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2017WinterShotcreteEMag

2016 Honorable Mention The Pacific By Jason Myers The Pacific, at 2155 Webster Street in San Francisco, CA, is a concrete building with two levels below grade and nine levels above grade with a total of over 250,000 ft2 (23,000 m2) of usable space. The building was constructed and completed in 1967 and spent most of its life as the University of Pacific School of Dentistry. The Dentistry school moved to a new location in 2014. After the school departed, the building was repurposed into 77 condominium units and 10 townhomes. As part of the repurposing, the existing façade of precast concrete was removed to allow for the installation of fullheight windows. This lightened the weight of the building considerably but in turn reduced its structural strength and rigidity. As part of the repurposing, the building needed to be brought up to current seismic codes. As a result, the building required extensive new strengthening of the shear walls and columns. The shotcreted additions to the shear walls were between 8 and 18 in. (20 and 45 mm) thick with typical field reinforcement of No. 7 (No. 22 metric bar) bars at 6 in. (15 mm) on center with various boundary element conditions. Additionally, all the columns not encased in existing or new shear walls were jacketed with shotcrete. This typically involved over 20 columns per floor. Overall, the project used over 1750 yd3 (1340 m3) of shotcrete and covered 65,000 ft2 (6000 m2) of surface area. One of the difficulties on the project was coordination, but ultimately this also showed one of the strengths of shotcrete. Due to existing site conditions, there were a lot of redesign issues as well as wall modifications because existing concrete sections were not plumb and straight. With the flexibility of shotcrete, we were able to easily increase the wall thickness areas as required to get proper reinforcement clearances. Also, with our easily moved shotcrete operations, we could move to different walls as the schedule Fig. 1: Typical reinforcement for shear walls and boundary elements on the fourth floor Fig. 2: Column encasement and shear walls reinforcement on the first-floor level 56 Shotcrete | Winter 2017 www.shotcrete.org


2017WinterShotcreteEMag
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