Our building is cracking at the corners even though the walls have regularly spaced expansion joints. At about a third of the joints, the sealant has squeezed out. This indicates to me that the joints are working. What is causing the cracking?

If the sealant has squeezed out of the expansion joint, the movement is greater than the sealant joint can accommodate. Either the sealant does not have adequate compressibility, or the expansion joint is too narrow. In any case, after the expansion joint stopped working, the cracking may have occurred as a result of thermal or moisture expansion of the brick.

The fact that not all of the joints indicate movement could mean that they are blocked or bridged. This could also explain why the joints that are functioning are moving more than expected. I recommend removing the sealant from those joints where it has not squeezed out to see if the movement is impeded. You should also check the spacing of the joints to see if more joints are required. If more joints are required, they can be introduced by saw-cutting completely through the wythe. Before doing this, make sure that the masonry will have adequate structural support.