CE 5510 - 2004
CE 5510
Advanced Structural Concrete Design
CE 5510 - 2004
Slender Column Design
Braced Slender ColumnDesign MomentsUnbraced Slender ColumnsAdjustments to Additional Moments
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Class Objectives
•Explain the effect of second order moments on axial force-moment interaction diagram
•Identify a column as slender (or not) Slender means that slenderness effects are to be considered as per code of practice.
•Determine the design moments for a slender column.
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Recommended Reading• James G. MacGregor, “REINFORCED CONCRETE:
Mechanics and Design”, 3rd Ed., Prentice-Hall, 1997, Ch. 12.
• Allen, A. H., “REINFORCED CONCRETE DESIGN TO BS8110 SIMPLY EXPLAINED”, E&FN Spon,
London 1988, Ch. 11• David A. Fanella, “Time-saving design aids for
reinforced concrete, Part 3: Column and walls”, STRUCTURAL ENGINEER, November 2001, pp 42-47.
The next few slides are from the Reinforced Concrete Council
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Introduction
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N – M Relationship (BS 8110)
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N – M Relationship (BS 8110)
Do you know why you can design for flexure only ifthe axial force is less than 0.1 fcuAc ?
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Design Charts for symmetrically reinforced rectangular cross-sections
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What is Buckling?
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What is buckling?
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What is Buckling?
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Slenderness Effects in Structures
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Classification of Structures
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Effective Length
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Effective Length
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Effective Length
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Effective Length (BS 8110)
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Effective Length
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Slenderness Ratio
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Slenderness Ratio
Bending and Axial Load
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Design Methods
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Design Methods
course
This is covered in detail later.
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Simplified Design Method
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Simplified Design Method
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Simplified Design Method
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Braced
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Simplified Design Method
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Simplified Design Method
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Simplified Design Method
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Bending about Both Axes
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Bending about Both Axes
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Bending about Both Axes
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Example: Calculate the area of steel required in the braced column
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ExampleA. H. Allen, pp 113-115
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Example: Slender Braced Column (Allen)
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BS 8110 : 1985
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Slender Beams