CHICAGO | General Developments

[Via Chicago]

Originally Posted by PittsburghPA

Does anyone know why this is taking so long?

i brought that question up a few months ago and didnt really get a definitive answer. seems to me like theyve run out of funding or into some more serious issue, there hasnt been a crew on site since last summer

[k1052]

Originally Posted by Via Chicago

i brought that question up a few months ago and didnt really get a definitive answer. seems to me like theyve run out of funding or into some more serious issue, there hasnt been a crew on site since last summer

They put up a plywood barrier along the property line in the last day or two. Previous to that I noticed that a few had been sent out to half heartedly clean up materials they'd piled on the sidewalk.

Really whatever their problems the city should require the sidewalk returned to service while they figure shit out.

[Blahshead]

Thanks for the insight on the concrete everyone! I had never heard of spawling before.

[HomrQT]

Originally Posted by harryc

Everything expands and contracts with changing temperature - concrete buildings not so much. All the recent ones I have seen have insulation - even on the slab edges, so probably even less.
Potholes are caused by cars driving over the hole repeatedly, not usually a problem in residential buildings ;-) .

Spalling - where the outer layer of concrete breaks off of the rebar IS a common occurrence, and probably a hefty special assessment. Not sure how much is due to thermal effects, and how much is do to salt+iron => Fe02, for the last 10yrs any rebar that may be exposed to salt has been vinyl coated (green in the photos).

Originally Posted by LouisVanDerWright

As Harry says, spawling is a major maintenance issue with concrete structures. The issue is that, no matter how well you coat or bury rebar, iron will rust when oxygen reaches it. That wouldn't be an issue except that oxidation of iron results in it gaining two oxygen atoms which means it is actually gaining mass out of the air and more mass means it takes up more space which means it expands and eventually shatters the concrete around it.

This is fix by continually repairing any cracks or spawling that is occurring to limit the amount of oxygen reaching the rebar as much as possible.

Why haven't companies moved to a fiberglass or basalt rebar instead to avoid these issues?

[wierdaaron]

Anyone know what’s going on with 700 South Clark, the one story warehouse with a curb cut between the Artcraft building and Burnham Point? There’s been construction going on there, they ripped the whole front off the building and looks like they might be adding stories. Wondering if it was bought by scientology to go along with their remodel next door.



Zoned DX-12 so could become anything. Sad to lose another brick streetfront though. 1918, killed after its 100th birthday

[LouisVanDerWright]

Originally Posted by HomrQT

Why haven't companies moved to a fiberglass or basalt rebar instead to avoid these issues?

It likely lacks the characteristics and workability that makes steel such a good building material. In theory the coated rebar should make it more or less a moot point anyhow. Everything requires maintenance and usually lasts a long time when properly taken care of.

When you consider the general durability of reenforced concrete, it's not really a big issue. I'm looking at a building now that's been vacant since the 70s with no upkeep and a leaking roof. There is some damage from spawling, but it's all basically cosmetic flaking even after 40+ years of neglect. It's going to take next to no work to fix once someone gets at it and the materials couldn't be cheaper. There are unreenforced structures all over the place that have stood since Roman times because they've been kept up. Imagine how long a structure like Nema or a 1920s factory or atomic era poured in place structures that pushed the boundaries of engineering like Marina City can last? Assuming someone patches Marina City at least once every 50 years or so it should be able to stand virtually forever. So the biggest reason no one has replaced it is that this building system already works very very well.

There are a lot of people trained in it as well which is one of the issues older masonry buildings have had; the skills and understanding of the system are lacking.

[Jim in Chicago]

Originally Posted by wierdaaron

Anyone know what’s going on with 700 South Clark, the one story warehouse with a curb cut between the Artcraft building and Burnham Point? There’s been construction going on there, they ripped the whole front off the building and looks like they might be adding stories. Wondering if it was bought by scientology to go along with their remodel next door.



Zoned DX-12 so could become anything. Sad to lose another brick streetfront though. 1918, killed after its 100th birthday

Not a clue and have been wondering. I think it abuts to the the planned development on LaSalle that I haven't heard much about recently. I wonder if it could be part of that.

I thought that the Scientologists were long out of the deal next door. That was planned before the economy went bust and the Scientologists began to run out of steam.

[wierdaaron]

CoS’s name is all over the building permits for the artcraft building.

The adjacent site on lasalle did get cleared last year (RIP surface parking lot), but for the two projects to connect back-to-back they’d have to destroy connectivity for the alley between them, which I don’t think happens.

[HomrQT]

Originally Posted by LouisVanDerWright

It likely lacks the characteristics and workability that makes steel such a good building material. In theory the coated rebar should make it more or less a moot point anyhow. Everything requires maintenance and usually lasts a long time when properly taken care of.

When you consider the general durability of reenforced concrete, it's not really a big issue. I'm looking at a building now that's been vacant since the 70s with no upkeep and a leaking roof. There is some damage from spawling, but it's all basically cosmetic flaking even after 40+ years of neglect. It's going to take next to no work to fix once someone gets at it and the materials couldn't be cheaper. There are unreenforced structures all over the place that have stood since Roman times because they've been kept up. Imagine how long a structure like Nema or a 1920s factory or atomic era poured in place structures that pushed the boundaries of engineering like Marina City can last? Assuming someone patches Marina City at least once every 50 years or so it should be able to stand virtually forever. So the biggest reason no one has replaced it is that this building system already works very very well.

There are a lot of people trained in it as well which is one of the issues older masonry buildings have had; the skills and understanding of the system are lacking.

Got it. Thanks for the insight.

[harryc]

May 1

[BonoboZill4]

UIC Engineering building:



This campus plus the IMD are really making the Near Southwest side an exciting area to pop into every once in a while

[Jim in Chicago]

Originally Posted by wierdaaron

CoS’s name is all over the building permits for the artcraft building.

The adjacent site on lasalle did get cleared last year (RIP surface parking lot), but for the two projects to connect back-to-back they’d have to destroy connectivity for the alley between them, which I don’t think happens.

Are those still the original permits from like 10 years ago?

I just found that 5 permits were issued about a year ago, which is about when the latest round of work began. Are those the ones that reference COS? The permits I can see online just say "owner". This building has quite the history, the most recent thing I find on the property records is that the city filed a Lis pendens against the COS in 2013.

[Jim in Chicago]

Originally Posted by Jim in Chicago

Not a clue and have been wondering. I think it abuts to the the planned development on LaSalle that I haven't heard much about recently. I wonder if it could be part of that.

I thought that the Scientologists were long out of the deal next door. That was planned before the economy went bust and the Scientologists began to run out of steam.

Assuming this building in numbered 700 S. Clark (nothing in that stretch seems to have street numbers on them...) the building permits say:

Description: ALTERATIONS AND REPAIRS TO EAST MASONRY EXTERIOR WALL OF AN EXISTING 1-STORY RESTAURANT BUILDING AS PER PLANS.

to call that a "restaurant building is a stretch, it's been nothing but various tire shops and parking garages for at least a decade. I sort of like that facade and am sorry to see it go.

There are other permits for "recoat/recover" and plumbing work.

The use of the word "restaurant" could bode well, I've long thought that would make an interesting restaurant space, but with the facade gone...

[JK47]

Originally Posted by LouisVanDerWright

There are unreenforced structures all over the place that have stood since Roman times because they've been kept up.

Interesting thing about Roman Concrete is that it was very different from the modern version we use based on Portland Cement. The mixture they used included volcanic ash and seawater that resulted in a material that had high tensile strength, little plasticity, resisted fracturing, and didn't degrade when exposed to seawater. In fact, as seawater penetrated the concrete it would react with the volcanic ash causing a reaction that reinforced the material preventing fracturing.

Which is one of the reasons why those structures in wet marine environments have survived millennia with little to no maintenance while modern concrete structures will, at a minimum, require some maintenance.

[Baronvonellis]

If the Roman concrete is more durable why isn't it being used now?

[aaron38]

I wrote a paper on ancient construction (not just Rome) back in the day. Roman concrete, such as in the pantheon, wasn't poured into forms like modern concrete. It was hand laid and hand pounded into place. It's more masonry than concrete. The pounding eliminated voids and air bubbles, made the concrete much more dense, stronger. As they built, they could vary the aggregate, structure, chemistry as they went. Essentially roman concrete was 3D printed - by hand. In no way would it be economical to build that way today.

[gandalf612]

Originally Posted by Baronvonellis

If the Roman concrete is more durable why isn't it being used now?

If I remember correctly no one has been able to recreate it, and also due to using volcanic ash it would be more expensive.

[ardecila]

Originally Posted by gandalf612

If I remember correctly no one has been able to recreate it, and also due to using volcanic ash it would be more expensive.

Fly ash from coal power plants has many of the same chemical properties as the volcanic ash the Romans used, and it's used in quite a few concrete pours these days.

But there are always trade-offs; in our cold climate, concrete actually needs air pockets inside to absorb the expansion of ice crystals from moisture in cold weather. It's a bad thing for it to be too dense. Pozzolanic concrete mixes (like Roman concrete or concrete with fly ash) are denser than traditional Portland cement mixes, and they could have bad spalling problems if exposed to freeze/thaw cycles. That's obviously not a problem in Italy...

[FlashingLights]

Anyone know whats going on with the building being demolished at Fremont & Blackhawk? (By SoNo) That building wasn't part of the prior factory that was on the site I thought? Thanks in advance for anyone that can clear up the confusion for me.

[JK47]

Originally Posted by Baronvonellis

If the Roman concrete is more durable why isn't it being used now?

The problem was that the techniques and knowledge was lost, along with most written records, when most of Rome burned between the 4th and 8th centuries. Not to mention the general reduction in literacy.

It wasn't until recently that we were able to determine the chemical composition. That said we still lack information on the ratios used to create the mixtures that comprise concrete...which is all the more difficult since...as said above...they tended to vary it as they went.