ASCESEI Standard Blast Protection of Buildings Design Criteria and Loadings

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ASCE/SEI StandardBlast Protection of
BuildingsDesign Criteria and Loadings

• Jon A. Schmidt, P.E., SECB, M.ASCE
• and
• Paul F. Mlakar, Ph.D., P.E., F.ASCE

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Summary

• Design Criteria and Loadings
• Chapter 1 - General (Schmidt)
• Chapter 2 - Design Considerations (Schmidt)
• Chapter 3 - Performance Criteria (Schmidt)
• Chapter 4 - Blast Loading (Mlakar)

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1.0 General

• 1.1 Scope
• Minimum requirements
• Accidental or malicious explosions
• Does not supersede other codes/standards
• Does not preclude use of materials/systems not
  specifically discussed

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1.0 General

• 1.2 Definitions
• 1.3 Symbols and Notation
• Listed in one place for entire document
• Ensures consistency between sections

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1.0 General

• 1.4 User Qualifications
• Licensed design professionals
• Blast characterization, structural dynamics
• Nonlinear behavior, numerical modeling
• 1.5 Information Sensitivity
• Useful to potential aggressor
• Must be appropriately protected

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2.0 Design Considerations

• 2.1 Scope
• Appropriate principles and design criteria
• 2.2 Risk Assessment
• Required when criteria not established by
• Applicable law, owner policy, industry standards
• Other prescriptive means
• Prepared by/with qualified professionals

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2.0 Design Considerations

• 2.2 Risk Assessment
• 2.2.1 Consequence Analysis
• Identification and evaluation of potential
  impacts
• Effect of asset loss on owner/user mission
• Time required to replace asset
• Relative value of asset in terms of
  cost/quantity/other measure

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2.0 Design Considerations

• 2.2 Risk Assessment
• 2.2.2 Threat Analysis
• Identification of potential explosives (type,
  quantity, location)
• Evaluation of relative likelihood
• Collateral damage potential
• 2.2.2.1 Accidental Threats scientific data
• 2.2.2.2 Malicious Threats existence,
  capability, history, intentions, targeting

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2.0 Design Considerations

• 2.2 Risk Assessment
• 2.2.3 Vulnerability Analysis
• Identification of structural/non-structural
  elements
• Failure would cause loss or compromise of assets
• Evaluation of relative likelihood of such failure
• Related to level of protection (3.3)

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2.0 Design Considerations

• 2.2 Risk Assessment
• 2.2.4 Risk Analysis
• Combination of consequence, threat, vulnerability
• Individual factors usually multiplied
• Product is measure of relative risk
• Mitigation priorities based on ranked resulting
  values

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2.0 Design Considerations

• 2.3 Risk Reduction
• 2.3.1 Consequence Reduction
• Asset redundancy
• Asset dispersion
• Interior layout
• Non-structural components and systems
• Contingency planning

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2.0 Design Considerations

• 2.3 Risk Reduction
• 2.3.2 Threat Reduction
• 2.3.2.1 Accidental Threats remote storage,
  policies and procedures for safe handling
• 2.3.2.2 Malicious Threats
• Standoff, access control and searches, other
  visible security measures, enclosure of columns
  in public areas
• Specific guidance for standoff, vehicle barriers,
  and landforms

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2.0 Design Considerations

• 2.4 Risk Acceptance
• Design to Risk
• Owner selects specific set of scenarios
• Minimize cost to achieve desired risk level
• Design to Budget
• Owner establishes amount to be spent
• Maximize protection within cost constraints

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3.0 Performance Criteria

• 3.1 Scope
• Design objectives
• Levels of protection
• Qualitative descriptions of damage
• Response limits

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3.0 Performance Criteria

• 3.2 Design Objectives
• 3.2.1 Limit Structural Collapse
• 3.2.2 Maintain Building Envelope
• 3.2.3 Minimize Flying Debris

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3.0 Performance Criteria

• 3.3 Levels of Protection
• Performance Goals
• I (Very Low) collapse prevention
• II (Low) life safety
• III (Medium) property preservation
• IV (High) continuous occupancy

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3.0 Performance Criteria

• 3.3 Levels of Protection
• 3.3.1 Structural Damage
• I (Very Low) up to onset of collapse
• II (Low) not economically repairable
• III (Medium) economically repairable
• IV (High) superficial

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3.0 Performance Criteria

• 3.3 Levels of Protection
• 3.3.2 Element Behavior
• Expressed in terms of expected damage
• Hazardous likely to fail and produce debris
• Heavy unlikely to fail, but significant
  permanent deformations unlikely to be repairable
• Moderate unlikely to fail, but some permanent
  deformations likely to be repairable
• Superficial permanent deformations unlikely

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3.0 Performance Criteria

• 3.3 Levels of Protection
• 3.3.2 Element Behavior

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3.0 Performance Criteria

• 3.3 Levels of Protection
• 3.3.3 Glazing Behavior
• Expressed in terms of ASTM F1642 hazard rating
• I (Very Low) Low Hazard
• II (Low) Very Low Hazard
• III (Medium) No Hazard
• IV (High) No Break

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3.0 Performance Criteria

• 3.3 Levels of Protection
• 3.3.4 Door Behavior
• Categories per ASTM F2247
• I (Very Low) dislodged from frame
• II (Low) IV inoperable, wedged in frame
• III (Medium) III operable only by removing
  hardware
• IV (High) I or II operable but may require
  moderate force

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3.0 Performance Criteria

• 3.4 Response Limits
• Apply to SDOF analysis for far range effects
• Ductility ratio and/or support rotation
• Vary by element material/type and level of
  protection
• Must check other potential failure modes
• Adapted from USACE PDC (antiterrorism)
• Commentary has tables from other sources

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3.0 Performance Criteria

• 3.5 Element Strength
• 3.5.1 Strength Increase Factors
• Average Strength Factor Expected strength
  exceeds minimum specified 1.10 for concrete and
  steel
• Dynamic Increase Factor High strain rate leads
  to higher effective strength varies by material
  and failure mode

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3.0 Performance Criteria

• 3.5 Element Strength
• 3.5.2 Strength Reduction Factors
• f 1 is permissible per current industry
  practice
• 3.5.3 Remaining Strength
• Use material-specific interaction equations
• Load combination (0.9 or 1.2)D(0.5L or 0.2S)
• Use 1.0D when D is well-defined (e.g., existing)
• Use 1.0L when full L likely simultaneous with
  blast
• Apply notional loads to ensure stability

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4.0 BLAST LOADS

• General
• Basic Procedure for External Blast
• Basic Procedure for Internal Blast
• Other Procedures

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GENERAL

• Common Situations Basic Procedure
• Other Situations Recognized Literature

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EXTERNAL BLAST
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INTERNAL BLAST
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OTHER PROCEDURES

• Recognized Literature
• Published information including, but not limited
  to, research findings, technical papers and
  reports that are approved by the authority having
  jurisdiction.
• The organization, political subdivision, office,
  or individual charged with the responsibility of
  administering and enforcing the provisions of
  this Standard. It shall be permissible for the
  authority having jurisdiction to be established
  by contractual agreement, when appropriate.

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QUESTIONS?