urbanSTL

I'm surprised to hear Park East was done on grade. It would just seem natural that there would be at least 1 floor underground for basic utilities and the like. Although I guess they could be all done through the top of the building. There wouldn't necessarily need to be a secant wall in order to still excavate after the piles are in place, as there wouldn't be the water retention issue that there is at the Spire site. In addition, a smaller excavation than that (such as a floor or two) would make that much more possible. Going by Park East, however, it seems as though this will likely not be the case. Thanks again Matt.

I wonder if the quicksand under the old post office goes under the tower site as well? I don't really know anything technical about the foundations of large modern buildings, but I do know that the quicksand in the area was quite a challenge to overcome historically. Would quicksand still cause enough of a design challenge to dictate the nature of the tower's foundation?

Does and doesn't change how you build. I would expect drilled piers would still be used, but slurry drilling would be necessary to keep the shaft from collapsing as drilling progresses down. There are plenty of methods for building on just about any type of ground.

I'm pretty sure the Roberts Tower has just one basement level.

Slightly OT, but it's interesting to note that in Houston, the water table is very high. No basements. Some of their biggest skyscrapers are built with some kind of "floating" foundation. As Matt says, you can pretty much build anything anywhere these days.

I don't know about Houston's water table, but homes in the southern US rarely have basements for a completely different reason. In STL the cold winter months necessitate a foundation below the frost line. Since digging is already required 3' - 4' below grade it is not a large cost difference to excavate for an entire basement since the necessary equipment is already on site. This in turn has made it a common practice, and even expected, that there is a basement in the home. It also gives the home a much higher value for a small investment. In the south, however, there is little to no frost line at all. Most homes are constructed slab-on-grade and require no excavation whatsoever. In order to build out with a basement excavating equipment must be ordered, time allowed for excavation, hauling of the soil must be delt with, forms laid, foundation materials purchased - all costs and schedule conflicts that would normally not be present. Sorry to go on like this, but it is a common misconception that the majority of housing in the US has basements, in fact most do not.



In the case of the Roberts Tower, it would make sense that they would include a basement level for utilites, storage and other functions, but it is in no means a necessity (the caisons are reaching far below the freeze point) and would purely be cost and design driven.

Just returned from a nice little downtown walk, don't know if it's there for the Tower or the plaza (don't know if it was there last time you dropped by matt), but there is a crane now parked on 8th street.

I noticed it today. Don't know which it's for, but the tower would make more sense since it's in the towers staging area. Likely for rebar cage assembly and placement. I'll try to get a better look tomorrow.

Then that makes two of us.

^You were asking how big they were drilling over on SSP. Here you go.

That's a hell of a shot!

Thanks for the info Newstl2020. I assume you contacted Drilling Service.



Rebar is in fact being tied. That is what the crane is for. You can see the casing for both shafts in the pics.



The views are going to be fantastic from every unit.

Wow! Late last month, we had the Centene and Mercantile Exchange announcements. Now ground has been broken at Roberts Tower, it will be broken soon at Park Pacific, and the Skyhouse site is being cleared. Is this a great time to be in Saint Louis or what?



I'm excited to see tangible progress at this site. It's going to be nice to see a modern structure like this across from the classic OPO.

drilling is being slowed slightly because the foundations of buildings formerly on the site remain beneath the surface. When the old buildings there were demolished they were simply tossed into the basement levels as fill and then capped. so now they're drilling down through an old foundation wall for about 20 feet of solid concrete. and there is one basment level in the new building.



park pac breaks on the 17th, i believe.

Great pics Matt. I'm not even going to bother with mine now, and that is DEFFINITELY a good thing, as you clearly have a much better camera than me . I was a little surprised at how early they quit work at the site. They were all cleaned up and cleared out by exactly 3. I ran into Cmedowntown (I believe (sp), a fellow forumer) who said they had been beggining work by 7, but leaving by 3 still seems awfully early to me (This might just be after seeing workers in Lumiere at around 12 at night, however.) Rebar cages are fairly large, look to be around 5-5 &1/2 feet tall. Very exciting indeed.

^There is a LOT more cashflow behind Pinnacle, than the Roberts. Casinos have deep pockets. The Roberts Brothers are doing well, by all means...but can't compare them to a casino project.

The Atlanta tower that AC posted is pretty sharp. If we end up with something that looks similar to that, It will make a great addition to OPO Square.

Does anyone know if it was the same firm that designed the two buildings? There's the diagonal streak in the main curtain wall and everything.

32 Caissons. Really? Wow. The entire site is only like 8400 SF. So, they are pretty much going to be drilling a good 20% of the site down and into bedrock.

^ I recently read a book about the development of Boston's Back Bay. Homes there have dozens of caissons underneath them, something like one every 2.5-3ft under all external and internal load-bearing walls. A home 25x75 feet could have as many as 100 of them depending on the internal configuration.

Grover wrote:^ I recently read a book about the development of Boston's Back Bay. Homes there have dozens of caissons underneath them, something like one every 2.5-3ft under all external and internal load-bearing walls. A home 25x75 feet could have as many as 100 of them depending on the internal configuration.

Sure they weren't talking about piles?

^ good call - same purpose though right? (I'm no engineer)