3810 RIVERFRONT BLVD BLDG B 2025-07-07

Mr. Eric Evans Shelter Holdings Plan Check Number: B1912-032, First Structural Review January 3, 2020 7. The pile construction consists of cast -in -place (CIP) reinforced concrete piles within a steel pipe casing per the typical details on Sheet S6.02. It is our understanding that the casings are only intended to facilitate construction of the concrete piles and reduce down -drag effects on the pile. Furthermore, the piles are not provided with corrosion protection and are therefore sacrificial. However, the structural calculations appear to consider the steel casing as part of the permanent lateral force resisting system. See "Table 2.2" of the FEM input defining the piles as concrete -filled steel pipes, and "Calculation Section 7.0: Pile Design" stating that the casing has been designed for the induced moments. The casing should not be considered in the design if it is not part of the permanent structure. The structural calculations should be revised as needed. The structural design may need to be revised. Additional comments are provided below addressing the pile design. See IBC Sections 1603.1, 1604.4, 1613.1, and 2205.1, ASCE 7-10 Section 12.7.3, and AISC 360-10 Section B3.14. 8. Detail 1/S6.02 specifies flexural and shear reinforcement for the CIP concrete piles extending for approximately 13.5 feet and 10 feet, respectively, below the pile cap. The reinforcement appears to be less than required by IBC Section 1810.3.9.4.2. The requirements of Section 1810.3.9.4.2.1 shall also be reviewed. Note that in addition to the prescriptive requirements, the reinforcement shall not be less than required by analysis. Per the pile finite -element analyses (FEA) in "Calculation Section 7.0: Pile Design" of the structural calculations, the piles do not achieve zero curvature at these depths; note that the FEAs for the piles are based on pinned tops instead of fixed, and therefore do not appear applicable to the design. The pile reinforcement shall be revised. See IBC Section 1901.5 Item 3. 9. The modeling for the piles in the finite element model (FEM) is not clear. Additional documentation clarifying the modeling should be submitted for review. See IBC Sections 1604.4 and 1613.1, and ASCE 7-10 Section 12.7.3. The following comments should be addressed: a. The pile sections in "Table 2.2" of the FEM input appear to specify that the piles are concrete -filled steel pipes. The permanent piles are understood to be CIP reinforced concrete piles. The piles sections should be verified and revised as needed. b. The piles are modeled as 15-foot deep column elements with fixed ends (i.e., bottom rotational restraint, fully -fixed to the grade beams at the top) and distributed lateral springs along their length. The spring values for the 16" and 18" piles are defined in "Table 2.6" of the FEM input as 6.4 k/in and 7.2 k/in, respectively. Documentation establishing this modeling criteria shall be submitted for review (e.g., calculations based on the geotechnical pile analysis, supplemental geotechnical recommendations, etc.). 10. The design of the piles provided in "Calculation Section 7.0: Pile Design" of the structural calculations is not clear. Supplemental documentation clarifying the design should be submitted for review. See IBC Sections 1604.1, 1604.4, and 1613.1. The following comments should be addressed: a. The maximum pile axial loads in "Appendix A — Pile Forces Summary' from the structural calculations only list the results of the allowable (ASD) load combinations. The results of the factored (LRFD) load combinations should also be provided. See also the axial -flexural "P-M" interaction diagrams in the pile design. 03200 dar Everett WAStreet98201 O 425.257.88577 fax O everett asgov/permitgov s Page 3 of 7