Building Construction Flashcards
Book 29 Building Construction
Roof Styles
Gable Hip Flat Bridge Truss Arch Sawtooth
Book 29 Building Construction
Gable Roof
Conventional
“A” Frame configuration
Rafters: 2x6” or larger
16-24” on center; 36” for steep pitch
Ridge: 1x6” ridge board or none if 2x6” rafters butted together
Book 29 Building Construction
Gable Roof
Lightweight
2x3” or 2x4” wood trusses held together by metal gusset plates
Top chord (compression), Bottom chord (tension), Webbing
18G, 3/8” penetration
Truss rafters 24” on center
Book 29 Building Construction
Roof Truss Clips
Nailed to bottom chord (every 3-5 trusses) and top plate of interior walls.
Provide stability for interior partition walls
Book 29 Building Construction
Hip Roof
Conventional
Ridge board, hip, valley, jack, and common rafters
Ridge 2x6” or larger
Rafters 16-24” on center
36” rough cut on older structures with steep pitched
Book 29 Building Construction
Bridge Truss
30s and 40s Truss members 2x12" Tie rods vertically for additional support Rafters 2x6 or larger 1x6 sheathing Plywood over existing if modified for EQ
Book 29 Building Construction
Bowstring Arch
30s, 40s, and 50s small and large commercials 2x12 or 2x14" lumber rafters 2x6" sheathing 1x6" plywood over existing if modified for EQ
Book 29 Building Construction
Lamella Arch
Egg crate, geometric, or diamond patterned roof
2x12” wood framing with steel plates and bolts
sheathing 1x6”
supported by exterior buttresses or internal tie rods with turnbuckles
Book 29 Building Construction
Lamella Arch
Hazards
Total roof collapse may occur if fire removes more than 20% of roof structure
Domino effect
Book 29 Building Construction
Tied Truss Arch
Similar to bowstring and lamella
uses metal tie rods to offer lateral support for the walls
Tie rods 5/8” with turnbuckles ensure arches do not push exterior walls outward
Top chords =laminated 2x12” or larger
Rafters 2x10” or larger
1x6” sheathing
Plywood over existing if modified for EQ
Book 29 Building Construction
Sawtooth
Commercial buildings to yield additional light and ventilation for manufacturing type occupancies
Rafters 2x8” or larger
wood and/or metal supports for bracing
Book 29 Building Construction
Conventional Flat
Rafters 2x6” or larger laid across outside walls
Sheathing 1x6 or plywood (3/8 to 5/8”)
Comp
Book 29 Building Construction
Wooden I Beam
Top(compression) and bottom(tension) parallel wooden chords connected by wooden stem
2x4” and 2x3” chords low grade of lumber
Stem 3/8” plywood or chip board
Connected by continuous glued-edge joint
Either top or bottom chord supported to wall
24” on center spacing
Book 29 Building Construction
Nailing Block
Perpendicular to top chords
4’ apart
Provides additional nailing surface for 4x8’ plywood
Book 29 Building Construction
Diaphragm Nailing
For nailing plywood
8’ crosses structural members
4’ parallel to structural members
staggered every 4’
Book 29 Building Construction
Open Web Roof
Top and bottom parallel wooden chords cross connected by steel tube web members
Top chord is supported; bottom chord unsupported
Chords either laid on edge or flat
Steel tube web members 1-2” cold rolled steel with ends pressed flat into a semicircular shape with hole punched through end
Flat ends inserted into slots in the chords and up to 1” steel pins driven through
Spans of 70’ of 2x3s and 2x4s by joining different lengths in glued, mitered “finger joints”
Book 29 Building Construction
Metal Gusset Plate
18G steel plates with prongs 3/8” penetration
1/2” plywood; Dwellings 3/8” or 1/2”
Book 29 Building Construction
Pannelized
Beams (laminated or metal) 6x36; 12-40’; up to 100’ length
Purlins 2x12” 8’
joists 2x4 2’
1/2” plywood decking
Book 29 Building Construction
Open Web Bar Joist
Top and bottom chords 1/8” steel and web supports solid 5/8” steel bar
Larger buildings may have bar joists as girders spaced up to 45’
Joists 8’ apart
Corrugated metal decking covered by alternating layers of tar and tar paper
Book 29 Building Construction
Steel
Loses strength at 1000 deg F
expands, twists and fails
Book 29 Building Construction
Lightweight Concrete Roof
Non Structural
Steel or wood sub-structure is covered by Corrugated Metal (Robertson decking)
Air entrained mixture of SAND, CEMENT, and occasionally PEA GRAVEL is pumped on top of corrugated metal decking
4x4” or 6x6” wire mesh 3-4” thick
Comp material makes up final layer
Insulative (near airports, freeways, etc)
Diamond blade or Carbide tipped wood blade
Book 29 Building Construction
Metal Construction Methods
CORRUGATED
Sub structure of wood or steel, covered with corrugated steel, aluminum or fiberglass
Quickly fail
Book 29 Building Construction
Metal Construction Methods
METAL BEAM
Sub structure of steel beams, usually coated with sprayed on fire retardant material
Skeleton is finished with exterior of concrete, masonry, glass or similar materials
2 stories to tallest high rise (modern high rise and multi story office buildings)
Book 29 Building Construction
Metal Construction Methods
METAL BEAM
HAZARDS
Vertical extension of fire and smoke to upper floors
Falling panels of glass or other building materials
Brick veneer
Metal beams expand 9”/100’ =push out walls
Book 29 Building Construction
Concrete Construction Methods
TILT UP
Concrete slabs that have been “tilted up” to form exterior walls
Up to 5 stories in height
Book 29 Building Construction
Concrete Construction Methods
TILT UP
HAZARDS
Lightweight construction for interior walls
Lightweight roof
Often has facade
Book 29 Building Construction
Masonry Construction Methods
BRICK PRE 33
UNREINFORCED MASONRY
- SAND and LIME mortar
- Lack of steel reinforcing rods
- 13” thick brick exterior walls
- Parapet walls around perimeter. 3’ above roof line; 5’ or more if used as facade on front
- “LET” floor and roof joists inside of exterior walls
- Straight roof sheathing
- “FIRE CUT” roof and floor joists
Book 29 Building Construction
Masonry Construction Methods
BRICK POST 33
LB EQ 1933
- Exterior walls at least 9” thick
- Masonry walls reinforced with “REBAR”
- ALL joists and rafters anchored to exterior walls usually with ledger board with metal hangers
- Cement in mortar
- DIAGONAL sheathing
Book 29 Building Construction
Masonry Construction Methods
BRICK POST 59
Tehachapi
- 4-6” CONCRETE BOND BEAM cap on top of parapet walls along public ways and exits
- Parapet walls less than 16” including bond beam cap
- “rafter tie plates”
Book 29 Building Construction
Rafter Tie Plates
- exterior walls drilled at roof rafter level and steel anchor bar/rod installed every 4’ and attached to existing roof rafter
- fire cut became ineffective
- steel anchor bar/rods secured to exterior of building by plate/nut combination
Book 29 Building Construction
Masonry Construction Methods
BRICK POST 71
Sylmar
EARTHQUAKE ORDINANCE
1. Anchoring walls to floor and roof systems
2. Strengthening roof construction (plywood, metal straps)
Book 29 Building Construction
Masonry Construction Methods
Unreinforced Masonry Windows
Deeply recessed window frames
“set” to inside of wall
exposes about 8” of brick return on exterior of building
arched or straight lintels
Book 29 Building Construction
Masonry Construction Methods
Kings Row
every 4-7 rows
one row will be laid “on end”
Book 29 Building Construction
Masonry Construction Methods
Earthquake Ordinace
- add steel bracing from parapet walls to roof structural members
- Metal straps across the width of the roof and attached to opposing walls
(usually 1/3 of the length of the building back from the front and rear walls - remove layers of comp and cover sheathing with 1/2” plywood, then covered with comp
Book 29 Building Construction
Primary danger from collapse?
Front and rear walls
Book 29 Building Construction
Metal straps across the width of the building are how many feet from walls?
3-4’
Book 29 Building Construction
Bungalow and Balloon construction were built when?
20s, 30s, 40s
Book 29 Building Construction
Bungalow and Balloon frame construction were utilized how?
Single family dwellings
Multi story habitational occupancies UP TO 4 Stories
Book 29 Building Construction
Curtain construction can be about ___ faster than conventional construction?
60%
Book 29 Building Construction
Pre 33 Characteristics
URM
Wood shiplap exterior, ballloon and bungalow construction with knob and tube wiring
Straight or diagonal roof sheathing
Book 29 Building Construction
33-50s Characteristics
Solid construction and compliant with building codes
Straight or diagonal sheathing
