Ch 22 pg 543-548 Structural Collapse Risks

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Questions and Answers

Which type of building has the least resistant to collapse during a fire?

Concrete buildings

Heavy timber buildings

Class 2 non combustible (correct)

Class 5 buildings

What material is typically more resistant to collapse than wood-frame buildings?

Brick

Wood composites

Heavy timber (correct)

Steel

In standard construction methods, what is more likely to happen before a typical wooden home collapses?

It expands due to heat

It experiences a partial collapse

It disintegrates

It burns through (correct)

Which class of building has the greatest resistance to collapse?

Class 1 buildings Signup and view all the answers

What type of buildings have the highest resistance to collapse?

Class 1 fireproof buildings Signup and view all the answers

Which structural element of the Windsor Building contributed to its partial survival during the fire?

Reinforced concrete core Signup and view all the answers

What was the primary cause of the collapse of WTC1, 2, and 7?

Use of lightweight modern construction materials Signup and view all the answers

What is the most dangerous condition associated with Class 1 buildings?

Localized collapse of the ceiling and spalding Signup and view all the answers

What might happen to I-beams in a Class 1 fireproof building during a fire?

I-beams may sag but do not cause total collapse Signup and view all the answers

Which statement is true concerning the performance of heavyweight buildings during high-rise fires?

They typically do not allow fire to spread from floor to floor. Signup and view all the answers

Which of the following fire incidents exemplifies the phenomenon of total combustibility without collapse?

The Plasco Building in Tehran. Signup and view all the answers

What is the primary reason some high-rise office fires do not lead to total collapse, despite combustibles being consumed?

The building's design and heavyweight structure. Signup and view all the answers

What factor is contributing to an increased risk of structural collapse in modern construction?

Emphasis on lightweight materials for cost reduction Signup and view all the answers

Which of the following incidents resulted in the highest number of firefighter fatalities?

World Trade Center collapse Signup and view all the answers

What is the primary reason structural collapse is viewed as a serious threat on the fireground?

It can happen with little warning and is often deadly. Signup and view all the answers

Which collapse listed is associated with the least firefighter casualties?

Wichita, KS, Chevrolet dealership in 1968 Signup and view all the answers

Which material is primarily used in the construction of the third most collapse-resistant building?

Class 3 ordinary construction Signup and view all the answers

What happens to the floor sheathing in the third most collapse-resistant building during a fire?

It fails before the floor joists Signup and view all the answers

What risk is associated with unusually high floor loads in these buildings?

Early failure of localized areas Signup and view all the answers

What should be done if unusually high or concentrated loads are discovered?

Report to the officer in charge immediately Signup and view all the answers

What defines the special category for collapse resistance regarding lightweight and truss-construction methods?

They are defined separately for collapse resistance purposes. Signup and view all the answers

What can lead to the collapse of subsequent floors in a building during a fire?

Collapses on upper floors can cause each successive floor to collapse Signup and view all the answers

What is the recommended distance for removing apparatus from the collapse zone during advanced fires?

The entire area for the full length of the frontage, for a distance from the wall Atleast 1 1/2 times the height of the wall Signup and view all the answers

Which condition can destabilize buildings, making them vulnerable to collapse during a fire?

Repeatedly being burned Signup and view all the answers

What can be the outcome of a seemingly minor fire in a structurally compromised building?

Potential for large-scale collapse affecting both walls and floors Signup and view all the answers

What is the primary reason Class 2 construction is less resistant to collapse when exposed to fire?

It consists largely of unprotected steel. Signup and view all the answers

Which characteristic of steel under heating poses a risk of collapse?

Steel expands and can push down structural supports. Signup and view all the answers

What structural effect occurs when steel cools after being heated and distorted?

It can contract without aligning with supports. Signup and view all the answers

Collapses in framed structures tend to be localized. What is typically the scope of such a collapse?

Areas between supporting members. Signup and view all the answers

At what temperature does steel begin to lose approximately half of its strength?

1,500˚F Signup and view all the answers

What is a primary characteristic of unframed buildings?

Most of the weight is supported by bearing walls. Signup and view all the answers

What typically happens when a vertical member fails in a building structure?

Extensive collapses are likely to occur as support systems are compromised. Signup and view all the answers

Which of the following materials is typically associated with unframed buildings?

Heavy timber, wood frame and brick and joist Signup and view all the answers

In what way do framed and unframed structures respond to collapses?

Unframed structures tend to experience more extensive collapses upon failure. Signup and view all the answers

Which structural system is more likely to cause severe damage throughout when a failure occurs?

Unframed structures due to their reliance on bearing walls Signup and view all the answers

Which structural element is considered the least critical in maintaining a building's stability?

Floor and roof decking Signup and view all the answers

What is a more serious consequence of failure in a building's structure?

Failure of columns and walls Signup and view all the answers

In the hierarchy of structural components, which element is ranked immediately below bearing walls?

Columns Signup and view all the answers

Which of the following represents a component that supports other structural elements but is not as critical as a column?

Girders Signup and view all the answers

How does the failure of a horizontal member like a beam compare to that of a column?

A beam's failure is less serious than a column's failure. Signup and view all the answers

Study Notes

Structural Collapse

Structural collapse occurs rapidly and can be fatal, though such incidents are relatively rare among firefighters.
Notable collapses with significant firefighter casualties include:
- Chicago Stockyards warehouse (1910) - 23 fatalities
- NYC 23rd Street building (1966) - 12 fatalities
- Vendome Hotel, Boston (1972) - 9 fatalities
- Waldbaum's Supermarket, Brooklyn (1978) - 6 fatalities
- Ford dealership, Hackensack, NJ (1988) - 5 fatalities
- Chevrolet dealership, Wichita, KS (1968) - 4 fatalities
- Two-story building, Brackenridge, PA (1991) - 4 fatalities
- World Trade Center on September 11, 2001 - 343 fatalities
Increased use of lightweight materials in construction raises risk for firefighters during fires.
Understanding collapse causes and preparation for them is vital for firefighter safety.

Building Collapse

Class 1 fireproof buildings have the highest resistance to collapse, designed with reinforced concrete or steel I-beams and rated for up to 4 hours of fire resistance.
These buildings typically experience localized damage instead of total collapses, aiding in evacuation and fire control.
The collapses of the World Trade Center buildings illustrate the dangers of modern lightweight construction materials.

Windsor Fire

The Windsor Building in Madrid suffered significant damage in 2005, with most of its steel frame collapsing while the concrete core remained standing.
The outer floor sections used medium-weight steel with partially load-bearing exterior walls.
The most hazardous scenario in Class 1 buildings arises from poured in place concrete structures.

Collapses and Their Effects

Lower floor collapses can lead to subsequent failures in higher floors, especially during advanced fires.
During fires, fire apparatus should be removed from the collapse zone, which extends half the height of the building from its wall.
Old industrial buildings prone to multiple fires may become unstable and collapse from seemingly minor flames.

Resistance to Collapse

Class 3 ordinary construction (brick and wood joist) has moderate resistance but may burn through before experiencing structural failure.
Class 5 wood-frame buildings represent the lowest resistance to collapse.
Metal or non-combustible materials generally provide better collapse resistance than wood frame or heavy timber.

Structural Components and Failure

Framed structures with protected steel or concrete systems resist total collapse, mainly collapsing in localized areas.
Class 2 constructions (metal/noncombustible) are susceptible to collapse due to large quantities of unprotected steel.
Steel expands when heated and can lose significant strength under high temperatures, leading to potential collapses as steel cools back into distorted shapes.

Prioritizing Structural Failure

Structural elements’ failure hierarchy indicates potential impacts on overall stability:
- Bearing walls are most crucial for support.
- Columns bear significant weight and are critical to stability.
- Girders support beams, followed by beams and joists, and finally the floor or roof decking.
Failure of vertical members (columns/walls) can lead to more severe collapses than the failure of horizontal members (beams).

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Description

Explore the dangers of structural collapse on the fireground. This quiz delves into historical incidents and their impact on firefighter safety. Understand the warning signs and prevent potential tragedies in emergency situations.