Millennium Tower (Filene's) | 426 Washington Street | Downtown

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datadyne007 said:
Oh wow! Thanks for peeking over the fence! I'll have to do the same on my way into work tomorrow.
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Hawley street has a ton of viewing spots through the fence. Essentially "windows" into the project site because the cloth is ripped. That's probably the best current area to check this out from street level.
 
DZH22 said:
Hawley street has a ton of viewing spots through the fence. Essentially "windows" into the project site because the cloth is ripped. That's probably the best current area to check this out from street level.
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Whoops, I was talking about the paving. My post was unclear.
 
Two questions for the steelworkers: (1) some of the thickest vertical rebar have steel plugs on the top ends that resemble a thick hockey pucks: what are they for? if to attach to the next piece up, why don't we see lots of welders making the connections when they add the next level? (2) why do some of the vertical rebar have those orange plastic caps on top -- purely for safety reasons so folks won't skewer themselves on them before they're encased in concrete? I asked a couple different folks onsite and they gave very detailed answers that didn't make any sense to me (unfortunately I'm not a steelworker): one said the hockey pucks are a kind of hook used to place them...they won't be removed before being imbedded in concrete...I didn't get that at all.
 
Gromit said:
Two questions for the steelworkers: (1) some of the thickest vertical rebar have steel plugs on the top ends that resemble a thick hockey pucks: what are they for? if to attach to the next piece up, why don't we see lots of welders making the connections when they add the next level? (2) why do some of the vertical rebar have those orange plastic caps on top -- purely for safety reasons so folks won't skewer themselves on them before they're encased in concrete? I asked a couple different folks onsite and they gave very detailed answers that didn't make any sense to me (unfortunately I'm not a steelworker): one said the hockey pucks are a kind of hook used to place them...they won't be removed before being imbedded in concrete...I didn't get that at all.
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I believe those "hockey pucks" you are describing on the large rebar are the alternative to the standard "rebar hook" technique. The rods might be too large to bend/hook and thus, a round disc at the end accomplishes the same as a hook. The hook and/or puck helps to maintain the rebar's stability at the end of the segments/beam/column within the concrete and acts to anchor the beam. It's not removed because it needs to be cast into the concrete. It quite literally hooks the rebar into the concrete.
 
Kind of splitting hairs here, but rebar is made out of steel, correct? A lot of people have said there is no steel in this project, and it's concrete only. But, isn't it technically both that are involved with this construction? (and, I guess, all concrete construction)
 
DZH22 said:
Kind of splitting hairs here, but rebar is made out of steel, correct? A lot of people have said there is no steel in this project, and it's concrete only. But, isn't it technically both that are involved with this construction? (and, I guess, all concrete construction)
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Reinforced concrete. The steel rebar is implied, as it is required. You can't have non-reinforced concrete. Sorry if I was unclear in my constant harping about there being no steel and confused anyone. I, and others, were simply trying to make the point that there are no "I-beams," unlike many other projects in Boston right now.
 
"I believe those "hockey pucks" you are describing on the large rebar are the alternative to the standard "rebar hook" technique."

And what's the "rebar hook" technique? the only rebar connections I can see are the wired connections where two pieces of rebar cross each other at right angles.
 
Gromit said:
"I believe those "hockey pucks" you are describing on the large rebar are the alternative to the standard "rebar hook" technique."

And what's the "rebar hook" technique? the only rebar connections I can see are the wired connections where two pieces of rebar cross each other at right angles.
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The rebar itself is physically bent/hooked at the end of its span within the concrete. This provides additional stability at the ends of the beam. I'm suspecting that those "pucks" are being welded to the ends of the large rebar to achieve the same purpose because the rebar may be too thick to bend properly.

135 DEG:
rst_illus_rebar-135-hook.png


180 DEG:
rst_illus_rebar-180-hook.png
 
Gromit said:
"I believe those "hockey pucks" you are describing on the large rebar are the alternative to the standard "rebar hook" technique."

And what's the "rebar hook" technique? the only rebar connections I can see are the wired connections where two pieces of rebar cross each other at right angles.
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The primary purpose of reinforcement in concrete is to resist tension forces arising from bending moment, uplift or lateral forces.

Hooking the reinforcing bar, usually either 90 deg or 180 deg transfers the tension in the bar to the concrete. As Data said it becomes more difficult to bend #8 (1" dia) reinforcement or larger, so fewer suppliers will carry them. There may also be not enough concrete to develop the full length or radius of the hook. For example a #10 bar would require at least 18" concrete depth to be properly developed. Or too many hooked bars close together may make a detail impractical. Or the contractor may want to split pours in such a way that a hook is impractical.

Here is a brief reference.

It is difficult to evaluate the reason for the detail you are asking about without some further description.

As an alternative the reinforcement may use a headed reinforcing bar which is a thick circular disk attached to the end of the bar. This detail is subset of mechanical fasteners of which there are other types particularly for splices.

The reinforcing 'connections' you described are for confinement or shear forces essentially for forces acting perpendicular to the main reinforcement. They are not really connected to each other, only tied together with heavy gauge wire to ensure proper placement.
 
They are called rebar terminators (http://www.erico.com/public/library/concrete/lt0434.pdf)

The rebar either comes threaded from the fab shop and the terminator is screwed on, or it is mechanically fastened to the end of a standard bar with set screws.

One big advantage of these is to reduce congestion in heavily reinforced areas (beams) where hooks on a large diameter bar is unfeasible.
 
datadyne007 said:
Excellent info paperless & Azimuth. Thanks for the details.
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Ditto from Gromit ! It took me a while to realize that the "hook" doesn't need to join another "hook" to do its job. It hooks into the concrete itself rather than onto another piece of rebar. Jetzt alles klar! danke.
 
If you are interested in the history of reinforced concrete, look no farther than Beverly, Massachusetts.

Highlights from an article located at a link below -

Engineer Ernest L. Ransome, who co-authored the 1912 book, "Reinforced Concrete Buildings", is noted for the use of iron rods to reinforce concrete.

His involvement in the construction of the massive United Shoe Machinery Corporation structure in Beverly, now the mixed-use Cummings Center.

In 1997, none other than architect critic (deceased) Ada Louise Huxtable, lauded the building, calling it the most significant concrete landmark in America. She described Ransome as "the father of reinforced concrete".

Her comments, the accomplishments of Ransome and the history of "The Shoe" can be found at this link,

http://www.cummings.com/arc.html

Pulitzer Prize winner Ms. Huxtable is shown here with Cummings Properties founder Bill Cummings in front of the complex.

hux.jpg


Some information on Cummings Center and more comments from Ms. Huxtable are found in this link,

http://www.cummings.com/ccinfo.html
 
Boston02124 said:
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This board had something of a collective freak out when the two seemingly mismatched types of glass started going up on the northeast face of the Burnham building, but the finished product ended up looking great.
 
EdMc said:
His involvement in the construction of the massive United Shoe Machinery Corporation structure in Beverly, now the mixed-use Cummings Center.

In 1997, none other than architect critic (deceased) Ada Louise Huxtable, lauded the building, calling it the most significant concrete landmark in America. She described Ransome as "the father of reinforced concrete".
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Well dang, my grandfather (RIP) worked at The Shoe right up to retirement and I had no idea it was so architecturally revered. Thanks for those links!
 
Yep, I remember hearing that "The Shoe" was a quarter mile long and that some employees who had to traverse the length of the building wore roller skates. Today, there are over 500 businesses. I've seen the factory many times from the road, now I'm going to have to pay my respect by going inside when I visit the folks next month.
 
They used cheap glass though. You can see the waviness, $2 more/sf would have made this wall sing.

cca
 
Given that it'll be more or less hidden by and reflecting the tower portion, I'm not sure that high quality glass was a priority on the Burnham portion. If the facade sampler is anything to go by, however, then the tower itself will have stunning glass.
 
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