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Historic Retrofit & Renovation

ISI has been retained by private owners and developers to renovate and retrofit many bay area buildings, several of which are on the Berkeley, Oakland and State of California Historical Landmark Register. ISI appeals to prospective clients’ due to our integrated design approach which integrates the architecture, the engineering and the construction materials and methods. ISI always approaches a retrofit by working with the historical structure’s inherent strength, which has proven itself by performing, in many cases for a hundred years or more and which was mostly designed by competent engineers and architects from an earlier era. Although this approach fly’s in the face of the typical approach, which disregards the inherent strength as outdated, it results in a cost efficient seismic retrofit leaving additional funds for renovation.

Hobart Hall, Berkeley, CA

When we began the project, Hobart, Julia Morgan’s flagship building for the American Baptist Seminary campus, was listed on the Berkeley un-reinforced masonry schedule. During our first reconnaissance, it became clear that the building had been improperly listed. What appeared to be brick bearing walls were in-fact brick facades over a reinforced concrete frame. This discovery enabled the building to be removed from the URM schedule and then seismically retrofitted under a “voluntary,” plan significantly reducing the cost. 

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Tioga - Seismic Retrofit, Berkeley, CA

The Tioga building was the first “Lift Slab” building to be constructed in California. Lift slab construction received a bad reputation after a 10-story building collapsed during construction killing 28 workers and engineers have deemed the construction unsafe since the 1987 collapse. However, there is nothing inherently unsafe about the system and upon investigation we found the building in excellent condition with high quality workmanship. Its only deficiency, based on the 2014Internationa Building Code, was seismic shear and torsion. To address the seismic deficiency while simultaneously making an architectural statement, the team at ISI designed the first tree-branching steel frame ever conceived.


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Second Church of Christ Scientist, Berkeley, CA

The Second Christian Science church is a Berkeley historical landmark and was on the unreinforced masonry ordinance. It couldn’t be demolished because of its landmark status and it couldn’t be retrofitted because the price tag was $5mill, far above the means of a 100-person congregation. ISI proposed a novel solution of injecting foam into the wall cavity to make both wythes of block work in concert (like a surfboard or SIP panel) and after testing two wall samples under a peer review process was issued a permit by the city of Berkeley for the retrofit. The total cost including permits, engineering and construction was less than $500,000, one tenth the cost of the traditional approach.

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