Safety Assessment Program Evaluator Student Manual

CA Emergency Mgmt. Agency Safety Assessment Program Evaluator Manual April 2011this building. This is an example of a longer term, more complex stabilization procedure that ispart of the repair process.The City of Santa Cruz deemed this building an imminent hazard. The potential for collapse wasgreat in even a moderate aftershock. Additionally, the building posed a significant threat to thepublic right-of-way. In this case, the roof and floors were removed, and the walls were stabilizedwith a system of “raker” shores. These are diagonal members connected together with steelbeams at the floor and the roofline. They are intended to replace the diaphragms and provideout-of-plane load support for the walls. The walls were damaged, but were still able to supportthemselves for in-plane loads. Each of these frames is in an “A” configuration to providemaximum support for the walls. During the repair process, these braces can remain in place untilsuch time as the new diaphragms are reconnected to the walls and can provide the lateral supportneeded for building stability. The raker shore frames are then removed and the final pieces ofthe diaphragm are installed. In this case, a building that was on the National Register of HistoricPlaces was saved, and the building was reopened for operation with an extended useful life.Photo courtesy Global Emergency ManagementFigure 3-13 – Marina District, San Francisco, 1989 Loma Prieta EarthquakeSometimes a building can look like a total loss, yet a simple method of stabilization can bedevised which can save the building from demolition. There were a number of buildings in SanFrancisco‟s Marina District that suffered soft story failure from the Loma Prieta Earthquake.The example in Figure 3-13 is definitely a potential collapse hazard, yet it was stabilized in arather simple manner. Large timbers, 8 by 8 or larger, were installed diagonally across thegarage openings. The braces were attached to the header across the top of all the openings. The93