Questions To Ask When Planning Seismic Retrofit:

These questions should be asked with the assistance of the team to determine acceptable alternatives. Since there is never a single right answer, the design team and code officials should work together to determine the appropriate level of seismic retrofit with the lowest visual impact on the significant spaces, features, and finishes of both the interior and exterior of historic buildings.

As with the illustrations above, this guide is not intended to proscribe how seismic retrofit should be done, but rather, to illustrate that every physical change to a building will have some consequence. By asking how impacts can be reduced, the owner will have several options from which to choose.

»Can bracing be installed without damaging decorative details or appearance of parapets, chimneys, or balconies?

»Are the visible features of the reinforcement, such as anchor washers or exterior buttresses adequately designed to blend with the historic building?

»Can hidden or grouted bolts be set on an angle to tie floors and walls together, instead of using traditional bolts and exposed washers or rosettes on ornamental exteriors?

»Are diagonal frames, such as X, K, or struts located to have a minimal impact on the primary facade? Are they set back and painted a receding color if visible through windows or storefronts?

»Can moment frames or reinforced bracing be added around historic storefronts in order to avoid unsightly exposed reinforcement, such as X braces, within the immediate viewing range of the public?

»Can shorter sections of reinforcement be "stitched" into the existing building to avoid removal of large sections of historic materials? This is particularly true for the insertion of roof framing supports.

»Can shear walls be located in utilitarian interior spaces to reduce the impact on finishes in the primary areas?

»Are there situations where thinner applied fiber reinforced coating would adequately strenghten walls or supports without the need for heavier reinforced concrete?

»Can diaphragms be added to non-significant floors in order to protect highly decorated ceilings below, or the reverse if the floor is more ornamental than the ceiling?

»Are there adequate funds to retain, repair, or reinstall ornamental finishes once structural reinforcements have been installed?

»Should base isolation, wall damping systems, or core drilling be considered? Are they protecting significant materials by reducing the amount of intervention?

»Are the seismic treatments being considered "reversible" in a way that allows the most amount of historic materials to be retained and allows future repair and restoration?