Options for reinforcing baseplate for increased lateral load

[EngDM]

Hey all,

What are my options if I determine that an existing baseplate / anchor bolt configuration is inadequate for the new lateral loads due to a new crane? Is the typical solution to weld on a plate extension with new bolts such that shear is satisfied and increase the pilaster width and dowel this new concrete to the existing concrete, perhaps providing a concrete bonding agent between the two pours?

When you have two concrete pours, is my understanding correct that the breakout cones still stop at the interface of the two pours?

 

[icebloom]

We have done baseplate extensions with drill and epoxy anchors previously for rectifications of this kind, with full butt weld between the existing plate and the new plate. Can also weld ribs/gussets as required to help spread the load.

If shear load transfer is perpendicular to the joint between the two pours (i.e. compressive in nature across the joint) I'd say you could consider the concrete as monolithic for analysis purposes. This will not be entirely accurate however if there is shear or tension across the joint, or if your dowels have tension in them from any uplift forces.

The best outcome for the joint would be to either use a bonding agent, mechanical roughening of the joint post pour, or even the roughening plus the bonding agent.

 

[canwesteng]

You should detail the reinforcement to transfer the shear between the two piers. In the past I've welded on "arms" to the column with plates allowing these to bear directly on the pedestal instead of relying on shear breakout.