I guess this "Curious Item" (Post 2447) *may* be this new DWR closeup picture. I've never seen such "snake looking" twisting of such a variety of rebar before. The closest would be the twisted rebar exposed from the crunched columns in the Oakland Cypress Street Viaduct after the 1989 Loma Prieta earthquake.
Wild.
Rebar Creature in Canyon.
Crunched columns & rebar from 1989 Loma Prieta earthquake (Oakland Cypress Street Viaduct).
That’s a lot of rebar - and it illustrates a rather violent demise of that section of the spillway! Water can be a real monster!
Could be where the wall rests atop the wall footing.
Standard construction practice is to place the footing first, with plenty of rebar sticking up to tie the wall securely to the footing. Then the wall forms are built around those ties after additional wall reinforcing rebar is placed.
Also, the tie rebar will need to be set off center toward the backfill face, so as to resist the overturning moment forces of the backfill.
I think I can explain the twisted ends for any interested — I know you understand it.
Usually, rebar is lapped something like 30 multiples of its diameter. This number goes up or down depending upon the thickness and placement in the design. It is tied together in that lap with annealed tie wire which has no strength after assembly. The deformations hold it from tension forces and the stressed are communicated because of development in bond of the lap.
When the initial break comes to the whole reinforced concrete member, the member bends and concrete crumbles at the break. As the forces continue to move part of the broken structural member, the crumbling continues until the bar is exposed enough to either expose laps that now separate or expose small counts of bar the the shearing of separation. These bars have become brittle from the repeated bending after the initial break in the member.
So what you end up with is bar bent to show where the member remnants were twisted in position at the time that the lap bar separated holding the broken piece in place. As the broken “wing” doesn’t break all the bar at once, the bars are twisted in different places as the wing finally separates.