7800 EVERGREEN WAY HYUNDAI Wetland Report 2025-08-05

If temporary cut slopes experience excessive sloughing or raveling during construction, it may become necessary to modify the cutslopes to maintain safe working conditions. Slopes experiencing problems can be flattened, regraded to add intermediate slope benches, or additional dewatering can be provided if the poor slope performance is related to groundwater seepage. 4.6. Pavement Recommendations 4.6.1.Subgrade Preparation We recommend the subgrade soils in new at -grade pavement areas be prepared and evaluated as described in Section 4.7.2. Pavement subgrade conditions should be observed during construction and prior to placing the subbase materials in order to evaluate the presence of zones of unsuitable subgrade soils and the need for overexcavation and replacement of these zones. 4.6.2. New Hot Mix Asphalt Pavement In light -duty pavement areas (e.g., automobile parking), we recommend a pavement section consisting of at least a 3-inch thickness of 1/2-inch hot -mix asphalt (HMA) per WSDOT Sections 5-04 and 9-03, over a 4-inch thickness of densely compacted CSBC per WSDOT Section 9-03.9(3). In heavy-duty pavement areas (such as driveways, truck traffic lanes, materials delivery), we recommend a pavement section consisting of at least a 4-inch thickness of 1/2-inch HMA over a 6-inch thickness of densely compacted CSBC. The base course should be compacted to at least 95 percent of the MDD obtained using ASTM D 1557. We recommend that proof -rolling of the subgrade and compacted base course be observed by a representative from our firm prior to paving. Soft or yielding zones observed during proof -rolling may require overexcavation and replacement with compacted structural fill. The pavement sections recommended above are based on our experience. Thicker asphalt sections may be needed based on the actual traffic data, truck loads, and intended use. All paved and landscaped areas should be graded so that surface drainage is directed to appropriate catch basins. 4.6.3. Portland Cement Concrete Pavement Portland cement concrete (PCC) sections may be considered for areas where concentrated heavy loads may occur. We recommend thatthese pavements consist of at least 6 inches of PCC over 6 inches of CSBC over a 12-inch-thick subbase. A thicker concrete section may be needed based on the actual load data for use of the area. If the concrete pavement will have doweled joints, we recommend that the concrete thickness be increased by an amount equal to the diameter of the dowels. The base and subbase layers should be compacted to at least 95 percent of the MDD. The subbase layer may consist of imported gravel borrow or common borrow. We recommend PCC pavements incorporate construction joints and/or crack control joints spaced at maximum distances of 12 feet apart, center -to -center, in both the longitudinal and transverse directions. Crack control joints may be created by placing an insert or groove into the fresh concrete surface during finishing, or by saw cutting the concrete after it has initially set-up. We recommend the depth of the crack control joints be approximately one-fourth the thickness of the concrete, or about 11/2 inches deep for the recommended concrete thickness of 6 inches. We also recommend the crack control joints be sealed with an appropriate sealant to help restrict water infiltration into the joints. GEOENGINEER� December6, 2021 Page 7 File No. 24 59-003-00