Res 4A Structural Collapse Flashcards
Tension Forces
Stretch members. Concrete and masonry have no tension strength
Compression Forces
Push on members. Crushed members tend to give warning such a splitting or bowing
Bending Forces
result of vertical loads caused by gravity pushing on slabs and beams. Roof rafters are subject to these forces
Tension and Compression of a beam
Tension bottom, compression top
Shear Forces
Occur in all beams and greatest at adjacent supports. Concrete, diagonal tension cracks.
Where are wood beams subject to shearing
Along a horizontal plane
Light Frame Construction
Skeletal structural framing system of wood or light gauge steel components.
Light Frame Construction degree of flexibility
High up to 300F, Low over 300F which produces a better image
Light Frame Construction is found
wood frame residential, multi-family low rise, light commercial up to 4 stories
Heavy Wall Construction
Independent structural or monolithic system making a grid.
Heavy Wall - Tilt Up Wall Construction
1-3 stories in height, multiple, monolithic, concrete wall panels with independent girder, column, and beams to provide lateral support for floors and roof.
URM Building
Unreinforced masonry building
Heavy Floor Construction
Typical cast in place concrete buildings
Pre Cast Construction
Modular concrete sections constructed on site with hazards at the connection points.
Cantilever Collapse
One end of floor hanging free, other end still attached, one wall has failed
Lean To Collapse
Wall fail or floor break/separation that causes one end to rest on a lower floor
Pancake Collapse
Upper floor fails and falls on lower causing lower floor to fail
V Type Collapse
Heavy loads cause floor to collapse near the center. Two voids created along outer walls
Tent Collapse
One end of floor collapses. Creating a void one EITHER side of the support member.
Secondary Collapse
Often more severe than the initial collapse
Safety Considerations Collapse
“Look outs” monitor structure for movement. Use of transit, plumb bob, level.
Briefing Collapse
Must be conducted, ensure understandings of
1) Rescue plan
2) Specific roles
3) Safety and hazard issues
4) Method of alerting and egress if unexpected failure
List of supporting tasks
Level 3 Account, mark collapse zone, control access, remove civilians, assign Safety officer, lookout crew, securing utilities, victim staging area
Collapse zone
At least 1 1/2 times the total height of structure
Victim removal priorities
1) on surface or lightly buried
2) Can be seen or heard
3) Known locations
Risk vs gain analysis factors
Collapse
1) Viability
2) potential for secondary collapse
3) existence of fire, HM, explosions
4) adequate resources to complete operation without stopping
Search methods Collapse
Visual, victims who can be heard, Call out and listen, TIC, search cam, listening device, canine
Six phases of structural collapse
1) Size Up and Assessment
2) Removal of surface victims
3) Voids and Accessible space search
4) Selected debris removal
5) General debris removal after all victims recovered
6) Termination
Emergency Communications
Evacuate Area - 3 short blasts 1 second each,
Stop all Operations/All Quiet - 1 Long Blast 3 seconds, Resume Operations 1 long 1 short
Structural Triage Assessment
How can we do the most good, in the shortest amount of time, with resources we have
Sides of a structure
Six sides, A,B,C,D, roof and basement
Hot Zone Collapse Zone
1/2 times greater than height and must be marked with yellow fire tape, L3 account
Warm Collapse Zone
Support activities, command post, staging area, cut station, rehab, medical
Cold Collapse Zone
Media, rescuers not assigned, civilians
Other agencies
DCEMA, DPW, DDOT, MPD, utilities, Red Cross
Structural Hazard Marking System Size and Color
2x2 square, orange spray, close to entry or arrow pointing to entry
Adjacent to Structural Hazard System box
Date marked, Time marked, Hazard identified, who marked
Just a square box (orange)
Building is safe and accessible
Square box with one diagonal
Building is significantly damaged, some areas safe some need shoring
Square box with two diagonals
Building is not safe to search.
Search and Rescue Marking System functions
1) rescue team has entered
2) search has been completed
3) who completed
4) the outcome of search
Search X left quadrant
Search Team
Search X upper quadrant
Date and time search was completed
Search X right quadrant
Hazards identified
Search X lower quadrant
of live and dead victims or no victims
While inside structure only markings on Search X are
right quadrant hazards and lower quadrant victims
Victim Marking System potential victim
A “V” two feet in height as near to victim as possible, arrows as needed
Victim Marking System confirmed victim
Must be from second dog or second tool, ADD circle around V
Victim Marking System confirmed dead
Horizontal line across V
Victim Marking System victim removed
X through circle
Victim Marking System writing
Rescue team designation
