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At 3:20 AM on August 24, 2014, the West Napa/Franklin Faults slipped and unleashed a 5.0 magnitude earthquake that shock the Napa Valley, downtown Napa, and the Goodman Mansion, a certified historically significant landmark. A little over a year later, Forbes and Sons Construction was contracted to replace interior footings under the middle of the structure. However, during excavation and attempting to tie in the new footings to the existing perimeter foundation, they discovered that the existing concrete perimeter foundation was not really a concrete foundation. Not only was it not concrete, but it wasn’t a foundation after all. It was merely a facade, a mortar “saddle encasing”, around an un-reinforced, crumbling brick foundation. This inadequate fabrication escaped the notice of experts, engineers, and seismic inspectors. Had proper direction been given to the engineers, this oversight could have been avoided. Forbes and Sons also discovered that less than 15% of the structure was anchored to anything that would hold it in place.
     Photo 1-C: (Click on arrows above) External evidence of structural compromise.
     Photo 1-D: Diagonal bracing under the external siding ran from foundation to roof. According to Forbes and Sons, this is what saved the structure from being shaken off the existing, crumbling, un-reinforced brick foundation. (See “Photos 3” below for more details on the foundation.)

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The complete structure needed to be stabilized on I-Beams. Once stabilized, Forbes and Sons Construction was able to excavate and remove the existing, un-reinforced, brick footings underneath the middle of the house. It was at this stage Forbes discovered that the concrete perimeter foundation was not actually a foundation. It was merely a mortar saddle casing (window-dressing) and had no structural benefit.
     Photo 2-B - 2-D (Click on arrows above to see) show the new, properly engineered, reinforced concrete perimeter foundation with anchor bolts to tie down the structure.
    During the “shoring-in-place” phase, it was discovered that the building was not level. At this time they raised one side of the structure approximately four inches to level it.

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The above photo shows an un-reinforced, basement footing that failed.
     Photo 3-B shows an exterior view of the mortar “saddle casing” that deceived the inspectors and engineers into thinking the perimeter footing was a reinforced, concrete foundation. This mortar casing was merely window dressing poured to hide the original 1880s, frail, brick foundation.
     Photo 3-C shows an interior cutaway view of the un-reinforced mortar casing around the original un-reinforced brick foundation.
     Photo 3-D shows the surprise that Forbes and Sons discovered after excavating and removing the interior brick footings under the middle of the Goodman Mansion. When trying to tie the new reinforced concrete footings into the existing perimeter concrete foundation, they discovered that the perimeter foundation was actually not a concrete foundation, nor was it reinforced. (The rebar showing at the bottom of the photo comes from the new footings and would be used to tie into the existing perimeter foundation.)

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The Goodman Mansion, built in the 1880s in Napa, California, is listed as a historically significant structure under a number of registries, including, (N.R.P.) NATIONAL REGISTER PROPERTY; (N.R.D. - N.A.F.) – NATIONAL REGISTRY DISTRICT; and (L.P.) LANDMARK PROPERTY; among others. As such, any construction or repair work performed must be done in accordance with strict guidelines. These guidelines include a mandate to salvage, catalog, conserve, and re-use any original materials removed from the structure, if possible.
     The above photo shows how each item is numbered for cataloging, storing, and re-using.
     Photos 4-B - 4-C show the storage racks for warehousing items until needed for reconstruction.
     Photo 4-D shows a log sheet used for cataloging removed items.

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