Photo Credit: Alex Mead
The parking structure above is a perfect example of earthquake retrofitting a structure. The crisscrossed red members on the front of the structure were added after the completion of the building to increase the strength in the event of an earthquake. If you look closely the connections of the frame to the ground are pin connections. These pin connections literally are large plates with simple holes connected by a rod. These pin connections allow for rotation of the joint, but do not allow the frame to move up, down, or side to side apart from ground motion.