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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