Shear walls are usually heaviest at the base, where seismic forces are strongest, and become thinner as they go up through the building. Braced framing stretches diagonally from the beam and column joints to create a triangulated vertical frame. Bracing limits building design because it requires consistent floor design so the braces can go through from top to bottom without interrupting the usage of space. If each floor is programmatically different, positioning the bracing is an architectural challenge. Bracing may be shaped in a variety of ways-x, v, and chevron shapes are among the most common.
Dampers soak up the energy of earthquake-induced motion, thereby limiting structural damage.
They are also effective at stopping the swinging motion a building is prone to with earthquake vibrations. All three have basically the same effect, allowing the building to move independently of the shifting ground. They perform differently, however. Rubber or elastomeric isolators are available in varying degrees of softness which allow different levels of movement. These allow the building to move, but pull it back into place.