2201 100TH ST SW AD SYSTEMS 2022-03-07

GeoTest Services, Inc. April 25,2017 2201 100th Street Southwest, Everett,WA Job No. 17-0186 should evaluate how the new design loads compare to the design loads for the existing building that was constructed in 1996. Depending on the results of this evaluation, it may be necessary for GTS to revise our recommendations in this section. Also note that there is a potential for cracking along the joints of both old and new foundations that may become more visible as a result of the new construction once the loads are applied to the new foundations. Allowable Bearing Capacity Assuming the above foundation support criteria are satisfied, continuous and individual spread footings founded directly on compacted structural fill placed directly over undisturbed, medium dense to dense, native soils, or on compacted structural fill placed atop these soils, may be proportioned using a net allowable soil bearing pressure of 2,500 pounds per square foot (psf). . The term "net allowable bearing pressure" refers to the pressure that can be imposed on the soil at foundation level resulting from the total of all dead plus live loads, exclusive of the weight of the footing or any backfill placed above the footing. The net allowable bearing pressure may be increased by one-third for transient wind or seismic loads. Foundation Settlement Settlement of shallow foundations depends on foundation size and bearing pressure, as well as the strength and compressibility characteristics of the underlying soil. Assuming construction is accomplished as previously recommended and for the maximum allowable soil bearing pressure recommended above, we estimate the total settlement of building foundations should be less than about one inch and differential settlement between two adjacent load-bearing components supported on competent soil should be less than about one half the total settlement. Because the new warehouse will be constructed adjacent to the existing building, there may be a potential for differential settlement between both the old and new structures, since the existing building was constructed in 1996 and thus would have already undergone some settlement over time. Floor Support Conventional slab-on-grade floor construction is considered feasible for the planned site improvements. Floor slabs may be supported on properly placed and compacted structural fill placed over properly prepared native soil. Prior to placement of any new structural fill for slab subgrade preparation, the native soil and/or existing fill subgrade should be proof-rolled as recommended in the Site Preparation and Earthwork section of this report and approved for continued construction. We recommend that interior concrete slab-on-grade floors be underlain by a minimum of 6 inches of compacted, clean, free-draining gravel with less than 3 percent passing the U.S. Standard No. 200 sieve (based on a wet sieve analysis of that portion passing the U.S. Standard No. 4 sieve). The purpose of this layer is to provide uniform support for the slab, provide a capillary break, and act as a drainage layer. If desired, additional protection against water intrusion below the slab could include a slab underdrain system to collect and direct water, if present, toward an approved discharge point. - Page 8 of 13