2010-0013 - Holy Rosary Parish structural.pdf
January 13, 2010
Ann Bullis, CBO
Building Official
City of Edmonds
th
121 5 Avenue North
Edmonds, WA 98020-3145
Subject: Holy Rosary Parish (Structural Only Review)
Address: 760 Aloha Street, Edmonds, WA 98020
Permit: 2010-0013
Per your request, Beck & Associates has completed a review of the
structural only
drawings and calculations for conformance with the 2006 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.
Lock Block Retaining Wall
1) Retaining walls are required to be designed considering a safety factor of 1.5 against
sliding and overturning. The current design provides a factor of safety of 1.1 against
sliding and 1.3 against overturning. The design of the Lock Block Retaining wall
should be revised utilizing the required safety factors. IBC 1806.1
Geotechnical
2) The geotechnical report (p. 12) indicates that both restrained and unrestrained walls
should be designed for:
a) surcharge pressures due to traffic, construction equipment, stockpiles, etc.
b) seismic pressures
need to be designed for the traffic/construction surcharge as
Restrained walls
recommended in the geotechnical report unless otherwise formally directed by the
geotechnical engineer. Revise the analysis and design accordingly.
need to be designed for both the traffic/construction
Unrestrained (cantilever) walls
surcharge and seismic pressures as recommended in the geotechnical report unless
otherwise formally directed by the geotechnical engineer. Additionally, the
recommended base friction coefficient in the geotechnical report is 0.40 (not 0.45 as
utilized in the design of the cantilever retaining walls). Revise the analysis and design
accordingly.
Permit 2010-0013
January 13, 2010
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3) ZZA (Terracon) recommends that they be retained to review the geotechnical aspects
of the project plans and specifications to verify that their recommendations have been
properly integrated. Provide a letter of review by ZZA (Terracon) indicating that their
recommendations have substantially been incorporated into the project plans and
specifications. Where corrections are required based on the geotechnical review,
those corrections need to be made to the plans and specifications prior to re-submittal
of the plans for our review.
Lateral
4) The correct Occupancy Category for this structure is III (covered structures whose
primary occupancy is public assembly with an occupant load greater than 300).
Accordingly, the following importance factors apply to the structure: IBC Table
1604.5; ASCE
I (seismic) = 1.25 ASCE Table 11.5-1
I (wind) = 1.15 ASCE Table 6-1
I (snow) = 1.1 ASCE Table 7-4
a) The correct Importance Factor was utilized for seismic design.
b) The Importance Factor for wind and snow was incorrectly taken as 1.0. The
analysis and design need to be revised accordingly. Consider design of the main
wind force resisting system as well as other elements resisting out-of-plane wind
forces.
c) The General Structural Notes will need to be revised to identify the correct
Occupancy Category and the correct associated importance factors.
5) For determination of wind pressures, Exposure B applies where the ground surface
roughness condition, as defined by Surface Roughness B, prevails in the upwind
direction for a distance of at least 2,600 feet. The site is located 2250 feet from the
shoreline. Therefore, the required exposure category is Exposure C. IBC 1609.4;
ASCE 6.5.6
a) It is apparent that seismic forces will govern design for this building. However, a
quick analysis should be provided to demonstrate that this is the case.
b) Analysis and design for walls resisting out-of-plane wind forces need to be revised
considering Exposure C wind forces.
c) Provide an analysis & design for columns resisting out-of-plane wind forces
considering Exposure C.
6) The Lower Roof (S2.3) has a diaphragm discontinuity irregularity (horizontal structural
irregularity #3). Therefore, the design forces are required to be increased by 25% for
connections of diaphragms to vertical element s and to collectors. Revise the design
accordingly. ASCE Table 12.3-1, 12.3.3.4
7) Provide an analysis for the anchorage of holdowns to concrete walls below in
accordance with ACI 318-05, Appendix D. Reference 6/S4.4.
S1.1 General Structural Notes
8) The Quality Assurance section of the General Structural Notes states that special
inspections are to be completed per the Special Inspection tables found in the IBC.
Please identify the specific special inspections from those tables that are required to
Permit 2010-0013
January 13, 2010
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be provided for this project. We recommend that the IBC tables be included within the
General Structural Notes.
9) Recommended allowable base friction coefficient (0.40) and passive pressures (300
pcf static; 400 pcf transient) should be included in the Geotechnical section of the
General Structural Notes (S1.1).
S2.1 Foundation Plan
10) The concrete pylon footing is specified to have bottom reinforcement only. However,
detail 6/S3.2 illustrates both top and bottom reinforcement. We would anticipate that
the footing would have both top and bottom reinforcement as it will resist overturning
of the pylon - it is not detailed to be braced by the roof framing. Provide an analysis of
the pylon footing to resist seismic forces.
S2.2 Main Floor Framing Plan
11) Please provide a key plan for the Main Floor Framing that is consistent with the plans.
It appears that grids identified in the calculations are incorrect or that numerous
framing changes have been made since the calculations were completed. Include
design of all members. We will be able to complete our review of the Main Floor
Framing once this is provided.
12) Provide detailing for the condition where steel beams cantilever out over the top of the
concrete foundation wall. Fore example, reference the W12x40 beam located along
grid 15 that cantilevers out from grid B to grid A.
13) It is apparent from the calculations that the shaded portion of the floor framing plan
indicates a lower dead load that is applied to the framing members (wood flooring in
lieu of tile on top of gypcrete). This should be specified on the plans.
14) Reference grid N. The SW3 shear walls and associated holdowns from above are
supported by the framing at the Main Floor level. The calculated holdowns are shown
along the grid Q shear line in lieu of the grid N shear line. Provide an analysis for
framing along grid N that supports the shear walls and overturning holdowns from
above.
a) Design & analysis are required to consider over strength forces for the design of
structural elements supporting discontinuous lateral-force-resisting elements (out-
of-plane offset irregularity). The connections of supporting members (and their
supporting members) are required to be designed to transmit the forces for which
the discontinuous elements were required to be designed. Provide a complete
load path to the foundation for the over strength forces. ASCE 12.3.3.3
b) The design forces are required to be increased by 25% for connections of
diaphragms to vertical elements and to collectors. ASCE 12.3.3.4
c) Over strength forces are required to be considered for design of collectors. ASCE
12.10.2.1
S2.3 Lower Roof Framing Plan
15) Provide calculations for the design of the W16x31 beams located along grid B and
grid Q.
16) Reference the Column Schedule. Specify the thickness of column C4, the HSS 4x4
column.
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January 13, 2010
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17) Provide detailing for the support of the west sunscreen structure (located between
grids 1 & 3 and between grids D & G). Specify connections to columns, etc.
S2.4 High Roof Framing Plan
18) According to the calculations, the HSS 6x6x1/4 beam located on grid 19 between
grids F & H is required to be HSS 10x6x1/2. Additionally, please note that the design
is based on a span of 26 feet while the plans scale to be closer to 28.5 feet. Please
coordinate.
S4.2 Typical Steel Framing Details
19) Reference detail 1/S4.2 Composite Floor Deck.
a) The detail specifies 6x6 W1.4 x W1.4 WWM, whereas the plans (S2.2) specify #4
@ 18 o.c. Please coordinate.
b) The detail specifies 20 gage decking, whereas the plans (S2.2) specify 18 gage
decking. Please coordinate.
c) Note 5 should reference the ICC research report. ICBO no longer exists.
20) Reference detail 3/S4.2 Roof Deck. The missing connection information in notes 3
& 4 need to be filled in, in accordance with the design.
S4.3 Steel Framing Details
21) Reference detail 12/S4.3. Specify the missing horizontal and vertical forces for which
the open web steel joists are required to be designed.
S4.6 Steel Framing Details
22) Reference detail 5/S4.6. Specify the required length of the 5/8 WHSs.
Please contact me should you have any questions or require clarification on any of the items
contained in this letter.
Respectfully,
Douglas Beck, PE, SE
Beck & Associates, PLLC