Bearing Plate Design of Precast Double Tee Dapped Stem

[JohnRwals]

Hi!

PCI released the 8th edition and changed dapped end plate design.
According to new method, hanger reinforcement needs to check bending diameter.
Sometimes, this bending pin diameter is UNREALISTICALLY too big.
As an example, when I modified with higher shear load condition and less concrete cover,
the diameter of bending pin could be 14".
(When only single vertical layer of strands should be used, hanger reinforcement should be two pieces of rebars.)

I would like to hear precast engineers' opinion about this new design method.

Thanks!
JR

 

[KootK]

1) I believe that the method is to address the concern expressed in my sketch below.

2) I believe that the current approach is intended to reflect the relatively new (to the US at least) curved bar node methodology for these situations.

3) I believe that the new provision is appropriate rather than excessive.

(When only single vertical layer of strands should be used, hanger reinforcement should be two pieces of rebars.)

4) I would not think that this shear transfer mechanism at the dap would be in any way related to the number of layers of flexural distressing strand. The one exception that I can think of is if some of of the shear is carried via harped prestressing strands. Even then, however, it's unlikely that the strands would develop meaningfully over the short length of the dap.