If working was on upper PT bar instead lower one, probability of joint failure between member #11 and #12 as cause of collapse is significant higher.
Right now I'm really more confused by this picture.
Member #11, #12, north deck and canopy position after collapse without deformation/destruction.
Any find something wrong, point me about please for recheck.
I see single asymmetrical concrete truss and ABC as not the best choices for a bridge.
All must be perfect designed and executed. Full collapse was half second only when bridge was looking safe and stable like a rock.
I searched for images with reference points and angles in same plane and mixed with a software editor capable to work with layers and transparency, GIMP in my case.
Images used:
Confirmation for north end of deck:
No traces from end of #12 outside deck: