1010 N BROADWAY EVCC 2018-01-01 MF Import

PROPOSED LIBERTY HALL,EVERETT COMMUNITY COLLEGE r Everett,Washington A.4-inch;diameter perforated drain pipe should be installed within the free-draining material at the base of each wall. We recommend using either heavy-wall solid pipe (SDR-35 PVC) or rigid corrugated polyethylene pipe (ADS N-12, or equal). We recommend against using flexible tubing for the wall drain pipe. The footing drain recommended above can be incorporated into the bottom of the drainage zone and used for this purpose. The pipes should be laid with minimum slopes of one-quarter percent and discharge into the storm water collection system to convey the water off site. The pipe installations should include a cleanout riser with cover located at the upper end of each pipe run. The cleanouts could be placed in flush mounted access boxes. Collected downspout water should be routed to appropriate discharge points in separate pipe systems. Pavement Recommendations Subgrade Preparation We recommend the subgrade soils in new pavement areas be prepared and evaluated as described in the "Earthwork" section of this report. We recommend placing a 12-inch thick imported gravel borrow subbase layer below the pavement sections described below. If the subgrade soils are excessively loose or soft, it may be necessary to excavate localized areas and replace them with additional gravel borrow or gravel base material. Pavement subgrade conditions should be observed and proof-rolled during construction and prior to placing the subbase materials in order to evaluate the presence of unsuitable subgrade soils and the need for over-excavation and placement of a geotextile separator. New Hot Mix Asphalt(HMA)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-inch HMA(PG 58-22) per WSDOT Sections 5-04 and 9-03,over a 4-inch thickness of densely compacted crushed rock base course per WSDOT Section 9-03.9(3). In heavy-duty pavement areas (e.g., truck traffic areas, materials delivery)around the building, we recommend a pavement section consisting of at least a 4-inch thickness of 1/2-inch HMA (PG 58-22) over a 6-inch thickness of densely compacted crushed rock base course. The base course should be compacted to •at least 95 percent of the maximum dry density (ASTM D 1557). We recommend that a proof-roll of the compacted base course be observed by a • representative from our firm prior to paving. Soft or yielding areas observed during proof-rolling may require over-excavation 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 subgrade conditions,traffic data and intended use. Portland Cement Concrete Pavement Portland cement concrete (PCC) sections should be considered for loading dock aprons, trash dumpster areas and where other concentrated heavy loads may occur. We recommend that these pavements consist of at least 6 inches of PCC over 6 inches of crushed surfacing base course. A thicker concrete section may be needed based on the actual traffic data. If the concrete pavement will have doweled joints, we recommend that the concrete thickness be increased by an amount GEOENGINEERS� June 10,2010 _ Page 19 File No.5836-010-00