Pragmatic Seismic Solutions

03/10/2017

10/26/2016

https://www.youtube.com/shared?ci=uNkz3CFrIh8

peare sada shared a video

10/26/2016

https://www.youtube.com/shared?ci=CkPmdDIDp4o

peare sada shared a video

10/26/2016

https://www.youtube.com/shared?ci=io5Mxf1pdHE

peare sada shared a video

10/26/2016

https://www.youtube.com/shared?ci=JLafKdAmIOY

peare sada shared a video

10/25/2016

https://www.youtube.com/shared?ci=vmCIi69WdHM

peare sada shared a video

10/22/2016

Does Retrofitting Work?

This fascinating report comes courtesy of the American Plywood Association

Santa Cruz Victorian Becomes Seismic Design Laboratory
In 1989, at the corner of Center and Elm streets in downtown Santa Cruz California, architect Michael O’Hearn unwittingly created a laboratory for the study of seismic retrofit design.

On that corner, at 214 and 210 Elm Street were two identical Victorian style homes. According to O’Hearn, the twins were built 90-100 years ago, by the same builder, with identical materials and using the same construction techniques.By 1984 when O’Hearn bought them, both houses had been through multiple remodels.

Although originally designed as single family homes, 210 Elm Street had become a five-plex, and 214 a four-plex. O’Hearn remodeled the pair yet again.He started by retrofitting #210, installing plywood panels as a sheer element on the cripple
walls. The sill plate was also bolted to the foundation. Unfortunately, there was no time to retrofit #214 before the 7.3 Loma Prieta earthquake hit on October 17, 1989.

In a sense, 214 Elm Street served as the control element in this unlikely experiment. “The building came apart in four sections, ” O’Hearn said. By contrast, 210 Elm Street, with its plywood shear panels and bolted foundation, suffered only minor damage. “The one that we had done some seismic structural work on ( #210) probably cost us $5,000 to repair. The other one ( #214) cost us $260,000 to repair” he said. “The whole building had to be jacked up and slid back together on a new foundation.

“For homes more than 20 years old located in areas of seismic activity, I strongly urge owners to consider seismic retrofitting,” O’Hearn said. “It’s cheaper to retrofit now than to repair after a quake”