Pier Design
Pier Design
(OP)
I am trying to design a small pier (4' x 6') to support a fish ladder in a river. We have already designed the pier itself. We cant figure out the foundation. The tough part is the dam the fish ladder is connected to is under a bridge. Also, under the bottom of there pier will be solid rock. There is no soil at all. We are not sure how to form the foundation of the pier. The water is relatively shallow, <10', and flows are not too high. There is no head room for a cofferdam because of low bridge clearance.
Any ideas?
Any ideas?






RE: Pier Design
Never, but never question engineer's judgement
RE: Pier Design
1. Select the location with relatively flat rock surface to place the pier.
2. Sizing the footing pad dimension, and forming underwater.
3. Place steel casing, just above the water and a distance above the bed rock, and place the concrete.
If sliding is a concern, you can key the footing into the rock by excavation, or install epoxy drill in dowells to fasten it.
An experienced under water construction contractor is essential in this case. Also, the season/timing of construction is quite important, to which affects water deepth and velocity of flow, if you have control over it.
RE: Pier Design