Confinement Reinforcement at Concrete Beam Ends

[bobbyflair]

Hello everyone,

I would like to get some different opinions about a typical detail I run across for bridge piers and pile caps. Typically, I see U bars at the ends of pier caps and pile caps. I have attached examples from Texas DOT standard plans and Pennsylvania DOT standard plans. I have highlighted the bars I am talking about. I have already asked this question to senior engineers in the past and have been told they are confinement, but I feel like there is more backstory to it than just that.

I understand that these can help with confinement and may even help with the development length of longitudinal reinforcement if detailed a certain way. I have been trying to find some sort of guidance for the requirement of these bars at these locations but haven't been able to find anything. It is my opinion that if the design of the cap is done without considering the benefits from these bars (development length of longitudinal reinforcement is not a problem) then they shouldn't be required. What do you think, am I missing something?

 

[jhnblgr]

Temperature and shrinkage bars and help hold the rebar in place.