1310 SE EVERETT MALL WAY Geotech Report 2022-10-25

' , Darden Restaurants, Inc. September 15,2011 Proposed Olive Garden—Everett,Washington Page 8 of 12 damage should some settlement of the supporting subgrade take place. ■ Cracking of slabs-on-grade is normal and should be expected. Cracking can occur not only because of heaving or compression of the supporting soil, but also because of concrete curing stresses. The occurrence of concrete shrinkage cracks, and problems associated with concrete curing may be reduced and/or controlled by limiting the water/cement ratio of the concrete, proper concrete placement, finishing, and curing, and by the placement of crack control joints at frequent intervals, particularly, where re-entrant slab corners occur. The American Concrete Institute (ACI) recommends a maximum panel size (in feet) equal to approximately three times the thickness of the slab (in inches) in both directions. For example, joints are recommended at a maximum spacing of 12 feet, assuming a four-inch thick slab. We recommend also that control joints be scored three feet in from, and parallel to, the foundation walls. Using fiber reinforcement in the concrete can also control shrinkage cracking. ■ Some increase in moisture content is inevitable because of development and associated landscaping. However, extreme moisture content increases can be largely controlled by proper and responsible site drainage, building maintenance and irrigation practices. ■ Backfill in areas supporting slabs should be moisture conditioned or dried by scarification and compacted. Backfill in all interior and exterior water and sewer line trenches should be carefully compacted. ■ Exterior slabs should be isolated from the building. These slabs should be reinforced to function as independent units. Movement of these slabs should not be transmitted to the building foundation or superstructure. 3.7 Drainaqe Considerations Water should not be allowed to collect in the foundation excavation, on the floor slab areas, or on prepared subgrade of the construction area either during or after construction. PSI recommends that footing drains be placed around the exterior of the building foundation to reduce the potential for migration of moisture into the building envelope. PSI recommends that roof drains be connected to a tightline leading to storm drain facilities. Pavement surfaces and open space areas should be sloped such that surface water runoff is collected and routed to suitable discharge points. We also recommend that ground surfaces adjacent to buildings be sloped to facilitate positive drainage away from the building. 3.8 Earthquake and Seismic Desiqn Considerations The project site is located within a municipality that employs the International Building Code, 2009 edition. As part of this code, the design of structures must consider dynamic forces resulting from seismic events. These forces are dependent upon the magnitude of the earthquake event as well as the properties of the soils that underlie the site. As part of the procedure to evaluate seismic forces, the code requires the evaluation of the Seismic Site Class, which categorizes the site based upon the characteristics of the subsurface profile within the upper 100 feet of the ground surface. To define the Site Class for this project, we have interpreted the results of soil test borings drilled within the project site and estimated appropriate soil properties below the base of