10105 19TH AVE SE Geotech Report 2018-01-02 MF Import

i , . . . ` Geotechnical Engineering Evaluation 1 Everett Veterinary Clinic February 21,2002 � NGA File No. 342902 Page l l assumption tliat tfie traffic will consist predominately of passenger cars and only cecasional light-tu medium-sized trucks. We assumed a pavement design life span of 20 years in our design. We have ( assumed the pavement subbase to be well-compacted granular subgrade. Some overexcavation and replacement with compacted granular fill might be needed to ach?eve a suitable subgrade. � � Site Drainage Surface Dreinege: The finished ground surface should be graded such that storm water is direcled to an Iappropriate storm water collection system. Water should not be allowed to st�nd in any ar�..a where footings, slabs,or pavements are to be constructed. �nal site grades should allow for drainage away from Ithe building. We suggest lhat the finished ground be sloped at a minimum gradient uf 3 percent for a distance of at least !0 feet away from the building. Surface water should be collected by permanent catch , basins and drain lines,and be discharged into an appropriate discharge system. Subsurfece Dralnage: We recommend fhe use of footing drains around the structure and behind all � �- retaining walls. Footing drains should be installed at least ! foot below plunned finished Floor slab. The L drains should consist of minimum 4-inch{liameter, rigid, slotted or perforated, PVC pipe surrounded by free-draining material wrapped in a filter fnbric. We recommend that the free-draining material consist of an 18-inch-wide zone of clean (less than 3 percent fines), granular material placed along the back of the I_ wall. Pea gravel is an acceptable drain material or drainage composite may also be used instead. The free-drnining muterial should extend up the wall to 1 foot below the finished surt'ace. The top foot of soil Ishould consist of impermeable �oil placed over pl•rstic sheeting or building paper to minim�u surfece water or fines migration into the footing drain. Footing drnins should discharge into tightlines leading to Ian appropriate collection and discharge point with convenient clennouts to prolong the useful life of the drains. Roof drains should not be connected to wall or footing drnins. i Shallow perched storm water may be encountered in building or utility excavations. If ground kvater is , encountered, the bottom of the excavation should bi sloped to drnin ro a low area where a sump and pump system should be installed and water pumped out oF the excavation. If severe seepage is encountered, cutoff or curtain drains may need to be installed on the uphill side of the planned excavations to capture Iground water and route it around the area to be developed. The need, extent, and depth of these drains should be determined at the tim:of construction, based on prevalent condition^.. � 12 NELSON GEOTECHN/CAL ASSOC/ATES, INC.