Building 22 is a group of five connected buildings, including four of the oldest buildings in San Quentin.  The oldest part of Building 22 includes the Dungeon, built in 1854, and may have been the oldest building in the State of California.  The retrofit typically included new plywood diaphragms, steel braced frames on the interior at the upper two levels, and concrete shear walls at the first level.  In the highly historically sensitive Dungeon, the retrofit included micropiles installed through the existing masonry walls, and limited new concrete shear walls.  The existing masonry barrel roof was replaced with a concrete diaphragm except for the last exposed wythe. 

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