STRUCTURES Flashcards

1
Q

WHAT ARE, AND WHAT KIND OF 4 STATIC LOADS ARE THERE?

A

APPLIED SLOWLY TO A STRUCTURE AND REACHES A PEEK WITHOUT FLUCTUATING GREATLY.

  • DEAD LOADS
  • LIFE LOADS
  • FOUNDATION LOADS
  • IMPACT OR KINETIC LOADS
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2
Q

4 FAILING CONDITIONS OF SEISMIC LOADS?

A
  • SOFT AND WEAK STORIES
  • DISCONTINUOUS SHEAR WALLS
  • VARIATIONS IN PERIMETER STRENGTH
  • REENTRANT CORNER
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3
Q

3 STRESS TYPES TO EXTERNAL FORCE?

A
  • TENSION
  • COMPRESSION
  • SHEAR
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4
Q

HOOK’S LAW, structures STRESS FORMULA

A

F = P / A

STRESS = TOTAL FORCE APPLIED / TOTAL AREA

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5
Q

FORCES WITHIN A BUILDING IN A SEISMIC EVENT - FORMULA

A

FORCES WITHIN A BUILDING IN A SEISMIC EVENT OR EQUAL TO THE WEIGHT OF THE BUILDING.

F = M*A

FORCE (F) = THE MASS (M) OF THE BUILDING x THE HORIZONTAL ACCELERATION (A)

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6
Q

3 structure types FOR SEISMIC RESTRAINT

A
  • MOMENT RESISTING FRAME
  • BRACED FRAME
  • SHEAR WALLS
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7
Q

10 SEISMIC MITIGATION strategies

A
  • -CONTINUOUS LOAD PATH
  • -LOW HEIGHT TO BASE RATIO
  • -EQUAL FLOOR HEIGHT
  • -SYMMETRICAL PLAN
  • -MINIMIZES TORSION
  • -UNIFORM SECTION
  • -SEISMIC RESISTING ELEMENTS AT PERIMETER
  • -SHORT SPANS
  • -NO CANTILEVERS
  • -NO OPENINGS IN DIAPHRAGMS
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8
Q

3 FUNDAMENTAL PRINCIPLES OF EQUILIBRIUM APPLIED BUILDINGS.

A
  • The sum of all vertical forces acting on a body must equal zero
  • The sum of all horizontal forces acting on the body must equal zero
  • The sum of all moments acting on the body must equal zero.
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9
Q

Allowable max BEAM STRESS - FORMULA

A

F = M / S

ALLOWABLE BENDING STRESS = MAX.MOMENT / SECTION MODULUS

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10
Q

MOMENT FORMULA FOR CENTER POINT LOAD

A

M = P*L / 4

MOMENT = POINTLOAD*LENGTH / 4

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11
Q

MOMENT FORMULA FOR UNIFORM LOAD

A

M = W*L^2 / 8

MOMENT = UNIFORM LOAD * LENGTH SQUARED / 8

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12
Q

WHAT AFFECTS THE BENDING MOMENT? what not?

A

LOAD, TYPE OF SUPPORTS & LENGTH AFFECT MOMENT,

Not: MATERIAL AND CROSS-SECTION

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13
Q

SHEAR FORCE FORMULA FOR POINT LOAD

A

V = W / 2

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14
Q

COLUMN SLENDERNESS RATIO

A

SLENDERNESS RATIO = L / R

L=Length

R = RADIUS OF GYRATION

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15
Q

SPAN STEEL GIRDERS IN FT

A

10-70

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16
Q

SPAN Flat wood trusses IN FT

A

40-150

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17
Q

SPAN Pitched wood trusses IN FT

A

40-100

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18
Q

SPAN Deep Long span joists IN FT

A

90-144

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19
Q

SPAN Glued lam beams IN FT

A

10-60

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20
Q

SPAN FLAT STEEL TRUSSES IN FT

A

40-300

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21
Q

SPAN PRESTRESSED SINGLE T IN FT

A

20-120

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22
Q

SPAN Prestress. conc girders IN FT

A

40-120

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23
Q

SPAN Conc arches IN FT

A

40-320

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24
Q

SPAN Suspended cables IN FT

A

450

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25
Q

SPAN Geodesic dome IN FT

A

400

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26
Q

Coefficient of expansion

A

expansion of material Measured in inches per degree F

Material specific

27
Q

Windload formula

A

Wind load / sf * area normal to wind = windload

28
Q

Max drift for building during winds/ storms

A

Should not exceed 1/5000 of the building height

29
Q

What is a diaphragm

A

Rigid floor a roof structure transferring lateral loads to vertical shear walls, braced frames, are rigid frames

When vertical - shear wall

30
Q

Minimum area occupied by columns and/or bearing walls

A

A Long Span System

  • Heavy wood trusses
  • Glue lam wood beams, wood arches
  • Steel frame, trusses
  • Open Web Structural Joists
  • Waffle Slab
  • Single or Double Tee Concrete
31
Q

Changes in use over time

A

Short Span, one Way Systems that can easily be modified

  • Light Gauge/Conventional Steel Frame
  • Wood systems (including masonry)
  • Site Cast 1 way concrete slab • Precast concrete slab
32
Q

Exposure to Adverse Weather

A

No reliance on onsite chemical processes

  • Steel
  • Wood
  • Precast Concrete without toppings or grouting
33
Q

Minimal off-site fabrication time

A

On-site construction with easily formed materials

  • Site cast concrete
  • Light Gauge Steel Framing
  • Platform Framing
  • Masonry
34
Q

Minimal on-site erection time

A

A lot of prefab/modular components

  • Single story rigid steel frame
  • Steel frame with hinged connections
  • Precast concrete • Heavy timber frame
35
Q

1-2 stories with minimal construction time

A

Lightweight/easy to form/prefab

  • Any steel
  • Heavy timber frame
  • Platform frame
36
Q

4-20 stories with minimal construction time

A

Lightwight/easy to form/prefab

  • Precast concrete
  • Conventional Steel Frame
37
Q

30+ stories with minimal construction time

A

Strong, lightweight, easy to assemble

  • Steel Frame
  • Site/Precast Concrete
38
Q

Minimal diagonal bracing or shear walls

A

Rigid Joint System Site cast concrete (With beams/ deep slab around columns

  • Single frame w/welded connections
  • Single story rigid steel frame
39
Q

Minimal dead load on foundation

A

Lightweight/Short Span

  • Any Steel
  • Any Wood
40
Q

Minimal structural distress due to unstable foundation

A

Frame without rigid joints

  • Steel frame with bolted connections
  • Heavy timber frame
  • Precast concrete system
  • Platform framing
41
Q

Concealed Spaces for MEP

A

Not add height to building

  • Truss
  • Open web joists
  • Light Gauge Steel Framing
  • Platform Framing
42
Q

shear (V) formulas

at apex and any given location

A
43
Q

Pointload center formulas

moment an shear

A
44
Q

Point Load off center,

moment and shear formulas

A
45
Q

point load vs distributed load

shear and moment diagrams

A
46
Q

Duration

A

Shaking duration above a certain threshold acceleration (0.05g)

47
Q

Velocity of earthquake

A

Measured in P waves and S waves, P waves are faster

48
Q

Displacement

A

Distance that points on the ground are moved from the initial position

49
Q

Frequenzy

High Frequency Waves

A

Small velocities and acceleration

50
Q

Frequenzy

Low Frequency Waves

A

Large velocities and displacements

51
Q

typ. periods (seismic)

A

one second per 10 stories

52
Q

Ground Amplification:

A

“Shaking levels at a site may be increased, or amplified, by focusing of seismic energy caused by the geometry of the sediment velocity structure, such as basin subsurface topography, or by surface topography.”

53
Q

Resonance:

A

Resonance

“the tendency of a system to oscillate with greater amplitude at some frequencies than at others”

54
Q

Allowable Beam Deflection

A

The maximum vertical displacement of the member as it bows under loading. These limits vary depending on code requirements, but may be similar to L/180, L/240, L/360, or L/480

A beam spans 20’. How many inches will it be allowed to deflect if required to meet a maximum of L/240?

20’ * 12” = 240” > 240” / 240 = 1” Allowable deflection

55
Q

• Gage line

A

• Gage line: standard dimension from corner edge of an angle to centerline of bolt holes. depends on size of angle

56
Q

Modulus of Elasticity of steel

A

29,000,000 psi

57
Q

Modulus of Elasticity of wood

A

± 1.100.000 psi

58
Q

area of circle

A

A = π r²

59
Q

area of sphere

A

A=4πr2

60
Q

1 kip/in2. = ? psi

A

1 kip-force/square inch = 1000 psi

61
Q

High-Strength steel bolts

A

A325 & A490

62
Q

Unfinished steel bolts

A

A307

he A307 bolts were once the standard for all applications, but are currently used predominantly for secondary uses that do not require the high strength provided by A325 or A490 bolts.

63
Q

Pressure P formula

A

Pressure P is defined as

P=F/A

where F is a force applied to an area A that is perpendicular to the force.