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The dangers in this photograph may not immediately be apparent. This is the view from around 11:00AM after we escaped two z-forms collapsing in our ditch. Actually it was a collapse of dirt that fell from beneath the sidewalk that knocked over the 24' steel z-forms. Anyhow...
Credit where it's due - our good fortune owes to the quick reflexes of the track-hoe operator, whose bucket crashed through the ladder in place to block the falling steel forms.
Here's the video from 8:30 that morning (and yes, those are folks working in an unshored tunnel under the steam tunnel...) where the forms are all "in place."
Look forward to an update on this - I don't have a copy of the International Building Code that gives actual numbers for setting z-forms (those long narrow steel plates) however the rule of thumb we were told was approximately one foot in the ground for every two feet above it... These are 24' forms in a 21-22' ditch and in many places the forms are sticking out ABOVE the trenchline.....
Setting z-forms may be a difficult process, and occasionally requires additional machinery. Moreover it is not uncommon to lose pieces of steel into the ground - retrieval being near-impossible. I guess the good news is that no z-forms were lost in this dig...
The other puzzler to me is that here after the collapse we now have a completely undermined sidewalk for a span of fifteen feet.... I guess it's like they say "watch for cracks in the sidewalk..." Had any of that fallen into the ditch there is no question that it would have demolished what little shoring was there.
Additional credits - Faulconer Construction on the ditch, WM Jordan general contractor, and Dear ole' UVa is to thank for bringing them together to build the CAS building.... maybe tomorrow we'll talk about how absolutely unnecessary this entire ditch line was to begin with (and how grossly incompetent the engineers were)... another story for another day...
