Chapter 15 Wood-Framed Building Collapse Flashcards
What are the three ways a wood frame building can collapse during a fire
- straight outward 90° angle
- the entire building may lean over and collapse on its side
- inward / outward collapse
what is a warning signal of a 90° angle wall collapse
often signaled by the corners of the falling wall splitting apart from the remaining walls
what are the warning signs on an inward outward collapse
may not exhibit any structural warning at all…. other than serious fire burning for a long time on the lower floor…hear sudden loud cracking noise
one of the warning signs of a lean over collapse
often indicated by the building slowly starting to tilt or leaning to one side
during a fire in a structure with masonry walls it is rare that more than one wall collapse, does that hold true of wood building collapse
no, braced frame wood buildings may have all four walls collapse
which of the three major types of wood frame construction presents the greatest firefighter danger
braced frame wood construction
why is it that braced frame wood construction with fire on the first floor of a three-story structure collapse more frequently than a two-story structure
fire destroys the bearing wall and the added weight causes collapse onto the unsupported side, the empty lot
where the four most widely used methods of wood frame construction
braced frame
balloon frame
platform frame
lightweight wood frame
brace frame construction is sometimes called
post and girt
was a drawback of balloon frame construction
vertical bvoid between the wall studs that extends from the foundation still to the attic And allows hidden flames smoke to penetrate the walls and spread vertically for two or three floors
what is the most widely used wood frame construction today
platform construction
from a fire protection standpoint why as platform construction superior to balloon or brace frame construction
there are no concealed wall voids that extend more than one floor
what is the danger of lightweight wood truss
his early floor and roof collapse, especially floors
in 2008 the underwriters testing laboratory documented that lightweight wood truss and sheet metal fasteners failure in__
less than 10 minutes of fire exposure
what are three factors that contribute to inward outward collapse of a brace frame wood building
- fire destruction of bearing walls
- failure at the mortise and tendon connection
- exterior wall overload
in older communities wood frame buildings were built closely together with the bearing walls usually being the ___, this practices change in suburban communities built from large plots of lands houses are designed to have bearing walls___
sidewalls
front and back walls
when braced-frame wood timber collapses it fails at the weakest point which is
the mortise and tendon joint
what effect does an exterior fire escape have on a wood frame building
the weight of his heavy metal structure attached to the outside wall can exert a slight pull on the starts causing axial loads to become eccentric loads
two types of masonry surfaces apply to the outside of old wood buildings
brick-and-mortar veneer
stucco coating
increase the collapse danger by adding considerable weight to the structure, and hiding major structural defects
are the three contributing causes of wood frame building collapse
fire destruction of bearing walls
mortise and tendon joint of brace frame wooden building
overload of exterior wooden wall
