Building Exteriors Flashcards
Kansas City Hyatt Disaster: How long was the Hyatt open before the disaster? and give some interesting points about this time
Began in 1978 and opened in 1980 [2 years super-fast turn around]
Opened for 12 months
Kansas City Hyatt Disaster: GIve some opportunities to prevent the walkway failure.
- Check with the original design and maintain consistency
- If designs do change ensure the load of the new design works
- When accidents happen (glass panel) actually check the materials.
Kansas City Hyatt Disaster: What was the cause of the structural failure of the walkway?
It failed at the connection point since the actual anticipated load it could handle was much lower in reality.
The Welled box beam being “toe to toe” is structurally weaker than an “I” steel beam.
Also, the hanging bars were split into two since the steel manufacturer could not produce it to that length.
Who was ultimately held responsible for the disaster and why?
Jack Gillum and his company GCE because his team pushed the responsibility back and forth thus not checking the connections for the walkway
Loads can be either Dead/Static or Live/dynamic Loads. What is the difference?
Dead loads are permanent while live loads are changing.
Dead loads: Constant/but changes (elevator)
Live Loads: Bridge with walking people
What are the two types of resonant forces?
Rhythmic: Straight forces: either up or down
Tangential: Non-linear forces: both up and down
How do downward loads create stress?
They cause TENSILE stress causing the force to come out the sides and push out from the center of the load.
How do upward loads create stress?
Upward loads cause COMPRESSIVE STRESS thus making the force come in.
How does tangential load create stress?
Tangential load causes SHEAR STRESS coming from both upward and downward directions.
What are some things to look for in maintenance?
-Cracks in the wall
-Water penetration
-Are both tight and welds in tact?
-Areas of change during last inspection
What to look for during window & door maintenance?
-Loose-fitting frames
-Cracked glass/glazing
-Deteriorated sealants
-Corrosion (metal frames)
-For operable windows, pins to restrict opening
-For doors, proper door-to-frmae alignment
What are the three goals for a building’s structural frame?
- Remain standing by resisting/supporting varying loads
- Provide a way to move the load from the point of impact to the most steady part object (the ground beneath the building aka the foundation)
- Provide redundancies so if a structural element was damaged or removed, a fatal collapse would not be imminent
Is steel very resistant or nonresistant to compressive tensile and/or shear stresses?
Stell is very resistant to both tensile and shear stresses
Who prepares the As-built and shop drawings?
Contractors:
As-builts: document what was actually built
Shop drawings
Who prepares the original working drawings?
Architect or Engineer
Purpose: Sent to the contractor for pricing and used by them when building in the field
Why do we use wired mess to reinforce concrete?
The wired mesh adds tensile strength to the concrete since regular concrete is not resistant to it.
What is the plastic layer used to deter moisture transfer in concrete called?
Vapor barrier:
Looks like a tarp/shower curtain
What are the issues that parking garages face in terms of deterioration?
Concrete parking recks require periodic PM work and repairs
Northern climates that use salt on roads in the winter also have to be aware it accelerates the wear on the epoxy seal and rusts the wire mesh in the concrete
What are the four purposes of building façades?
- Weather proofing
- Thermal performance
- Mitigating air infiltration
- Sound attenuation
Describe U-value and R-value
U-value is the rate of heat transfer: the lower this value the better
(keeps the inside and outside temps steady)
R-value the thermal resistance: the higher this value the better
(Keep in mind there is no set range all of it is comparative)
How often should you inspect a façade?
At least twice per year
What does having a double-glazed/ double panel of glass do for a building?
The temperature transfer is reduced since there is an air gap between the two layers thus reflecting it back and lowering the total heat transferred.
What are the two main reasons you would have a Built-up Membrane Roofing? (BUR)
It is very durable, has high insulation factor but it does cost more
Why would you choose single-ply membrane roofing?
[Less popular than BUR]
-Flexible
-Easy to install/repair
-Long life
-Cost-effective
What is flashing in terms of roofing
Flashing is the transition between the membrane and other objects on the roof
What is a parapet wall and why does a cap do for it?
A parapet wall is the extension of the wall on a building
The cap prevents damage and pushes water away from it
What is the difference between an equipment curb and an equipment stand?
The equipment stand is much smaller but both are used to not put heavy equipment directly on the roofing membrane
How does an infrared roof scan help?
It pinpoints moisture penetration under the roof in order to repair it
What is the heat island effect?
The heat island effect is when the downtown area had a higher avrg temperature because of the absorption of heat.
