asce 7 10 presentation on seismic bracing for mep systems
TRANSCRIPT
International Seismic Application TechnologyEngineered Seismic Bracing Systems
and Services
ASCE 7-10 SEISMIC DESIGN REQUIREMENTS FOR MEP NON-STRUCTURAL COMPONENTS
For :GAYNER ENGINEERS
Presented by Tim Lindfelt, Regional Engineering Manager
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Why Is Seismic Bracing Required for MEP Systems
Life Safety Functionality
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EXAMPLE:1994 NORTHRIDGE EARTHQUAKE
80-90% of the damage was to NON-structural elements
10 Essential Hospitals temporarily inoperable due primarily to water damage, broken glass, dangling light fixtures, and lack of emergency power due to failures in the distribution or control systems.
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PERFORMANCE OF PUBLIC WATER SUPPLY SYSTEMS IN HISTORIC
EARTHQUAKES
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SEISMIC BRACING IS A CODE REQUIREMENT
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AREAS REQUIRING SEISMIC BRACING
Seismic Ground Acceleration Code Changes “G-Force”
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SEISMIC DESIGN REQUIREMENTS FOR NONSTRUCTURAL COMPONENTS
CHAPTER 13
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BRACING/SUPPORTS FOR MEP SYSTEMS MUST BE ENGINEERED BY A PE AND
REVIEWED AND APPROVED BY THE AHJ
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IMPORTANT GENERAL TERMS
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Component Importance Factor (Ip)
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Ip =1.5 EXAMPLES
Examples of life-safety :• Fire protection system• Smoke exhaust system• Power to life-safety/hazardous
systems• Emergency Power• Flammable, toxic, hazardous
Examples of Risk Category IV Buildings :
• Acute Care Hospitals• Emergency Response
Centers/Shelters• Fire/Police Stations• Air Traffic Control Towers• Water Facilities Supplying OCC
CAT IV Buildings• Some Buildings
Storing/Processing Hazardous Materials
• Strategic National Defense
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SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS
13.3.1 – SEISMIC DESIGN FORCE
UPPER LIMIT
LOWER LIMIT
With Modal AnalysisWithout Modal Analysis
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SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS
FLOOR MOUNTED per TABLE 13.6-1High Deformability Component
ap = 1.0 and Rp = 2.5 (ap/Rp = 0.4)
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SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS
FLOOR MOUNTED per TABLE 13.6-1
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Spring Isolated Componentap = 2.5 and Rp = 2.0 (ap/Rp = 1.25)
SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS DISTRIBUTED per TABLE 13.6-1
Pipes welded or brazedap = 2.5 and Rp = 12.0 (ap/Rp = 0.2)
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SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS
DISTRIBUTEDPipes threaded, coupled, etc
Ap = 2.5 and Rp = 6.0 (ap/Rp = 0.42)
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SEISMIC DEMANDS ON NONSTRUCTURAL COMPONENTS
DISTRIBUTEDLow Deformable Material (Glass or Cast Iron
ap = 2.5, Rp = 3.0 ap/Rp = 0.83)
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GLASS PIPES CAST IRON PIPES
WHAT REQUIRES BRACING? PER 13.1.4: SUSPENDED/WALL MOUNTED COMPONENTS OVER 20LBS OR 5PLF
FLOOR MOUNTED EQUIPMENT OVER 400LBS OR CENTER OF GRAVITY 4 FT OR HIGHER ABOVE FLOOR
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WHAT REQUIRES BRACING….
ELECTRICAL SYSTEMS (RACEWAYS): SEISMIC DESIGN CAT. C,D,E,F:
Ip=1.5– Conduit > 2.5” dia. (SDC C)Ip=1.0 and 1.5 – Conduit > 2.5” dia (SDC D, E, F)Ip=1.0 and 1.5 – Trapezed Conduit/CT ≥ 10plfConduits > 2.5” attached to panels, cabinets or other equipment shall be installed with flexible connections.
13.6.5.6:
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WHAT REQUIRES BRACING….
ELECTRICAL SYSTEMS cont.: Light Fixtures, Lighted Signs, Ceiling Fans
• Vertical supports shall be designed for 140% of operating weight with simultaneous horizontal force of 140% of operating weight.
• Lights within a ceiling grid < 56 lbs does not need additional bracing• Connection to structure shall allow a 360 degree range of motion if no
bracing is provided
13.6.1:
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WHAT REQUIRES BRACING….
HVAC SYSTEMS: SEISMIC DESIGN CATEGORY C,D,E,F:
Ip=1.0 or 1.5 – Duct ≥ 6 Sq. Ft. or weigh > 17 lb/ft**Provisions must be made to avoid impact with larger ducts
or mechanical components, or the ducts must be protected in the event of such impacts
Ip=1.0 or 1.5 –Ducts supported on trapeze ≥ 10 lb/ftIp=1.0 or 1.5 – Inline Equipment > 75lbs , unbraced pipes attached to inline equipment shall have flex connections
Note: All smoke control/hazardous /toxic ductwork requires bracing with no size exceptions.
13.6.7:
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WHAT REQUIRES BRACING….
PIPING SYSTEMS: SEISMIC DESIGN CAT. C:
Ip=1.0 – No bracing required for single hung pipeIp=1.5 – Piping > 2” dia.Ip= 1.0 and 1.5 – Trapezed Piping ≥ 10plf
SEISMIC DESIGN CAT. D,E,F:Ip=1.0 – Piping > 3” dia. (Cast Iron > 2” dia)Ip=1.5 – Piping > 1” dia.Ip=1.0 and 1.5 – Trapezed Piping ≥ 10plf
13.6.8:
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WHAT REQUIRES BRACING….
PIPING SYSTEMS cont.: Item 3: Piping has an Rp < 4.5 per Table 13.6-1, piping
systems and attachment shall be designed for the seismic forces and relative displacements of Section 13.3.
13.6.8.3:
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Ap Rp
GENERAL EXCEPTIONS TO THE RULES
12” RULE: Must be ALL hangers on a run Provisions are made for the piping to accommodate expected
deflections (flexes at components with relative displacements) Assure that components does not swing and damage another utility.
13.6.5.6, 13.6.7, 13.6.8:
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GENERAL EXCEPTIONS TO THE RULES
12” RULE cont.: ELECTRICAL CONDUITS AND MECHANICAL DUCTS:
• If rods are used as hangers, swivels shall be provided to prevent inelastic bending in rods.
• Rods and anchors will have to be designed for bending due to seismic forces in Section 13.3 if swivels are not installed
PIPING SYSTEMS:• If rods are used as hangers, swivels, eyenuts, or other
devices to prevent any bending in the rods.
13.6.5.6, 13.6.7, 13.6.8:
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DAMAGING IMPACT & CONSEQUENTIAL DAMAGE
13.2.3:
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• Unbraced component shall not damage an essential component.
Hazardous exhaust flue
Unbraced pipe
TYPICAL BRACING RULES - PIPING
Transverse Max Spacing : Steel/Cu = 40 ft ; Cast Iron = 20 ft Longitudinal Max Spacing : Steel/Cu = 80 ft ; Cast Iron = 40 ft Min Run Length = 10 ft A Brace Within 2ft of 90deg Turn Can Work for Both Sides
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ASCE REQUIRES : HOLISTIC SEISMIC DESIGN
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SUSPENDED PIPING BRACING METHODS - TRANSVERSE
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SUSPENDED PIPING BRACING METHODS - LONGITUDINAL
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SUSPENDED PIPING BRACING METHODS – CABLE TRANS & LONG
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SEISMIC BRACING- WHAT NOT TO DO!
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SEISMIC BRACING- WHAT NOT TO DO!
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ROOF TOP SUPPORTS Wind forces shall be designed per section
29.5 Wind provisions for components and
cladding is now in chapter 30 Wind provisions on equipment is part 6 Compare section 13.3 vs WIND SECTION
29.5
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ROOF TOP SUPPORTS Detailing for wind design shall
be per Ch 13 (13.1.6 c) Code compliance requires
“Positive Attachment” to structure.
Friction resistance cannot be used
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ROOF TOP EQUIPMENT ASCE 29.5 and 29.5.1
• Wind loads shall be increased by 1.9 if your roof top equipment or structure is on a roof that is no more than 60ft from grade.
• Studies from Texas Tech University showed that the wind gust factor is actually 1.63 compared to 0.85 that was in ASCE 7-02. The 1.9 factor was used to increase the pressure based on the testing (1.63/0.85 = 1.9).
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ROOF SCREENS DO NOT REDUCE WIND LOADS ON STRUCTURES
Definition of mechanical screens per 2010 CBC
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FEMA 549 ATTACHMENT OF ROOFTOP EQUIPMENT IN HIGH WIND REGIONS
INTERSTORY DRIFT
Caused by earthquake forces Deflection is typically 1% of
story height MEP systems physically attached
to two different floors Methods to mitigate effects:
- Use flex couplings/hose- Use slotted mounts - Spring isolators
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INTERSTORY DRIFT AFFECTS ON PIPING DROPS INTO EQUIPMENT
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VIDEO OF PIPE RUPTURE AT CONNECTION TO EQUIPMENT - SHAKE
TABLE TEST
Welded/Brazed Connections Outperformed Threaded
Watch here
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FORCES ON A PIPE DROPPING INTO A FLOOR MOUNTED EQUIPMENT
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FORCES ON A PIPE DROPPING INTO A FLOOR MOUNTED EQUIPMENT
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DEFORMED FLEX
FORCES ON A PIPE DROPPING INTO A FLOOR MOUNTED EQUIPMENT
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DEFORMED FLEX
TYPICAL FLEX CUTSHEETS
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SEISMIC RELATIVE DISPLACEMENT
Components will respond differently in an earthquake. Provide adequate flexibility.
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SEISMIC BUILDING JOINTS
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SEISMIC ON THERMALLY ACTIVE PIPING
Avoid over bracing hot water and steam piping
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THERMAL PIPING RISER DESIGN
Guide
AnchorSpring Mount
Guide
Guide
Spring Mount
Anchor
Spring Mount
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PIPING INSULATION VS LOAD PATHTRADITIONAL METHOD
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PIPING INSULATION VS LOAD PATHCODE COMPLIANT METHOD
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Pre-Insulated Pipe Support Integral Attachment Support
Example: 10” Pipe with 2” Insulation – Hot Water Service, 200°F
No Direct Path for Heat Loss Direct Path for Heat Loss thru TeeHeat Loss = 100 Btu/hr Heat Loss = 2500 Btu/hr
HEAT LOSS THRU PIPE SUPPORT –PRE-INSULATED VS INTEGRAL
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PRE-INSULATED ANCHOR ENGINEERED DATA SHEET
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BRACING/SUPPORTS FOR MEP SYSTEMS MUST BE ENGINEERED BY A PE AND
REVIEWED AND APPROVED BY THE AHJ
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Special Seismic Certification13.2.2: Manufacturer Submit Cert of Compliance for Approval to the
Registered Design Professional and Building Official Designated (Ip=1.5) Equipment Options : Testing / Analysis / Experiential Data Registered Design Professional must state requirements on
Construction Documents
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IBC REQUIRES SPECIAL INSPECTION For Ip=1.5 Systems
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IBC REQUIRES SPECIAL INSPECTION For Ip=1.5 (Designated Seismic Systems)
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• Inspector needs to check• Label of equipment• Anchorage or mounted conforms to certificate of
compliance
IBC 2012 REQUIRES SPECIAL INSPECTION MEP COMPONENTS
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SEISMIC BRACING IS PART OF INSTALLATION THEREFORE NEEDS TO BE INSPECTED ALSO
Mechanical Engineer of Record Duties Define Ip for Each Component Determine List of Special Seismic Certifications Review Subcontractor Submittals (Seismic Bracing and
Anchorage Submittals) Statement of Special Inspections
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Contractor Statement of Responsibility
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ISAT’S APPROACH TO COMPLY WITH CODE
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ISAT OPA-0485-07 Only large MEP Design-Vendor with 2007 Specific
OPA!!
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SEISMIC BRACING SUBMITTAL DRAWINGS
Each Seismic Location is Detailed on the Plans and Denoted with a Location Specific I.D. Number
A Seismic Bracing Legend is Added to Assist Installers, Inspectors, and
Reviewing Engineers in Understanding the Constraints of
the Design
ISAT’s Structural Engineers “Wet” Stamp Each Layout with Their Stamp from the Project State
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IN-HOUSE CUSTOM ENGINEERING
California Licensed PE’s, SE’s, ME’s Custom Details and Calculations ELECTRONIC “WET STAMPS”
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Seismic Bracing Inserted and Coordinated Within The Model
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Custom Bracing Installation Solutions
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Point Load Maps
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Deck Pour/Insert Coordination
GPS Total Station68
Example: Cable Bracing Kit
Kits Labeled with:
-Contractor Name
-Project Name
-Drawing #
-Building Area/Floor
Cables are Pre-Tied to custom lengths, field adjustable, with correct brackets installed.
(No need to field cut and swage cables, no “hunting” for correct materials)
Correct concrete anchors, beam clamps, wood connections, etc. are included in each kit. (No quote surprises, No “hunting” for Anchors)
Appropriate quantity of Rod Stiffener components are included in each kit. (No surprises in the quote (stiffeners are usually an add with other systems), No “hunting” for materials)
Installation Details are in each kit
Kit Production and Material Shipment…
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ISAT’s “Blue Banger Hanger”Cast-In-Place Concrete Deck Inserts
IBC COMPLIANT
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Buy American Act
ISAT’s Seismic Bracing Kits and Blue Banger Hangers, labeled as such, are a “Domestic Construction Material” under FAR 52.225-9 and FAR 52.225-2
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PHD STRUT PRODUCTS
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PHD PIPE HANGER PRODUCTS
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Stiffy Supports – Light Duty Low Voltage Engineered Supports
Typical Vibration Isolation
• Spring hangers for suspended equipment, piping,
and duct
• Un-housed spring mounts
• Seismically restrained spring mounts
• Neoprene mounts
• Neoprene hangers
• Equipment frames (e.g. cooling towers)
• Equipment inertia bases
• Riser supports (anchors, guides, and springs)
• Most material complies with Buy American Act
Flexible Hose and Expansion Joints
Flexible Hose• Stainless, bronze, • CSA certified for natural gas• Variety of end fittings• Custom lengths
Rubber sphere expansion joints Expansion compensators Seismic expansion joints
• V-loops for easy nesting• U-loops• Drain ports• O2 cleaned, capped, and bagged for medical gas• CSA certified for natural gas
PTFE bellows and hose
Los Angeles, CA (HQ)San Francisco, CASan Diego, CASacramento, CAPhoenix, AZLas Vegas, NVPortland, ORSeattle, WASalt Lake City, UTDenver, COCharlotte, NC Atlanta, GANew York, NYSan Juan, Puerto Rico
ISAT Office Locations
ISAT is opening additional offices in geographic regions where building code compliance for nonstructural seismic restraints is
becoming more stringent.
ISAT’s Website…www.isatsb.comA wealth of information at your fingertips!
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