BC 3 Flashcards
reactions (R)
the forces within a structure that resist applied loads
loads (L)
applied loads
equilibrium
when a structure can support a load equal to or less greater than L
stresses
tension-pull apart or tensile stress
compression- squeezes
shear- slides one plane against adjacent plane
external load alignments unique stresses
axial load
eccentric lad
torsional load
water live load
water at a depth of 3 inches will cause 21 lbs/sq foot
primary consideration for wind load calculations
direct pressure
typical lifespan of a building
50 years
most significant force generated by earthquake
lateral
base isolation
shear systems-elastomeric bearings placed in a layer between the building and foundation
siding systems- special plates that slide on each other in order to isolate the building from horizontal shear force
soil pressure
exerts lateral load against foundation
active soil pressure
the pressure exerted by the soil against the foundation
passive soil pressure
the force of the foundation against the soil
soil liquification
sandy soil near water is looser and saturated with water and entrapped water prevents sand particles from moving closer together reducing the soils ability to support a structure
beam
member that carries loads perpendicular to its longetudinal dimension
I beam
top flange of the beam carries compressive stress. bottom flange of the beam carries tensile stress. center horizontal line of the web is known as the neutral exit because the tensile and compressive stresses are zero but the neutral axis is the maximum point of shear stress
columns
structural members designed to support axial loads
tall thin columns fail by buckling
short buckle fail by crushing
arch
curved structural member with primarily compressive interior stresses
cables
usually straight
curve when supporting loads over a distance
tensiles stress
trusses
framed structural units made of groups of triangles in one plane
true truss is made only of straight members
top and bottom are called chords
middle section called web or diagonals
lightweight steel trusses
bar joists
connectors used with steel trusses
steel gusset plates
rivets
welds
connectors used with wood trusses
pins or bolts
gusset plates
structural adhesives
brackets
metal straps
space frames
3 dimensional truss
well suited to support uniformly distributed loads