Tru Truss Desi Desig gn Consi Consid deration ions
Truss Design Considerations
Truss Design Considerations Design Design Implic ations Considering the Effects of Loading, Member Orientation Orientation and Support
Effect of tension vs. compression on member sizes Potential buckling failure modes and approaches to preventing Potential for stress reversal Overall lateral stability (lateral-torsional buckling) Member redundancy: Determinate vs. Indeterminate Trusses
Truss Design Considerations Effect of tension vs. compression on member sizes Potential buckling failure modes and approaches to preventing Potential for stress reversal Member redundancy: Determinate vs. Indeterminate Trusses Overall lateral stability (lateral-torsional buckling) Truss Pedestrian Bridge
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Truss Design Considerations
Munich Airport Pedestrian Bridge
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Truss Design Considerations Effect of tension vs. compression on member sizes Potential buckling failure modes and approaches to preventing Potential for stress reversal Member redundancy: Determinate vs. Indeterminate Trusses Overall lateral stability (lateral-torsional buckling) Truss Member Buckling Considerations (Schodek fig. 4.28)
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Truss Member Buckling Considerations (Schodek fig. 4.29)
Truss Pedestrian Bridge, Greece
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Truss Design Considerations
Theoretical zero force members that provide buckling resistance to top chord
Truss Design Considerations Effect of tension vs. compression on member sizes Potential buckling failure modes and approaches to preventing Potential for stress reversal Member redundancy: Determinate vs. Indeterminate Trusses Overall lateral stability (lateral-torsional buckling)
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Variations in Truss Member Forces (Schodek fig. 4.23)
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Variations in Truss Member Forces (Schodek fig. 4.23)
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Truss Design Considerations
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Truss Design Considerations Effect of tension vs. compression on member sizes Potential for stress reversal Potential buckling failure modes and approaches to preventing Overall lateral stability (lateral-torsional buckling) Member redundancy: Determinate vs. Indeterminate Trusses Truss Lateral Buckling (Schodek fig. 4.30)
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Methods of Providing Resistance to Truss Lateral Buckling (Schodek fig. 4.31)
Kansai International Airport, Japan , Renzo Piano
Truss Design Considerations Effect of tension vs. compression on member sizes Potential for stress reversal Potential buckling failure modes and approaches to preventing Overall lateral stability (lateral-torsional buckling) Member redundancy: Determinate vs. Indeterminate Trusses
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Truss Design Considerations
Illustrations: Daniel L. Schodek: Structures, fifth
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
edition; Pearson Prentice-Hall, 2004
Truss Stability & Determinacy
Truss Stability & Determinacy
(Schodek fig. 4.18)
(Schodek fig. 4.18)
Illustrations: Daniel L. Schodek: Structures, fifth
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
edition; Pearson Prentice-Hall, 2004
Truss Stability & Determinacy Truss Stability & Determinacy
(Schodek fig. 4.05)
(Schodek fig. 4.18)
Illustrations: Daniel L. Schodek: Structures, fifth
edition; Pearson Prentice-Hall, 2004
Truss Determinacy Formula n = 2j – 3
for determinacy
n = Number of truss bars j = Number of joints
n > 2j -3 n < 2j -3
indeterminate unstable
n =9, j =6 2(6)-3=9 =9 O.K. n =11, j =7 2(7)-3=11 =11 O.K.
n =8, j =6 2(6)-3=9 >8
Unstable!
∴
n =10, j =6 2(6)-3=9 <10 indeterminate, but stable
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Truss Design Considerations
Truss Connection Considerations (Onouye fig. 10.2)
Truss Assembly Details
Illustration Source: http://www.ce.berkeley.edu/~boza/courses/cee122/lectures/lecture2/connect-brace.jpg
Truss Connection Considerations
Connection Eccentricity Produces Moment — P edestrian Bridge in Greece
Illustration Source: http://www.ce.berkeley.edu/~boza/courses/cee122/lectures/lecture2/connect-brace.jpg
Truss Connection Considerations
K nife-Plate Connections — Cutler Anderson Architects
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Truss Design Considerations
Grace Episcopal Church, Bainbridge Island, WA — Cutler Anderson Architects
Capitol Hill Library, Seattle, WA — Cutler Anderson Architects
Curvilinear façade supported by 3D linear truss framework: Band Shell, Millennium Park, Chicago, IL — Frank O. Gehry
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Truss Design Considerations
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