(Update: The foundation for the center pier of the Miami Signature Bridge
used over 500 truckloads and took 33 hours using five concrete mixing plants.)
The 92-story Trump Tower in Chicago was the world's tallest concrete-reinforced building when it was completed. It is built on a "mat" --- a steel-reinforced 200x66x10-foot monolith of 5,000 cubic yards of self-consolidating concrete (SCC) that was continuously poured in 22 hours by 30 9-yard trucks making 550 trips from Prairie Material Sales near Chicago and Halsted
. (I notice from the satellite image that they receive materials via barge.) This was the first use of a new cooler, thicker concrete mix that supports 10,000 psi at 56 days instead of the customary 7,000 psi. For this reason chemists were on hand to test the concrete's consistency and temperature through out the pour in a makeshift laboratory. Two conveyor belts were used to double the pouring capacity.
(Update: I'm saving images of Yard 32 because industry is being kicked out of the North Branch area.)
|Carlos Ferran posted, used with permission|
UP 1430 leads YNO68 north to North Ave. Yard with a generous count of 6 high cube boxcars from Tribune
. Taken from high above River West.
Jan 2, 2020.
The 5,000 yards is a small percentage of the 180,000 total needed by the building. But the rest was poured in smaller sections using concrete pumps. A custom-built pump imported from Germany was used to handle the uppermost stories because so much force was needed to push the concrete that high.
Chicago has had a history of record holding reinforced concrete buildings.
- 1964: the two 60-story Marina City towers
- 1990: 64-story Prudential Plaza, but just for a few months
- 1990: 65-story building at 311 South Wacker Drive
- 2009: 92-story Trump Tower
(October 3, 2005 ChicagoTribune
has some updated numbers: 4,600 instead of 5,000 yards, three conveyors instead of two, and 500 trips instead of 600.
Prarie's Yard 32 has dual central mix plants on site. The distance to the site would not be far enough to mix the concrete in the trucks. The trucks did not use the most direct route so that they could avoid driving within a few feet of an outdoor restaurant on a Friday night. (PRWEB
If you can tolerate the narration, Discovery's High Strength Mix Design video
shows the unloading of a barge and some of the mixing plant equipment. One point made by the video is that just ounces of five special ingredients are added to a 9-yard batch to create SCC
with higher strength and lower temperatures than normal. The video of pouring a slab
makes me appreciate the host for Dirty Jobs.
An article about the 2015 162x47x10 mat pour for 150 N. Riverside Drive
|150 N. Riverside - Courtesy of Riverside|
Investment & Development Company
(Update: a new link
) mentions the extensive testing Prairie did before the pour "to pinpoint the right levels of polycarboxylate-based, high-range water reducer and high-volume
cementitious supplements such as fly ash to assure the mix would pump
well without segregating." Another advantage of SCC is that it flows around the rebar so that the pour does not need as much vibration. And, unlike the 2009 Trump pour, this pour could be pumped, even in 27 degree temperatures. The mixing plant used boilers to raise the mix temperature to 60 degrees. There is a webcam of the construction site
. You can hit a "play" button to see a time-lapse of what has been done so far. (Update: the steel for this building was rolled in Differdange Luxembourg. [AM-sections
The Trump Tower record should have been broken by a 6,600 yard pour of a mat that is 140 feet in diameter and 11 feet deep that will support a 550 foot emission stack for a $300 million pollution (sulfur dioxide and nitrous oxide) control project for Minnkota (BismarckTribune
Another Big Continuous Pour
They started with six concrete-pump trucks
and 120 ready-mix trucks to pour 1,700 truckloads carrying 13,799 cubic yards of concrete in 20 hours. A truck was arriving every 45 seconds. [HoustonChronical
] Note at -0:12 in this time-lapse video that the big crane seems to be placing a porta-potty in the middle of the new pad.
|HoustonChronical, Photo 1|
|HoustonChronical, Photo 10|
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