Connection design

1. Basic Structural Theory
Concepts and construction

2. Vertical (y-axis only)
Forces

3. Lateral (x-axis only)
Forces

4. Rotational – Moments and Bending
Forces

5. Pin
Constrain x & y
Rotate freely
Connections

6. Pin
Constrain x & y
Rotate freely
Connections

7. Pin
Constrain x & y
Rotate freely
Connections

8. Fixed / Moment-Resisting
Constrain x & y
Constrain rotation
Connections

9. Fixed / Moment-Resisting
Constrain x & y
Constrain rotation
Connections

10. Fixed / Moment-Resisting
Constrain x & y
Constrain rotation
Connections

11. Wood
Materials

12. Wood
Materials

13. Wood – hidden defects
Materials

14. Wood – termite and rot
Materials

15. Wood - flammable
Materials

16. Wood - flammable
Materials

17. Steel
Materials

18. Steel – shapes: Wide Flange
Materials

19. Steel – shapes: American Standard – no
longer common
Materials

20. Steel – shapes: Tube
Materials

21. Steel – shapes: Pipe
Materials

22. Steel – shapes: Angle
Materials

23. Steel – shapes: Channel
Materials

24. Steel – shapes: Tee
Materials

25. Steel
Materials

26. Steel
Materials

27. Steel
Materials

28. Steel
Materials

29. Steel – not fireproof
Materials

30. Steel – not fireproof
Materials

31. Steel – fireproofing
Materials

32. Concrete
Materials

33. Concrete
Materials

34. Concrete - CMU
Materials

35. Concrete - CMU
Materials

36. Concrete
Materials

37. Concrete – always steel-reinforced
Materials

38. Concrete – rebar
Materials

39. Concrete – rebar
Materials

40. Columns
Components
Column – Vertical Load
Axial load – Compression & Tension

41. Columns - wood
Components

42. Columns - wood
Components

43. Columns - steel
Components

44. Columns - steel
Components

45. Columns - steel
Components

46. Columns - concrete
Components

47. Columns - concrete
Components

48. Columns - concrete
Components

49. Columns – buckling due to compression
Components

50. Columns - buckling
Components

51. Columns - buckling
Components

52. Beams – simply supported (or using pin
connections)
Components

53. Beams – deflection is a problem before
structural failure occurs
Components

54. Beams – camber to oppose deflection
Components

55. Beams
Components
Basic loads (forces)
Reactions are the same for Concentrated loads and
Distributed loads
Beam stresses are different
w = P/ l

56. Beams
Components
Greater deflection
Greater max. moment
w = P/l

57. Beams – resist bending using Fixed
connection
Components
Gr eat er def l ect i on
Gr eat er max. moment

58. Beams – resist bending using Fixed
connection
Components
Gr eat er def l ect i on
Gr eat er max. moment

59. Beams –Fixed connection
Components

60. Beams –Fixed connection
Components

61. Beams –Fixed connection
Components

62. Beams – stresses
Compression, Tension, Neutral Axis
Concepts
C
N
T

63. Beams – stresses
Compression, Tension, Neutral Axis
Concepts

64. Beams – controlling deflection
Concepts
Factors influencing deflection:
P = load
l= length between supports
E = elastic modulus of material (elasticity)
I = Moment of inertia (depth/weight of beam)
Dmax = Pl 3
/ 48EI

65. Beams – controlling deflection
Elastic modulus – property of material
Concepts
Elastic modulus of materials
Structural Steel = 200 GPa (29,023,300 lb/in2
)
Titanium = 110 GPa (15,962,850 lb/in2
)
Aluminum = 70 GPa (10,158,177 lb/in2
)
Concrete = 21 GPa (3,047,453 lb/in2
)
Douglas Fir = 13 GPa (1,886,518 lb/in2
)
Why are titanium and aluminum used in aircraft?
Density of materials
Structural Steel = 489 lb/ft3
Titanium = 282 lb/ft3
Aluminum = 169 lb/ft3
Concrete = 150 lb/ft3
Douglas Fir = 32 lb/ft3

66. Concepts
Density of materials
Structural Steel = 489 lb/ft3
Titanium = 282 lb/ft3
Aluminum = 169 lb/ft3
Concrete = 150 lb/ft3
Douglas Fir = 32 lb/ft3
Yield Strength of materials
Structural Steel=350-450 MPa
Titanium (Alloy)=900-1400 MPa
Aluminum=100-350 MPa
Concrete=70 MPa
(compressive)
Douglas Fir= N/A
1 lb/in2
= 6891 Pa
Beams – controlling deflection
Elastic modulus – property of material

67. Beams – controlling deflection
Moment of Inertia
Concepts
Moment of Inertia of beam
Dependent on cross-sectional geometry
Not dependent on material properties
Icc = Mo me nt o f i ne r t i a o f a r e c t a ng l e a bo ut
t he ne ut r a l a x i s – i . e . i t ’ s c e nt r o i d =
wi d t h x he i g ht 3
/ 1 2
Ixx = Mo me nt o f i ne r t i a o f a r e c t a ng l e a bo ut
a n a x i s p a r a l l e l t o t he ne ut r a l a x i s = Icc +
wi d t h x he i g ht x ( d i s t a nc e be t we e n a x e s ) 2
Ce nt r o i d = S ( Ar e a x d i s t a nc e t o be nd i ng
a x i s ) / ( To t a l a r e a )

68. Beams – controlling deflection
Moment of Inertia
Concepts

69. Beams – controlling deflection
Truss : Triangulated frame = deep beam
Concepts
Triangulated frame (Truss) – increase depth of beam
Triangulated – all members axially loaded – no moments / no bending

70. Beams – controlling deflection
Truss : Triangulated frame = deep beam
Concepts

71. Frames – simple frames
Components

72. Components
Frames – simple frames

73. Components
Frames – simple frames

74. Components Frames – simple frames – racking due to
lateral load

75. Components Frames – simple frames – racking due to
lateral load

76. Components
Frames – shear panel to prevent racking

77. Components
Frames – shear panel to prevent racking

78. Components
Frames – shear panel to prevent racking

79. Components
Frames – shear panel to prevent racking

80. Components Frames – triangulation to prevent
racking

81. Components Frames – triangulation to prevent
racking

82. Components Frames – triangulation to prevent
racking

83. Frames – Rigid Frame / Moment Frame
Components
Rigid Frame – Vertical load
Reduce deflection: Rigid connection
Columns resist force and deflect

84. Frames – Rigid Frame / Moment Frame
Components
Thrust develops at base of columns
and must be resisted
(beam / foundation / grade beam)

85. Frames – Rigid Frame / Moment Frame
Components
Rigid Frame – Lateral load
Resists racking

86. Frames – Rigid Frame / Moment Frame
Components
Rigid Frame – Lateral load
Resists racking

87. Frames – Rigid Frame / Moment Frame
Components
Rigid Frame – Lateral load
Resists racking

88. Frames – Rigid Frame / Moment Frame
Components
Rigid Frame – Lateral load
Resists racking

89. Cantilver - Simple
Frames
Cantilever
Rigid / Moment connection

90. Cantilver - Simple
Frames

91. Cantilver - Simple
Frames
tension
compression
moment (force-couple)

92. Cantilver – Simple
More bending stress and deflection
than simply supported beam
Frames
Greater deflection
Greater max. moment

93. Cantilver – Backspan
Reduces bending stress and deflection
without rigid connection
Frames
Lesser deflection
Lesser max. moment

94. Cantilver – Backspan
Frames

95. Primary, Secondary, Tertiary structure
Components
Primary Structure:
•Foundations
•Columns or bearing walls
•Beams that attach to
columns or bearing walls
Secondary Structure:
•Beams, joists or slabs that
attach to Primary Structure
Tertiary Structure:
•Beams, joists or slabs that
attach to Secondary
Structure

96. Overview
Funicular Structures
Tensi on ( Cabl e)
Compr essi on ( Ar ch)

97. Cable-suspension
Funicular Structures

98. Tension structures:
May include beams to control curves
Funicular Structures

99. Tension structures:
Rigid elements acting as fabric
Munich Olympic Stadium, Frei Otto
Funicular Structures

100. Inflatable structures
Funicular Structures

101. Inflatable structures
Funicular Structures

102. Arch
Funicular Structures

103. Arch:
La Sagrada Familia inverted
structural model
Funicular Structures

104. Funicular Structures Arch:
La Sagrada Familia inverted
structural model

105. Funicular Structures Arch:
La Sagrada Familia inverted
structural model

106. Thin-shell structures
El Oceonográfico, Valencia:
Felix Candela
Funicular Structures

107. Thin-shell structures:
TWA Terminal JFK Airport, Eero
Saarinen
Funicular Structures

108. CSUN Parking Structure 1994
Bad things

109. World Trade Center 9/11/2001
Bad things

110. World Trade Center 9/11/2001
Bad things

111. Tacoma Narrows
Bad things