1

STRUCTURAL COLLAPSE AWARENESS

Office Of The State Fire Marshal OF

Illinois

Rescue Specialist Certification Program1998

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 US&R 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 RAINRoof Collapse Due To OverloadOccurs In

Long Span Construction

With Relatively Flat Roofs

Roof beams / Trusses Fail = Partial CollapseSnow Buildup Can Cause More Complete

Collapse Due To Failure Of Vertical Supporting Elements

25

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

CONSTRUCTION PROBLEMS

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

FunctionsSearch 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

uCOMBINATION 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 IntegritySteel 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 WeaknessesColumns 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 WeaknessesChanging 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

100

COURSE REVIEW