A chronicle of the CTA substation project on the Red Line between Loyola and Morse stations in Chicago (with occasional posts about other construction projects)
Thursday, August 29, 2013
Saturday, August 24, 2013
Day 300: 24 August 2013
The wall scaling continues on this sunny Saturday as more rebar is added to the west and north faces in preparation for building a concrete wall, which should be poured by the end of next week. The rebar comes in a variety of shapes: there are straight pieces that come in different lengths; hook pieces that have either a 90ยบ or a hook-shaped bend near the end; and stirrups, which are omega-shaped and are used to separate the different levels of rebar (these are also called standees when installed in a vertical standing position to separate different horizontal levels as was seen in the preparations for the mat slab). All of these are secured together with short lengths of tie-wire.
Clearing some of the orange barrier fencing away in order to complete a section of rebar. |
The north wall. |
Friday, August 23, 2013
Day 299: 23 August 2013
The mat slab was uncovered today and looks solid enough to bear the weight of the world. Now the focus is on building a vertical network of rebar along the wall separating the substation from the trackbed. The rebar comes in a variety of different shapes, which is easier to see in these pictures than in the earlier pictures looking down from above on the preparations for the slab. This stage of the work involves a lot of climbing as the first two pictures pictures show.
The shorter, z-shaped lengths of rebar are transported by crane in what look like gigantic white shopping bags.
A low wall is being constructed on the street-side of the site.
Thursday, August 22, 2013
Day 298: 22 August 2013
Here are a couple of shots of the women at work. I am always happy to see women doing the kinds of jobs that were not readily available to us when i was young and had a strong back and a full supply of knee cartilage. Here's a brief personal narrative, that might shed some light on why i am so glad to see better work opportunities for women:
When i was a young lass back in the 1970s, i applied for a job through a government-sponsored training program only to be told that i couldn't be hired because it was a "man's job." I finally got the job by circumventing the government official and having the boss (whom i knew) call directly and tell them to hire me. There were two trainees. The other one was a guy who weighed about 95 pounds, had long stringy hair, and believed he could cast a spell to make any woman fall in love with him (spoiler alert: he couldn't!). I outweighed him by about twenty-five pounds of muscle and could out-armwrestle half the guys i knew. Yet he was considered the more capable and appropriate hire, and got the job without any difficulty, while i had to fight to get it. Thank goodness for progress!
More rebar! And another climbing performance worthy of American Ninja Warrior.
By noon, some much-needed rain began to fall. The concrete got a nice cool shower while the workers took a break for lunch.
Wednesday, August 21, 2013
Tuesday, August 20, 2013
Day 296: 20 August 2013
After all the excitement yesterday, things were a little slower today as the concrete slowly goes through the curing process. I had a very interesting conversation with the site superintendent today, who patiently explained some of the procedures involved after the concrete is poured. Since i haven't had much to do with science since that unfortunate little explosion i accidentally caused in high school chemistry class, a lot of what he said about core samples and psi strength and whatnot went over my head. But it was interesting to learn that the concrete actually produces heat while it is curing (a process that takes several days).
I also learned that the green coating on the rebar is epoxy; it helps protect the rebar from oxidizing (rusting). Without this protection, the rebar will rust and expand, in turn causing the concrete to crack. Since i have the misfortune of working in a building with a lot of exposed rusty rebar in the facade, i knew what he was talking about, though i didn't know the process that caused it.
Monday, August 19, 2013
Day 295: 19 August 2013
It was a very long, very productive day on the substation site today. The workday began sometime around 3:00 AM. I know this because when i awoke at 3:30 the crew was already hard at work.
Working under the stars, 3:30AM Monday. |
By 5:30 in the morning, the concrete had already started to flow at the south end of the site. By day's end, the massive infusion of concrete would bury all the rebar that's been laced through the site in the past couple of weeks. Large floodlights helped illuminate the worksite.
Once i was officially up for the day and embarked on my morning stroll with Doggie Demeanor, i got a better look at things at ground level. I think this was the biggest crew on the job at one time since the project began. Farwell Ave. was closed and looked like a parking lot filled with pick-up trucks, SUVs, and cars.
The concrete was delivered to the site via the long armature/tube seen here.
The view through the opening in the fence. |
One cement mixer leaves and is quickly replaced with another. I was told that over the course of the day, more than forty trucks full of concrete were emptied into the site.
Making your way through the site is a precarious undertaking. |
Smoothing the concrete after it's poured. |
By 10:45 AM, all that remained to be done was this section at the north end of the site.
And by 1:00 PM, a four-foot deep pad of concrete covered the entire site.
Smoothing the surface. |
Meticulously smoothing the surface. |
This makes me claustrophobic. |
By mid-afternoon, parts of the fresh concrete were being covered with a protective tarp.
Before 6:00PM, the final section was covered with tarp, and the remaining workers finally saw the end of a very long day.
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