Ch. 4 Masonry Wall Collapse Flashcards
There are the 3 ways a Masonry exterior bldg. wall can collapse what are they?
90 degree-the wall may fall straight out
Curtain fall-The wall may straight down
Inward-outward-the top of the wall falling inward and the bottom falling outward.
Of the 3 ways a masonry exterior bldg. wall will collapse what is the most common?
The 90 degree collapse
How far will a 90 degree wall collapse onto the ground?
The wall will fall straight out with the top of the wall striking the ground, a distance equal to the height of the falling section measured from the base of the wall. Bricks and lintels may bounce or roll out farther
When bowstring truss roofs include hip rafters sloping down from the front and rear bowstrings, one end of the hip rafters is tied to the outermost truss section and the other end is tied into the masonry wall. If the bowstring trusses are weakened by fire, and the roof fails, the load of the falling roof is transferred to what masonry walls?
The front and rear walls. The top section of the masonry wall will fall inwards & the bottom section outwards.
The “collapse zone” is the area adjacent to a unstable wall that FF’s should not be allowed to enter. As a general rule it is the distance equal to the height of the wall. This may be increased to 1-1/2 to 2 times the height of the wall for what 3 reasons?
- A truss roof triggers a wall collapse
- An explosion triggers the wall collapse
- if ordered by the IC
WALL ATTACHMENTS NEW SECTION*
GENERAL INFORMATION
Façade-the front of a bldg., may include a parapet wall, marquee, canopy and/or a cornice
Parapet- a continuation of an exterior wall above the roof level
Marquee-a large metal structure attached over the entrance to a store or theater. A marquee extends from the front wall out to the street and is used to display signs
Cornice-is a horizontal ornamental construction along the entire front wall of a bldg., usually near the top
Canopy-is a cloth, wood or metal covering over a bldg. entrance designed to protect people from the weather.
The area beneath the marquee, canopy, or cornice is considered to be ________ the building.
Fill in the blank
INSIDE the building
What is the most dangerous canopy we might encounter?
The most dangerous canopy is a metal (corrugated tin) or wood shed suspended over a truck loading area, covered with tar paper, and thus extremely combustible.
