, and has an average discharge of ~22,000 ft3/s (~620 m3/s).
The dam itself is 1244 ft. (379 m) wide, 726 ft. (221 m) tall, and 660 ft. (200 m) thick at the base, tapering to 45 ft. (15 m) across at the top.
Lake Mead, the Hoover reservoir, extends 110 mi (177 km) behind the dam and covers 157,900 acres (639 km2). It holds a volume of 28.537 million acre-feet of water (35.2 km3).
Important Statistics:
Earth moved/excavated: 5.5 million yds3 (4.2 million m3)
Earth/rock fill placed: 1 million yds3 (765 thousand m3)
Concrete poured: 4.36 million yds3 (3.3 million m3)
Metal used: 88.985 thousand tons (80.726 thousand tonnes)
Price tag: $49 million US in 1936
Power output per generator: 13 130 MW, 2 127 MW, 1 68.5 MW, 1 61.5 MW
Power output total: 2704 MW
Planning/Preliminary Work:
Hoover was born out of the Colorado River Compact, considered by seven states (California, Arizona, Utah, Colorado, New Mexico, Nevada, Wyoming) and signed in 1929 by all but Arizona, which was unhappy about the water-sharing agreements outlined in the document. Originally planned for, and called, the Boulder Canyon Dam Project, it was decided to instead build Boulder Dam, as it was still called, in steeper, narrower Black Canyon. This was done to reduce the amount of concrete and construction needed to build the dam.
Black Canyon before the dam was built.
With this done, the construction would proceed in phases: first, the four diversion tunnels would be blasted and excavated. Once these were open, the cofferdams would be built and the dam site drained. Once this was done, the dam itself, essentially one gigantic monolithic interlocking piece of concrete, would be constructed and poured. The final pieces would be the penstocks, spillways, powerhouse, etc.
As well as the dam and related construction itself, a new town, Boulder City, had to be built to house the army of workers necessary to finish the project, as well as two cement plants, a highway, and a railway line built specifically for the dam, as well as a set of power lines all the way from San Bernardino, 222 miles (355 km) away. In addition, once the sides of the canyon had been prepared, a gantry had to be constructed to get the concrete, men, and materials to the middle of the dam and out again. Once the plans had finally been drawn up and finished, construction itself could begin.
Initial construction in Black Canyon.
Initial concrete mixing plant for the dam.
Schematics and Blueprints:
Nice schematic that breaks formatting
Construction:
The first task was to build the diversion tunnels. These four tunnels would ensure that the still mighty Colorado flowed around the construction zone. Blasting began in May 1931 and was completed in November 1932. In order to make the work go faster, platform called “drilling jumbos” were constructed on the back of ten-ton trucks. These allowed an entire side of the tunnel to be worked on at once, and a total of eight were constructed. More than 1.5 million yds3 (1.14 million m3) of rock were removed to dig the tunnels.
A drilling jumbo, and lining the tunnel with concrete.
Work began on the upstream cofferdam even before the diversion tunnels were finished, in September 1932. A horseshoe-shaped dike was dug to protect it, and once the river began flowing through the Arizona side tunnels, work began to go much faster. 250,000 yds3 (191,000 m3) of earth had to be excavated to provide a good bedrock for the 98 ft. (30 m) high, 750 ft. (229 m) wide, and 450 ft. (137 m) long dam. A 6 in. (15 cm) thick concrete face was put on the upstream side laid over a 3 ft. (~1 m) layer of rock. The downstream side had a thick rock fill covering.
The drained construction site and the lower cofferdam.
The downstream cofferdam was a compacted earth fill dam 66 ft. (20 m) high, 350 ft. (107 m) long and 550 ft. (168 m) thick at the base. A thick rock fill was put on the downstream side. All tolled, it contained about 300,000 yds3 (230,000 m3) of material. To protect the lower dam, a large rock barrier was built 350 ft. downstream to cut off backflow from the diversion tunnels. This was 54 ft. (17 m) high, 375 ft. (114 m) long and 200 ft. (61 m) thick at the base. All this was completed before the spring of 1933, and the dams held against the spring floods.
While the upper dam was being constructed, the cliffs were high-scaled. The men who had this job, obviously, were called the high-scalers. This was the most dangerous job of the entire project. These men would rope up using simple harnesses and then descend the steep canyon walls with jackhammers and dynamite. Their job was to smooth out the cliff walls and prepare it for the mass of concrete that would fill the canyon. This work had to be completed before the lower cofferdam could be constructed.
Finally, the main dam could be constructed; the first concrete was poured in June 1933. This was done using forms of varying size from 25 by 25 ft. (8 by 8 m) to 25 by 60 ft. (8 by 20 m). The forms rose just five feet at a time, and ice-cold water had to pumped through a series of pipes laid out in the forms to prevent the concrete from cracking as it dried, heated up, and then cooled. Once the concrete in a form had completely dried and cooled off, the pipes were sealed and pressure grouted. The interlocking vertical joints on each form were also grouted as the dam grew. Slowly the dam began to rise at a regular pace, and the last concrete was poured in the main dam in May 1935; Lake Mead had begun to fill in February.
All that was left was to construct the spillways, intake towers, penstocks, and powerhouse. These were all completed by March 1, 1936, when the dam opened for business two years ahead of schedule.
The intake towers.
The powerhouse under construction.
The generators and shaft gallery.
Spillways.
Upstream face, almost finished.
Transformers outside the powerhouse.
Trivia/other stuff:
So much concrete was poured at Hoover Dam that if it had been poured as one giant block, it would have taken 125 years for it to cool down to ambient temperature; it would have cracked and crumbled to uselessness along the way. Poured the way it is, the concrete at the center of the dam is still curing.
96 people died during construction, mostly due to falling objects (no one is buried in the dam's concrete).
One of the dam engineers, Burl Rutledge, nearly died when he fell from the canyon rim. Oliver Cowan, a high scaler, swung out and caught him by the leg, and another scaler, Arnold Parks, swung over and helped pin him to the rock face until he could be hoisted to safety.
High scaling wasn't just about drilling and blasting; the scalers would often perform stunts for workers below, and contests were held among them to see who could perform the best ones.
The plaza on the Nevada side of the dam has a star chart on it that plots the stars and various Solar System bodies in their precise locations on September 30, 1935, the day FDR dedicated the dam. They are precise enough that if one had the necessary knowledge, they could both calculate the precession of the Earth's axis and determine the exact date of the dedication from some basic astronomical observations and the artwork alone. Interestingly, the stars plotted are drawn to show their absolute magnitudes, rather than their apparent magnitudes.
A statue dedicated to the high scalers also appears on the dam:
I don't think I can do this story of the dam's mascot justice.
Sources:
Bureau of Reclamation site
Google image search on Hoover Dam
Just for images! I swear!
PBS site on Hoover
More Information:
BBC Program summary
Really, check the Wikipedia links section. Or Google.
The most recognizable and famous American dam, Hoover sits in Black Canyon on the border of Arizona and Nevada. It holds back the part of the Colorado River, which starts in the Rocky Mountains and flows down to northern Mexico; it has had so many dams built across it that it no longer reaches the Sea of Cortez.
The Colorado River is ~1,470 mi (~2,330 km) long, starts at ~9-10,000 ft. (~2700 m), has a ~240,000 mi2 (~629,000 km2) watershed, and has an average discharge of ~22,000 ft3/s (~620 m3/s).
The dam itself is 1244 ft. (379 m) wide, 726 ft. (221 m) tall, and 660 ft. (200 m) thick at the base, tapering to 45 ft. (15 m) across at the top.
Lake Mead, the Hoover reservoir, extends 110 mi (177 km) behind the dam and covers 157,900 acres (639 km2). It holds a volume of 28.537 million acre-feet of water (35.2 km3).
Important Statistics:
Earth moved/excavated: 5.5 million yds3 (4.2 million m3)
Earth/rock fill placed: 1 million yds3 (765 thousand m3)
Concrete poured: 4.36 million yds3 (3.3 million m3)
Metal used: 88.985 thousand tons (80.726 thousand tonnes)
Price tag: $49 million US in 1936
Power output per generator: 13 130 MW, 2 127 MW, 1 68.5 MW, 1 61.5 MW
Power output total: 2704 MW
Planning/Preliminary Work:
Hoover was born out of the Colorado River Compact, considered by seven states (California, Arizona, Utah, Colorado, New Mexico, Nevada, Wyoming) and signed in 1929 by all but Arizona, which was unhappy about the water-sharing agreements outlined in the document. Originally planned for, and called, the Boulder Canyon Dam Project, it was decided to instead build Boulder Dam, as it was still called, in steeper, narrower Black Canyon. This was done to reduce the amount of concrete and construction needed to build the dam.
Black Canyon before the dam was built.
With this done, the construction would proceed in phases: first, the four diversion tunnels would be blasted and excavated. Once these were open, the cofferdams would be built and the dam site drained. Once this was done, the dam itself, essentially one gigantic monolithic interlocking piece of concrete, would be constructed and poured. The final pieces would be the penstocks, spillways, powerhouse, etc.
As well as the dam and related construction itself, a new town, Boulder City, had to be built to house the army of workers necessary to finish the project, as well as two cement plants, a highway, and a railway line built specifically for the dam, as well as a set of power lines all the way from San Bernardino, 222 miles (355 km) away. In addition, once the sides of the canyon had been prepared, a gantry had to be constructed to get the concrete, men, and materials to the middle of the dam and out again. Once the plans had finally been drawn up and finished, construction itself could begin.
Initial construction in Black Canyon.
Initial concrete mixing plant for the dam.
Schematics and Blueprints:
Nice schematic that breaks formatting
Construction:
The first task was to build the diversion tunnels. These four tunnels would ensure that the still mighty Colorado flowed around the construction zone. Blasting began in May 1931 and was completed in November 1932. In order to make the work go faster, platform called “drilling jumbos” were constructed on the back of ten-ton trucks. These allowed an entire side of the tunnel to be worked on at once, and a total of eight were constructed. More than 1.5 million yds3 (1.14 million m3) of rock were removed to dig the tunnels.
A drilling jumbo, and lining the tunnel with concrete.
Work began on the upstream cofferdam even before the diversion tunnels were finished, in September 1932. A horseshoe-shaped dike was dug to protect it, and once the river began flowing through the Arizona side tunnels, work began to go much faster. 250,000 yds3 (191,000 m3) of earth had to be excavated to provide a good bedrock for the 98 ft. (30 m) high, 750 ft. (229 m) wide, and 450 ft. (137 m) long dam. A 6 in. (15 cm) thick concrete face was put on the upstream side laid over a 3 ft. (~1 m) layer of rock. The downstream side had a thick rock fill covering.
The drained construction site and the lower cofferdam.
The downstream cofferdam was a compacted earth fill dam 66 ft. (20 m) high, 350 ft. (107 m) long and 550 ft. (168 m) thick at the base. A thick rock fill was put on the downstream side. All tolled, it contained about 300,000 yds3 (230,000 m3) of material. To protect the lower dam, a large rock barrier was built 350 ft. downstream to cut off backflow from the diversion tunnels. This was 54 ft. (17 m) high, 375 ft. (114 m) long and 200 ft. (61 m) thick at the base. All this was completed before the spring of 1933, and the dams held against the spring floods.
While the upper dam was being constructed, the cliffs were high-scaled. The men who had this job, obviously, were called the high-scalers. This was the most dangerous job of the entire project. These men would rope up using simple harnesses and then descend the steep canyon walls with jackhammers and dynamite. Their job was to smooth out the cliff walls and prepare it for the mass of concrete that would fill the canyon. This work had to be completed before the lower cofferdam could be constructed.
Finally, the main dam could be constructed; the first concrete was poured in June 1933. This was done using forms of varying size from 25 by 25 ft. (8 by 8 m) to 25 by 60 ft. (8 by 20 m). The forms rose just five feet at a time, and ice-cold water had to pumped through a series of pipes laid out in the forms to prevent the concrete from cracking as it dried, heated up, and then cooled. Once the concrete in a form had completely dried and cooled off, the pipes were sealed and pressure grouted. The interlocking vertical joints on each form were also grouted as the dam grew. Slowly the dam began to rise at a regular pace, and the last concrete was poured in the main dam in May 1935; Lake Mead had begun to fill in February.
All that was left was to construct the spillways, intake towers, penstocks, and powerhouse. These were all completed by March 1, 1936, when the dam opened for business two years ahead of schedule.
The intake towers.
The powerhouse under construction.
The generators and shaft gallery.
Spillways.
Upstream face, almost finished.
Transformers outside the powerhouse.
Trivia/other stuff:
So much concrete was poured at Hoover Dam that if it had been poured as one giant block, it would have taken 125 years for it to cool down to ambient temperature; it would have cracked and crumbled to uselessness along the way. Poured the way it is, the concrete at the center of the dam is still curing.
96 people died during construction, mostly due to falling objects (no one is buried in the dam's concrete).
One of the dam engineers, Burl Rutledge, nearly died when he fell from the canyon rim. Oliver Cowan, a high scaler, swung out and caught him by the leg, and another scaler, Arnold Parks, swung over and helped pin him to the rock face until he could be hoisted to safety.
High scaling wasn't just about drilling and blasting; the scalers would often perform stunts for workers below, and contests were held among them to see who could perform the best ones.
The plaza on the Nevada side of the dam has a star chart on it that plots the stars and various Solar System bodies in their precise locations on September 30, 1935, the day FDR dedicated the dam. They are precise enough that if one had the necessary knowledge, they could both calculate the precession of the Earth's axis and determine the exact date of the dedication from some basic astronomical observations and the artwork alone. Interestingly, the stars plotted are drawn to show their absolute magnitudes, rather than their apparent magnitudes.
A statue dedicated to the high scalers also appears on the dam:
I don't think I can do this story of the dam's mascot justice.
Sources:
Bureau of Reclamation site
Google image search on Hoover Dam
Just for images! I swear!
PBS site on Hoover
More Information:
BBC Program summary
Really, check the Wikipedia links section. Or Google.
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Instant Sunrise
- Jedi Knight
- Posts: 945
- Joined: 2005-05-31 02:10am
- Location: El Pueblo de Nuestra Señora la Reina de los Angeles del Río de Porciúncula
- Contact:
Hey, I have some construction photo's of the Kariba Dam on my hard drive. They were Kodachrome slides that my grandfather took of the dam during construction and I scanned in.
The dam is on the Zambezi river, and straddles the border between Zimbabwe and Zambia.
If anyone wants to do the Kariba Dam, I have some extra photos for you.
The dam is on the Zambezi river, and straddles the border between Zimbabwe and Zambia.
If anyone wants to do the Kariba Dam, I have some extra photos for you.
