Chapter 13 - Reading Buildings Flashcards
Axial Load
A load that is imposed through the centroid of another object
Balloon Framing
A construction method in which continuous wood studs run from the foundation to the roof, and floors are placed on a shelf (called a Ribbon Board) that hangs on the interior surface of the studs
Beam
A structural element that transfers loads perpendicularly to the imposed load
Brittle
Description for a material that will fracture or fail as it is deformed or stressed past its designed limits
Cantilever Beam
A beam supported at only one end, or a beam that extends well past a support in such a way that the unsupported overhang places the top of the beam in tension and the bottom in compression
Collapse Zone
The area that is exposed to trauma, debris, and/or thrust should a building collapse.
Column
A structural element that transmits a compressive force axially through its center
Compression
A force that causes a material to be crushed or flattened axially through the material
Connection
A structural element used to attach other structural elements to one another
Continuous Beam
A beam that is supported in three or more places
Curtain Wall
A non-load bearing wall that supports only itself and is used just to keep weather out
Dead Load
The weight of the building itself and anything permanently attached to it
Ductile
Description of a material that will bend, deflect, or stretch as a force is resisted, yet retain some strength
Eccentric Load
A load that is imposed off-center to another object
Emergency Evacuation
A strict order for all crews to immediately escape from a building interior or roof leaving hose lines and tools that can impede rapid retreat behind
Engineered Wood
A host of products that consist of many pieces of native wood glued together to make a sheet, a long beam, or a strong column
False Work
Temporary shoring, bracing, or formwork used to support incomplete structural elements during building construction
General Collapse
The complete failure of a building to resist gravity
Girder
A beam that carries other beams
Hybrid Building
A building that is a mix of multiple NFPA 220 types or that does not fit into any of the five types
Lintel
A beam that spans an opening in a load bearing masonry wall, such as over a garage door opening (often called a “Header”)
Live Load
Any force or weight, other than the building itself, that a building must carry or absorb
Partial Collapse
An event in which the building can accept the failure of a single component and still retain some strength
Platform Framing
A construction method in which a single story wall is built and the next floor is built on the tops of the wall studs, creating vertical fire stopping to help minimize fire spread
Precautionary Withdrawl
A directive for crews to exit a building interior or roof in an orderly manner, bringing hoses and tools along
Raker
A diagonal brace that serves primarily as a column but must absorb some beam forces as well
Shear
A force that causes a material to be torn in opposite directions perpendicular or diagonal to the material
Spalling
The crumbling and loss of concrete material when exposed to heat
Spreader
A seemingly decorative star or other metal plate used to distribute force over more bricks or blocks as part of an unseen corrective measure that exists inside a building
Structural Element
The primary load bearing column, beam, or connection used to erect a building
Tension
A force that causes a material to be stretched or pulled apart in line with the material
Torsional Load
A load that is imposed in a manner that causes another object to twist
Truss
A series of triangles used to form an open-web structural element to act as a beam
Veneer Wall
A decorative wall finish that supports only its own weight
Collapse Concept
ISO’s must be able to give the IC a judgment regarding the collapse potential of a given building being attacked by fire
Load Concept
Loads are static and dynamic weights applied to a building and are divided into dead and live loads
Three Ways Loads are Imposed
Axially - Through the center
Eccentrically - Off center
Torsionally - Twisting
Forces created by Imposed Loads
Compression - Crushing
Tension - Pulling
Shear - Tearing
Structural Elements
Name of the primary load-bearing portions of a building
NFPA 220
Building Types: Type 1 - Fire Resistive Type 2 - Noncombustible Type 3 - Ordinary (Masonry Walls, Wood floors+roof) Type 4 - Heavy Timber Type 5 - Wood Frame
Eras of Building Construction Type
Founder’s Era - Prior to WW1
Industrial Ery - WW1-WW2
Legacy Era - WW2-1980’s
Lightweight Era - 1980’ to Present
Occupancy Use
The use of the building that was intended upon construction
5 Step Method of Decision Making
- Identify the building classification using a type/era/use/size approach
- Identify the fire and heat locations, and determine whether structural elements are being attacked
- Analyze the transference of loads that pass through the building and envision weak links
- Analyze the passage of time and its impact on materials
- Determine collapse potential and communicate warnings and collapse zones
Typical Weak Links of a Building during a Fire
Connection points, Trusses, Overloaded elements, clear/open floor and roof spans, facades, parapets, lightweight stairs, void spaces
Late Indicators of Collapse
Sagging floors and roofs, cracks in masonry, settling noises, bulging or leaning walls, large volumes of fire attacking structural elements
Communicating Collapse Potential
Should be done based on one of the following circumstances:
emergency evacuation
precautionary withdrawal
planning awareness
Collapse Zone Concept
ISO must communicate established collapse zones, which are exclusionary or “No Entry” zones for everyone. The 1 1/2 rule is a starting place for creating zone distances, although masonry can collapse three times the height of the wall outwards
