J Line - Building Science Flashcards
what are considered live loads?
described as static, repetitive, or dynamic. Live loads can be human-caused or they can be environmental
what are some examples of live loads?
snow, wind, rain, people,
what is considered a static load?
an external force that is applied and healed for a period of time. (furniture)
why is furniture considered a live load even tho it can’t move
furniture can still be moved or placed somewhere else
what is considered a repetitive load?
a repetitive force on the structure (cars on a bridge are a repetitive load)
what is a dynamic load?
a load that can change over time (cars on a bridge stopping and starting)
what loads can wind produce?
static and dynamic
what load is a tornado or hurricane?
dynamic load
what load is produced by Rain and snow?
Static Loads
what is considered a dead load?
all building materials, a constant gravitational load
what are the four types of stresses acting on a structure?
Compression, tension, torsion and shear
what is compression?
the force acting to squash an object
what is tension?
the force of pulling an object apart its length
what is torsion?
when the object is twisted
what is shear stress?
when loaded components try to slide together or apart
where is the shear point on a load bearing beam?
the inside of the wall point where the beam meets the corner of the top plate or beam pocket. (Vertical Shear)
what if a beam has both horizontal and vertical loads?
the beam can experience diagonal shear stress
what is the force in the middle of a beam?
the neutral zone, compression on top and tension on the bottom
what does it mean for a member to have good tensile strength?
won’t break under tension stress
what has more resistance to lateral loads? veneer sheathing or lumber sheathing?
veneer sheathing
what direction does lumber sheathing get installed?
diagonally
why is it good to place blocking immediately in the perimeter of the boxing joists?
it provides less stress on nails and more area for load bearing walls on top
how can you reduce rotational loads on a floor?
by decreasing the on meter spacing of bridging or blocking from the max 7 feet
how can the compressive and tensile forces at the corners a building be further supported?
By running the sheathing past the end of the stud of the intersecting wall
what percent is reduced of wall strength if sheathing nails are overdriven?
40-50%
what does the building envelope protect from?
rain, wind, groundwater, soil gases from entering the building
what is frost jacking?
caused by the expansion of water when it freezes
what is the best method of preventing frost jacking?
extending the foundation below the frost level
when is hydrostatic forces occur?
when the depth of the excavation is below the water table
what are two ways hydrostatic pressure is controlled?
with proper waterproofing and proper drainage
what are 2 systems of waterproofing?
self-adhering membrane and superset dimpled membrane
what is conduction?
heat energy transferred through solid
what is convection?
heat transferred through a liquid or air
what is a convection current?
when hot air rises it will pull cold air from out side in
what is radiation?
when heat is transferred from a source to an object without heating the space in-between
what is relative humidity?
the amount of moisture heals in the air
what air can hold more moisture?
warm air
what is the Due point?
the air temperature when condensation has occurred. (Fog) 100% humidity
where is the vapour barrier in a wall?
on the warm side between drywall and framing
what are the saturation levels?
indoor air quality
where is the air barrier?
same as vapour barrier in a wall (polly)
