Why vertical Shear (FZ) due to Prestress is minimum where the eccentricity is maximum?

Question:

The vertical shear force diagram due to PT is not being displayed correctly. Please provide help to identify flaws.
Answer:

The vertical shear(Fz) due to tendon primary would change with the curvature (sine theta) of the cable along the span.  


More the cable have angular change more would be vertical shear. As could be checked in the attached model, the cable profile is straight at the ends of the pier( start of the cable) hence the shear is minimum and same is true where the cable has more angular change, the shear would be maximum.
 


Consider another example of sample model file to to check> 




it can be understood with simple cantilever beam example below>

In the case below, the cable is curved at the anchorage location (right end) > Maximum vertical Shear Force  





In the case below, the cable is Straight at the anchorage location (right end) > minimum vertical Shear Force  




Regards,
Akshay Magar
Structural Engineer








Creation date: 6/30/2021 12:23 PM      Updated: 6/30/2021 5:32 PM
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