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Flashcards in 8 Masonry And Ordinary Construction Deck (64)
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31

Exterior brick wall is usually constructed with a vertical cavity between the exterior and interior wythes. Known as a

Cavity wall

32

Cavity walls are intended to

Prevent water seepage through mortar joints to interior and increase insulation. Requires metal ties

33

Masonry walls can be reinforced by

Placing vertical steel rods in a cavity between two wythes. Either brick or brick and block.

34

Reinforcement of masonry walls can also be accomplished with what

Buttresses, flying buttresses, and pilasters

35

Because mortar provides little tensile strength the individual openings in masonry walls must be supported by

Lintels

36

Lintel

Beam over an opening in masonry wall, made of steel, concrete or reinforced masonry

37

Lintels and to a lesser extend, arches, are most common means to supporting loads over masonry openings. Corbelling isn't used only when

Where the Architectural styling makes it attractive

38

Parapet

Portion of the exterior wall that extends above roof line. Low wall at edge of roof. Found on exterior masonry walls and fire walls of buildings with combustible roofs

39

Parapet walls project how high

1-3 ft or more

40

Parapets, especially in front pose what risk to firefighters.

Collapse

41

Most basic and traditional type of masonry building

Where extrior load bearing walls support interior wood floors and roof rafters and joists

42

Ordinary construction is aka

Type III, masonry wood joisted

43

In many residential and commercial buildings wood joists are rest on a beam pocket which is

A pocket several inches into wall that is deep enough to suitable support the beam

44

When pocketed into a masonry wall a joist will be cut at a slight angle known as

Fire cut

45

Fire cut

Angled cut made in end of wood joist resting in masonry wall allowing beam to freely fall away from wall in case of failure of beam. Prevents beam from acting as lever pushing wall out.

46

Where a beam transmits a large vertical load to a wall,nether wall may be built out and increased in thickness to support it , known as

Pilaster

47

Fire resistance of masonry walls depends on

Type of masonry unit used and thickness of wall

48

Hollow block can crack and spall. Wall of fire rated cmu or brick a an have fire resistance time of

2-4 hrs or more

49

An officer must monitor changes or growth in masonry wall cracks because

Changes or growth can indicate impending collapse

50

Mortar can erode form elements such as rain by

Rain seeping in, freezing and causing expansion which causes mortar to crack or flake

51

Cracks in masonry can be caused by

Foundation settling or saggin interior beams from rot or damage

52

Structural deterioration of masonry walls prior to fire will contribute to

Structural failure under fire conditions

53

If masonry walls begin to bulge or lean out, a way of stabilizing it is with

Steel Tie rods, parallel to joists though the wall with bearing plates outside like washers, sometimes in shape of stars.

54

Tie rods in masonry wall may indicate repair however it may

Be a part of original design

55

Potential problems for steel tie rods

Heated under fire, expand, reducing strength and weakening walls.

56

Tie rods used for repair are generally

Less compatible with design of building, may just be form of steel channels
Not uniformly positioned or spaced on walls
Other indications of repair like mortar repair near tie rod bearing plates

57

Masonry walls usually collapse because of

Failure of interior beams by collapse, pushing against walls forcing them out.

58

Collapse zone of masonry wall is

At least the height of the building. Corners are safest.

59

Facia

Flat horizontal or vertical board at outer face of cornice, broad flat surface over storefront or below cornice. False front or mansard roof face

60

Mill construction

Exterior masonry, interior timber beams or laminated, classified as type IV