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Mr. Rick Heide <br />Design Build Services, Inc. <br />Plan Check Number: B2210-031, Second Building Review <br />December 5, 2022 <br />2. Continuing with the previous comment, the adjacent house will be within the influence zone <br />for the retaining wall. Geotechnical observation is required for this project. A list of the <br />required geotechnical observations should be provided in the construction drawings. See <br />IBC Sections 107.1 and 107.2.1. The following is a summary based on a review of the <br />construction drawings: <br />a. Installation of temporary shoring system at excavations (IBC Section 1803.5.10). <br />b. Movement monitoring of adjacent structures (IBC Sections 1803.5.7 and 1804.1). <br />c. Underpinning of adjacent structures (IBC Sections 1803.5.7 and 1804.2). <br />d. Placement and compaction of structural backfill (IBC Section 1804.3). <br />3. Structural and geotechnical special inspections are required for this project. A statement on <br />special inspections has not been provided and should be submitted with the permit <br />documents. The statement should include a table listing each type of special inspection and <br />shall specify the extent of each inspection (e.g., continuous, periodic) per IBC Section <br />1704.3.1. See IBC Sections 107.1, 1704.2.3 and 1704.3. <br />4. The wall has been designed as laterally supported at the top. However, the wall is a <br />cantilever structure. Note that the wall should not be considered to have effective lateral <br />restraint at each end from the stairs and return wall, nor do these features provide restraint <br />along the top of the wall. See IRC Section R301.1.3, and IBC Sections 1603.1, 1604.1, <br />1604.2, and 1604.4. The following comments should be addressed: <br />a. The wall reinforcement is located on the compression face of the wall, not the <br />tension face, and will not effectively reinforce the wall. <br />b. The wall do not have an adequate footing (i.e., insufficient heel length) to resist <br />global overturning forces. <br />c. Continuing with the previous comment, the footing reinforcement does not extend <br />into the heel. The heel lacks shear and flexural strength. See IBC Section 1901.2. <br />d. The proposed excavation is approximately 8 feet deep and is estimated to be at <br />least 6 to 8 feet wide include overcutting for the heel construction. The adjacent <br />house footprint is within the influence zone for the retaining wall. The wall design is <br />required to include dead and live surcharge pressures from the adjacent house <br />concurrent with active pressures. See IBC Section 1605 and 1610.1, and additional <br />comments below. <br />e. The retaining wall loads are required to include seismic surcharge pressures <br />concurrent with active pressures. See IBC Section 1605 and 1803.5.12(1). <br />f. The wall has been designed using a 35 pcf active pressure. While this is typical <br />for a cantilever retaining wall, this value is low for a wall laterally -supported at the <br />top. The active pressure should be increased if the design is changed to provide <br />lateral restraint at the top. <br />g. The maximum wall height should be measured from the top of the foundation. <br />h. Continuing with the previous comment, the bottom of foundation elevation should <br />be specified in the retaining wall detail. <br />0 3200 Cedar Street <br />Everett, WA 98201 <br />© 425.257.8810 O <br />425.257.8857 fax <br />permitservices@everettwa.gov <br />everettwa.gov/pe rm its <br />Page 2 of 3 <br />