Mendenhall Valley Library

To accurately assess the existing subsurface conditions at the site two types of field exploration methods were employed; CME-55 truck mounted drill test holes and excavator machine dug test pits. Four (4) drill test holes to 30’ below ground surface were drilled with our in-house CME-55 drill truck. Test holes were advanced using 8” hollow-stem auger boring methods with standard 2inch O.D. split spoon sampler driven into the bottom of the borehole with 140-lb automatic trip hammer with an impact height of 30-inches. Soil samples were obtained at frequent intervals and selected representative samples were tested in PDC’s in-house laboratory. Samples collected were analyzed for pertinent physical and engineering properties of the soil relative to the proposed construction. Eight (8) machine dug test pits were also performed on the site to provide a visual representation of subsurface soil conditions and true ground water conditions. Representative bulk samples were collected for each soil layer encountered in the test pits from either the undisturbed test pit wall, or from the excavator bucket. Samples collected were analyzed for pertinent physical and engineering properties of the soil relative to the proposed construction.

The geotechnical report included seismic analysis, allowable bearing capacity and settlement analysis, liquefaction potential analysis, retaining wall/basement load factors, dewatering, frost protection, building site preparation, parking/access preparation, underground site utilities and corrosion resistant construction recommendations. PDC performed periodic Special Inspection services for monitoring the building foundation excavation, proof rolling and structural fill placement beneath the building.