Structural Collapse Structural Collapse Operations IIOperations II

Course Objectives:Course Objectives:

Describe the six sided surveyState the principle weakness of light frame

and heavy URM structuresState 3 methods to monitor structural

stabilityState the two main objectives of a shoring

system

Objectives Continued:Objectives Continued:

State three areas where shoring placement should be considered

Calculate the estimated weight of a given rubble pile

State the components of a shoring systemState greatest safety concern when

performing lifting operations

Objectives Continued:Objectives Continued:

State the possible indicators of secondary collapse

State the duties of a given team assignmentConstruct a horizontal shore, vertical shore,

T-spot shore and raker shores

Six Sided SurveySix Sided Survey

SIDES OF STRUCTURESIDES OF STRUCTUREStreet or address side is side A

700 Block Alpha Street

SIDE THREE

SIDE ONE

SIDE FOUR

SIDE TWO

Quadrants within StructureQuadrants within StructureAlso use and MARK column grid

700 Block Alpha Street

E

Quad. B

Quad. A

Quad. C

Quad. D

MULTI - STORY STRUCTURESMULTI - STORY STRUCTURES

Ground Floor is 1, Second is 2, Third is 3, etc.

First Floor below grade is B-1, Second is B-2, etc.

Basic Building TypesBasic Building TypesReviewReview

Light frame-Wood frameHeavy wall-URM, tilt-up, low rise wallsHeavy floor-concrete frame

buildings/bridgesPre-cast concrete buildings

Light (Wood) Frame Light (Wood) Frame

1-4 stories in heightPrincipal weakness in lateral strength of the

wallsWalls become “wracked” causing offsetting

of the floorsMasonry chimneys can crack and fallStructures can shift off of foundationFire load significant

Light Frame – HouseLight Frame – House

Cripple Wall Type Hi - Footing 6s

Most likely Aftershock hazards = Falling heavy objects

Rackedcripple wall

SeparatedEntry Roof

Roof Tilefalls off

Gas &Water

Masonry veneerfalls off

Elec

Brick chimneycracked & mayfall

Racked HouseRacked House

I.4-1

Heavy wall URMHeavy wall URM

Parapets, full walls fall off due to inadequate anchors

Often times weak mortarWalls can separate from wood floors/roofBroken bricks often line streets

Heavy Wall - URM BuildingsHeavy Wall - URM Buildings

Most Hazards are Brittle & Lethal falling objects

Elec

GasWater

Slip offbearing

Unsupportedroof & floorURM

corner

Crackedwall piers

Cracked parapets& split or peeled walls

URM can fall20 ft frombldg. face

Looseequip

10s

Heavy Floor Concrete FrameHeavy Floor Concrete Frame

Columns break at intersections with floor beam

Short columns in exterior walls get high tension/shear forces by surrounding concrete

Bending/punching shear failure at intersections of flat slabs and columns

Weak concrete can compound problems

Heavy Wall - TU BuildingsHeavy Wall - TU Buildings

Leaningwalls

Crackedwalls

Separation of roof membersfrom wall bearings

Slip at allinterior roofconnections Wall top tension failure

Aftershocks can cause additional wall & roof collapses 1s

Pre-Cast Concrete BuildingsPre-Cast Concrete Buildings

Joint failures between roof/floors/wallsWall panels separate from the building and

fallProgressive collapse can be caused by joint

failure between column and beam or slab and wall panel

Precast Concrete BuildingPrecast Concrete Building

Elec

Gas

Crackedwalls w/broken connsOverload fromupper collapseLoose debris

Partly fallen slabs & beams

Cracked corbelsBeam collapse ?

Leaning wallcheck conns

Water

Aftershocks cause loosely connected parts to shift & fall.Debris piles of large parts can shift & trap rescuers

5s

May Co GarageMay Co Garage Badly damaged in Whittier 87 EQBadly damaged in Whittier 87 EQ

1.4-36

Simple Hazard MitigationSimple Hazard Mitigation Avoid

– Need effective barrier system

Removal– Lift off, push over, pull down

Exposure reduction– How long do we need to be in the area?– Risk is a function of severity and exposure– limit time exposed to hazard– limit number of personnel exposed

Similar to Time, Distance, & Shielding Rule used in Hazmat

Other Hazard MitigationOther Hazard MitigationVertical & Lateral Shoring

– system with slow failure mode

Lateral BracingVertical Tieback

– use crane to hang structure

Monitor - with alarm & escape systemRecognize & Refer Hazard (hazmat)

Methods to MonitorMethods to Monitor

STABILITYSTABILITY

Devices Previously Used in Devices Previously Used in US&R US&R

Plumb bob Levels Engineers transit Electronic tilt meter & levels Crack measuring devices

Levels placed to monitor Levels placed to monitor column rotation (buckling) column rotation (buckling) between 2nd & 3rd floorsbetween 2nd & 3rd floors

OKC-37

Use of Devices Use of Devices Plumb Bob hung from small structure to

compare to a point on the ground - observe change in a leaning structure– Use of Laser Pointer or Laser Level could be

more accurate & effective

Transit / theodolite to establish a vertical line that will compare a point on a dangerous building to a point on the ground to detect additional tilt / movement

ShoringShoring

BASIC BASIC DEFINITIONDEFINITION

SHORING for US&R is the TEMPORARY SUPPORT of ONLY THAT PART of a DAMAGED STRUCTURE that is REQUIRED for CONDUCTING OPERATIONS at REDUCED RISK

WE INSTALL WE INSTALL RESCUE RESCUE

SHORING TO SHORING TO PROTECTPROTECT

“US”“US”

SHORING SIZE-UPSHORING SIZE-UPidentify structural hazards, damage and identify structural hazards, damage and

potential victim locationspotential victim locationsdetermine best method to mitigate the determine best method to mitigate the

hazard and damagehazard and damagedetermine the type & placement of shoring determine the type & placement of shoring

systems in relation to structural hazards and systems in relation to structural hazards and potential victim locationpotential victim location

DOUBLE FUNNEL DOUBLE FUNNEL PRINCIPLEPRINCIPLE

NEED POSTS / SHORES with ADJUSTABILITY & POSITIVE CONNS

NEED LATERAL BRACINGNEED SYSTEM with FORGIVENESS

COLLECT LOAD

DISTRIBUTE LOAD

The SHORING The SHORING SQUADSQUAD

SHORING TEAMSHORING TEAM

SHORING OFFICERSHORING OFFICER

MEASURING FFMEASURING FF

SHORING FFSHORING FF

CUTTING TEAMCUTTING TEAM

LAYOUT FFLAYOUT FF

CUTTING FFCUTTING FF

TOOL & EQUIP FFTOOL & EQUIP FF

GENERAL RULES OF THUMB GENERAL RULES OF THUMB NORMAL CAPACITY OF UNDAMAGED NORMAL CAPACITY OF UNDAMAGED

CONSTRUCTIONCONSTRUCTION

One undamaged wood framed floor will support one damaged wood floor

One undamaged steel framed floor will support one damaged steel floor

It takes two undamaged reinforced concrete floors to support one damaged concrete floor

NORMAL CAPACITY OF UNDAMAGED NORMAL CAPACITY OF UNDAMAGED CONSTRUCTIONCONSTRUCTION

Useful info for shoring multi-story buildings. – shoring should be placed under damaged beams, etc. – multi-level shoring should align from story to story

The thickness of debris from heavy, exterior walls, etc. must also be taken into account – In URM buildings, wall debris can easily weigh

more than a normal story

VERTICAL SHORING VERTICAL SHORING SYSTEMSSYSTEMS

WOOD POSTS ELLIS CLAMPS T - SPOT SHORE WINDOW / DOOR LACED POSTS CRIBBING STEEL PIPE TRENCH SHORES

METAL FRAMES & JOIST

PNEUMATIC SHORES

SPECIALTY SHORES

SCREW JACK by ELLISSCREW JACK by ELLIS

Adjustable metal foot for 4x4 and 6x6 wood posts

6 inch adjustment - set half way to get 3 in. up & down

Metal Foot is stronger than wood post

Use sole to spread load

ELLIS SHORES - 4x4 ELLIS SHORES - 4x4 adjustableadjustable

Need 2 Ellis Clamps to make a pair of 4x4 into Adjustable 4x4 shore

Need Ellis Jack Failure Mode is by clamp

crushing the side grain of the post - Gives Warning

12-0

max

7-0

max

6”12

”6”

2s

Ellis jack, clampsEllis jack, clamps

Shor-7

Vertical Vertical ShoresShores

Ellis clampsEllis clamps

Ellis FootEllis Foot

Shor-6

PNEUMATIC SHORESPNEUMATIC SHORESAIRCRAFT ALUMINUMAIRCRAFT ALUMINUM

18” EXTENDING TO 16’18” EXTENDING TO 16’

DO NOT USE AIR TO SET THESE STRUTS DO NOT USE AIR TO SET THESE STRUTS IN A STRUCTURAL COLLAPSEIN A STRUCTURAL COLLAPSE

WORKING LOAD VARIESWORKING LOAD VARIESDEPENDING ON LENGTHDEPENDING ON LENGTH

PNEUMATIC SHORESPNEUMATIC SHORES Adjustable shore with length up to 16

ft - Manufactured by Airshore, Paratech, & Holmatro

Have swivel & other feet Should be set manually using

adjustable collar or sleeve nut - DON’T USE AIR SET IN US&R

Working Load decreases with length and should be based on tests using swivel ends

Best use is as initial shore

2s

Airshore - A.R.TAirshore - A.R.T

Shown as single, Shown as single, vertical shore - plusvertical shore - plus

triple, column triple, column shore w/special shore w/special

plate at each endplate at each endARTvert1

Airshore - A.R.TAirshore - A.R.T

showing window & showing window & door shores w/U door shores w/U

type connection at type connection at top top

ARTvert2

““T” Spot T” Spot ShoreShore

for initial for initial stabilization stabilization

onlyonly

T - SPOT SHORET - SPOT SHORE

Standard, 12” x 12” Standard, 12” x 12” GussetGusset

Temporary ShoreTemporary Shore

Basically UnstableBasically Unstable

Limit Header to 3 feetLimit Header to 3 feetand center on Loadand center on Load

Post strength isPost strength isbased on heightbased on heightas for Vertical Shoreas for Vertical Shore

The The WINDOWWINDOW SHORE SHORE

STABILIZE WINDOW OPENINGSTABILIZE WINDOW OPENING

SUPPORT DAMAGED HEADERSUPPORT DAMAGED HEADER

1 inch THICKNESS FOR EVERY FOOT 1 inch THICKNESS FOR EVERY FOOT OF HEADER OPENINGOF HEADER OPENING

Construct In-placeConstruct In-placeMethodMethod

Pre-constructed Method,Pre-constructed Method,

Build frame with plywood Build frame with plywood

gussets at each corner, gussets at each corner,

insert in opening, then addinsert in opening, then add

Wedges at side and shim at Wedges at side and shim at

toptop

WindowWindowShoreShore

InInMasonry Masonry

wallwall

THE DOOR THE DOOR SHORESHORE

RESUPPORT ENTRANCERESUPPORT ENTRANCE

SUPPORT WALL BREACHSUPPORT WALL BREACH

1 inch THICKNESS FOR 1 inch THICKNESS FOR EVERY FOOT of HEADER EVERY FOOT of HEADER

LENGTH LENGTH

VERTICAL SHOREVERTICAL SHORERESUPPORT UNSTABLE FLOORS RESUPPORT UNSTABLE FLOORS

OR ROOFSOR ROOFS

POSTS UNDER FLOOR BEAMSPOSTS UNDER FLOOR BEAMS

MID-POINT BRACING AT 9 ft CEIL. MID-POINT BRACING AT 9 ft CEIL. HT (Posts over 8ft plus header & sole)HT (Posts over 8ft plus header & sole)

VERTICAL WOOD SHORINGVERTICAL WOOD SHORING• 3/4” Ply gussets ea. end ea. 3/4” Ply gussets ea. end ea.

interior post, 1 side min. (dbl interior post, 1 side min. (dbl gusset + add on opposite gusset + add on opposite side of diag brace at post side of diag brace at post bottom)bottom)

• 2x6 diag braces2x6 diag braces

• Full width wedges w/ keeper Full width wedges w/ keeper nails. (can’t adjust them)nails. (can’t adjust them)

• Nail 2x6 diag. brace w/5-16d Nail 2x6 diag. brace w/5-16d to sole, header and to each to sole, header and to each postpost

Reinforce access w/shoringReinforce access w/shoring

HORIZONTAL SHOREHORIZONTAL SHORESTABILIZE PASSAGEWAYSSTABILIZE PASSAGEWAYS

2 - 3 SUPPORT STRUTS2 - 3 SUPPORT STRUTS

DEBRIS WEIGHT WILL DEBRIS WEIGHT WILL

DETERMINE THE SIZEDETERMINE THE SIZEAND # OF STRUTS NEEDEDAND # OF STRUTS NEEDED

Provide horizontal Provide horizontal shoring in access shoring in access corridorcorridor

SOLID SOLE RAKERSOLID SOLE RAKER

The Raker Shore of ChoiceThe Raker Shore of ChoiceGenerally Erected at 45 Degree AngleGenerally Erected at 45 Degree AngleCan Be Utilized on Solid Ground As Well As Can Be Utilized on Solid Ground As Well As

EarthEarthPre-assemble and Carry Into PositionPre-assemble and Carry Into PositionMust Erect Minimum of Two ShoresMust Erect Minimum of Two ShoresUsed to Re-support Unstable or Leaning Used to Re-support Unstable or Leaning

WallsWalls

RAKER SHORE RAKER SHORE ANGLESANGLES

DEGREE PITCH LENGTHDEGREE PITCH LENGTH

45 45 degdeg 12/1212/12 1717

60 60 degdeg 12/7 12/7 1414

Calculating length of rake:Calculating length of rake:

60 degree angle raker: Insertion height in feet multiplied x 14 = length of rake– Example: 8’ x 14 = 112” (9’ 4”)

45 degree angle raker: Insertion height in feet multiplied x 17 = length of rake– Example: 8’ x 17 = 136” (11’ 4”)

Raker end cutsRaker end cuts

ANGLE CUTSANGLE CUTS

45 DEGREE CUT45 DEGREE CUT

1 1/2 RETURN CUT1 1/2 RETURN CUT

SOLID SOLE RAKERSOLID SOLE RAKER

33

44

55

FULL TRIANGLE (FIXED) FULL TRIANGLE (FIXED) RAKER SOLID SOLE TYPERAKER SOLID SOLE TYPE

Solid sole

Solid sole w/ nailed cleat, wedgesSolid sole w/ nailed cleat, wedgesand anchor system at end or and anchor system at end or drill-ins thru solid soledrill-ins thru solid sole

4x4, 6x6 Raker depending on length4x4, 6x6 Raker depending on lengthand lateral & mid-point bracingand lateral & mid-point bracing

4x4, 4x6 Wall Plate w/ drill-ins to wall4x4, 4x6 Wall Plate w/ drill-ins to wall

2x4, 2x6 Nailed Cleat, 17-16d min2x4, 2x6 Nailed Cleat, 17-16d min..

2x6 braces 2x6 braces to reduce L/d of rakerto reduce L/d of raker

Build these away from wall andassemble at wall in pairs or moreas system with lateral bracing

Solid sole rakersSolid sole rakers

Second Option for Raker ShoringSecond Option for Raker Shoring Generally Utilized in Earth or Where Debris is at the Generally Utilized in Earth or Where Debris is at the

Base of the WallBase of the Wall Erected the Same Except for the Base of the ShoreErected the Same Except for the Base of the Shore Can Be Partially Pre-erected Before InstallationCan Be Partially Pre-erected Before Installation Should be erected at 60 degree angle, whenever Should be erected at 60 degree angle, whenever

possible possible

SPLIT SOLE RAKERSPLIT SOLE RAKER

SPLIT SOLE RAKERSPLIT SOLE RAKER

SPLIT SOLE RAKER BASESPLIT SOLE RAKER BASE((also use for Sloped Floor Shore on Earthalso use for Sloped Floor Shore on Earth))

WEDGESWEDGESinside Uinside U

SOLE PLATE3-2x6x 18” or2 Layers 3/4”x18”sq plywd

U-CHANNEL4x4x 18” with 12”x 3/4x 12” ply gussets ea side

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGS

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGSCharacteristics

– Neoprene/butyl rubber– Steel kevlar reinforced– Variety of sizes– Maximum capacity is calculated at 1

inch of lift– Very low capacity at max height

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGSApplication

– Maximum stack of two high

– Lift is limited to capacity of small bag

– Larger bag on bottom

– Keep pressure in large bag less than small bag

– Centers of bags MUST be aligned

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGS

COLUMN OF AIR

LOADLOAD

BASE OF SUPPORT

INCREASED SURFACE AREA = INCREASED LIFTING CAPACITY

LOADLOAD

BASE OF SUPPORT

COLUMN

O

F

A

I

R

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGSAIR BAGAIR BAGINFLATEDINFLATED

REDUCED REDUCED SURFACE SURFACE AREA AREA CONTACTCONTACT

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGSDimension Capacity Lift Ht. Weight6”x 6” 1.5 Tons 3” 2 lbs6”x 12” 3.2 3.5 310”x 10” 4.8 5 415”x 15” 12.0 8 1015”x 21” 17.0 9 1320”x 20” 21.8 11 1624”x 24” 31.8 13 2228”x 28” 43.8 16 3036”x 36” 73.4 20 48

HIGH PRESSURE AIR BAGSHIGH PRESSURE AIR BAGSI.D. Tag is right on BagI.D. Tag is right on Bag

HIGH PRESSURE AIR BAGS HIGH PRESSURE AIR BAGS & CRIBBING& CRIBBING

SPREADING & PUSHINGSPREADING & PUSHING

LIFTING AND STABILIZING LIFTING AND STABILIZING IRREGULAR OBJECTSIRREGULAR OBJECTS

PIPES & CYLINDERSPIPES & CYLINDERS

WEDGES AND WEDGES AND CRIBBINGCRIBBING

SHIMS (WEDGES)SHIMS (WEDGES)

Use of shims to Use of shims to change directionchange direction

““MARRYING” WEDGESMARRYING” WEDGES

WRONGWRONGRIGHTRIGHT

CRIBBINGCRIBBING6000 lbs. per contact point6000 lbs. per contact point

Four point systemFour point system Nine point systemNine point system

CRIB STABILITYCRIB STABILITY

LOADLOADMUST MUST

BEBE

CENTERCENTER1/31/3OFOF

CRIBCRIB

CRIBBINGCRIBBING

CALCULATING CALCULATING WEIGHTSWEIGHTS

CALCULATING THE WEIGHTS CALCULATING THE WEIGHTS OF COMMON MATERIALSOF COMMON MATERIALS

LENGTH x WIDTH x HEIGHT = CUBIC FT

Steel Steel 490 lbs. per cubic foot ( pcf) 490 lbs. per cubic foot ( pcf)

Concrete 150 pcfConcrete 150 pcf

EarthEarth 100 pcf 100 pcf

Wood 40 pcfWood 40 pcf

Weights continued:Weights continued:

Add 10 to 15 psf for wood/metal interior walls– each floor

Add 10 psf or more each floor or furniture etc.– More for storage

Add 10 psf or more for Rescuers Concrete or masonry rubble = 10 psf per inch

CALCULATING THE CALCULATING THE WEIGHTS OF COMMON WEIGHTS OF COMMON

MATERIALSMATERIALSLENGTH x WIDTH x HEIGHT x WEIGHTLENGTH x WIDTH x HEIGHT x WEIGHT

20’ X 4’ X 2’ = 160cf x 150pcf = 24,000 lbs.20’ X 4’ X 2’ = 160cf x 150pcf = 24,000 lbs.

20 20 feetfeet

4 4 feetfeet

2 2 feetfeet

EXAMPLEEXAMPLE Assume that this 20ft x 30ft classroom has an 8” thick

concrete roof with 6” of debris on it WHAT IS THE TOTAL LOAD TO SHORE ?– 8” concrete = 100 psf x 20 x 30 = 60,000 lb– 6” debris = 60 psf x 20 x 30 = 36,000 lb– Lights, ducts, ceiling, etc. = 5 psf = 3,000 lb– Rescuers = 10 psf x 20 x 30 = 6,000 lb* -------------- TOTAL = 105,000 lb

= 105 Kips

* 6,000 lb Rescuers allows for 24 - 250 lb peopleIs this reasonable ? If not use more, this is MINIMUM

Structural Hazard Markings Structural Hazard Markings ReviewReview

STRUCTURE / HAZARDS STRUCTURE / HAZARDS MARKMARK

Structure relatively safe for S&R ops. There is little chance of further Collapse. – Victims could be trapped by contents– or could be unconscious

STRUCTURE / HAZARDS STRUCTURE / HAZARDS MARKMARK

Structure is Significantly Damaged. Some areas may be relatively safe, but others may need shoring, bracing, removal, and/or monitoring of hazards– Building could be completely pancaked

STRUCTURE / HAZARDS MARKSTRUCTURE / HAZARDS MARK Structure is NOT SAFE for Rescue Ops

and may be subject to Sudden Collapse. Remote search Ops may proceed at significant risk. If rescue Ops are undertaken, Safe Haven areas, & rapid evacuation routes (with Structure Monitoring) Should be Created.

STRUCTURE / HAZARDS STRUCTURE / HAZARDS MARKMARK

Arrow next to Marking Box indicates the direction of Safest Entry to Structure

STRUCTURE / HAZARDS STRUCTURE / HAZARDS MARKMARK

HM indicates hazardous material condition in or adjacent to structure. S&R Ops normally will not be allowed until condition is better defined or eliminated.

HM

STRUCTURE / HAZARDS STRUCTURE / HAZARDS MARK - SUMMARYMARK - SUMMARY

15JUN92

HM NATURAL GAS

OR-1

No entry until gas is turned off. When it’s mitigated, should line out the HM

mark and record new date and TF

BUILDING MARKING BUILDING MARKING SYSTEMSYSTEM

SEARCH ASSESSMENT MARKING

SEARCH ASSESSMENT MARKSEARCH ASSESSMENT MARK

First slash madewhen entering

Crossing slash made as TF exits

15JUL921400 HR

RATS

3 DEAD

OR-1

2’ x 2’ X neareach entry

BUILDING MARKING BUILDING MARKING SYSTEMSYSTEM

VICTIM LOCATION MARKING

VICTIM LOCATION MARKINGVICTIM LOCATION MARKING

CA 6

CA 6

CA 6

CONFIRMEDLIVE VICTIM

REMOVED VICTIM

CONFIRMEDDEAD VICTIM

CA 6

POTENTIALVICTIM

Basic Approach to US&RBasic Approach to US&RIdentify the Problem

– PrioritizeFind Victims

– Re-prioritizeMitigate Hazards

– Risk vs RewardRemove Victims

– Medically stabilizeCreate no new victims

Basic Building SAR PlanBasic Building SAR Plan(initial phases)(initial phases)

Reconnoiter– determine structure type– obtain / draw plans– access hazards– interview neighbors, etc.

Prioritize Site– develop hazard mitigation alternatives– callout / listen search– condition of voids & basement

Basic Building SAR PlanBasic Building SAR Plan(initial phases)(initial phases)

Initial Search– use K-9 in safe & less safe areas– use technical search equip.– use existing vertical shaft opngs– use existing horizontal openings with great care– search from stable to un-stable– re-prioritize vs live finds

Basic Building SAR PlanBasic Building SAR Plan((main phase - days long ?)main phase - days long ?)

Selected cutting / removal– cut vert opngs & re-search– initial shoring for access– avoid unshored overhead slabs, etc.– re-check shoring after cutting & removal– continue - cut opng & re-search– shore victim area for rescue ops– Struc Spec gives continuing aid to rescue