3410 TERMINAL AVE 2018-03-09 - Laserfiche WebLink

SI ON MMLS N,INC. In addition to the subsurface conditions, our analyses assume that the pile center-to-center spacing is greater than three pile diameters. Based on conversations with MN,the current planned pile spacing is approximately 10 feet,midway between the existing piles,which is greater than 3 diameters of the proposed pile size. We have reviewed axial loads provided to us by MN. Based on these axial loads and the uncertainty in the subsurface conditions,we recommend pile tip elevations and contingency lengths as shown in Table 1. The pile sizes and contingency lengths shown in Table 1 were ' chosen by the design team based on discussions between Shannon&Wilson,MN and the Port. We understand that MN has performed lateral pile evaluations based on our recommendations 1 and the results of that analysis indicated the lateral fixity is developed above the recommended pile tip elevations indicated in Table 1. Actual pile penetrations and capacities should be determined during construction with pile dynamic testing using the pile driving analyzer(PDA) 1 and the observed pile driving resistance. 6.2.2 Lateral Resistance We understand that MN will analyze lateral resistance using the computer program LPILEPLus We estimated soil parameters for input into LPILEPLus based on the two design profiles,laboratory testing results, and our experience. Table 2 summarizes the LPILEPLus soil lateral resistance input parameters for lateral static loading. 1 6.2.3 Pile Tip Soil Springs We understand that MN will analyze the wharf structure using a spring analysis. This type of analysis requires the use of an vertical elastic spring to represent the response of the pile tip to axial loading. The value of this elastic soil spring depends on the nature of the soils that the pilings are driven into and the loads applied to the pile. We have evaluated the subsurface conditions at this site relative to similar sites in which full-scale static load tests have been performed. Based on these load tests in similar subsurface conditions as this site, an elastic spring constant of 2,200 kip/inch can be used to represent the response of the pile tip to applied axial loads that do not exceed our recommended allowable capacities. Based on our experience,this spring constant is generally applicable to axial loads that do not exceed 500-600 kips where we expect the soil deflection below the tip of the pile to be elastic. For axial loads that exceed 500 to 600 kips up to approximately 900 to 1,000 kips, soil deflection below the pile tip becomes non-linear,which results in the value of the vertical soil spring being reduced to approximately half or more of the previously recommended value. For ' 21-1-21962-003-R2.docx/wp/cp 21-1-21962-003 9