Structural Design of Bridge Abutment

[Demonic996TT]

Hello All,
I am new to the board and am designing the steel for a bridge abutment. The 4'8" wide, 5'6" in height 24' long abutment sits upon a footing which is 7'8" wide, 25' long and 30" deep. The abutment sits 1ft to the right eccentric on top of the footing. I have designed for Temp/Shrinkage according to AASHTO and provided greater than 1/8 in sq per ft of height. My question is can flexure reinforcement be neglected? As far as shear, would it be valid to use the end reaction for HS20 live load plus the dead as Vu? As far as connecting the footing to the abutment, I treated the abutment as a cantilever resisting Pa and Ps (active and surcharge pressures) as well as braking forces; took the moment at the fixed point as design moment and provided adequate development length. Does this sound correct?

 

[vandede427]

How could you possibly design the abutment as a cantilever and neglect flexural reinforcement?

 

[Demonic996TT]

I neglected steel along the bottom of the abutment(where the abutment sits on the footing); what I am trying to design is the amount of steel extended down into the footing from the abutment (essentialy what would be flexural reinforcement in a cantilever). Does this make sense?

 

[ishvaaag]

Any containment structure that uses walls will have to respect the mechanic of the loadings. Some of the biggest moments at cantilever walls (even if folded plates in plan) will be at their roots, hence the flexural reinforcement needs to be properly anchored in the footing ... it is a continuum.

 

[DaveAtkins]

It will be the same as the steel in the abutment--assuming you properly designed the abutment for the moment where abutment meets footing.

DaveAtkins