ESBGU <br />Pavement analysis was not completed for Green Lane. We recommend the <br />pavement design be completed in accordance with the City of Eugene Public <br />Improvement Design Standards Manual (2016). <br />Signal Pole Foundation Analysis and Design <br />Analysis for the signal pole foundation was completed following the requirements <br />of the ODOT Geotechnical Design Manual (2016).We anticipate the traffic signal <br />supports will use standard pole design in accordance with ODOT Standard Drawing <br />TM653 and the ODOT Traffic Structures Design Manual (2018b). <br />Drilled shaft lengths for the signal poles are typically predicated on lateral rather <br />than vertical loads. Allowable Stress Design (ASD) methods were used since the <br />base reactions in Table 1 are service loads. <br />The signal pole type had not been established at the time this report was prepared. <br />Therefore, we completed analyses to calculate minimum depths for SM1, SM2, <br />SM3, and SM4 signal poles. Details for the signal poles were obtained from ODOT <br />Standard Drawings TM650 to TM653 (effective December 1, 2018 to May 31, 2019). <br />The recommended drilled shaft diameter is 36 inches for signal poles SM1 through <br />SM3 and 42 inches for SM4. Table 1 summarizes the base reactions recommended <br />to determine the appropriate drilled shaft lengths. <br />Table 1. Signal Pole Standard Maximum Base <br />Reactions <br />Axial Shear Moment <br />Signal Pole Type <br />(kips) (kips) (kip-ft) <br />SM1 2.10 5.15 80.39 <br />SM2 2.66 6.23 105.41 <br />SM3 3.49 7.77 138.43 <br />SM4 4.51 9.00 173.46 <br />Based on the conditions encountered in BH-1, we anticipate the subsurface <br />conditions for the signal pole foundation will consist of ±5.5 feet of medium stiff <br />clay followed by loose silty sand to a depth of ±12feet and dense to very dense <br />gravel thereafter. For analysis, we assumed an undrained shear strength of 0.6 ksf <br />for the clay and a friction angle () of 32 degrees and a unit weight of 110 pcf for <br />the silty sand. <br />Brom’s method was used to establish the minimum drilled shaft lengths. Table 2 <br />summarizes the embedment depths for the signal poles assuming a factor of safety <br />of 2.15 (per the ODOT Traffic Structures Design Manual 2018). These embedment <br />depths exceed the minimum depths recommended in Figure 2-3 of the ODOT Traffic <br />Structures Design Manual. We should be contacted during construction to confirm <br />the assumed conditions and adjust the foundation lengths, if needed. <br />Santa Clara Transit Center January 15, 2019 <br />Geotechnical Investigation 7 Project 2181060 <br />Eugene, Oregon Rowell Brokaw <br />