Presentation on theme: " OOOOps! OOOOps! Deputy Chief (retired) Vincent Dunn defines a collapsing structure "as any portion of a burning structure that collapses due to fire."— Presentation transcript:
Deputy Chief (retired) Vincent Dunn defines a collapsing structure "as any portion of a burning structure that collapses due to fire damage."
Reviewing the 5 types Examining inherent hazards of each.
made from non-combustible materials that do not add to the fire load usually massive steel components that are encased in concrete cast-in-place concrete, or the slabs may be poured off-site most resistant to collapse.
28 days to fully cure to a point that collapse is no longer a threat. connection points have been the result of a catastrophic failure
: The structural steel is encased with a light fire-resistive coating sheetrock or a sprayed-on coating . These structures employ a lightweight parallel steel bar joist system that holds up a corrugated steel roof deck ( Timberlake HS Gym)
the materials that make up the roof covering a large amount of windows in the front wall opening is spanned with a steel lintel that will support a free-standing parapet wall. If this lintel is compromised in any fashion, it can result in a complete failure of the parapet wall employs a pre-cast wall slab that is tilted into place Each slab is braced with steel rods or rebar and insulated at the sides with each other
use load bearing walls of masonry construction, the roof and the floor can be made of wood. can be either balloon frame or braced frame construction
older buildings may also have a parapet wall at the roof line, but with a twist: there may also be a cornice 25 feet will have an additional steel I-beam support called a channel rail Spreader plates, in the shape of stars, plates, or channel sections but beware the spreader plates that are irregular in placement
Exterior walls are brick or other type of masonry, the columns being a minimum of eight inches by eight inches used to house commercial occupancies originally the second-most resistant to collapse.
buildings more resistant to collapse neglect, shoddy renovations, and weak connection points can cause complete failure These trusses can be parallel chord or bowstring
walls, floors, roofs, and other structural members are made up entirely of wood Braced frame Balloon frame Platform frame
Braced frames resist gravity load in bending and axial compression, and lateral load in axial compression and tension by triangulation, much like trusses
are all wood . Two-by-four studs may in fact be holding up an entire upper floor, with no built-in compensation supports many of these structures have a veneer wall, made of decorative masonry materials are attached to the wood wall, placing an eccentric load on the wall
Lightweight construction components, such as trusses, truss joist I-beams (TJIs) and Oriented Strand Board (OSB) larger square footage, but are being constructed with half of the materials that were used in the past
the roof or floor supports fail on one side of the structure, and the opposite side of the floor is still connected
lower walls or floor joists fail, due to heavy loads located in the center of the floor. two voids, one near each exterior wall.
dropping the floors and the roof on top of each other Voids will be created between the floors
collapse occurs when one or more walls have failed other end of the floor is still attached to the other bearing wall. the most dangerous type of collapse to operate in adequate shoring must be in place before operations can commence.
the flooring separates from the exterior bearing walls, but still is supported by one or more interior walls
entire wall falls out as one unit, falling outward Masonry walls collapse more commonly in this fashion V structures with veneer walls can fall victim to this collapse as well.
a masonry wall falls almost straight downward Curtains Curtains https://video.search.yahoo.com/video/play;_ylt=AwrTHQh8UqxU mjEAVhtXNyoA;_ylu=X3oDMTB0Njd0NGhwBHNlYwNzYwRjb2xv A2dxMQR2dGlkA1NNRTgwN18x?p=fire+building+collapse+youtu be&tnr=21&vid=C67B7817CA F9CC67B7817CA F9C &l=29&turl=http%3A%2F%2Fts2.mm.bing.net%2Fth%3Fid%3DU N %26pid%3D15.1&rurl=http%3A%2F%2F J0UtY&sigr=11ahobk0t&tt=b&tit=NEW+YORK+BUILDING+COLL APSES+AFTER+FIRE!&sigt=117s9r4i9&back=https%3A%2F%2Fse arch.yahoo.com%2Fsearch%3Fp%3Dfire%2Bbuilding%2Bcollapse %2Byou%2Btube%26type%3D2button%26fr%3Dymyy-t- 999%26ei%3DUTF-8&sigb=135ndp5f6
the wall literally breaks in two, with the bottom section of the wall falling outward, and the top floors falling inward Braced frame buildings are known to fail in this fashion. This type of collapse occurs more commonly in wood frame buildings, many times without warning.
Iight my fire Iight my fire Religious reporter Religious reporter Top IQ contestants Top IQ contestants
What are the 5 types of construction? What type possess the least collapse risk? What is critical about a cantilever collapse? If we have a fire on main street how much protection are do we need if we have a 90 degree full wall collapse?