Wednesday, March 07, 2012

Log Piles

I am currently working on a large job where the ownership group is retrofitting a historic structure in San Francisco to a more modern use. This structure was originally built following the 1906 earthquake in San Francisco. Part of the modernization process is the seismic and structural strengthening of the existing structure.

This strengthening includes modernizing the foundation which consists of 100+ year old wood piers as shown in the photos below. The building is partially in an area of engineered fill with a high water table and the piers have been perpetually saturated from the water table and a lack of oxygen. This has resulted in piers that are in a nearly pristine state. Many of these piers will remain in place as new micropiles are being added to accommodate the new use. There piers are being used to support five stories of masonry above.