170623_Westgate Edmonds - Permit Correction Response.pdf
1511 THIRD AVENUE
SUITE 323
SEATTLE, WA 98101
TEL 206.957.3900
FAX 206.957.3901
www.quantumce.com
June 23, 2017
Douglas Beck
Beck & Associates, PLLC
16425 SE 66th Street
Bellevue, WA 98006
Subject: Permit #2016-1538 – Westgate Village
Quantum Project #16369.01
Dear Douglas:
We have received the correction notice on the above-referenced project dated April 12, 2017. Below are
the responses to the structural comments. All changes to the drawings due to a plan check comment have
been clouded on the drawings and marked with a Delta 1.
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GENERAL
Geotechnical
1. The geotechnical engineer, PanGEO is required to review the plans to confirm that their
recommendations are properly incorporated into the design and construction drawings (p. 12).
The review, along with any additional recommendations, shall be summarized in letter format.
It is our understanding that PanGEO will review the design drawings prior to the start of
construction to verify that the recommendations of the geotechnical report match what is
shown on the drawings.
LATERAL
General
2. Both the wood shear wall system and the concrete shear wall systems have Horizontal Structural
Irregularity #5, Nonparallel System Irregularity. Provide calculations to demonstrate that the
requirements for this irregularity are met. ASCE 7-10, Table 12.3-1
Additional seismic load combinations for orthogonal effects (100% + 30%) have been analyzed
for the structure per the requirements of ASCE 7-10, section 12.5.3a. Please see the attached
calculation pages (1 to 7) for the updated load combinations and wood shear wall results.
Permit #2016-1538 – Westgate Village
June 26, 2017
Page 2
The concrete shear walls at Level 1 below the transfer podium slab were originally designed for
the orthogonal effects required by ASCE 7-10, section 12.5.3a and table 12.3-1. Refer to the
original calculation pages (CL-12 to CL-18) for the load combinations used for design.
3. Provide calculations to demonstrate that allowable story drifts are within the limits of ASCE 7-
10. ASCE 7-10, 12.12
Please see the attached calculation pages 8 (wood floors) and 17 to 19 (L2 conc. slab) for the
building story drifts. The story drifts are within the allowable limits.
4. Provide calculations for chords at the following locations. ASCE 7-10, 12.10
a) Wood levels – It is apparent that the double top plate will serve as the chord. In some cases,
there is a discontinuity in the double top plate of exterior walls where the exterior wall jogs.
Please address these conditions.
b) Concrete levels
a) At the wood levels, the top plate is adequate for the chord forces between the perpendicular
shear walls. Please see the attached calculation page 9. Where ever the exterior wall jogs,
there is typically a perpendicular shear wall, so no drag struts are needed for the
discontinuous top plates to transfer loads into the floor diaphragm.
b) At the concrete transfer slab (L2), the continuous slab edge reinforcement is adequate for
the chord forces as shown on the attached calculation page 20.
5. Provide calculations to demonstrate that the Level 2 PT deck and connections have adequate
strength to transfer forces to the concrete shear walls. Are collectors required at any locations?
ASCE 7-10, 12.10
Refer to the attached calculation pages (21 to 23) for the shear transfer analysis between the
concrete slab and shear walls. The slab dowels shown in the typical concrete details (S303) are
adequate to transfer the lateral forces between the slab and walls with no additional collectors
or reinforcement required.
Lateral – Wood
6. The diaphragms of the wood levels are permitted to be idealized as rigid when the computed
maximum deflection of the diaphragm itself under load is less than or equal to two times the
average deflection of adjoining vertical elements of the lateral force-resisting system of the story.
Please provide calculations that demonstrate that this criteria is met for each level. SDPWS 4.2.5
Please see the attached calculation page 10. As shown, the diaphragm deflections are much
smaller than the shear wall deflections; thus, the upper wood floor diaphragms are assumed to
be rigid for the design.
Permit #2016-1538 – Westgate Village
June 26, 2017
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7. It is unclear from the calculations whether accidental torsion is considered in the analysis for the
semi-rigid/rigid analysis being used. Please provide documentation that demonstrates accidental
torsion is being considered. ASCE 7-10, 12.8.4.2; SDPWS 4.2.5
Please see the original calculation page WL-11 for the accidental torsion input (5%) in each
direction at the floor diaphragms.
8. Provide calculations to check for torsional irregularity for each level of the wood lateral force-
resisting system. If torsional irregularity does exist, provide calculations to demonstrate that
amplification of accidental torsion is considered and the criteria of SDPWS 4.2.5.1 are met.
ASCE 7-10, 12.8.4.3; SDPWS 4.2.5.1
Amplification of accidental torsion is not required. Please see the attached calculation pages
(11 to 14) for the torsional irregularity analysis at the upper wood floors.
DRAWING SHEETS
S100 – Structural General Notes
9. Reference the Design Criteria. It appears that the Wind Base Shears identified in the General
Structural Notes are inconsistent with the analysis provided. Please coordinate.
The wind base shear on sheet S100 has been updated to reflect the base shear for the entire
building. Please see the attached calculation pages (15 & 16) that show the base shear for the
entire structure vs the base shear for just the wood levels.
10. Note #13, Special Inspections, is general in its requirements for special inspections. The plans
need to specify the required inspections and testing and extent of inspections or testing for each
material. The statement of special inspections is required to identify the following: 1704.2.3,
1704.3
a) The materials, systems, components, and work required to have special inspections or tests.
b) The type and extent of each special inspection
c) The type and extent of each test
d) Additional requirements for special inspections or tests for seismic as specified in 1705.12
and 1705.13.
e) For each type of special inspection, identification as to whether it will be continuous,
periodic, or performed in accordance with the notation used in the referenced standard where
inspections are defined.
The Special Inspections note (#13) has been revised on sheet S100 and a Special Inspections
schedule has been added on sheet S102.
11. Reference the Geotechnical Section, #16.
a) An allowable soil bearing pressure of 6,000 psf is not included within the geotechnical report.
Provide documentation from the geotechnical engineer regarding the use of a 6,000 psf
Permit #2016-1538 – Westgate Village
June 26, 2017
Page 4
bearing pressure. Revise the foundation design as required (some of the foundations are
currently designed based on an allowable bearing pressures of 6,000 psf).
b) The passive soil pressure (350 pcf) includes a factor of safety of 2. This should be identified
on the drawings.
c) The soil coefficient of friction (0.50) includes a factor of safety of 1.5. This should be
included in the drawings.
a) It is our understanding that PanGEO will be providing a letter that indicates the use of
6,000psf for allowable soil bearing at the lower parking level based on previous
correspondence during the project design phase. The General Notes (S100) and
Foundation Plan (S200) have been revised to clearly show all the footings that were
designed for 6,000psf allowable soil bearing.
b) The passive soil pressure note has been revised on the General Structural Notes.
c) The soil coefficient of friction note has been revised on the General Structural Notes.
S200 –Parking Level / Foundation Plan
12. Foundation Plan Notes #5 should also reference the geotechnical report for subgrade preparation
and vapor barrier recommendations (p. 9).
The Foundation Plan Note (#5) has been revised.
S201A – Level 1 Framing / Mild Reinforcing Plan
13. A discontinuous shear wall occurs at the shear wall located along grid C3 between grids CD &
CE. Also reference 6/S303. This is considered to be an In-Plane Discontinuity in the Lateral
Force resisting System. Please address this condition and demonstrate compliance in accordance
with ASCE 7-10. ASCE 7-10, Table 12.3-2
The Level 1 framing plans have been revised to remove the discontinuous shear wall at the
stair location. The wall at this location will either be a non-bearing concrete or CMU partition
wall to separate the stairs from the parking area. Refer to the attached calculation page 21 for
the updated shear wall forces without this wall. By inspection, the remaining shear walls are
adequate to resist the slightly increased lateral forces.
14. Reference the column located at grids CB/C3. According to the calculations, top reinforcement in
the E-W direction is required to be 8#6T (p. PT-139). Please coordinate.
The structural plan (S201A) have been revised to show the correct top reinforcement to match
the calculations.
S202A – Level 2 Framing / Mild Reinforcing Plan
15. Reference the attached 11x17 plan with redlined mark-ups. There are numerous differences
between the plans and the analysis. Provide coordination and address each item. I have provided
references on the marked-up plan to corresponding calculation pages.
Permit #2016-1538 – Westgate Village
June 26, 2017
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The structural framing plan (S202A) has been revised to show the correct slab reinforcement
and has been further coordinated with the calculations. Refer to detail 18/S302 for the
concrete beam reinforcement at the Level 2 transfer podium.
S202B – Level 2 Framing / Post-Tensioning Plan
16. Reference Post-Tensioning Plan Note #9. This slab is actually required to be designed to have a
3-hour rating. Clearance requirements are met with the current design. However, the note should
be updated to identify the correct rating.
The plan note (#9) on sheet S202B has been revised.
S202C – Level 2 Wood Framing Plan
17. The shear wall located approximately along grid C10 between grids CH and CJ is required to be
provided with DF studs according to the calculations (p. WL-30). Please coordinate.
Notes specifying DF#2 studs at holdown posts have been added to sheet S202C and detail
20/S400.
S203 – Level 3 Framing Plan
There are a couple of areas on this level which have gravity loads which are unsupported from above.
Please address the following areas:
18. Reference the attached pdf showing a Partial 3RD Floor Framing Plan from S203, labeled ‘Area
1’. Please address the locations indicated where loads are unsupported from above.
The roof loads are transferred at the Level 4 framing (S204) where the walls don’t stack below.
All the remaining bearing walls stack at each level down to the concrete transfer slab. At the
Level 4 framing, blocking has been added between the joists for the short exterior walls at the
amenity spaces. The long wall at the corridor has been shifted to align with the walls below.
Please see sheet S204 for the framing revisions.
19. Reference the attached pdf showing a Partial 3RD Floor Framing Plan from S203, labeled ‘Area
2’. Please address the locations indicated where loads are unsupported from above.
Refer to the response for comment #18 (similar framing revision).
S204 – Level 4 Framing Plan
There are a couple of areas on this level that support deck loads of 100 psf. It appears that the joists are
undersized.
20. Reference the attached pdf showing a Partial 4TH Floor Framing Plan from S204, labeled ‘Area
1’. Please address the locations indicated where joists are required to support a 100 psf live load.
Hatching has been added to the framing plan (S204) to indicate where the 100psf live load
occurs. The floor framing has been designed and revised accordingly.
Permit #2016-1538 – Westgate Village
June 26, 2017
Page 6
21. Reference the attached pdf showing a Partial 4TH Floor Framing Plan from S204, labeled ‘Area
2’. Please address the locations indicated where joists are required to support a 100 psf live load.
Refer to the response for comment #20 (similar plan revision).
S301 – Typical Concrete Details
22. Reference 6/S301 – Typical Site Retaining Wall. PanGeo recommends that Mirafi 6000 or
equivalent be provided at the face of the wall in order to prevent the potential build-up of
hydrostatic pressures. This should either be specified on the detail or the geotechnical report
should specifically be referenced for backfill and drainage recommendations. (p. 8)
Detail 6/S301 has been revised to include the note for the drainage material behind the
retaining wall.
S303 – Concrete Details
23. Reference 1/S303 – PT Slab/Slab-On-Grade Transition. Detail 18/S301 is referenced. It appears
the reference should be to 17/S301. Please coordinate.
The note has been revised to indicate the correct detail reference. Please refer to detail 2/S303.
* * * * *
Please feel free to call me at 206-957-3900 if you have any questions regarding our responses.
Sincerely,
Quantum Consulting Engineers, LLC
Todd Schoentrup, P.E.
Senior Project Engineer