HomeMy WebLinkAboutCA_Letter from Engineer_190305_v219011 Wood-Sno Road NE, Suite 100
Woodinville, WA 98072-4436
Phone: (425) 814-8448
Fax: (425) 821-2120
BTL
ENGINEERING
PROJECT RECORD
Date: October 31, 2018
To: Quadrant Homes
14725 SE 36th Street
Bellevue, WA 98006
Attn: Tatyana Sirotisnky
From: Brian Lampe
Plan: Lakeview (Lots 14 and 17) Pages: 2
RE: Prescreening Checklist
Tatyana,
The following addresses the outstanding prescreening checklist items from the City of Renton. Note that there is no
permit intake reference number as this is a generic screening:
Structural
3. Lateral calcs sheet L2.9:
d. The truss temporary and permanent bracing shall be per IRC Sections 502.11.2 and 802.10.3 as well as the
Truss Plate Institute’s Building Component Safety Information.
The truss manufacturer shall provide the bracing information so have them coordinate. The building
department may require the truss shop drawings along with the submittal or they may allow a deferred
submittal.
See Note 6.5, item N. on S1.1 of the structural drawings.
e. Truss alteration shall not occur unless the approval of a design professional as indicated in IRC Sections
502.11.3 and 802.10.4.
The truss manufacture’s documents should include this information. I have added to the end of Note
6.5, highlighting that the trusses shall not be modified.
6. Joists shall be laterally supported at the ends by full-depth solid blocking not less than 2 inches nominal in
thickness; or by attachment to a full-depth header, band or rim joist, or to an adjoining stud to provide lateral
support to prevent rotation. Additionally, in Seismic Design Categories D0, D1 and D2, lateral restraint shall be
provided at each intermediate support. The drawings do not indicate this requirement. Please revise the drawings
to include this requirement and resubmit the drawings for review. See IRC Sections 106.1.1 and 502.7.
Note that the framing is designed in accordance with IBC which supersedes the IRC so Seismic Design
Categories D0, D1 and D2 don’t exist and is replaced by Seismic Design Category D.
The drawings properly show the joist bracing. Note that the floor systems used are trusses (upper floor)
and I-Joists (main floor) and are subject to the manufacturer’s recommendation in accordance with
Exception 1.
8. Simpson SDS screws…
Note that the framing is designed in accordance with IBC so the IRC tables have been superseded by design.
Deck ledger demand load is (60psf + 10psf) x (9.75ft/2) = 341#/ft
Capacity of deck ledger detail shown in 17/S3.3 is (2 rows SDWS22400DB screws @ 12”oc) =
385#/screw x 2 screws/ft = 700#/ft
Alternately, the Simpson table referenced shows maximum 7”oc screw spacing for a 10-ft span. We have
equivalent of 6”oc and a 9’-9” span.
Note these screws have a “double barrier coating” equivalent to ASTM A153. See also note 6.9 on S1.1.
RECEIVED
11/16/2018
aalexander
BUILDING DIVISION
PR16000315
B18006356
V2
REVISION
Received: 03/06/2019 / aalexander
BUILDING DIVISION
APPROVED
BUILDING DIVISION
THIS SET OF APPROVED PLANS MUST BE ON THE JOB AT ALL
TIMES DURING CONSTRUCTION. THIS BUILDING IS NOT TO BE
OCCUPIED UNTIL AFTER FINAL INSPECTION BY THE RENTON
BUILDING DIVISION AND RECEIPT OF CERTIFICATE OF
OCCUPANCY.
APPROVAL SHALL NOT BE CONSTRUED AS THE AUTHORITY TO
VIOLATE OR CANCEL ANY PROVISIONS OF CODES, ORDINANCES,
OR OTHER REGULATIONS ENFORCED BY THIS CITY.
DATE: 04/24/2019
Page 2
9. Detail 16/S3.4 indicates a pinned connection at the gable end of the wall…
Detail 16/S3.4 shows GWB ceiling bracing the top of the wall. No diagonal bracing is required. GWB is
capable of supporting 35-plf (seismic) and 70-plf (wind) in accordance with IBC Table 2508.5. Load demand
at top of wall is 34-plf (seismic: 5psf x 13.5ft/2) and 68-plf (wind: 10psf x 13.5ft/2).
10. Our review indicates that a “flat” 2x member, e.g.; 2x6, needs to be connected to the 2x diagonal wood bracing…
This will not apply. We don’t have bracing at the wall top plate. Bracing for the gable studs, as required, will
be less than 6’-3” as the maximum gable height is 4’-6”.
11. The drawings do not indicate lateral load attachments of the decks to the house…
Lateral load is resolved with the ledger decking. As the deck is nestled in the main house recess, pull-out due
to rotation is unlikely. However, the ledger connection parallel to the deck joists resolves pull-out at one end
and we added a DTT1Z to resolve pull-out at the open end. A theoretical demand on the pull-out is 50#
(2850# x 0.15 x 0.7 x 9.75ft/2 I 29ft). Capacity of side ledger (for pull-out) is 5390# (385#/screw x 2 screws/ft
x 7ft). Pull-out capacity of DTT1Z w/ SDWH and (3)SD#9 = 420#.
Please call if you have any questions.
Sincerely,
Brian Lampe, P.E., S.E.
BTL Engineering