SMACNA Seismic Restraint Manual

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SMACNA Seismic Restraint Manual

• Mark Terzigni
• Project Manager
• SMACNA Technical Resources

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History

• 1976 Guidelines for Seismic Restraint of
  Mechanical Systems
• (Sheet Metal Industry Fund of Los Angeles)
• 1982 Guidelines for Seismic Restraints of
  Mechanical Systems and Plumbing Piping Systems
• (Sheet Metal Industry Fund of Los Angeles and The
  Plumbing and Piping Industry Council , Inc.)

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History

• 1991 Seismic Restraint Manual Guidelines for
  Mechanical Systems
• (SMACNA)
• Included larger ducts
• Included conduit
• Created Seismic Hazard Level (SHL)
• 1993 Appendix E
• Corrections and Clarifications
• Specific Requirements for OSHPD
• OSHPD Approval

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History

• 1998 Second Edition
• 2000 ANSI Approval
• 2000 Addendum 1

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QUESTION??

• What is the Issue?

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ANSWER

• Physics!!

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PHYSICS

• F Ma

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Code Considerations

• OLDER CODES
• BOCA
• Fp AvCcPacWc
• SBCCI
• Fp AvCcPacWc
• ICBO
• Fp ZIpCpWp

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All Codes Take the Form of

• Fp Cs Wp
• Where Cs A series of constants given in the
  building code
• Cs is a measure of acceleration

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Current Codes

• International Building Code (IBC) 2000-2003
• Fp 0.4ap SDS Wp (1 2Z/h)
• Rp/Ip
• Uniform Building Code (UBC) 1997
• Fp apCaIp (1 3hx/hr) Wp
• Rp

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The Form is the Same

• IBC
• 0.4 apSDS is a measure of acceleration
• Rp/Ip
• UBC
• apCaIp is a measure of acceleration
• Rp

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Simplifying

• IBC
• Fp CsWp (1 2Z/h)
• UBC
• Fp Cs(1 3hx/hr)Wp

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The Components

• IBC (1 2Z/h)
• and
• UBC (1 3hx/hr)
• Are Adjustments for the Anticipated Force Levels
  Depending on Location in the Building

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Basic Equation

• Fp CsWp
• Where Cs includes the Location Adjustment Factors

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Rearranging the Equation
Fp Cs
Wp Cs
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• The SMACNA Seismic Restraint Manual has Tables
  for Four Values of Cs
• These Tables are Identified as Seismic Hazard
  Level (SHL)

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SMACNA SHL Values

• SHL A Cs 1.0
• SHL B Cs 0.75
• SHL C Cs 0.50
• SHL D Cs 0.25

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The Design Professional Should

1. Calculate Cs from the Information in the
   Applicable Local Building Code
2. Calculate the Values of Cs at the Various
   Attachment Locations in the Building
3. Indicate the Required SMACNA SHL Tables to be
   Used at the Different Attachment Locations

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Terms

• Occupancy Category
• I IV Table 1-1 ASCE-7 05
• Seismic Design Category
• Section 11.6 ASCE-7 05
• Seismic Hazard Level
• A-D based on seismic acceleration SMACNA

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ASCE-7 05
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General Requirements

1. Details provide lateral bracing system. Typical
   vertical supports per local building code must be
   used.
2. Thermal expansion not given but must be
   considered.
3. Duct construction to conform to the appropriate
   SMACNA publications.

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General Requirements

1. Pipes will conform to ANSI/ASME B 31.9 Building
   Services Piping Code.
2. Brace in-line equipment independently of ducts
   and pipes.
3. Cold formed angles to conform to the requirements
   of the latest "Specifications for the Design of
   Cold-Formed Steel Structural Members" (AISI) (FY
   33 KSI)

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General Requirements

• Hot rolled shapes and plates to conform to ASTM
  A36. Pipes used as braces to conform to ASTM
  A120 or A53.
• Cables to have minimum breaking strength. Per
  Table 3-2.

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General Requirements

1. Bolts to conform to ASTM A307.
2. Expansion anchors per Table 3-3. Proprietary
   connectors may be used where values are greater.
3. Welding to conform to AWS D1.1 using shielded or
   submerged ARC method.
4. Brace conduit same as equivalent weight of pipe.

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General Requirements

1. Do not mix solid and cable bracing.
2. Bracing for equipment NOT included.
3. All runs will have a minimum of two transverse
   and one longitudinal braces.
4. A run is defined as any change in direction
   except as allowed by offsets.

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Bracing of Ducts

• Seismic supports are not required for HVAC
  ductwork when the Ip 1.0 if either of the
  following conditions is met for the entire duct
  run
• Ducts are suspended from hangers 12 in. or less
  as measured from the top of the duct to the
  bottom of the support where

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Bracing of Ducts

• the hanger is attached. Hangers must be
  positively attached to the duct within 2 in. of
  the top of the duct with a minimum of two 10
  sheet metal screws. Lateral motion will not cause
  damaging impact with other systems. Lateral
  motion will not cause loss of vertical support.
• Ducts have a cross-sectional area of 6 ft2 or
  less.

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Bracing of Ducts

1. Transverse and longitudinal bracing per tables
   (Chapters 5, 6, 7 and 8).
2. Ducts may be grouped. Select bracing
   requirements based on combined weight. Minimum
   of two sides to be attached to horizontal or
   vertical angles.

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Bracing of Ducts

1. Wall penetrations may replace transverse brace.
   Solid blocking required.

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Bracing of Pipes or Conduit

1. Brace fuel oil, and gas (such as, fuel gas,
   medical gas, and compressed air) as per local
   codes.
2. Brace all pipes 3 inch nominal diameter or larger.

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Bracing of Pipes - Conduit

1. Transverse and longitudinal bracing as per tables
   (Chapters 5, 6, 7 and 8).
2. Provide joints/connections capable of
   accommodating seismic displacements where pipes
   pass through building seismic or expansion joints
   or where pipes connect to equipment with
   vibration isolators.

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Bracing of Pipes - Conduit

• Seismic supports are not required for piping
  systems where one of the following conditions is
  met
• Piping is supported by rod hangers hangers in
  the pipe run are 12 in. (305 mm) or less in
  length from the top of the pipe to the supporting
  structure

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Bracing of Pipes - Conduit

1. hangers are detailed to avoid bending of the
   hangers and their attachments and provisions are
   made for piping to accommodate expected
   deflections.
2. High-deformability piping is used provisions are
   made to avoid impact with larger piping or
   mechanical

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Bracing of Pipes - Conduit

• components or to protect the piping in the event
  of such impact and the following requirements
  are satisfied
• For Seismic Design Categories D, E or F where Ip
  is greater than 1.0, the nominal pipe size shall
  be 1 in. (25 mm) or less.

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Bracing of Pipes - Conduit

1. For Seismic Design Category C, where Ip is
   greater than 1.0, the nominal pipe size shall be
   2 in. (51 mm) or less.
2. For Seismic Design Category D, E or F where Ip is
   equal to 1.0, the nominal pipe size shall be 3
   in. (76 mm) or less.

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• Vertical risers not specifically engineered will
  be laterally supported with a riser clamp at each
  floor.

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DEFINITIONS

• TRANSVERSE BRACE - those designed and installed
  to restrain movement in the direction
  perpendicular to the piping or duct run

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DEFINITIONS

• LONGITUDINAL BRACE - those designed and installed
  to restrain movement in the direction parallel to
  the piping or duct run
• RUN (Piping or Duct) - a straight length with no
  changes in direction except as allowed by offsets

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Elements of a Seismic Restraint

• Brace
• Attachment to the Component
• Attachment to the Structure

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Bracing Members

• RIGID
• Angles
• Pipes
• Strut Channels

• NON-RIGID
• Cables

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Connection to the Element

• Ducts
• Pipes

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Connections to Ducts

• The SMACNA Seismic Restraint Manual Contains 12
  Different Details for Connecting to Ductwork,
  Rectangular and Round

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FIGURE 4-2 SIDE BRACING FOR RECTANGULAR DUCTS
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FIGURE 4-3 SIDE BRACING FOR RECTANGULAR DUCTS
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FIGURE 4-4 CABLE SIDE BRACING FOR RECTANGULAR
DUCTS
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FIGURE 4-5 SIDE BRACING FOR RECTANGULAR DUCTS
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FIGURE 4-6 CENTER BRACING FOR RECTANGULAR DUCTS
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FIGURE 4-7 CABLE CENTER BRACING FOR RECTANGULAR
DUCTS
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FIGURE 4-8 FLOOR SUPPORTED DUCT
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FIGURE 4-9 SINGLE HANGER SPACING FOR ROUND
DUCTS33-36 INCHES (838-900 MM)
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FIGURE 4-10 SINGLE HANGER CABLE BRACING FOR ROUND
DUCTS33-36 INCHES (838-900 MM)
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Connections to Piping/Conduit Systems

• The SMACNA Seismic Restraint Manual Contains 10
  Different Details for Connecting to
  Piping/Conduit Systems

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FIGURE 4-13 TRANSVERSE BRACING FOR PIPES
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FIGURE 4-14 STRUT BRACING FOR PIPES
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FIGURE 4-16 LONGITUDINAL BRACING FOR PIPES
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FIGURE 4-18 CABLE BRACING FOR PIPES
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FIGURE 4-20 STRUT BRACING FOR PIPE TRAPEZE
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FIGURE 4-21 CABLE BRACING FOR PIPE TRAPEZE
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FIGURE 4-22 FLOOR SUPPORTED PIPES
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Tables
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Table 5-1 Side Bracing For Rectangular Ducts, SHL
A, L2' 8" (MAX.)
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Table 5-2 Side Bracing For Rectangular Ducts With
Rod Hangers, SHL A
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Table 5-6 Bracing For Round Ducts, SHL A
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Table 5-7 Schedule For Bracing Pipes And Conduit,
SHL A
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Table 5-8 Schedule For Bracing Pipes On Trapeze,
SHL A
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Connection to the Structure
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Connections to the Structure

• The SMACNA Seismic Restraint Manual Contains 8
  Levels for Connection into Concrete
• (2) 1 Bolt Connection
• (3) 2 Bolt Connections
• (3) 4 Bolt Connections

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Connections to the Structure

• The SMACNA Manual Contains
• (6) Alternative Connections to Concrete
• (6) Details for Connection to Steel
• (3) Details for Connections to Wood

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FIGURE 8-1 CONNECTIONS TO CONCRETE
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Table 9-1 Schedule For Typical Connections To
Structural Supporting Members
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Miscellaneous Connections
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Miscellaneous Connections

• The SMACNA Manual contains
• Specific Details on Various Connections
• Bracing for Hubless Cast Iron Pipe
• Riser Bracing for Hubless Pipes
• Seismic Joints in Pipes

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Miscellaneous Connections

• The SMACNA Manual contains
• Welded Tabs for Pipe Connections
• Stiffeners Saddles at Pipe Clamps

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FIGURE 8-2 ADJUSTABLE CONNECTIONS TO CONCRETE
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FIGURE 8-4 ALTERNATE CONNECTIONS TO CONCRETE
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FIGURE 8-6 CONNECTIONS TO CONCRETE FILL ON STEEL
DECK
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FIGURE 8-12 CONNECTIONS TO STEEL
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FIGURE 9-5 CABLE END CONNECTION
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FIGURE 9-10 RISER BRACING FOR HUBLESS PIPES
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FIGURE 9-17 WELDED TABS
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PROJECT Getty Center - Brentwood, California
SIZE 6 Buildings, 110 Acres, 100 Year Life, 945,000 SF
COST 1 Billion
TIME Start 1989, (1992), Complete 1997
MECHANICAL 4350 Tons Cooling - Central Plant
PIPING/SHEET METAL 30 Million (No Equipment)
SEISMIC RESTRAINT COST 3 Million
SEISMIC REQUIREMENTS 10.0 Richter Earthquake
SEISMIC DESIGN (Mechanical) Contractor/Consultant
SEISMIC SOURCES SMACNA Guidelines/Consultant
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Other Resources

• ASHRAE
• A Practical Guide to Seismic Restraint