Chapter 3 - Building Construction Flashcards
What are the 3 categories that Building Construction are broken down into?
Residential, Commercial, High Rise
What are the categories that Residential building construction are broken down to?
Balloon Frame
Platform(Conventional)
Lightweight
Describe Balloon Frame.
Wall studs run entire length of the walls, sole plate to attic
2nd Floor joists are nailed off to a ledger, runs along interior wall studs
Describe Platform or Conventional.
Major difference, removed ledger
1st and 2nd story capped by header or sole plate
How do you identify a balloon frame vs conventional from the street?
Windows or doors that line straight up the building
What are some shared features of balloon frame and conventional construction?
True dimensional lumber Basements are below grade floors Either Lath and plaster or 1x6" TNG ceilings Cedar shingle or ship la siding Wall studs 16 on center
How do you identify conventional roof construction?
True dimensional lumber 2x4 or 2x6" Rafters rest on top plate, nailed to ridge beam 16" on center Rafter tails exposed Decking is 1x6 TNG or skip sheathing
How is lightweight construction identified?
Uses smaller dimensional lumber
Trusses are held by gusset plates, uses OSB
Built within last 30 years
2x4 rafter tails seen
Where are the areas of strength on a lightweight roof?
Lower roof line, valleys, hips, and the ridgeline
What are the hazards of lightweight construction?
Shortened collapse time
Rapid deterioration under fire conditions
Single truss failure can bring down large sections of roof
What are the challenges of lightweight construction?
Roof tiles, heavy and must be removed
Zero lot lines are common
What are the identifying characteristics of apartment complexes?
Similar to residential with Balloon frame, conventional or lightweight
What are the 2 classes of commercial buildings?
Conventional and lightweight
What are the conventional roof trusses?
Bridge, Lamella, Arched
Describe the bridge truss.
Large heavy lumber, secured with metal tie rods
tie rods support 2x6” rafters and 1x6” sheathing
Identified from the outside by roof sides and ends are sloped, and flat along middle elevation
Describe a Lamella arch.
Rafters are in a diamond pattern with large dimensional lumber and 1x6” sheathing
Found in old gyms or Multipurpose rooms
Describe Arch truss.
Large dimensional lumber, top chord arched under compression
Also known as Bowstring
Describe conventional flat roofs.
Large dimensional lumber, 2x6 or larger rafters
16 inches on center
May have 1x6” sheathing or 3/8 to 5/8 plywood decking
Where are the areas of strength on conventional flat roofs?
Perimeter and directly over the beams
What are some hazards for conventional flat roofs?
Metal hangars are known to fail
Bottom side of plywood may have burned out, without any indication from the top side
What are URM characteristics?
Brick or cinderblock, relies solely of masonry for the strength
Strengthening tie rods or plates to help hold the building together
What is a king row?
Bricks turned so ends face out, strength
How can you tell the difference between poured in place and tilt ups?
Poured in place - solid, unsectioned concrete walls
What are some characteristics that maybe found in lightweight commercial roofs?
Wooden I beams
Open web beams
Open web bar joists
Panelized roof systems
Describe wooden I beams
Consist of a top and bottom chord
Stem of the I beam made of OSB
Spaced 2’ apart
Where are flat panelized roofs commonly found?
Concrete tilt ups
What is the spacing of the purlins on lightweight panelized flat roofs?
8’ with the 2x4 rafters connected to them. Rafters are perpendicular to the purlins with 2’ on center spacing
What is the approximate LB/SQ Foot of an older high rise?
11-12 pounds per square foot
What is the approximate LB/SQ Foot of a modern high rise?
8-10 pounds per square foot
What are the 2 categories of high rise construction on Sacramento?
Steel frame and poured in place
Describe steel frame.
Commonly found in large commercial buildings, uses steel beams to make a frame
Steel frame buildings have a common core(Elevator, stairs, utilities)
Makes large open floors
Describe the pour in place.
Most commonly used in SHRA buildings
Concrete is poured into place with wood forms and connected by steel to form the floors
