Collapse Patterns

This is what were here for

Collapse Patterns Lean-to collapse V-shape collapse Pancake collapse Cantilever collapse

Collapse Patterns Lean-To V-Shape Pancake Cantilever

Lean-To Floor Collapse

V-Shape Floor Collapse

Cantilever Collapse

Pancake Collapse

Condition of Voids Different void types will have significant impact on victims and their accessibility Victims do not survive well in tightly compacted collapse areas consisting of masonry rubble, or broken concrete Open survivable voids are often found under wooden floor panels that collapse into angular, interlocking planes Survivable voids have been found under concrete structures where floors have projecting beam elements that hold slabs apart Partially collapse structures may have large triangular voids

This is what were here for

General Types of Building Construction Hazards Light Frame Heavy Wall Construction Heavy Floor Construction Precast Construction

Light Frame Hazards Weakened wall and connections Broken utilities Combustible materials Cracked or leaning walls Separation from foundations Cracked or leaning chimneys or veneer walls Separated porch or upper story connections Loose roof tiles or roof equipment Broken glass and damaged door frames

Light Frame Access Considerations Horizontal entry through existing cavities Breaching through walls Vertical access through floor/roof from top down Remove/shore hazards as required

BRICK PATTERN THAT IDENTIFIES UNREINFORCED MASONRY. HAS BOND (HEADER) ROW AT ABOUT EVERY SIX ROWS. AT FRONTS OF BUILDINGS, THE PATTERN MAY BE HIDDEN BY FANCY MASONRY VENEER

Heavy Wall Hazards Broken utilities Weakened perimeter load bearing walls and connection to floor and roofs Broken parapets, chimneys, ornamental masonry Broken walls and columns Broken structural connections Cracked wall corners, windows, door frames Unsupported collapsed floors Loose HVAC or roof equipment

Heavy Wall Access Considerations Horizontal entry through existing openings Vertical access through floor/roof from above Hand removal of bricks may be required Large pieces of wall may be removed by clamshell bucket on crane or excavator

Tilt-Up Hazards Broken utilities Separation of walls and roof, leading to partial collapse of either or both Collapse of walls or roof Falling roof beams, ceilings, non-structural items

Tilt-Up Access Considerations Horizontal entry through existing openings Vertical access through roof/floor Cut holes in wall panels 2 feet minimum from joints Remove wall panels and large roof sections by crane

Heavy Floor Hazards Weakened columns and poor connections between floors and columns Broken utilities “Empty cage” – concrete column failure Broken structural connections Diagonal shear cracking in support beams Broken infill or shear walls Loose HVAC or roof equipment

Heavy Floor Access Considerations Find any existing vertical access shaft Preferred access made by cutting through slabs from above victim/collapse Cut non-bearing or infill walls after proper assessment Remove large pieces after all connecting rebar's have been cut

Precast Construction Hazards Weakened interconnection of structural components – floors, wall panels and beams Broken utilities Broken walls, cracked corbels at beam-to-column connections Cracked columns at top and bottom joints Broken wall panels Loose HVAC or roof equipment

Precast Access Considerations Cut through thinner horizontal sections for vertical access from above Carefully remove larger covering pieces with crane Horizontal entry through existing cavities Cut through wall panels 2 feet minimum from joints