Tag Archives: concrete

Foundations for a Tall Building

I have already posted a couple of times about the construction next to our old apartment in Chicago.  The demolition of the Sun Times building was here and the removal and replacement of Wabash Avenue was here.  This was all associated with the construction of the new tower.  Since the plot on which this tower was going to be built was pretty small, it couldn’t be a traditional steel frame skyscraper.  The provide the stiffness needed for such a slender tower, it had to be constructed of concrete.

This required a substantial foundation.  First was the need to clear out the old foundations.  The Sun Times building had been constructed on top of a ton of piles that were timber poles driven in to the ground.  These all had to come out before anything else could be done.  Tons of them would be lying around at various times as they were pulled out prior to being taken away.

Next was the need to drill down for the new piles.  I seem to recall that they went down about 130 feet but my memory may be off on that.  Some of the piles were really wide while others were slightly narrower.  Larger drills would take out the earth and then steels cylinders would be inserted in to the whole.  Rebar reinforcements would be inserted before the concrete could be poured in to make the final pile.  This process was repeated across the site over a course of months.

All of this was the precursor to the main foundation.  The building was built on top of a concrete raft.  This sat on top of all of the piles.  It was a single pour.  The whole pour took about 48 hours.  A steady stream of trucks brought the concrete in from a mixing plant a couple of miles away.  The mix was a special high strength one and each truck was tested as it arrived.  Pouring such a volume of concrete continuously required great care because the material generates heat as it sets and there was constant monitoring to ensure that the overall temperature remained within range.  Once they started, they couldn’t stop.

The whole thing apparently went to plan and the result was a large concrete base on which the rest of the construction effort would build.  After months of preparation, finally it was time for things to start going up again.

R44 Pilot Showing Off for the Camera

I was wandering along the runway at Concrete towards the end of the day during the fly in.  A Robinson R44 had been doing pleasure flights throughout the day and was landing well up the field from where I spent a lot of my time.  I had photographed it as it came over a couple of times but soon lost interest.  However, as I wandered along, I happened to be near his landing spot when he came back from another trip.  I was far better placed to get a shot or two so I did.  However, he spotted me and, instead of following his normal approach routine, he brought the helicopter to a hover in front of me facing at me as they all looked at me while I looked at them.  As long as I kept shooting, he didn’t go anywhere so eventually I just lowered the camera and waved.  At that point he turned around and landed.

Building a Big Box

I have stayed in the same hotel in Addison TX a couple of times recently for work trips.  The view from my window has been of a building site that has been progressively developing on each visit.  On one morning, I was just getting ready to check out when I could see the crew getting ready to lift a concrete panel into place.  The crane they were using was a substantial beast.  The crew were scattering to different locations to carry out their roles and then they started lifting the panel.  They had several lift lines which could be controlled individually to allow the, to rotate the panel as required.  Sadly I had to go before they finished.  I should be back before too long, though, so I shall see how progress is going.

 

What Are These Stretches of Concrete

I had a lot of time to look around while I was at Rainbow Canyon.  As the day wore on and the sun came around, I started to have a clearer view to the south.  In the morning, it had been quite foggy in that direction but that was burning off and I could see the above view.  It looked a bit like there was a runway out there but it was so far away, I couldn’t be sure.  When I got home, I looked on Google Maps.  Sure enough, there are some long stretches of what looks like concrete but no indication of what there are.  Do any of you know?  The place is called Millspaugh if you want to look it up.

Parallax Preferences

This post is really a question about what people like in an image and what they are prepared to tolerate.  I was at Concrete for the vintage aircraft fly-in up there a while back.  This is an event where you get to be very close to the aircraft.  I was able to experiment with shutter speeds that were very low to get lots of prop blur.  Because the planes are so close, you are not using a long lens and so the low shutter speeds are less likely to cause a problem with camera shake.

However, another problem comes to the fore.  Since you are so close, using a low shutter speed and photographing something that is moving past you, you get parallax issues with sharpness on the plane.  The different parts of the plane are moving at different speeds relative to you as it passes so, if one part of the plane is sharp, another part is unlikely to be so.  The question is, what is acceptable.

I have spoken to friends about this in the past.  One or two of them have expressed their unhappiness with having a blurry part of the airframe.  Others prefer the blur this allows to the background to emphasize the speed.  Some are most bothered about the amount of blur on the prop.

My first instinct with a shot is whether the nose is sharp.  For me this is a bit like whether the eye is sharp on a wildlife shot.  If the nose is sharp, I can tolerate a blurry back end.  But, when the plane is going away from you, the tail is more prominent in the view.  In this case, is it better to have the tail sharp than the nose since the blur of the backend will be the thing you see first and will drive your first impression of the image.  I would really like to know what people prefer.

Lookout Post Skeleton

At the bottom of the Devil’s Slide trail, there are the remains of a building.  This appears to have been a lookout location.  There were a number of military installations here at one point.  Just south of the tunnel entrance and up on the headland is the concrete core of what was once one of the buildings.  The ground has eroded away at the base of the structure and the walls have gone in some places but the concrete core is still there.  It has been covered by graffiti artists over the years and is still popular with the more adventurous types.  A couple was climbing into it while we were there.  It looks pretty cool on a sunny day.  On a cold and foggy day, I suspect it will be a bit more depressing.

I Can Hear You Coming

CRW_0313.jpgIn the days before radar, there were other techniques that were used for trying to detect inbound enemy aircraft.  One of them was the use of sound.  Dotted along the southeast coast of the U.K. are a number of locations with devices for focusing sound.  One of them is located in the hills above Hythe.  This is one of the simpler forms that were used.  Despite the age, the contract structure is still in good shape.  With the introduction of radar, these sites were redundant but they do provide an insight into the trying of any idea to gain an advantage in another era.