Hi I’m a graduate student at the University of Oregon doing some research on H-blocks (double-open-ended, speed block). While its pretty scarce around here I have heard that its relatively prolific in California (due to rebar spacing based on seismic issues). I’m coming at this from an ergonomics perspective though I am an architecture student. Does anyone have any experience designing/ working with H-block? Any info would be greatly appreciated.
Thanks,
Morgan
Years ago we taught the masonry design course for the Army Corps of Engineers and they were always pushing the use of open-ended units. It makes great sense to me - no need to thread the block over rebar. Maybe more importanly is that the rebar can be in place, sticking up out of the foundation or the previous lift, before the block is laid. From an inspection/QA standpoint that makes it easy to verify proper steel placement.
I’ve heard (although not sure I believe) that there is a lot of breakage during shipment becuause the end web is missing. Other contractors have told me that there really wasn’t that much breakage.
I’ve also heard that open-end units are used in the Omaha area, because there is a producer there that really pushes them. I don’t know why it isn’t used more, really. Seems like productivity would increase and quality would be better.
You might want to talk to some people at the National Concrete Masonry Association or Masonry Institute of America and see if they have any info on pruduction rates.