2018-0447 Edmonds Recovery Beck struc.pdfBeck & Associates, PLLC
Structural Engineering & Code Consulting
May 18, 2018
Leif Bjorback
Building Official
City of Edmonds
121 5t' Avenue North
Edmonds, WA 98020-3145
Subject: Northpoint (Structural Review)
Permit: BLD2018-0447
BLD2018-0448
Per your request, Beck & Associates has completed a structural review of the drawings and
calculations for conformance with the 2015 International Building Code (IBC), as adopted and
amended by the State of Washington and the City of Edmonds.
Our review of the plans and calculations indicates that corrections are necessary prior to permit
issuance. The applicant should address the following comments in itemized letter format in addition
to making corrections & revisions to the drawings. Corrections and revisions to the drawing should
be clouded so that they are clearly identifiable.
General
General
1) Shannon & Wilson, Inc. is required to provide a geotechnical review of the plans and
specifications to determine that they are consistent with the recommendations. Shannon &
Wilson, Inc. should summarize their review in a summary letter, providing any additional
recommendations as needed. All recommendations are required to be addressed within the
design drawings resubmitted for our review (p. 14 of 16)
Analysis
G ravity
2) Sections 2 & 4A, as indicated in the structural calculation Table of Contents, were not included in
the structural calculations. Please submit these sections in response to this review letter.
3) Provide calculations or other documentation that demonstrates that the existing Level 2 structure
can support the gravity loads as required for this project and as indicated on sheet S-0-21.
4) Provide calculations to demonstrate that the existing roof framing can support imposed loads from
mechanical equipment and mechanical screening.
5) Provide calculations and detailing for lateral anchorage of all mechanical units.
I ntorni
16425 SE 66 t h Street, Bellevue, WA 98006 * beckpllc@msn.com * PH: 206-313-3739
BLD18-0447 (Struct Rvw)
May 18, 2018
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6) Vertical combinations of lateral resisting elements are required to be addressed in accordance
with ASCE 7-10, 12.2.3.1.The upper system (plywood shear walls) is permitted to be designed
using its own design coefficients (R, omega, Cd). The lower system (concrete shear walls) is
required to be designed for its own coefficients (R, omega, Cd). Forces transferred from the
upper system to the lower system are required to be increased by multiplying by the ratio of the
higher response modification coefficient to the lower response modification coefficient. ASCE 7-
10, 12.2.3.1
a) Provide an analysis that is consistent with these requirements.
b) Provide an analysis that demonstrates that the concrete shear walls are designed for their
own appropriate design coefficients (R, omega, Cd).
7) This building meets the criteria of ASCE 7-10, 12.2.3.3 so the building with a horizontal
combinations of resisting elements (plywood shear walls, concrete shear walls) may be designed
using the least value of R for the different structural systems found in each independent line of
resistance. This is for your information only. No response is required. ASCE 7-10, 12.2.3.3
8) Diaphragms and collector elements.
a) The value of R used for design of the Level 2 diaphragm is required to be the least value of R
for any of the systems (wood shear wall, concrete shear wall) used at that level and below.
Update the analysis, design, and detailing accordingly. ASCE 7-10, 12.2.3.3
b) Collector elements and collector element connections to the concrete shear walls are
required to be designed considering overstrength. Provide complete design of these
collector elements. ASCE 7-10, 12.10.2.1
9) Reference page 17 of 117 of the submitted calculations. Seismic base shear does not appear to
be based on all weight that is required to be considered for seismic load determinations. While
the loading diagrams identify interior and exterior wall loads, these loads do not appear to have
been included in the weight used for determination of seismic loads. All mass needs to be
considered. ASCE 7-10, 12.7.2
10) Provide calculations to demonstrate that lateral boundary elements (HSS columns) are adequate
to resist all imposed load combinations, including gravity (DL, LL, Snow) and seismic. 1605
Drawing Sheets
S-001 — S-004 — General Structural Notes
11) Update the General Structural Notes. Overall, there is a lot of information that is not applicable
to this project or that is incomplete. Update the Notes to the specifics of this project.
12) Update the Geotechnical Information section, consistent with and referencing the geotechnical
report.
13) Under Design Loads, Snow, a reference is made to the City of Seattle. The authority having
jurisdiction for this project is the City of Edmonds. Update the plans accordingly.
14) Update the Seismic information, consistent with the calculations provided.
15) Reference the Lateral Analysis Section. Special Concrete Shearwalls are identified at the 2nd Floor
Level.
a) Provide calculations or other documentation that demonstrates that the concrete shear
walls do indeed meet the criteria to be special concrete shearwalls. Please be aware that
ordinary reinforced concrete shear walls are not permitted to be used in Seismic Design
Category D. ASCE 7-10, Table 12.2-1
16425 SF 66' Street, Bellevue, WA 98006 . beckpllc@msn.com - PH: 206-313-3739
BLD18-0447 (Struct Rvw)
May 18, 2018
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b) Specify the seismic response coefficient, Cs, for the special concrete shear walls.
S-101 — Level 1 Framing Plan
16) Specify required diaphragm and diaphragm connection to supporting framing.
S-102 — Level 2 FraminLy Plan
17) Specify required diaphragm and diaphragm connection to supporting framing.
18) Drag struts are called out at a couple of locations. However, information is missing. Specify the
struts, connectors, and provide detailing for connection of the struts to the shearwalls.
S-103 — Roof Framing Plan
19) Specify required diaphragm and diaphragm connection to supporting framing.
20) Shear wall SW-1 needs to be labeled on the plan.
21) Drag struts are called out at a couple of locations. However, information is missing. Specify the
struts, connectors, and provide detailing for connection of the struts to the shearwalls.
S-221 — Shearwall Elevations
22) Reference 1/S221 — SW-1 Elevation. Specify required straps above the openings as required by the
calculations.
23) Reference 2/S221 — SW-2 Elevation. Specify required straps above the openings as required by the
calculations.
S-581 —Typical Wood Framing Details
24) Reference 6/S-581.
a) Illustrate and specify all required connections from the shear wall to the concrete wall below.
b) This detail needs to be called out on the plans where they apply.
25) Reference 7, 8, & 9/S-581.
a) Illustrate and specify all required connections from the shear wall to the concrete wall below.
b) These details need to be called out on the plans where they apply. If they are not applicable to
this project, they should be removed from the drawing set.
S-591 — Light Gage Steel General Notes Schedules and Framing Details
26) Reference details 12, 19, & 20/S-591. These details call out "sure -board." However, sure -board is
not used on this project. Update the details accordingly.
27) Reference 16/S-591 — Light Gage Shear Wall Schedule.
a) Reference the column "typ wall stud except at abutting panels." 33 mil material is specified.
However, 43 mil (18 GA) material is required per the Simpson catalog in order to achieve the
required shear wall values. Please revise.
16425 SF 66' Street, Bellevue, WA 98006 . beckpllc@msn.com - PH: 206-313-3739
BLD18-0447 (Struct Rvw)
May 18, 2018
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b) Reference the columns "panel edge screws" and panel field screws." Screws are identified by
number (Ex: #10, not 10d). The designations need to be updated. Furthermore, the specific
screws for which this project is designed should be specified (Simpson #10 CBSDA fasteners) for
connection of sheathing to the light -gage steel. Update the schedule accordingly.
c) Reference the column "fasten top track to framing above."
i) Provide documentation (from Simpson) of the acceptability of using Simpson A35 clips to
connect light -gage steel to wood. Specify required fasteners (screws to the light -gage steel
and screws/nails to the wood).
ii) Provide calculations to demonstrate the A35s and fasteners are adequate for the imposed
loads.
d) Reference the column "bottom track attachment" "anchorage to concrete." Y2" DIA x 4" Titen
HD anchors are required at 12" o.c. in order to transfer imposed forces (per calculations).
Please revise.
e) Reference the column "bottom track attachment" "bottom track." 54 mil bottom tracks are
specified. However, detail 18/S-591 requires 68 mil bottom tracks. Provide coordination.
f) Reference the Notes. Note #5 provides specifications for nails. However, screws are used for
these shear walls. Provide specifications for the required screws.
S-592 — Light Gage Steel Framing Details
28) Reference detail 5/S-592. This detail needs to be called out on the plans.
29) Reference detail 6/S-592. This detail is not applicable and should therefore be removed from the
drawing set.
30) Reference detail 10/S-592. Illustrate and identify all connectors for shear transfer to the concrete
shear wall.
31) Reference detail 16/S-592 —Typical Elevation of Shearwall with Holdown Straps.
a) "Solid bIkg to match width of post above" is specified between HSS holdowns. Provide
calculations to demonstrate that this adequately transfers compression loads in all cases.
Revise the detail as necessary to illustrate actual conditions.
b) Double holdowns are specified on the shear wall elevations in all cases. The detail needs to be
updated to reflect these conditions.
32) Reference 13/S-592. This detail is not applicable (never are holdown straps called out on the plans)
and should therefore be removed from the drawing set.
33) Reference 18/S-592 —Typical Holdown at Base.
a) Double holdowns are specified on the shear wall elevations in all cases. The detail needs to be
updated to reflect these conditions.
b) Specify required embedment of holdown anchors. This does not appear to be provided
anywhere in the drawing set.
S-721 — Steel Canopy and Stair Details
34) Reference 6/S-721 — South Canopy Detail.
a) Provide an analysis for all elements of this canopy, including the foundation.
16425 SF 66' Street, Bellevue, WA 98006 . beckpllc@msn.com - PH: 206-313-3739
BLD18-0447 (Struct Rvw)
May 18, 2018
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b) The required axial strength of cantilever column elements, considering only the load
combinations that include seismic load effects, is required to not exceed 15% of the available
axial strength, including slenderness effects. Provide an analysis to demonstrate that this
criteria is met. ASCE 7-10, 12.2.5.2
c) Foundations used to provide overturning resistance at the base of cantilever column elements
are required to be designed to resist the seismic load effects including overstrength factor of
Section 12.4.3. Provide an analysis to demonstrate that this criteria is met. ASCE 7-10, 12.2.5.2
d) We assume the columns will be designed and analyzed as ordinary cantilever columns (R=1.25;
overstrength = 1.25; Cd = 1.25). If they will be designed as special cantilever columns, all the
requirements for special detailing (AISC 341-10) will need to be met. AISC 341-10
35) Reference 16/S-721 — East Canopy Detail.
a) Provide an analysis for the foundation.
b) The required axial strength of cantilever column elements, considering only the load
combinations that include seismic load effects, is required to not exceed 15% of the available
axial strength, including slenderness effects. Provide an analysis to demonstrate that this
criteria is met. ASCE 7-10, 12.2.S.2
c) Foundations used to provide overturning resistance at the base of cantilever column elements
are required to be designed to resist the seismic load effects including overstrength factor of
Section 12.4.3. Provide an analysis to demonstrate that this criteria is met. ASCE 7-10, 12.2.5.2
d) We assume the columns will be designed and analyzed as ordinary cantilever columns (R=1.25;
overstrength = 1.25; Cd = 1.25). If they will be designed as special cantilever columns, all the
requirements for special detailing (AISC 341-10) will need to be met. AISC 341-10
S-731 — Mech Screen & Misc Roof Details
36) Reference 6 & 8/S-731 — Mechanical Screening. Specify the maximum spacing of vertical posts that
connect to the roof structure.
37) Reference 9/S-731 — Mechanical Screen Post Base Plate.
a) Specify the weld of the post to the base plate.
b) Given the load on the posts (M=134 k-in, ASID, per calcs), it is clear that the connections to the
wood framing and of the wood framing to resist the loads are inadequate. Provide an analysis
and complete design for these resisting elements, including addressing fall protection forces.
38) Reference 11/S-731 — Typ Fall Protection Anchor. Provide a complete analysis and detailing/specs
for the anchor and its connection to the wood framing below.
39) Reference 13/S-731 — Screen Wall Details. Specify all elements, including angles, bolts, etc.
Please contact me should you have any questions.
Respectfully,
Douglas Beck, PE, SE
Beck & Associates, PLLC
16425 SF 66' Street, Bellevue, WA 98006 . beckpllc@msn.com - PH: 206-313-3739