huangyhg

rebar connection for precast retaining wall
i'm slightly apprehensive about using cast-in inserts (ferrules) for moment transfer across the precast-insitu joint for a precast wall panel with an insitu base.
attached shows the detail i'm considering, with the wall used as a retaining wall.
is it appropriate to use the full insert (ferrule) pull out value?
thanks, john
g'day john,
i generally only use the length of the anchor past the node point (assuming we are using a strut tie analysis) as contributing to the haeussler formula, so say you panel is 150thick 40mpa you have 40 cover and 12mm bar for the panel, rb12t1 (100 long). that leaves you say 40mm, thus
p = 0.972 x l^2 x b^2/3
where: p = pullout capacity of shear cone in newtons
l = effective embedment depth in mm
b = concrete compressive strength in mpa
max load is= 19kn compared to 79 max anchor strength.
this is fairly conservative, but i sleep well at night. and i justify this by the fact that reid bar when they did there test they used recessed foot anchor, thus a cast-in bolt wouldn't give them full strength. i would also confine the anchors with a few horizontal bars just for fun.

when in doubt, just take the next small step.

thanks rowingengineer
i feared as much, we are both reluctant to use full capacity.
the other detail i've used is with cogged bars protuding from the face with enough length for a normal coupler. its disadvantage is that the panels can't then be stacked, and the potential damage to the bar 'tails'.
are you aware of any other detail that could be used?
here is a sketch of a rw that i consider to be cheap and nasty. this is what i can rember off the top of my head for the small rw i did, i beleive we used a less than 10mm agg concrete and had a very nice note about how the concrete got vibrated around the 50diameter hole (can't rember if the hole was 50dia or 80dia). but i think you get the idea.
when in doubt, just take the next small step.

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借用达朗贝尔的名言：前进吧，你会得到信心!
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