Specifications 12Zo 5 W 70" Ave_
FIELD TECHNICAL INFORMATION
Application recommendations for work at the wall or ceiling
401 Suspension Systems for Acoustical Lay -in Ceilings
REVISED 10/09 Seismic Design Categories D, E & F
NOV 2 3 2011
This document has been revised _ tt
C1 1 O('
based on current Building Code ET.):; ! ;NC
standards. In all buildings, other than
structures classified as essential
•
facilities, suspended ceilings installed
in accordance with the prescriptive `
provisions of the 401 document are
deemed to comply with the current •
building code interpretation. • :
This document provides the IBC -2009 `� �� '
referenced standards for the
installation of suspension systems
for acoustical lay -in ceilings. General Recommendations
Incorporation of this document will • Referenced sources per hierarchy: 2009 IBC (International Building Code),
American Society of Testing Materials (ASTM C 635, ASTM C 636, ASTM
provide a more uniform standard E 580/E 580M), American Society of Civil Engineers (ASCE 7 -05) and Ceil-
ings and Interior Systems Construction Association (CISCA).
for installation and inspection. This • Partitions that are tied to the ceiling and all partitions greater than 6 feet in
document is designed to accomplish height shall be laterally braced to the structure. Bracing shall be indepen-
dent of the ceiling splay bracing system. Source: ASCE 7 -05 section 13.5.8.1
the intent of the International • For further information on bracing of non -load bearing partitions refer to
NWCB technical document #200 - 501.
Building Code (IBC) with regard
• • All main beams are to be Heavy Duty (HD). Source: ASCE 7 -05 section 13.5.6.2.2 a
to the requirements for seismic • All cross tees shall be capable of carrying the design load without exceed -
design category D, E and F for ing deflection equal to 1/360 of its span. Source CISCA zones 3 -4
• These recommendations are intended
suspended ceilings and related items. for suspended ceilings including grid,
Unless supported by engineering, panel or tile, light fixtures and air
terminals weighing no more the 4 lbs.
the suspension system shall be _ per square foot. Source: ASCE 7 -05 section
}I 13.5.6.1
installed per these requirements. maximum 3'
(76mm) • All wire ties are to be three tight turns
Manufacturers' recommendations — y__ around itself within three inches. Twelve
gage Hanger wire spaced 4 foot on cen-
should be followed where.applicable. - ter (figure 1). Source: ASTM C 636 item 2.3.4
11 • Changes in ceiling planes will require
figure positive bracing.
Source: ASCE 7 -05 13.5.6.2.21
NORTHWEST WALL & CEILING BUREAU SUSPENSION SYSTEMS FOR ACOUSTICAL LAY -IN CEILINGS
figure 2 Lateral Force Bracing (figures 2 and 3)
Lateral force Bracing • Ceilings constructed of lath and plaster or gypsum board, screw or nail at-
tached to suspended members that support a ceiling on one level extending
- from wall to wall shall be exempt from the lateral force bracing requirements. .
45 or less , .e. 45 or less Source: CISCA zones 3 -4
' • • Lateral force bracing is the use of vertical struts (compression posts) and
splay wires (see figure 2).
. . • 1„ 12 gygd • For ceiling areas exceeding 1,000 square feet, horizontal restraint of the ceil-
45° or less t � brace ing to the structural system (lateral force bracing) shall be provided.Source:
' 45° or less wires
ASCE 7 -05 section 13.5.6.2.2 c
• Lateral Force Bracing shall be 12 feet on center (maximum) and begin no
Cross tee Mare beam — farther than 6 feet from walls. Source: CISCA Seismic zones 3 -4
• Seismic splay wires are to be four 12 gage wires attached to the main beam.
• Wires are arrayed 90° from each other and at an angle not exceeding 45° from
figure 3 the plane of the ceiling. Source: CISCA Seismic zones 3 -4
• Maximum Recommended Lengths for • Seismic splay wires shall be attached to the grid and to the structure in such
Vertical Struts a manner that they can support a design load of not less than 200 pounds or
• the actual design load, with a safety factor of 2, whichever is greater (figure
EMT CONDUIT 6b). Source: CISCA zones 3 -4 . .. •
• "Powder- driven shot -in- anchors" (PAF's), when used for seismic application
1/2" EMT conduit up to 5'10" as part the prescriptive path in Seismic Design Categories D, E and F, shall
3 /a" EMT conduit up to 7' 8" have an ICC -ES approval for seismic applications and shall require "special •
inspection" irrespective of the type of occupancy category the structure is in. •
1" EMT conduit up to 9' 9" PAF anchors for kicker wires (splayed wires installed for purposes other than
METAL STUDS seismic restraint) are exempt from this requirement. Source: State of Oregon, Buildi
• Codes Division
Single 1 /a" metal stud (20 gauge) up to 12' 0" • Splay wires are to be within 2 inches of the connection of the vertical strut to
suspended ceiling. Source: CISCA Seismic zones 3 -4
Back -to -back 1 /e" metal stud up to 15' 0" • Rigid bracing may be used in lieu of splay wires. Source: ASCE section 13.5.6.2.2 c
(20 gauge)
• Ceilings with plenums less than 12 inches to structure are not required to
Single 2' /z" metal stud (20 gauge) up to 13' 6" . have lateral force bracing. Source: Portland Building Department
• Vertical struts must be positively attached to the suspension systems and the
Back -to -back 2' /z" metal stud up to 15'0" structure above. source: CISCA 3 -4
(25 gauge)
• The vertical strut may be EMT conduit, metal studs or a proprietary compres-
Source: Portland Building Department sion post (see figure 3). .
Note: Plenum areas greater than 15'0• will require engineering
calculations. Wall Moldings (figures 4a and 4b)
• Wall moldings (perimeter closure angles) are required to have a horizontal
figure 4a flange 2 inches wide. One end of the ceiling grid shall be attached to the wall -
Attached Wall Molding Requirements molding, the other end shall have a 3% inch clearance from the wall and free to
slide. Source: ASCE 7 -05 section 13.5.6.2.2 b
ALL
. (202 rn .• • Where substantiating documentation has been provided to the local jurisdic-
W tion, perimeter clips may be used to satisfy the requirements for the 2 -inch .
closure angle. Source: State of Oregon, Building Codes Division
p ' 0 0, • The grid shiall - be attached at two adjacent Valli rivets oiapproved meth-
od). Soffits extending to a point at least level with the bottom plane of the grid
-. and and independently supported and laterally braced to the structure above are
(50 rrm
2* (5 mm) ."..i `cl deemed to be equivalent to•walls. Source: State of Oregon, Building Codes Divsion
,4 Sp Bars (figure 4b)
figure 4b • Spreader (spacer) bars shall be used to prevent the ends of the main beams
Unattached Wall Molding Requirements and cross tees at perimeter walls from spreading open during a seismic event.
Perimeter wires shall not be in lieu of spreader bars. Source: CISCA Seismic zones
lam,
3-4
WALL m ''- -- . '''r'" m' • Spreader bars are not required at perimeters where runners are attached
directly to closure angles.
0
!'\--401 b0r suitable 5p,Oa°Or • Wire tying is an acceptable alternative to spreader bars.
other
eararma ° •Spreader bars are not required if a 90 degree intersecting cross or main is
0 ' I kee •
\ / c ompo nents Irom
Ya' (rgmm) \ apr6a0�O apes within 8 inches of the perimeter wall.
,m m Otl000p° ware `�0%o • Where substantiating documentation has been provided to the local jurisdiction, •
,
, perimeter clips may be used to satisfy the requirements for spreader bars.
Source: State of Oregon, Building Codes Division
NORTHWEST WALL & CEILING BUREAU • SUSPENSION SYSTEMS FOR ACOUSTICAL LAY -IN CEILINGS
•
•
Hanger (Suspension) Wires (figures 5a and 5b) figure 5a
• Hanger and perimeter wires must be plumb within 1 in 6 unless (figure 5a)
counter sloping wires are provided (figure 5b). Source: ASTM C 636 section 2.1.4 •
- • Hanger wires shall be 12 gage and spaced 4 feet on center or 10 gage
spaced 5 feet on center. Source: ASTM C 636
• Any connection device at the supporting construction shall be capable of car-
rying not less than 100 pounds. Source: CISCA zones 3 - a mum6
• Powder - driven shot -in anchors (PAFS) are an approved method of attachment
for hanger wires. Source: State of Oregon, Building Codes Division mil
• Terminal ends of each main beam and cross tee must be supported within 8
inches of each wall with a perimeter wire (see figure 4 & 5 b). Source: CISCA zones 3 -4
• Wires shall not attach to or bend around interfering material or equipment. A figure 5b • Countersloping
trapeze or equivalent device shall be used where obstructions preclude direct
suspension. Trapeze suspensions shall be a minimum of back -to -back 1% inch
cold - rolled channels for spans exceeding 48 inches. Source: CISCA zones 3 - 7 / 3 n 6 w \
Electrical fixtures ,.y'`'
•4 upe :Az; \
• Light fixtures weighing less than 10 pounds shall have one 12 gage hanger
r
wire connected from the fixture to the structure above. This wire may be slack.
Source: CISCA Seismic zones 3 - 4
• Light fixtures weighing more than 10 pounds and less than 56 lbs. shall have
two 12 gage wires attached at opposing corners of the light fixture to the
structure above. These wires may be slack. Source: CISCA Seismic zones 3 -4.
• Light Fixtures weighing more than 56 lbs. shall be supported directly from the figure 6a
structure above. These wires must be taut. Source: CISCA Seismic zones 3 -4
• Pendant mounted fixtures shall be directly supported from the structure above Vertical hanger wire attachment
using a 9 gage wire or an approved alternate support without using the ceiling •
Shot -in anchor if 3/4
suspension system for direct support. Source: CISCA Seismic zones 3 -4 ;,]
• Tandem fixtures may utilize common wires.
Structural concrete I
Ceiling clip max.
Mechanical Services
• Terminals or services weighing 20 lbs. but not more than 56 lbs. must have two III
3 turns
12 gage wires connecting them to the ceiling system hangers or the structure
above. These wires may be slack. Source: CISCA Seismic zones 3 -4 Vertical hanger wire
• Terminals or services weighing more than 56 lbs. must be independently
supported directly from the structure above. These wires must be taut. Source: figure 6b
CISCA Seismic zones 3 -4
Splayed seismic bracing wire attachment
Seismic Separation Joints (figure 7)
• For ceiling areas exceeding 2,500 square feet, a seismic separation joint or full dri:l -in expansion anchor ;T
height wall partition that breaks the ceiling shall be provided unless analyses •
are performed of the ceilings bracing system, closure angles and penetrations Structural concrete
to provide sufficient clearance. Source: ASCE 7 -05 section section 13.5.6.2.2 d Steel strap 1' wide x 2' long x
12 gage minimum '.
• The layout and location of the seismic separation joint shall be per the design- 3 turns
er of record and noted on the plans. If a seismic separation joint is required by Splayed seismic bracing wire
the designer, the designer may use the generic joint detailed in this document
or a proprietary joint. The amount of free movement (gap design) shall be a
minimum of 3 /4 inch. Source: State of Oregon, Building Codes Division
• In lieu of seismic separation joints, the ceiling may be divided into areas less figure 7
than 2500 square feet by the use of partitions or soffits as follows: partitions shall
extend a minimum of 6 inches above the level of the plane of the grid and shall
be independently braced to the structure above. Soffits shall extend to a point at
least level with the bottom plane of the grid and shall be independently supported ti ti
•
and laterally braced to the structure above. Source: State of Oregon Building Codes Division ti i I
• Other than partitions and soffits, seismic joints may not be used as part of a
fire rated ceiling assembly unless substantiating documentation is provided.
Source: State of Oregon Building Codes Division
Sprinklers ::
For ceilings without rigid bracing, sprinkler head penetrations shall have a 2 inch — t t • . oversize ring, sleeve or adapter through the ceiling tile to allow free movement of at • i Flange
least 1 inch in all horizontal directions. Flexible head design that can accommodate ` m inim um - R °et
1 inch free movement shall be permitted as an alternate. Source: ASCE 7 -05 13.5.6.2.2 e
NORTHWEST WALL 6 CEILING BUREAU • SUSPENSION SYSTEMS FOR ACOUSTICAL LAY -IN CEILINGS
•
GLOSSARY FOR THIS DOCUMENT (regional terminology may vary)
CROSS TEES LATERAL FORCE BRACING PERIMETER WIRES
The cross member that interlock with The bracing method used to prevent Hanger wires placed within eight inches
the main beams, also known as cross ceiling uplift or restrict lateral move- of the surrounding walls.
runners or cross T -bars. ment during a seismic event. Lateral
•
force bracing consists of vertical struts PLENUM
DIFFUSER and splay wires. The space above a suspended ceiling.
A circular or rectangular metal grill
used for the passage of air from a MAIN BEAM SLACK WIRE
ducted system. The primary suspension member sup- A 12 gage wire that is not tight or taut.
ported by hanger wires, also known as
ESSENTIAL SERVICE BUILDINGS the main runner, carrying tee, carrying SPREADER or SPACER BAR
An buildings designed to be used A bar with notches to prevent the sus -
Any g g runner or mains.
by public agencies as a fire station, pension system from separating, also
police station, emergency operations MOLDING /CLOSURE ANGLE called a stabilizer bar.
center, State Patrol office, sheriff's A light gauge metal angle or chan- SPLAY WIRES
office, or emergency communication nel fastened to the perimeter wall or Wires installed at an angle rather than
dispatch center. partition to
perpendicular to the grid.
support the perimeter ends of an ac-
GRID coustical ceiling grid. VERTICAL STRUTS
The main beams and cross tees of the The rigid vertical member used in
suspension system. PERIMETER CLIPS lateral force bracing of the suspension
Proprietary angle bracket attached di- system. Also known as compression
HANGER WIRE rectly to the wall molding /closure angle y P
10 or 12 gage soft annealed wire used which allows for 3 /4" movement in the posts, seismic pods, seismic struts.
as primary support for the grid system. event of seismic activity and interlocks Common materials are electrical con -
Also called suspension wires. properly with ends of grid system. duit (EMT), metal studs or proprietary
products.
1032 -A NE 65th St. The NWCB has been serving the construction
F WC B II Seattle, WA 98115 industry for over forty years. It is recognized
Phone (206) 524 -4243 as a technical authority, educational body and
Fax (206) 524 -4136 spokesperson for the wall and ceiling industry. It
NORTHWEST WALL b CEIUNG BUREAU
Toll Free (800) 524 -4215 provides services to architects and the con -
info @nwcb.org struction community on all matters relating to
www.nwcb.org the diversified wall and ceiling industry.
As the industry's development and coordina-
NWCB - Oregon tion organization, the NWCB saw the need to
Phone: (503) 295 -0333 establish a document to provide clarification and
Fax: (503) 295 -2733 the intent of NEHRP (National Earthquake Haz-
ards Reduction Program) an agency of FEMA
B.C. Wall and Ceiling Association (Federal Emergency Management Agency). It
Phone: (604) 575 -0511 is meant to serve as a set of recommendations
Fax: (604) 597 -7208 and is not intended for any specific construction
project.
Alberta Wall and Ceiling Association
Phone: (403) 250 -7045 The NWCB makes no express or implied war -
Fax: (403) 291 -9515 ranty or guarantee.
ALASKA • IDAHO • OREGON • WASHINGTON • ALBERTA • BRITISH COLUMBIA • SASKATCHEWAN
•
Building Codes Division Statewide Code Interpretation
Working with Oregonians
to ensure safe building
construction while 2010 OSSC (effective July 1, 201 0)
supporting a positive •
business climate. Section 1613.1.
REVISED: July 1, 2010
2010 OSSC Section 1613.1, •
Code Section:
ASCE 7 -05 Section 13.5.6
2010 OSSC
Code Edition: -
ASCE Standard 7 - 2005.
• Update code/standard editions.
• Update reference to NWCB Technical Bulletin (TB) 401. The
previously referenced version; "TB 401 - Oregon " is no longer
available.
Revision Synopsis: • Update.note V a : The threshold for lateral force bracing of •
• suspended ceilings has increased from 144 square feet to 1000 square •
feet in the 2010 OSSC.
•
• Removal of text regarding grace period for adhesive, screw and
expansion anchors as complying product is available.
Subject: Construction requirements for Suspended Ceiling Systems.
Question: What are the minimum requirements of the Oregon Structural Specialty Code
for the construction of suspended ceiling systems
•
Answer: I. The following options are available:
a. An engineered ceiling system designed for appropriate forces,
b. Prescriptive ceiling systems per CISCA standards as provided
below, except for ceiling systems in structures classified as
Occupancy category III or IV:
i. in Seismic Design Category C, construction in accordance •
with CISCA standards for seismic zones 0 -2.
All of the notes in section IV of this interpretation shall be
applicable in addition to the CISCA requirements.
ii. in Seismic Design Categories D through F, construction
in accordance with CISCA standard for seismic zones 3
• Building CodesDiyision Department "of Consumer. .and - Business Services • State.ofOregon — - -- -- • -
1535 Edgewater NW Salem, Oregon • PO Box 14470 Salem, OR 97309 -0404 •:'�\
• 503 -378 -4133 • TTY 503- 373 -1358 • Fax 503 -378 -2322 • bcd.oregon.gov
In accordance with OAR 918 -008 -0110, the information contained in this statewide code interpretation is
legally binding on any party involved in activities regulated b applicable Oregon law, applicable Oregon regulations
or the state building code. If the information contained in this statewide code interpretation is cited as a basis
for a civil infraction, a representative of the jurisdiction trust cite the interpretation number found in this document.
•
•
•
and 4 with modifications as noted in ASCE 7 -05
standard.
All of the notes in sections IV and V of this interpretation
shall be applicable in addition to the requirements contained
in ASCE 7 -05 and the CISCA standards for Seismic Design -
Categories D through F.
c. Two additional compliance options are available based upon
ASCE 7 -05 Sections 13.2.5 and 13.2.6:
• i. Shake table testing of components and their supports, to
determine their seismic capacities, in accordance with.
ICC Acceptance criteria 156. {Section 13.2.5 of the
ASCE 7-05.), or
• ii. Seismic qualification by experience data based on
•. • nationally recognized procedures. {Section 13.2.6 of
• the ASCE 7 -05.}
II. Northwest Wall & Ceiling Bureau - Technical Bulletin 401: In
structures other than those classified as occupancy category III or IV,
suspended ceilings installed in accordance with the prescriptive
provisions of NWCB TB 401 are deemed to comply with this
interpretation.
NWCB TB 401 contains information compiled from the different
applicable documents such as ASCE Standard 7 -05, IBC 2010, ASTM
Standard C635 and CISCA and is available at the following internet
• • address: •
htt•p://www.nwcb.oulima files /401 %,20Suspensiont u20Sv
stems% 20for%, 20Acoustical %20Lav- in %20Ccilinrrs(2009 ).pdf
. All of the notes in sections IV and V of this interpretation shall be
. applicable in addition to the requirements contained in NWCB TB
401.
III. The Seismic restraint for suspended ceiling systems in structures
• classified =as •Occupancy :Categuryilll = and =l V, -are required-to be -
• designed for the. specific project and the anchorage of the ceiling
system is required.to be periodically special inspected in Seismic
Design Categories D, E, and F in accordance with the provisions of the
current edition of the Oregon Structural Specialty Code. •
• IV. • GENERAL NOTES. The following notes are applicable to sections I
and II:
'a. SPECIALTY CEILINGS. Specialty ceilings, Must be installed
using an engineered design and may not use the provisions of
this interpretation. Specialty ceilings include but are not
limited to those:
i. Incorporating arched ceilings, curved or curvilinear
ceilings or sloped ceilings; or
•
• - 2-
•
•
ii. Having no direct connection to the surrounding walls or
• supports, such as "free floating" or "cloud" ceiling
elements.
b. TILES. Suspended ceilings installed to this interpretation may
use either standard acoustical lay -in ceiling panels, tegular or
kerfed ceiling panels.
c. SPREADER BARS.
i. Wire ties are deemed equivalent to spreader bars
ii. Spreader bars are not required if a 90 degree intersecting
cross or main is within 8 inches of the perimeter wall.
iii. Spreader bars are not required at perimeters where
ceiling grid ends are attached to closure angles.
d. WIRE GAUGE: The minimum wire size shall be US Steel Wire
•• Gage #12 (0.1055 inch).
V. Notes Specific to Design Categories D through F
a. Lateral force bracing is required for ceilings over 1000 square
•
feet.
b. Ceilings with interstitial spaces less than 12 inches to framing
are not.required to have lateral force bracing.
c. GRID ATTACHMENT: The suspended ceiling grid shall be
attached to two adjacent walls. Soffits complying D(ii)(2) are
• deemed to be equivalent to walls. The other end of the grid in
each horizontal direction shall have a 0.75 in (19 mm) clearance
from the wall and shall rest upon and be free to slide on a
closure angle.
d. SEISMIC JOINTS •
i. For ceiling areas exceeding 2,500 square feet, a seismic
separation joint shall be provided. The layout and
location of seismic separation joints shall be per the .
•
designer of record and noted on the plans.
•
ii. In lieu of seismic separation joints, the ceiling may be
divided into areas less than 2,500 square feet by the use
of partitions'or soffits as described below.
1. Partitions. Where used, partitions shall extend a
minimum of 6 inches above the level of the
• plane of the grid and shall be independently
• braced to the structure above.
2. Soffits. Where used, soffits shall extend to a
point at least level with the bottom plane of the
•
grid and shall be independently supported and
laterally braced to the structure above.
— iii: - -- Other-- than - partitions and soffits, seismic joints -may not • • - - •
be used as part of a fire rated ceiling assembly unless
substantiating documentation is provided.
iv. The minimum •movement that must be accommodated at
3
•
•
•
•
•
seismic joints is 3 /4 of an inch.
e. PERIMETER CLIPS: Where substantiating documentation is
provided, perimeter clips may be used to satisfy the following
requirements:
i. 2 inch closure angle
ii. Spreader bar requirements
f. Sprinkler Heads: Flexible head design that can accommodate I
inch free movement in any direction shall be permitted as an
alternate to the requirement for 2 inch oversize rings, sleeves or
adapters through the ceiling tile.
Powder driven shot -in anchors" when used for seismic
application part of the prescriptive path in Seismic Design
Categories D E, & F shall an ICC -ES approval for
seismic applications and shall require "special inspection"
irrespective •of the type of "occupancy category" the structure is
in. Anchors for kicker wires (splayed wires installed for
purposes other than seismic restraint) are exempt from this
requirement.
As of the issuance of this interpretation, approved load testing
values for the use of "powder driven shot -in- anchors" in
normal- weight concrete over a metal pan deck have not been
established. Until such time as approved load testing values are
established, an on -site pull -test of such assemblies is required.
The. test shall demonstrate that the anchor can support a
minimum 250 1bs for not less than 10 seconds and be conducted
by an. approved testing agency. At a minimum, such testing
shall be performed on 5% of the total number of wires but no
less 5. Test samples shall be selected from dispersed locations.
On Site Test Failures.
In case of pull test failures, the testing agency shall notify the
local jurisdiction. An increased level of testing, as described
below, shall be conducted. All failed anchors shall be replaced.
Increa testing requirements.
' — -- -- • - 1:` =A iriinimum of 6 anchors iri the immediate vicinity of the
•
• failed anchor shall be tested.
2. • In the event of any additional failure, all anchors placed on
•
the same day shall 'be tested.
•
• • • Load testing results are required to be submitted to the local
jurisdiction for approval prior to the ceiling grid inspections.
•
• VL Upgrading of Existing. Ceilings;
a. C eilings' without Seismic Bracing. Where existing ceilings arc
without seismic bracing, the ceiling system shall be brought
• into' substantial compliance with current code requirements
when 50% or more of the ceiling tile is altered, repaired or
replaced as part of a general space alteration, or if all of the
-4-
•
ceiling system is removed.
Substantial Compliance means installation of the following
items where required in new construction;
i. lateral force bracing (splayed wires)
ii. compression struts
iii. slack wires on all light fixtures and air terminals.
This requirement does not trigger the need for;
i. 2 inch closure angle as specified in section Il
ii. Seismic separation joints
iii. 1 inch movement in all directions around sprinkler
pendants
These upgrades are not required when:
i. removing portions of tiles or panels and/or grid to alter
ductwork, sprinkler pipe, etc.
ii. portions of a ceiling are removed only to facilitate the
installation of sprinkler piping.
b. Ceilings without Compression Struts. Where existing ceilings
have seismic bracing but do not have compression struts at the
. center of the splayed wires, the addition of compression struts
will only be required when and where the grid is replaced, •
altered, raised or lowered.
Analysis: Building Codes Division staff has obtained clarifications from both the ASCE
and CISCA staff regarding the intent of provisions in their respective
documents. Both documents intended to allow the prescriptive construction of
suspended ceilings in accordance with the methodology provided in the
• appropriate CISCA standard along -with the modifications listed in ASCE 7-
05.
Richard S. Rogers, Structural Program Chief
Contact:
richard.rogers@state.or.us (503) 378 -4472 •
•
•
- 5-