1907 W MUKILTEO BLVD 2021-11-15 - Laserfiche WebLink

.- � ... 4111 Plan Review and Comment Response Memorandum NGA File No.9452E 18 Connell Residence Retaining Wall October 10,2018 Everett,Washington Page 2 I feet while the embedded portion of the soldier piles will be a minimum of 20-feet. The soldier piles will be spaced at a maximum of 4-foot on center. The shoring wall appears to have utilized design values of 60 PCF for active pressure and a seismic surcharge of 8H in accordance with our previous report. A value of 60 PCF for passive pressure beginning at a depth of two feet below the ground surface in front of the wall was also included in the design. In our previous report, we recommended that passive pressure in front of the wall be neglected due to the sloping nature of the ground below the wall. However, in our opinion, utilizing a minimal passive pressure of 60 PCF on the below grade portion of the piles is feasible. Tie-back anchors consisting of 6-inch diameter grouted Titan anchors are proposed to restrain the upper portion of the retaining wall laterally. Voids between the existing retaining wall and new timber lagging are to be filled with 2-inch clean crushed rock. All other recommendations provided in our previous report should be strictly followed. CITY OF EVERETT PUBLIC WORKS REVIEW CONCERNS AND OUR RESPONSES Review Comment 2: On Detail 1/S1.1 as well as the permit calculations appear to include the use of passive pressures in the design of the permanent shoring walls. The last line of the second full paragraph on Page 8 of the geotechnical report indicates that passive resistance pressures should not be included in the below- grade portions of the pile in the shoring design. Please clam and/or revise the drawings and calculations as required or provide a narrative indicating use of passive design pressures for the shoring design which appear to be inconsistent with the geotechnical recommendations. Response: Based on our review of the provided plans, we understand that a value of 60 PCF was utilized as passive resistance on the below grade portion of the retaining wall. In our opinion, utilizing a passive pressure of 60 PCF for the below grade portion of retaining wall is feasible from a geotechnical standpoint. CLOSURE We recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities comply with contract plans and specifications. We trust this memorandum should satisfy your needs at this time. Please contact us if you have any questions or require additional services. o-o-o NELSON GEOTECHNICAL ASSOCIATES, INC.