Maximum height of hauling wall abutment in rock ?

[tatox]

Hi
We got the hauling bridge that may had tall abutment. The soil in near river was too soft, with rock bottom, and the extended length bridge will lay on the mudstone rock. I believe extending the bridge will give more confidence since the pier near river will be very high, with 18m soft soil and directly to rock.
Since the extending will lay on the rock, i suggesting some caisson foundation or shaft foundation. We are suggesting that height of the abutment max height will be 8-9m for pre-eliminary (not yet counted), while some US code gave max 3-4m, and canada around 10m.
When it very tall, i doubt the caisson will be support out overturning, and will need shaft pile for foundation.
What the max height abutment by the code? or possible assume bottom is rock kayer.

 

[BridgeSmith]

There are no height limitations in the bridge design specifications. The abutment will have to be designed for the loading. With a tall wall on caissons, this would typically be accomplished with 2 rows of caissons - a front row in bearing, and a back row to resist uplift/overturning.