Week 70 (North bond beam progress)

The star of this week’s show is the North bond beam.  Last week the framing went up to support the bond beam, and this week the blocks started going up.  First things first: the blocks are graded and the ones that make the grade are placed into position:

gradedblocks.jpg

There are actually a lot more than that…

moregradedblocks.jpg

The first block is placed on the frame:

firstnorthbondblock.jpg

I’ll pause here to reflect on what the above picture demonstrates: everything gets measured at every step.  Remember last week how carefully we measured the level of the frame?  Well, it all gets measured again.  As does the second block that’s placed.  Note the small blue object in the mason’s hand (which you can see in detail by clicking the photo).  That’s a 1/16th inch spacer, used to even up the level of the top of the block:

secondnorthbondblock.jpg

Another mason does the same thing coming from the other side:

oppositenorthbondblock.jpg

Despite having more than 50 specific types of prefabricated blocks, this part of the job requires us to “take apart” our standard blocks.  Here’s a block that’s been notched along its length to function as a bond beam, and across its middle to hold soffit steel:

soffitbondblockcut.jpg

Progress:

northbondbeamprogress.jpg

The empty bond beams, in progress, from above:

emptybondbeams.jpg

By the end of the week, the bond beams are laced with steel, and lots of it.  The engineer originally called for 3 pieces of #5 rebar (5/8″) with 1″ minimum concrete surrounding each piece.  For reasons known only to them, the block manufacturer has two types of bond beam blocks designated by the code “8UF”, one shaped like a “U” (which is the standard bond beam and/or lintel shape) and one shaped like a “V”.  They made us “V” shaped blocks and the shape of the “V” was too narrow to meet the engineer’s requirements.  Our crew chief suggested that instead of 3 pieces in each of the two outer beams, we could place 2 pieces across the three effective bond beam members.  Here’s how large that #5 rebar looks in context:

number5rebardetail.jpg

Not only is it pretty chunky, but the 20′ lengths overlap by a good 6′.  See how quickly these “V” shapes are filled:

number5rebarlong.jpg

Now the matrix of the shear wall, bond beam, and soffit steel show their interleaved, interlocking nature:

shearwallmatrix.jpg

The second course of the three-course bond beam begins to take shape:

northbondbeamcourse2.jpg

Meanwhile, the South shear walls received two lifts of grout, making our grout piles that much smaller:

groutsandpile.jpg

Finally, the shape and dimensions of the Music Room soffit are now apparent in outline:

soffitsteel.jpg

With luck we’ll have continued good weather, and perhaps a completed bond beam by the end of next week.  We’ll see!

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