4003 NASSAU PL 2016-01-01 MF Import

i ' , ' ' I � � � �- �- �_ � Geotechnical Engineering Report Kvemmo Single-Family Residence 4003 Nasspu Place, Everott September 17, 2002 NGA File No. 356 � 02 Page 11 refusal. The above design capaciry is based on theoretical numerical pile driving analysis. If liigher pile capacities are proposed, we recommend that a minimum of two pile load tests be performed lo verify the higher design values. We recommend that the piles be loaded to at least 200 percent of the design capacity, and that we be retained to observe the pile load test. A factor of safety of 2 could be used to reduce the ultimate capacity achieved from the pile load test to a design capacity. Acrual pile load test procedures could be discussed with your contractor at the time of testing. We do not recommend using a design capacity of more than 10 tons for 4-inch pin piles, regardless of the outcome of the pile load test. Final pile depths should be expected to vary somewhat and will depend on the depth of the existing fill and nature of the underl��ing competent soils and gound water conditions. Based on our understanding of site soil conditions, we estimate that the piles could be advanced up to 20 feet or more below existing ground surface before the recommended refusal criterion is met. The pin piles should penetrate a minimum of 5 feet into the native soil in order to develop the design capacity. Piles that do not meet this minimum embedment criterion should be rejected, and replacement piles should be driven after consulting with the structural engineer on the new pile locations. Duc to the relatively small slendemess ratio of pin piles, maintaining pin pile confinement and lateral support is essential to preventing pile buckling. Pin piles should not stick above finished ground surface. Also, our test pit explorations excavated in 1987 encountered logs in the fill and other debris thet could potentially obswct the pin piles. Obstructed piles should be relocated or additional piles driven after consulting with your swctural engineer. It may be prudent to have a backhce available on site to remove shallow obstacles that may be encountered during pile driving. Lateral Loads Vertically driven pin piles do not provide meaningful latera: capacity. However, battered piles can provide a lateral component. The degree of batter, and number and locations of battered piles should all be detertnined by your structural engineer. We recommend that the battered piles be embedded a minimum of ]2 inches into the foundation concrete and that sufficient steel reinforcement be placed around the piles to reduce the potential for pile pull-out. NELSON GEOTECHNICAL ASSOClATES, INC l��,