Hoover Dam

[Big Cholla]

Researched It

Isn't the best temp for concrete to cure is 55 degrees. They had hose or cooling lines with cold water. They poured the overpasses here at night this summer and ran cooling lines. In the winter they had portable heating lines.

Your question caught my interest this evening and so I reached into my bookcase and got my Father's official USBR "CONCRETE MANUAL". The USBR used the building of Hoover Dam as it's laboratory in writing several 'manuals' for establishing Official USBR guidelines for similar construction post Hoover Dam. My Father's best concrete placement crew was used in performing all the various concrete emplacement these experimental tests required. He was given the manual that I have in my hands days after its official publication in 1936. Anyway, The best that I can come up with as far as "The Optimal" temps for the liquid concrete mass is a recommended range of 60 deg. to 70 deg.for development of maximum compress-ability psi. The 'heat of hydration' is exothermic, so the minute water mixes with cement the resulting mix starts producing heat. My Father told me that they used ice cooled water in the mixers (they called them Batch Plants) during the heat of the summer to hold that 'mix' heat down. So, I think your suggested 55 deg. F. is a little low for that optimum mix temp for strength. I did find that all the base lines for affects of variables affecting final strength is based on a mix temp of 70 deg. and a atmospheric temp of 70 deg. So, 70 deg. seems to be a favorite starting place for the USBR Engineers at least in the '30s and '40s. I do know that atmospheric temp is the most uncontrolled variable on the job site and that a lot of "ad mixtures" are available to be added to a concrete formula to compensate for too hot of a day temp or a too cold of a day temp.

An aside; Most people have no idea what an important contribution "ice" made to the construction of Hoover Dam. The USBR built a 'state of the art' ice plant along side the railroad in Boulder City. Tons of block and crushed ice went to the dam site every day during the summer with lesser amounts during the winter. Most of the drinking water barrels were iced down. While the Engineers, Construction Bosses and Clerks of the Works, all had buckets of ice in their job shacks with small fans blowing across the ice. Certain fittings of metal pieces had to be iced down while the mating pieces were warmed with 'rosebud blow torches' for a tight field fit.
My Dad said, "If ice wasn't in existence when Hoover Dam construction started, it would of had to be invented." ......

 

[walkinghorse]

Yes. A Dumpy level has the long telescope and 4 leveling screws. A Wye level is the same with the addition of clamps that loosen and allow you to swap the telescope 180°

You youngsters that have never set up a 4 screw instrument!

They are more difficult!

Reminded me of times past. Working two of the screws with one hand simultaneously. Amazed some of the beginners! Solid leg tripods that you spread one leg further to get the plate close to level before using the screws.
Remember folding wood rules and the trick of simply extending one arm to open it quickly! Whenever you had a new kid starting you could count on multiple rules being broken when they tried to imitate. Or the claim that you were using a old rule and they had a new rule which was stiff!

 

[Big Cholla]

Ah, Memories of a Simpler Time

Reminded me of times past. Working two of the screws with one hand simultaneously. Amazed some of the beginners! Solid leg tripods that you spread one leg further to get the plate close to level before using the screws.
Remember folding wood rules and the trick of simply extending one arm to open it quickly! Whenever you had a new kid starting you could count on multiple rules being broken when they tried to imitate. Or the claim that you were using a old rule and they had a new rule which was stiff!

You just keep hitting my 'memory' buttons; After my college surveying course was over I swore that I would never use a Dumpy Level again,,,,and I haven't. And, My Father used to constantly tell me, "A folding rule and a set of blueprints will keep you out of trouble more than anything else you can bring to the jobsite." ..... I still have one of his folding rules here someplace.

And I want to extend a big "THANKS" to you for starting this thread. Here on the world's best firearms forum, a thread about a big lump of concrete in the desert has given me more personal pleasure than even talking about the tuning of S&W revolvers! ............

 

[walkinghorse]

You just keep hitting my 'memory' buttons; After my college surveying course was over I swore that I would never use a Dumpy Level again,,,,and I haven't. And, My Father used to constantly tell me, "A folding rule and a set of blueprints will keep you out of trouble more than anything else you can bring to the jobsite." ..... I still have one of his folding rules here someplace.

And I want to extend a big "THANKS" to you for starting this thread. Here on the world's best firearms forum, a thread about a big lump of concrete in the desert has given me more personal pleasure than even talking about the tuning of S&W revolvers! ............

Your welcome! Been fun and informative for me too!
Serious question now.........you tune S&W revolvers????????
Next thing you will be telling me is there are kydex holsters for registered magnums and engraved revolvers!!!!

 

[Big Cholla]

LOL, Of Course There Are

Your welcome! Been fun and informative for me too!
Serious question now.........you tune S&W revolvers????????
Next thing you will be telling me is there are kydex holsters for registered magnums and engraved revolvers!!!!

You just find a really good soft leather holster maker who will stuff his good holster into an oversized Kydex holster. .....

In all seriousness, if one is sensitive about the condition of the finish on their handgun, they should not use Kydex!

 

[NYlakesider]

Walkinghorse & Big Cholla, a heartfelt THANKS to both of you. This has been an extremely good /informative thread.

I have done Hoover twice, both times before the security got ramped up. As a pipefitter/welder I have worked on all sorts of projects. Before I was a pipefitter I worked for a bridge building contractor and have done plenty of concrete pouring!

Worked at two Nuke sites and a few fossil fuel power plants so I have a better than average idea of what’s what with power generation and large construction in general.

In fact during one tour our rather new guide was explaining about some of the rather large pipes in the dam. I very gently told him when pipes get that big we tend to call them penstocks. (I think he knew that but was a bit shy and possibly just forgot due to his newness!)

FWIW the lake I live on is actually a flood control reservoir (controls the Hudson River) and has a fair size earthen dam impounding a heck of a lot of water. This capacity is needed as NORMAL winter snow & spring rain will put a lot of water behind the dam. It is pretty well phased out now for power generation.
.

 

[3d deader]

Photo of dam taken a few days before the presidential election.

 

[ddixie884]

The first time I crossed it was in the middle of the night little over 30 yrs ago. I stopped in the middle, got out of my pickup and walked around to look. No traffic, real quiet. Later after I started trucking, I crossed it many times, even oversize. Things sure have changed..............

 

[pmanton]

Wasn't Hoover first named Boulder Dam..

I'm 78 and my parents always called it Boulder Dam

 

[pmanton]

But the problem is LACK of water. Lake Mead is down over 100', and not recovering.

All over the West this is a problem.
I took this picture several years ago on a trip down south. It's in Northern California. I apologize for the haze there were a lot of fires at the time. .

 

[shouldazagged]

I am not an engineer, but I have always found it a solid idea to practice the The Engineering Fudge Factor.

When I started engineering school at Purdue in 1955--didn't last, I have zilch for mathematical aptitude--we referred to that as Diddle's Constant.

 

[shouldazagged]

Ten thousand years? That's remarkable, considering that it was built long before the introduction of KFC mashed potatoes and they had to use concrete.