AASHTO Elastomeric Bearing Pad Question

[TypeIV]

In the LRFD, or any other AASHTO code, I don't understand the statement in the LRFD commentary for Stability of Elastomeric Bearings, C14.7.5.3.6, "This freedom to move horizontally should be distinguished from the question of whether the bearing is subject to shear deformations relevant to ....."

How is it distinguished?

 

[miecz]

All this is saying is that - If a keeper block is present, it prevents sidesway buckling, and equation 4 need not be checked. At the same time, horizontal shear deformation is possible due to thermal expansion and must be considered relevant to 14.7.5.3.4 and 14.7.5.3.5.