SEISMIC REQUIREMENTS OF THE 2003 INTERNATIONAL BUILDING CODE

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SEISMIC REQUIREMENTSOF THE 2003 INTERNATIONAL
BUILDING CODE

• Presented By
• John Pouliot, P.E. President, JP Engineering,
  Inc. Member CT Chapter ASHRAE
• With valuable assistance from
• Richard Szewczak, P.E. President, Szewczak
  Associates
• Presented at the CT Chapter ASHRAE Dinner Meeting
• February 8, 2007

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GOALS

• To understand the requirements of the building
  codes relative to seismic restraint of mechanical
  and electrical systems in buildings.
• Compare our previous code requirements to those
  in the new 2003 IBC.
• Figure out how to make our life easy.

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GOALS

• Understanding the requirements of the building
  codes relative to seismic restraint
• Requires thorough reading of the code.
• Requires interpretation of some excerpts.
• Often requires help from other resources.

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GOALS

• Compare our previous code requirements to those
  in the new 2003 IBC
• 1996 BOCA Building Code
• Simple 4 step process
• 2003 International Building Code
• Robust 12 plus step process

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GOALS

• Figure out how to make our life easy
• Best Scenario Find a way out of it!
• There are options that eliminate seismic
  restraint.
• Use the simplest calculations and criteria.
• Use the exceptions granted, based on mountings
  and support.
• Engage an expert.

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Old BOCA Code Trail.(The four step process)

• Determine the buildings Seismic Hazard Exposure
  Group. (Table 1610.1.5.)
• Determine the system or components Performance
  Criteria Factor (Table 1610.6.4(1)
• Determine the Seismic Performance Category
  (Requires input from your structural engineer.)
• Verify if Section 1610.6, exception 3 will allow
  you to be exempt from seismic restraint.

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BOCA Table 1610.1.5 This table describes the
Seismic Hazard Exposure Group. Basically, it
identifies how much life hazard there may be in a
building based on its occupancy or the nature of
how critical it is for the building to survive a
seismic event. High Occupant Density Emergency
Facilities Run of the mill buildings Group I
buildings get you out of a lot of work.
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BOCA Table 1610.6.4(1)Determines Performance
Criteria Factor.Basically describes how
critical your mechanical or electrical components
are, relative to life hazard if the component
were to fail.Higher numbers reflect more hazard
to life due to failure.Lower numbers reflect
less hazard to life due to failure.
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BOCA Section 1610.6This section basically
indicates that all M/E components shall be
designed and constructed to resist seismic
forces.However the section offers Exception 3
which states, Architectural, mechanical and
electrical components and systems in buildings
that are assigned to Seismic Performance Category
B or C, are in Seismic Hazard Exposure Group 1
Buildings and have a performance criteria factor
of 0.5 are exempt from the requirements of this
section.
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Making our life easy..

• If you meet the criteria stated in Exception 3,
  there are no seismic requirements for M/E
  components in many buildings except
• Fire Protection Systems
• Hazardous piping systems such as gas or other
  combustible or flammable liquids or gases.
• Elevators
• Emergency Power Systems

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Newly adopted 2003 International Building Code

• Longer process - 12 or more steps.
• Not all information is actually in the 2003 IBC.
• IBC makes reference to ASCE Standard 7-02.
• ASCE 7-02 takes you through the Exemption
  search.

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Preliminary Steps

• Qualify that what youre designing is a structure
  or a component.
• Mechanical and electrical equipment and systems
  qualify as components.
• Architectural components might be generally
  described as non-structural elements ceilings,
  soffits, fascias, partitions, non-bearing walls,
  windows doors, etc.
• This session deals with components only.

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Preliminary Steps (contd)

• Verify if customer or client is satisfied with
  minimum code requirements. (Mission critical
  facilities, high value contents, etc.)
• Confirm your findings with building officials
  prior to submitting construction documents.

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The path through the 2003 International
Building Code to determine the Seismic
Requirements for Mechanical and Electrical
Systems better known as The 12 Step Program
to Making Our Lives Easier
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Step 1

• Identify the Soil Site Class
• Table 1615.1.1 defines the soil site class.
• Youll need help or advice from a structural
  and/or geotechnical engineer to identify the Soil
  Site Class.
• Basically, Class A is the best (hard rock) down
  to Class F which is the worst (clay, swamps,
  etc.)
• If not known, the default class is Class D

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IBC Table 1615.1.1Defines Soil Site ClassIn
section 1615.1. it states that When the soil
properties are not known in sufficient detail to
determine the site class, Site Class D shall be
used unless the building official determines that
Site Class E or F soil is likely to be present at
the site.Again, geotechnical engineer can
probably get you a better Class with definitive
data.
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Step 2

• Determine the Spectral Acceleration Coefficient
• Found in 2005 CT State Supplement, Appendix K
• Lists each town in CT and gives the coefficient.
  Record both
• Short Period Spectral Acceleration (Ss)
• One (1) Second Spectral Acceleration (S1)
• (Youll need these numbers later.)

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2005 Supplement Appendix KSpectral Accelerations
(SS S1)
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Step 3

• Establish the Site Coefficients (Fa Fv)
• Check IBC Tables 1615.1.2(1) and 1615.1.2(2) and
  record the site coefficients for both short
  period and 1 second accelerations.
• All CT towns will have short period values
  below 0.5 and 1 second values below 0.1.

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IBC Tables 1615.1.2(1) 1615.1.2(2)Use the
Site Class and Spectral Response Accelerations to
determine the Site Coefficients.
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Step 4

• Calculate the Maximum Spectral Accelerations
  (SMS SM1)
• Use IBC Equations 16-38 for the short period
  acceleration and 16-39 for the 1 second
  acceleration.
• Eq. 16-38 SMSFaSs
• Eq. 16-38 SM1FvS1

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Step 5

• Calculate the Code Required Design
  Accelerations (SDS SD1)
• Use IBC Equations 16-40 for the short period
  acceleration and 16-41 for the 1 second
  accelerations.
• Eq. 16-40 SDS 2/3 SMS
• Eq. 16-41 SD1 2/3 SM1

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Step 6

• Establish and determine the Seismic Use Group
  using IBC Table 1604.5.
• Verify actual occupant load of building. The
  number of occupants has a significant effect.
• Compare the occupant load to the building code
  use group (assembly, educational, institutional,
  etc.)
• Verify the type of building (emergency operations
  and shelters, critical power, etc.)

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IBC Table 1604.5Determining the Seismic Use
Group here is the same as the old BOCA Seismic
Hazard Exposure Group.Select the Category
from the building descriptions in the table.
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Step 7

• Establish the Seismic Design Category
• Use IBC Tables 1616.3(1) and 1616.3(2).
• Using the calculated Design Spectral
  Accelerations from step 5 and the determined
  Seismic Use Group category, select the Seismic
  Design Category.
• Will be a letter A through D.
• Whichever is the higher letter will be your
  required Seismic Design Category.

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IBC Tables 1616.3(1) and 1616.3(2)Derives the
Seismic Design Category based on the Seismic
Use Group from step 6 and the calculated Design
Spectral Acceleration from step 5.Check
against both tables and use the Seismic Design
Category with the highest letter value.Now
were ready to look for the exceptions to the
Seismic Requirements
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Step 8

• IBC Section 1621 is the section that states that
  Architectural, mechanical and electricalcomponen
  ts and elements..shall meet the requirements of
  Section 9.6 of ASCE 7, except as modified
• This is where IBC drops the easy step by step
  procedures that were previously in BOCA.

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Step 9

• Get copy of ASCE (American Society of Civil
  Engineers) Standard 7-02 Second Edition.
• Most structural engineers and civil engineers
  have this or you can buy a copy.

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Step 10

• Section 9.6 of ASCE 7 establishes the minimum
  design criteria for architectural, mechanical,
  electrical and other non-structural elements in
  buildings.
• Much of the criteria is resisting forces,
  displacements, etc.
• Much of what was developed in previous steps from
  IBC is contained earlier in ASCE 7 as structural
  design standards.
• Much of the structural criteria in IBC is derived
  from ASCE 7.
• Now, speed-read your way to the exceptions.

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Step 11

• Check for exceptions.
• Use Seismic Design Category letter derived from
  step 7.
• Category A and B gets you off everything.
• Category C relieves you from certain components
  determined in step 12.
• Categories D, E F relieves you from seismic
  requirements based on flexibility of the
  connection of components and mounting height and
  the weight and support of components. (A bit
  more complicated, but worth the effort to
  investigate.)

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ASCE Section 9.6.1. This page contains the group
of exceptions that were not to be found in IBC
the way they were in the BOCA. Work your way
through and determine how you might comply with
the exceptions.
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Step 12

• Determine, record, and list which components
  require seismic restraint.
• Double check Section 9.6.3. This section gives
  the specific criteria for equipment, ducts,
  pipes, conduits, etc. and contains the
  recognizable language relative to short hangers
  (less than 12), size limitations, hazardous
  contents, etc. This relieves many requirements.

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Step 13

• Prepare construction documents with adequate
  clarity for proper bidding and construction and
  to demonstrate acceptable conformance to the Code
  for the AHJ.
• This is where the actual load and displacement
  calculations and actual detailing of restraints
  comes in.

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Specifications Detailing

• Amount you do depends on your appetite for
  calculations and detail drawings.
• Performance specifications are an option.
• Resources available
• SMACNA
• Military Specifications and details
• Other government documents
• Vendor assistance

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If Not Exempted

• Must calculate lateral restraint forces in
  accordance with ASCE equations 9.6.1.3-1 or
  9.6.1.3-2.
• Eq. 9.6.1.3-1 has you look up lots of factors
  which may be difficult.
• Eq. 9.6.1.3-2 shortcuts you by placing in a few
  conservative factors, thus making it a shorter,
  easier calculation.
• Use 9.6.1.3-2 first. If the force or load
  bearing element seems excessive, use 9.6.1.3-1 to
  lighten the material burden.

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• Usually the labor to put it in far exceeds the
  cost of the materials themselves, so 9.6.1.3-2
  will almost always work well on most jobs.
• Verify that the building structure will withstand
  the forces imposed on it by your mechanical
  equipment.
• If in doubt, get Professional Help.

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THE END(At Last!)