structural systems Flashcards
design considerations when selection a struct system?
appropriate span?
relationship to program? (weight/heavy load?)
related loads
material choice (wood, concrete, etc)
local market
short spans
usually small or residential projects
wood framing & light gauge steel framing
8’-16’
wood framing & light gauge steel framing
multiple studs/elements at small increments. overbuilt. easy to install. redundnacy. simple. burn quickly :(
heavy timber
dangerous if one element fails. in a fire the outer ring will char and protect the interior better
types of wood framing
balloon, platform, stick built
balloon framing
historically important to USA. lower skill based, allowed for very fast construction. vergy dangerous for fire back in the day. studs go all the way up
foundation > stud > rim joist > joist
platform frame
build studs/walls on floor then tilt up. studs stop and start at each floor. better for safety. not good for insulation
medium spans
small commercial, everyday business. post & beam traditional style
column > girder > beam > joist > decking
steel 25’-35’
concrete 20’-30’
engineered wood 15’-50’
camber
preadjust beam so that when loaded it won’t sag
long span
60’L
many considerations - shipping, deflection, temp expansion/contraction
lack of redundancy
long span 1 way
linear members that span 1 direction, resist beam bending. typically primary members bridge long direction and secondary span in between. support floor or roof
long span 2 way
distribute loads to supports in both directions. complex 3D load resistance
girder
rolled steel members, max 72’L
can add more capacity by welding top/bottom cover plates
ie. plate girder - steel plate & angles
can be tapered at mid point where moment is higher
typ used in structure to span/transfer load between 2 columns spaced further apart (ie. hotel lobby)
rigid frame
vert/horiz members + joints resist loads by flexure. moment transferred from beams to columns
fixed or pin connections
type for warehouse, manuf plants
truss
composed of straight members formed into triangles. members will either be in tension or compression
very effecient for long span
high strength to weight ratio
open webb joist
prefab truss
K series - 60’ span
LH series - long span, 96’ span
DLH series - 144’ span
vierendeel truss
series of rigid rectangular frames (instead of triangles)
used when dont want diagonal members
very large
glulam beam
max 60’
prestressed concrete
1-way long span
counteracts tension
single tee, double tee, AASHTO girder
post tensioned concrete
precast w/ sleeves, run tendons, crank tension when curing
1 way long span
6 major considerations of cost of 1 way structure
equip, type of system, material, labor, construction time, integrations w/ other bldng systems
2 way systems
space frames, dome, thin shell, folded plate, suspension
space frame
3d system that transfers loads thru network of members attached at nodal points
very effecient
resists compression & tension
has alot of redundancy
design considerations of 2 way structure
insulation, water proofing, drainage, installation $$$
