STRUCTURAL COLLAPSE AWARENESS

1
STRUCTURAL COLLAPSE AWARENESS
2
COURSE OVERVIEW

• Scope
• Knowledge Base To Identify Collapse Conditions
• Knowledge To Determine Type Of Structure
• Provide Tasks For First In Companies
• Establish ICS / IMS
• Assess Incident Magnitude
• Identify Potential Hazards
• Surface Rescue Of Accessible Victims

3
COURSE OVERVIEW (CONTINUED)

• Requirements
• Firefighter II
• Course Completion
• End Of Course Exam
• State Written Exam
• Review Objectives In Manual

4
STRUCTURAL COLLAPSE AWARENESS

• Causes
• Dangers
• Rescues

5
CAUSES

• Tornadoes
• Wind Storms
• Floods
• Vehicle Accidents
• Construction Accidents
• Fires

6
ASSOCIATED DANGERS

• Secondary Collapse
• Gas Electrical Hazards
• Fire
• Explosions
• HazMat Spills
• Uncontrolled Animal Life
• High Number Of Initial Injuries
• Uncontrollable Crowds

7
RESCUES ARE RARE

• Minimal Number Of Incidents
• Dangerous Due To Lack of Experience
• Limited Funding For Training Equipment
• Hazards Are Hidden
• False Sense Of Security
• May Require Numerous Unusual Resources

8
GENERAL PRINCIPLES

• Strategies Of Initial Size-Up
• Principle of Collapse Awareness
• Initial Spontaneous Response
• Planned Community Response
• Void Space Rescue
• Technical Urban Search Rescue

9
STRATEGIES OF INITIAL SIZE-UP

• Assess Affected Area
• Scope Magnitude Of Incident
• Number Of Structures Involved
• Size Of Structures Involved
• Integrity Of Affected Structures
• Stability Of Affected Structures

10
STRATEGIES OF INITIAL SIZE-UP (CONTINUED)

• Evaluate Each Area
• Occupancy Types
• Number Of Known / Potential Victims
• Availability Of Access To The Scene
• Environmental Factors That Affect The Incident
• Available / Necessary Resources Needed

11
PRINCIPLES OF STRUCTURAL COLLAPSE AWARENESS

• To Save Trapped Victims From Around Collapsed
  Structures, While Minimizing The Risk To Them And
  To Rescue Personnel

12
PRINCIPLES OF INITIAL SPONTANEOUS RESPONSE

• Types Of Responders
• Remove Surface Victims
• Remove Lightly Trapped Victims
• Accounts For 80 Of Total Rescues

13
PRINCIPLES OF INITIALRESPONSE (CONTINUED)

• Survival Rate Relatively High
• Skilled Responders
• Can Participate
• Better Organize The Response

14
PRINCIPLES OF A PLANNED COMMUNITY RESPONSE

• Community Response (Awareness Level)
• First In Fire Companies
• Police / Local Emergency Management / PW
• Rescue Non-Structurally Trapped
• Call-out / Hail System
• Visual Search
• Light Lifting Of Contents
• Light Hazard Mitigation

15
VOID SPACE RESCUE

• Technical Rescue Teams
• Trained Personnel
• Risk / Benefit Decision
• Accessing Voids Thru Existing Openings
• Cut Small Openings - Walls / Floors
• Shoring
• Provides Safety for Rescuers / Victims

16
TECHNICAL USR

• Technically Trained Rescue Forces
• Specialized Equipment To Perform Operation
• Immobilized For A Ten-Day Long Effort
• Selected Sites
• Re-evaluated
• Re-searched
• Prioritized
• Extensive Cutting and Shoring
• Cranes May Be Used

17
DESTRUCTIVE FORCES

• Earthquakes
• Wind
• Floods
• Snow
• Heavy Rain

18
DESTRUCTIVE FORCES (CONTINUED)

• Construction Problems
• Explosions
• Structural Decay
• Fire
• Transportation Accidents

19
EARTHQUAKES

• Cause Shaking
• Greatest Effect
• Weak / Heavy Structures
• Structures Dynamically Coupled With
  Their Sites
• Model Building Codes

20
WIND

• Hurricanes And Tornadoes Cause Damage
• Wind Velocity
• Airborne Missiles
• Tidal Surges
• Differences In Atmospheric Pressure
• Light Non-engineered Buildings And Structures
• Penetration
• Leading To High Uplift Blowout Forces

21
FLOODS

• Riverine Flooding
• Flash type
• Rapid water rise
• High velocity
• May Produce A Wall Of Water Effect
• Other Type
• Slow Unconfined Flow
• Over A Low Lying Broad Area

22
FLOODS (CONTINUED)

• Coastal Flooding
• Caused By Severe Storms
• May Be Combined With High Tides
• Step Up Surges Of Hurricanes Combined With Their
  High Winds Produce Combined Forces From Wind And
  Flooding

23
FLOODS (CONTINUED)

• Flooding Damage
• Hydrostatic Lateral Pressure / Lifting
• Hydrodynamic Forces Due To
• Velocity
• Wave Height
• Debris Impact From Waterborne Objects

24
SNOW AND HEAVY RAIN

• Roof Collapse Due To Overload
• Occurs In
• Long Span Construction
• With Relatively Flat Roofs
• Roof beams / Trusses Fail Partial Collapse
• Snow Buildup Can Cause More Complete Collapse Due
  To Failure Of Vertical Supporting Elements

25
CONSTRUCTION PROBLEMS

• Lack Of Temporary Lateral Bracing
• Inadequate Vertical Shoring
• Failures can occur
• During Concrete Pours
• While Placing Large Roof Beams And Trusses
• While Lifting Large Concrete Slabs
• Other Overloads
• Stockpiling Of Materials
• Non Engineered Alterations

26
EXPLOSIONS

• Gas buildups
• Natural gas
• Propane
• Anhydrous ammonia
• Smoke explosions
• Bombs
• Dusts W/ Less Than 5 Visibility

27
EXPLOSIONS (CONTINUED)

• Effect
• Lightweight Wood and Steel Components
• Weakest Part Blown Out to Reduce the Pressure
• Entire Roof or Wall May Be Blown Out
• Reinforced Concrete Structure Contains Blast
• Greater Loss of Life
• Floor Collapse If Columns and Walls Are Damaged
• Precast Structure Very Vulnerable
• Large Concrete Parts May Become Disconnected
• Or Blown Out Leading to Progressive Collapse

28
STRUCTURAL DECAY

• Collapse of older buildings and bridges
• Vertical Members Fail Leading To Multi-Floor
  Collapse
• Unreinforced Masonry Walls Can Be Left Full
  Height
• Walls Could Fall
• In On Floor Debris Pile
• Out Into The Street
• Into Adjacent Buildings
• Very Dangerous

29
FIRE

• Wood or Metal Roofs / Floors
• Often Collapse Due To Burn Through
• Can Pull Exterior Masonry / Concrete Wall In
• Leave Them In An Unbraced Condition
• Steel Structures Have Less Strength Due To The
  Loss of Original Heat Treatment
• Remaining Concrete Structures Can Be Damaged Due
  To Spalling
• Concrete Shear Walls Can Be Cracked Due To The
  Expansion Of Floors

30
TRANSPORTATION ACCIDENTS

• Vehicular And Other Transportation Accidents Have
  Caused Collapse
• Due To Impact
• Spillage Of Large Quantities Of Materials

31
INITIAL INFORMATION GATHERING

• Critical To The Transition Of The Technical
  Rescue Teams (TRT) In To The Incident
• Trts Shall Verify All Information Obtained From
  the First Responders
• The Physical and Emotional Issues First
  Responders Have Encountered
• Physically and Emotionally Draining Work
• Not Believing Any Others Have Survived
• Emotions of the Relatives and Friend of the
  Missing
• Rescuers Tend to Experience Closure of the
  Incident Prematurely

32
INITIAL INFORMATION GATHERING (CONTINUED)

• Gather Information Swiftly And Unemotionally as
  Possible
• Test Current Assumptions
• Record Structural Information
• Verify Information With Your Own Assessment

33
IDENTIFICATION OF BUILDINGS

• A Standardized System Shall Be Used To Locate A
  Building On Any Block
• Use Existing Numbers
• Fill In Numbers Unknown Due To Damage
• If All Are Unknown
• Keep All Numbers Small
• Odds One Side
• Evens The Other

34
STANDARD SYSTEM FOR BUILDING LAYOUT

• Sectors A, B, C And D
• Start at street and go clockwise
• If more than 4 sides use more letters
• Multiple Stories Are Designated
• Utilize Existing Building Designations
• Sector 1, 2, 3, 4, etc.
• Basements Are Designated
• Utilize Existing Building Designations
• B1, B2, B3, etc.

35
QUADRANTS WITHIN THE BUILDING

• Quadrant 1
• Quadrant 2
• Quadrant 3
• Quadrant 4

36
BUILDING TRIAGE

• Disasters That Have Many Seriously Damaged or
  Collapsed Buildings Require a Method to
  Prioritize Them
• Method Must Identify and Quantify Criteria That
  Will Have a Higher Probability of a Successful
  Rescue
• Method Should Also Be Simple Enough So That All
  Levels of Rescuer Can Effectively Perform It
• Happens Immediately After the Disaster

37
BUILDING TRIAGE (CONTINUED)

• Recon/Evaluation Teams Prioritize All Affected
  Structures To Aid In Response Planning
• Local Emergency Responder May Triage To Evaluate
  The Overall Impact And Evaluate Their Own
  Priorities
• USAR Teams May Triage To Prioritize Multiple
  Buildings In Their Assigned Areas Or Even triage
  To Prioritize Sections Of A Large Structure

38
BUILDING ASSESSMENT

• Time Of Day
• Occupancy
• Structural Type
• Building Age
• Collapse Mechanism
• Prior Intelligence
• Search And Rescue Resources Available
• Structural Condition Of Building

39
STRUCTURAL CONDITION OF BUILDING

• Is Stabilization Needed?
• None
• Minor
• Extensive
• Danger of Additional Collapse
• Low Probability
• High Probability

40
STRUCTURAL CONDITION OF BUILDING (CONTINUED)

• NO GO Conditions
• Structures on Fire
• HazMat Spills
• Any Other Conditions That Make Search Rescue
  Too Risky

41
BUILDING MARKING

• Developed To Inform The Emergency Responders Of
  The Hazards
• Based On 2 Ft. By 2 Ft. Square Using Orange Spray
  Paint
• Placement
• Adjacent to the Most Accessible Point of Entry
• After the Structural/Hazards Evaluation Has Been
  Completed

42
DETAILED STRUCTURAL EVALUATION

• Only After Priority List Of Structures Is
  Established
• Utilize Check-off Sheets

43
RESCUE TEAMS DEALING WITH RED TAG STRUCTURES

• Greatest Concern
• Partially collapsed buildings
• Term Safe
• Different from safe for occupancy
• All structures are deemed damaged
• Safe for rescue team is a value judgment

44
RED TAG STRUCTURES (CONTINUED)

• Specialists to Work in Pairs to Evaluate
  Structures
• Rescue Specialist
• Hazmat Specialist
• Second Opinions Are Critical
• Place Evaluation Marking on Building
• Near Each Entry
• UHR-4B (Page 91)

45
SEARCH RESCUE ASSESSMENT MARKING

• Functions
• Search In Progress
• Search Completed w/ Outcome

46
STRUCTURAL MEMBERS AND VERTICAL LOAD SYSTEM

• There Are Three Major Fundamentals of Structural
  Design. These Fundamentals Follow the Laws of
  Gravity, With Each Resisting It in a Certain
  Manner. These Fundamental Concepts Are
• Horizontal Members
• Vertical Members
• Combination Trusses

47
HORIZONTAL MEMBERS

• Span From Vertical Support To Vertical Support
• Must Have Strong Tensile Attributes
• Have Little Or No Compressive Values

48
HORIZONTAL MEMBERS(CONTINUED)

• Materials Steel, Concrete And Wood
• Steel
• Suited For Horizontal Design
• High Tensile Values
• Concrete
• Compressive In Nature
• Requires Addition of Steel Reinforcing
• Wood
• Limited Compressive Values
• Limited Tensile Qualities

49
VERTICAL MEMBERS

• Provide Support For Horizontal Or Spanning
  Members
• Need Strong Compressive Attributes With Little
  Or No Tensile Values

50
VERTICAL MEMBERS(CONTINUED)

• Materials Steel, Concrete And Wood
• Steel
• Tensile in nature
• Low compressive value
• Concrete
• Suited for vertical design
• Requires addition of steel reinforcing
• Wood
• Limited compressive values
• Limited tensile qualities

51
COMBINATION TRUSSES

• Structural Members Utilize Both Properties Of
  Structural Design, Vertical Horizontal Members,
  To Maintain Integrity

52
COMBINATION TRUSSES (CONTINUED)

• Components Function In Both Tension And
  Compression In Normal Spans
• Top chord is typically compressive in nature,
  attempting to push or hold components apart
• Bottom chord is typically tensile in nature,
  attempting to downward forces due to loading
• Intermediate components function in both tension
  and compression. Working to resist forces of top
  and bottom chord pulling together

53
MATERIAL PROPERTIES

• There Are Four Fundamental Materials Utilized for
  Building Construction. Each Specific Material
  Has Its Own Limitations and Benefits When
  Associated With Specific Building Size, Height
  and Structural Integrity. These Materials
  Include
• Wood
• Steel
• Concrete
• Masonry - Reinforced Unreinforced

54
WOOD

• Tough, Fibrous, Natural Material
• Strength Contingent on Species
• Inherent Defects Cause Stress Concentrations.
  I.E.... Knots, Splits and Uneven Grain
• Wood Strength Is Classified As Bending Stress
  (Fb), Contingent on Species

55
WOOD (CONTINUED)

• Since Wood Is Natural Fibrous, It Provides
  Additional Structural Benefits, Such As
• Nailed and Bolted Connections Adequately Secure
  Members
• Wood Sheathing of Structures Provides Good
  Earthquake Resistant Design, Contingent on
  Adequate Nailing

56
STEEL

• Tough, Light, Ductile and Man Made.
• Steel Must Be Fire Proofed to Ensure Structural
  Integrity
• Steel Is Often Considered the Ideal Building
  Material
• Steel Can Be Slightly Damaged or Bent and Still
  Maintain Structural Integrity
• Warning of Structural Collapse Is Evidenced by
  Sagging Members

57
STEEL (CONTINUED)

• Structural Steel Can Be Efficiently Connected by
  Bolting, Welding or Riveting (Riveting Is Typical
  to Older Structures)
• Steel Framing Must Be Braced to Prevent Weakening
  or Buckling

58
CONCRETE

• Strong Compressive Abilities With Minimal
  Tensile Strength.
• Steel Reinforcing Is Typically Added to Provide
  Additional Strength.
• Longitudinal Steel Tension Members In
  Concrete Beams
• Stirrups Shear Resistance In Beams At Support
• Horizontal Ties Confine Steel In Place

59
CONCRETE (CONTINUED)

• Concrete Can Be Strengthened As Follows
• Pretensioned Cables Are Pre-Stressed Prior to
  Placement of the Concrete and Cast Directly in
  Poured Concrete.
• Post-Tensioned Cables Are Placed in Continuous
  Sleeve Prior to Placement of Concrete. Once the
  Concrete Has Cured, the Cables Are Tensioned With
  the Use of a Mechanical Device. Thus Inducing
  Stress in the System

60
CONCRETE (CONTINUED)

• Cracking
• Cosmetic Shrinkage Cracks
• Structural Differential Cracks

61
MASONRY (REINFORCED AND UNREINFORCED)

• Components Of Construction
• Clay Brick
• Hollow Concrete Blocks
• Mortar

62
MASONRY (REINFORCED AND UNREINFORCED)

• Properties
• Reinforced Masonry (RM)
• Steel Is Typically Added to Add Tensile
  Strength
• Unreinforced Masonry
• Does Not Utilize Internal Steel Reinforcing
• It Is Not Compatible With Seismic Regions
• Integrity Of Wall
• Contingent on Workmanship
• Specifically - Mortar Joints and Reinforcing
  Placement

63
MASONRY (REINFORCED AND UNREINFORCED)

• Construction Of Masonry Wall
• Three or More Bricks End to End, for Five or Six
  Courses Vertically
• Then a Brick Is Placed at 90 Degrees (Header
  Course) To Tie Inside To Exterior
• Strength Of Mortar Bond
• Contingent on Mortar Design
• High Lime Content Provides Low Strength but
  Better Workability
• Low Lime Content Yields Higher Strength With Less
  Workability

64
BUILDING TYPES

• Based On The Inherent Strengths And
  Weaknesses Of Specific Building Materials And
  Construction Methods, Each Specific Building Has
  Its Own Design Methodology And Integrity Concern.

65
CATEGORIES

• Wood Frame Buildings (W)
• Diagonally Braced Steel Frame Buildings (S2)
• Light Gauge Metal Buildings (S3)
• Concrete Frame Buildings (C1), (C3)
• Concrete Shearwall Buildings (C2)
• Precast Concrete Frame Buildings (PC2)
• Post Tensioned Lift Slabs
• Tilt Up Concrete Wall Panel Buildings (TU)
• Masonry Buildings (URM / RM)

66
WOOD FRAME (W)

• Typically One To Four Stories In Height
• Classifications By Method
• Platform
• Balloon

67
WOOD FRAME (W) (CONTINUED)

• Principle Weakness Maybe In The Lateral Strength
  Of Walls
• Racked Openings
• Brittle First Story Failures
• Shifting Off Foundation
• Damage To The Masonry
• Fire

68
DIAGONALLY BRACED STEEL FRAME (S2)

• One To Twenty Stories In Height
• Typically Non-Structural Exterior Covering
• Diagonal Members Providing Structural Stability

69
DIAGONALLY BRACED STEEL FRAME (S2) (CONTINUED)

• Principal Weaknesses
• Story Drift
• Shedding
• Brittle, Finish Materials
• Whipping
• Buckling (Compression)

70
LIGHT GAUGE METAL BUILDINGS (S3)

• One Story Pre-Engineered Buildings
• Sheathed With Metal Siding and Roofing.
• Principal Weaknesses
• Loss of Sheathing Loss of Structural Integrity
• Whipping Action
• Weakest Link Theory

71
CONCRETE FRAME BUILDINGS (C1) AND (C3)

• Older Structural Frames Are From One To Thirteen
  Stories in Height
• Hazardous Configurations
• Soft First Stories (High, Open Framing)
• Open Front Structures (Typical Retail Structures
  of One and Two Stories)
• Corner "L" Shaped Structures Due to Torsion

72
CONCRETE FRAME BUILDINGS (C1) AND (C3) (CONTINUED)

• Principal Weaknesses
• Columns Break at Intersection With Floor Beams
• Severe Structural Cracking
• Weak Concrete and Poor Construction

73
CONCRETE SHEARWALL BUILDINGS (C2)

• One to Thirteen Stories In Height
• With Structural Walls on All Four Sides
• "Punched Openings" for Doors and Windows.
• Principal Weaknesses
• X- Cracking of Wall Sections Between Punched
  Openings.
• Severe Cracking or Collapse of Columns May Occur
  in Soft Stories

74
PRECAST CONCRETE FRAME (PC2)

• One to Ten Stories In Height
• Precast Wall Panels May Be Made for Taller
  Applications
• Typical Weaknesses
• Joint Failures
• Wall Panel Separation
• Progressive Collapse (Domino Effect)

75
POST-TENSIONED LIFT SLABS

• Typically Three to Thirteen Stories in
  Height
• They Are Laterally Braced With Cast in Place
  Concrete Walls
• Slab Construction
• Typically 6" to 8" in Thickness
• Poured As a Pancake And Lifted Into Position

76
POST-TENSIONED LIFT SLABS (CONTINUED)

• Principal Weaknesses
• Changing Effects of Reinforcing Members During a
  Building Collapse
• Structures Become an Unreinforced System Due to
  the Above Condition

77
TILT UP CONCRETE WALL BUILDINGS (TU)

• Usually One to Three Stories in Height
• Components
• Poured Concrete Wall Panels
• Wood Framing For
• Roof Structures
• Floors
• Concrete Floors
• Steel Framing With 1 1/2 Concrete Filled Deck
  Floors

78
TILT UP CONCRETE WALL BUILDINGS (TU) (CONTINUED)

• Principal Weaknesses
• Wall Separation
• Suspended Panels Fall Off
• Short Weak Columns
• Most Failures Are Limited to Exterior Walls

79
UNREINFORCED MASONRY BUILDINGS (URM)

• Usually From One to Six Stories in Height
• Components
• Unreinforced Walls
• Wood Floors.
• Principal Weaknesses
• Inadequate Anchors for Parapets
• Weak Mortar Cause Split Walls
• Non-Load Bearing Walls Tend to Fail Earlier.
• Lack of Interior Supports

80
ADVERSE STRUCTURAL LOADING

• Earthquake
• Wind
• Explosion
• Fire
• Flood
• Bracing, Urban Decay And Overland

81
EARTHQUAKE

• Lateral loads
• Gravity weight
• Vertical loads

82
WIND

• Damage
• Elevation and Terrain Effects Velocity
• Partial Loss of Exterior Sheathing / Cladding
• Peeling off of Masonry
• Destructive Missiles

83
WIND (CONTINUED)

• Collapse
• Up Lift Pressures
• Roof or Wall Collapse Due to Loss of Lateral
  Support
• Tall Unsupported Walls Are Unstable
• Buckling or Bending of Light Metal Building
• Closed to Open Type Building

84
EXPLOSION

• Conversion of Energy
• Shock Waves
• Terrorism

85
FIRE

• Burn Through Material
• Distorted Steel
• Spalling Concrete

86
FLOOD

• Pressure
• Hydrostatic Lateral
• Hydrostatic Lifting Pressure
• Damage
• Partly or Completely Move Buildings From
  Foundation
• Broken or Tilted Foundation Walls
• Undermined Foundations
• Impacted Objects

87
BRACING, URBAN DECAY AND OVERLOAD

• Gravity Loading
• Inadequate Materials

88
GENERAL COLLAPSE PATTERNS

• Lean To
• Failure of a Single Bearing Wall
• Requires Stability of a Second Bearing Wall
• V-Shape
• Interior Support Fails
• Requires Stability of Two Exterior Walls
• More Common in Urban Decay / Overloaded Column
  Failure

89
GENERAL COLLAPSE PATTERNS (CONTINUED)

• A-Shape
• Exterior Supports Fail
• Requires Stability of Interior Column / Wall
• Pancake
• All Vertical Supporting Members Fail
• Floors Collapse on Top of Each Other

90
GENERAL COLLAPSE PATTERNS (CONTINUED)

• Cantilever
• Pancake With Extended Floors
• Most Dangerous Type of Collapse
• Overturn
• Failed Shearwall
• Foundation Failure

91
SURVIVABILITY PYRAMID

• Spontaneous Rescue
• Community Response
• Emergency Service Providers
• USAR Task Forces

92
BASIC SEARCH AND RESCUE PLANNING

• Stage I
• Recon
• Immediate Rescue of Surface Victims
• Scene Organization Management
• Stage II
• Exploration Rescue From Likely Survival Places
• Locating Victims Using the Hailing System
• Breaching Shoring

93
SEARCH AND RESCUE PLANNING (CONTINUED)

• Stage III
• Selected Debris Removal
• Handling Removing a Victim
• Stage IV
• General Debris Removal
• No Live Victims - Body Recovery

94
SEARCH AND RESCUE PLANNING (CONTINUED)

• Stage V
• Post Incident Debriefing
• Critique
• CISD

95
HAZARD CONTROL

• General
• Hazard Reduction By Type
• Victim Access By Type
• Rescue Operations Checklist

96
GENERAL

• Avoid
• Shore
• Remove
• Recognize

97
HAZARD REDUCTION BY TYPE

• Light Frame Buildings
• Heavy Wall - URM
• Heavy Wall - TU Low Rise Reinforced Masonry
• Heavy Floor Buildings
• Precast Buildings

98
VICTIM ACCESS BY TYPE

• Light Frame Buildings
• Heavy Wall - URM
• Heavy Wall - TU Low Rise Reinforced Masonry
• Heavy Floor Buildings
• Precast Buildings

99
INCIDENT DOCUMENTATION

• Size Up Information
• Structure Type
• Occupancy
• Hazards
• Basic Safety Checklist