J-1 Task 1 Flashcards
What are Live Loads?
Variable, non permanent loads that act on a building structure
How can Live Loads be described?
Static, repetitive, or dynamic
How are live loads caused?
Human caused or they can be environmental
What is a Static Load?
External force thats applied and held in a fixed position for a specific amount of time
Example of a static load caused by gravity is the weight of a piece of furniture
What is a repetitive load?
Repetitve load that repeats itself, may be caused by gravity or the momentum of an object
Example is a car crossing a bridge placing temporary repetitive gravitational loads on the bridge
What is dynamic load?
Is a load that can change over time
Example is the repetive action of cars braking and accelerating on a bridge
What kind of loads does wind affect on a building?
Can create both static and dynamic loads
What kind of loads does rain and snow create?
Static live loads, these gravitational loads are transferred vertically through a building structure
What is the formula for snow load?
S=(Cb x Ss) + Sr
For specified snow load, what does S=?
S= specified snow load for the roof
For specified snow load, what does Cb=?
Basic snow load roof factor
For specified snow load, what does Ss=?
Ss= 1-50 year ground snow load in kPa for buildings geographical location
For specified snow load, what does Sr=?
1-50 year rain load in kPa for building geographical location
Roofs 4.3 metres (14’) in width use what percentage of ground snow load?
45% of ground snow load, 55% of ground snow load over 4.3m
What kind of load does an earthquake put on a house?
Exerts a dynamic load on buildings that can be catastrophic
How many seismic zones in BC?
The code divides british columbia into three seismic zones
What is a dead load?
A dead load is constant, caused by the gravity acting on all of the building materials
What is examples of “heavy construction”?
Increased dead load due to concrete floor toppings and/or tile roofing, for seismic reasons
What is the dead load for wood frame construction?
Treated as 0.5 kPa (10 lb per square foot)
What gives objects their weight?
Gravity, the force of gravity acts toward the centre of the earth
Is a plumb line in vancouver parallel with toroto plumb line?
No, plumb lines radiate from the centre of the earth and are not parallel
What are four common stresses acting on a building?
Compression
Tension
Torsion
Shear
Live and dead loads applied to a building structure result in stresses, what happens if left unchecked?
Stresses may deform the building structure
What is compression?
Force acting to squash an object
What is tension?
Pulling force that acts to lengthen an object
What kind of stresses does a beam endure?
Compression and tension, top is under compression while the bottom is under tension
What is torsion?
The force caused when one or both ends of an object are twisted in opposing directions
What reduces torsion?
Symmetry reduces torsion (balance)
Balance between stiff and ductile (elastic) building materials also helps ease stresses of torsion
What is shear stress?
Shear stess occurs when there are pushing or pulling forces acting in opposing directions on a solid component
Which directions can shear be?
Horizontal, vertical, or diagonal
What results in horizontal shearing?
Deflection and vertical loading
What is an example of a vertical shear?
Beam acting on a column, stress in the beam at the edge of the column is a vertical shear
What is a diagonal shear?
Building components that are under both horizontal and vertical shear stesses experience diagonal shear
Explain how concrete can be a live load and then a dead load?
When concrete is placed it is a live load, when it has hardened to become part of the building, it becomes a dead load
What is the combined live and dead load per square foot for a living room floor?
40+10=50 lb./ft^2
What concern is there when a point load exists?
Point loads cause to extreme compressive stress where they bear
