Ch 3 - Structural Design Features Of Buildings Flashcards
Bending moment
A reaction within a structural component that opposes a vertical load. Exceeding causes failure
Forces on a building
Gravity
Vibration (wind, building systems, vehicular traffic)
Temperature
Shrinkage
Stresses on a building (internal)
Tension
Compression
Shear
Tension (tensile stress)
Pulls material apart
Compression
Squeezes the material
Shear
Slides one plane of material past and adjacent plane
Stresses from external loads
Axial (load applied to center and perpendicular to cross member)
Eccentric (perpendicular to cross member but not in center)
Torsion (off-center and at an angle to or in the same plane as cross member)
Factor of safety
Ratio of the failure point to the maximum designed stress
Dead load
Weight of structure, structural members, and building components that are permanently fixed to the building
Live load
People, weather, and other non permanent items
Static load
Steady, motionless, constant
Dynamic load
Involve motion and are capable of delivering energy in excess of the object’s weight
Dewatering
Removing water from a building or roof
Water static load
3 inches water adds 21 pounds per sqft
Seismic load types
Lateral
Torsional
Resonant
Seismic activity accommodations in construction
Expansion joints
Damping mechanisms to absorb resonant energy
Base isolation - isolates rest of building from horizontal movements
Soils pressure load
Soil exerts a lateral pressure on the foundation
Structural accommodations for loads
Beams
Arches
Columns
Cables
Trusses
Space frames
Simply supported beam
Supported beneath both ends, free to rotate
Restrained beams
Rigidly supported at each end. Better fire resistance than simply
Cantilever beams
Supported at one end (balconies)
Overhanging beams
Similar to cantilever with additional support
Continuous beams
May span several vertical supports
Type of load supported by columns
Axial
Stresses in an arch
Compression and tension
Space frame
Three dimensional truss
