0.TheoryIntro

0.TheoryIntro - Formation of Structures Bars → trusses...

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Unformatted text preview: Formation of Structures Bars → trusses Theory and Design of Structures I Elementary Theory of Structures Seawall Blocks → walls Other examples: Brick walls Pyramids, etc. The design process Classification Classification Loading Department of Civil Engineering The University of Hong Kong 1 Loading Superimposition Department of Civil Engineering The University of Hong Kong 2 Actual and Idealized Structures Actual and Idealized Structures Actual and Idealized Structures Supports and Reactions Hinge support Supports and Reactions Roller support R β Department of Civil Engineering The University of Hong Kong 3 Supports and Reactions Fixed support Supports and Reactions Clamped roller support Supports and Reactions Elastic support Pin joint or hinge joint Joints Joints Rigid joint External Forces Department of Civil Engineering The University of Hong Kong 4 Internal Forces Internal Forces Internal Forces Free Body Diagrams Overall Rigid Body Stability and External Determinacy of a Planar Structure 2 reaction components: Unstable Geometrically Stable Structure • A structure is geometrically stable if for any incipient movement, a resistance to this movement is developed. • This requires the presence of at least three non-concurrent non-parallel forces. • A structure that has sufficient number of reactions but incorrectly placed for stability is geometrically unstable. 3 reaction components: Stable and statically determinate 4 reaction components: Stable and statically indeterminate to the first degree No. of redundant components of reaction = degree of statical indeterminacy Note that there are 3 equations of equilibrium for planar structures. Department of Civil Engineering The University of Hong Kong 5 Geometric Instability Equations of Condition External Determinacy r<c+3 r=c+3 r>c+3 Unstable Determinate (provided there is no geometric instability) Indeterminate Two-force members Geometrically Stable Structure The End Department of Civil Engineering The University of Hong Kong 6 ...
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This note was uploaded on 12/01/2010 for the course CIVL 2007 taught by Professor Profchai during the Spring '10 term at HKU.

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