SMACNA Seismic Restraint Manual
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Transcript of SMACNA Seismic Restraint Manual
SMACNA Seismic Restraint Manual
Bob WasilewskiProject Manager, Technical Resources
SMACNA
ANSI/SMACNA 001-2000Approved by ANSI July 31, 2000
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.)
History1991 – 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
History
1998 – Second Edition
2000 – ANSI Approval
2000 – Addendum #1
QUESTION??
What is the Issue?
ANSWER
Physics!!
PHYSICS
F = Ma
Code Considerations
OLDER CODES1. BOCA
Fp = AvCcPacWc
2. SBCCIFp = AvCcPacWc
3. ICBOFp = ZIpCpWp
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
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
The Form is the Same
IBC0.4 apSDS is a measure of acceleration
Rp/Ip
UBCapCaIp is a measure of acceleration
Rp
Simplifying
IBC
Fp = CsWp (1 +2Z/h)
UBC
Fp = Cs(1 + 3hx/hr)Wp
The Components
IBC (1 + 2Z/h)and
UBC (1 + 3hx/hr)
Are Adjustments for the Anticipated Force Levels Depending on Location in the Building
Basic Equation
Fp = CsWp
Where Cs includes the Location Adjustment Factors
Rearranging the Equation
=Wp
Cs
Fp
The SMACNA Seismic Restraint Manual has Tables for Four Values
of Cs
These Tables are Identified as Seismic Hazard Level (SHL)
SMACNA SHL Values
SHL C = Cs = .21
SHL B = Cs = .42
SHL A = Cs = .67
SHL AA = Cs = 1.0
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
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.
General Requirements
4. Pipes will conform to ANSI/ASME B 31.9 Building Services Piping Code.
5. Brace in-line equipment independently of ducts and pipes.
6. 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)
General Requirements
7. Hot rolled shapes and plates to conform to ASTM A36. Pipes used as braces to conform to ASTM A120 or A53.
8. Cables to have minimum breaking strength. Per Table 3-2.
FS = 2.0FS = 5.0
General Requirements9. Bolts to conform to ASTM A307.10. Expansion anchors per Table 3.3.
Proprietary connectors may be used where values are greater.
11. Welding to conform to AWS D1.1 using shielded or submerged ARC method.
12. Brace conduit same as equivalent weight of pipe.
General Requirements
13. Do not mix solid and cable bracing. 14. Bracing for equipment NOT included.15. All runs will have a minimum of two
transverse and one longitudinal braces. 16. A run is defined as any change in
direction except as allowed by offsets.
Bracing of Ducts1. Brace all ducts with a cross sectional area
of 6 square feet or larger. Brace flat oval ducts the same as rectangular ducts.
2. Exception - Hangars 12" in length or less as measured from the top of the duct to the supporting structure. Hangars must be positively attached to the duct within two inches of the top with a minimum of two No. 10 sheet metal screws.
Bracing of Ducts
3. Transverse and longitudinal bracing per tables (Chapters 5, 6 and 7).
4. Ducts may be grouped. Select bracing requirements based on combined weight. Minimum of two sides to be attached to horizontal or vertical angles.
Bracing of Ducts
5. Wall penetrations may replace transverse brace. Solid blocking required.
Bracing of Pipes - Conduit
1. Brace fuel oil, gas (such as, fuel gas) medical gas and compressed air as per local codes.
2. Brace piping in boiler, mechanical equipment and refrigeration mechanical rooms 1 ¼" inch or larger.
Bracing of Pipes - Conduit3. Brace all pipes 2 ½ inch nominal diameter or
larger.4. Exception - Pipes suspended from individual
hangers 12" or less as measured from the top of the pipe to the supporting structure. For pipes on a trapeze, the 12" exception is measured from the upper face of the horizontal trapeze member or the bottom of the pipe.
Bracing of Pipes - Conduit
5. Transverse and longitudinal bracing as per tables (Chapters 5, 6 and 7).
6. 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.
Bracing of Pipes - Conduit
7. Branch lines may not be used to brace main lines.
Vertical risers not specifically
engineered will be laterally
supported with a riser clamp at each
floor.
DEFINITIONS
TRANSVERSE BRACE - those designed and installed to restrain movement in the direction perpendicular to the piping or duct run
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
Elements of a Seismic Restraint
Brace
Attachment to the Component
Attachment to the Structure
Bracing Members
RIGIDAnglesPipesStrut Channels
NON-RIGIDCables
Connection to the Element
Ducts
Pipes
FIGURE 4-2 SIDE BRACING FOR RECTANGULAR DUCTS
FIGURE 4-3 SIDE BRACING FOR RECTANGULAR DUCTS
FIGURE 4-4 CABLE SIDE BRACING FOR RECTANGULAR DUCTS
FIGURE 4-5 SIDE BRACING FOR RECTANGULAR DUCTS
FIGURE 4-6 CENTER BRACING FOR RECTANGULAR DUCTS
FIGURE 4-7 CABLE CENTER BRACING FOR RECTANGULAR DUCTS
FIGURE 4-8 FLOOR SUPPORTED DUCT
FIGURE 4-9 SINGLE HANGER SPACING FOR ROUND DUCTS33-36 INCHES (838-900 MM)
FIGURE 4-10 SINGLE HANGER CABLE BRACING FOR ROUND DUCTS33-36 INCHES (838-900 MM)
FIGURE 4-13 TRANSVERSE BRACING FOR PIPES
FIGURE 4-14 STRUT BRACING FOR PIPES
FIGURE 4-16 LONGITUDINAL BRACING FOR PIPES
FIGURE 4-18 CABLE BRACING FOR PIPES
FIGURE 4-20 STRUT BRACING FOR PIPE TRAPEZE
FIGURE 4-21 CABLE BRACING FOR PIPE TRAPEZE
FIGURE 4-22 FLOOR SUPPORTED PIPES
Tables
TABLE 5-1 SIDE BRACING FOR RECTANGULAR DUCTS, SHL A, L=2' 8" (MAX.)
TABLE 5-2 SIDE BRACING FOR RECTANGULAR DUCTS WITH ROD HANGERS, SHL A
TABLE 5-6 BRACING FOR ROUND DUCTS, SHL A
TABLE 5-7 SCHEDULE FOR BRACING PIPES AND CONDUIT, SHL A
TABLE 5-8 SCHEDULE FOR BRACING PIPES ON TRAPEZE, SHL A
Connection to the Structure
FIGURE 8-1 CONNECTIONS TO CONCRETE
TABLE 8-1 SCHEDULE FOR TYPICAL CONNECTIONS TO STRUCTURAL SUPPORTING MEMBERS
Miscellaneous Connections
FIGURE 8-2 ADJUSTABLE CONNECTIONS TO CONCRETE
FIGURE 8-4 ALTERNATE CONNECTIONS TO CONCRETE
FIGURE 8-6 CONNECTIONS TO CONCRETE FILL ON STEEL DECK
FIGURE 8-12 CONNECTIONS TO STEEL
FIGURE 9-5 CABLE END CONNECTION
FIGURE 9-10 RISER BRACING FOR HUBLESS PIPES
FIGURE 9-17 WELDED TABS
FIGURE 9-20 288-POUND (MAX.) VARIABLE AIR VOLUME TERMINAL
SMACNA Guidelines/ConsultantSEISMIC SOURCES:
Contractor/ConsultantSEISMIC DESIGN (Mechanical):
10.0 Richter EarthquakeSEISMIC REQUIREMENTS:
3 MillionSEISMIC RESTRAINT COST:
30 Million (No Equipment)PIPING/SHEET METAL:
4350 Tons Cooling - Central PlantMECHANICAL:
Start 1989, (1992), Complete 1997TIME:
1 BillionCOST:
6 Buildings, 110 Acres, 100 Year Life, 945,000 SFSIZE:
Getty Center - Brentwood, CaliforniaPROJECT:
Other Resources
ASHRAE –
A Practical Guide to Seismic Restraint
Other Resources
FEMA1. 2000 Provisions (FEMA 368)2. 2000 Commentary (FEMA 369)3. Installing Seismic Restraints For
Mechanical Equipment (FEMA 412)4. Installing Seismic Restraints For Duct &
Pipe (FEMA 414)
FEMA Distribution Center 1-800-480-2520