1802 W MARINE VIEW DR 2016-01-01 MF Import

-6- In this area, timber piles are commonly driven wit6 an air or steam pile driving hammer delivering 15,000 foat-pounds of energy per blaw, such as a Vulcan O1. For the range of estimated_required permanent vertical pile capacities (approximately 6 kips) and the requirement for minimal settlement of the circuit switcher, driving criteria are estimated to be about 20 blows per foot as calculated by the Engineering yews formula. This should be reevaluated once the piles and pile driving equipment have been selected. Based on the soil conditions encountered at the recent explorations, we estimate that the required permanent pile capacities should be achieved with a penetration of about 5 to 10 feet into "competent foundation soil" (dense to very dense sand). Piles are expected to penetrate through tfie organic silts and silty sands relatively easily.;.` =_ A dense silty sand and gravel fill was encountered in boring B-2 from the ground surface to a depth of 4 feet. 7his layer, if it is present at the pile driving location, may cause high stresses to develop in the small diameter wood piles. Ground vibrations, which may,affect the adjacent dead end tower, may also develop. If the dense layer 'is encountered, and problems arise during driving, this layer should be excavated at the pile location before driving the pile. The piles will be installed in an area which most probably is in a salt water environment and therefore ma;/ be subjected to attack by inarine borers. For this reason, the piles should be pressure-treated with creosote with a minimum retention rate of 20 pounds per cubic foot in accordance with marine pile requirements of the American Wood Preservers Associatian (AWPA) C3. The piles should also have an American Wood Preservers Bureau (AWPB) quality mark MP-2 and should have a minimum allawable si:ress of at least 1200 pounds per square inch. Due to the high driving stresses imposed to the pile as it is driven into the dense sand a suitable bearing distance, the piling should be strapped to minimize damage to the pile tip from penetration into the sand and the pile butt from the driving hammer. Two straps, 19 and 24 inches respectively from the butt, and two straps approximately 6 and 12 inches from the tip, should be banded as tightly as possible, using either hand or a pneumatic tensioner. co�r«� co�,n�a Hw