reinforced concrete design column interaction diagram

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CE514D2-REINFORCED CONCRETE DESIGN

TO DISCUSS HOW THE COLUMN INTERACTION DIAGRAM WAS MADE.

TO DISCUSS THE IMPORTANT POINTS OF THE DIAGRAM.

TO DISCUSS HOW IT IS BEING USED.

COLUMN INTERACTION DIAGRAM

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The COLUMNCOLUMNCOLUMNCOLUMN STRENGTHSTRENGTHSTRENGTHSTRENGTH INTERACTIONINTERACTIONINTERACTIONINTERACTION

DIAGRAMDIAGRAMDIAGRAMDIAGRAM is a curve plot of points; where

each point has two ordinates. The first

ordinate is bending moment strength and

the second is the corresponding axial force.

Both ordinates are linked with eccentricity.

The shape of the curve, or the strength

interaction diagram, can be defined by

finding the ordinates of major seven points.



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Point 1: axial compression at zero moment.

Point 2: maximum axial compression load permitted by code at zero eccentricity.

Point 3: maximum moment strength at the maximum axial compression load permitted by

code.

Point 4: compression and moment strength at zero strain in the tension side reinforcement.

Pont 5: compression and moment strength at 50% strain in the tension side reinforcement.

Point 6: compression and moment strength at balanced conditions.

Point 7: moment strength at zero axial force.



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Concrete crushes before steel yields

Steel yields before concrete crushes

Note: Any combination of P and M outside the envelope will cause failure.



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Point 1 Axial Compression at Zero Moment

Point 2 Maximum Permissible Axial Compression at Zero

Eccentricity

TIED SPIRAL


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Point 3 Maximum Moment Strength at Maximum Permissible Compression


Fv = 0

M = 0


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Point 4 Axial Compression and Zero Moment at

Zero Strain


Point 5 Axial Compression and Moment Strength at

50% Strain


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Point 6 Axial Compression and Moment Strength at

Balanced Conditions


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Point 7 Moment Strength at Zero Axial Force


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DESIGN USING NONDESIGN USING NONDESIGN USING NONDESIGN USING NON----DIMENSIONAL DIMENSIONAL DIMENSIONAL DIMENSIONAL

INTERACTION DIAGRAMSINTERACTION DIAGRAMSINTERACTION DIAGRAMSINTERACTION DIAGRAMS

1. Calculate factored loads (Pu , Mu ) and e for relevant load combinations2. Select potentially governing case(s)3. Use estimate h to calculate h, e/h for governing case(s)4. Use appropriate chart (App. A) target g

(for each governing case)5. Select

n

c g

Pf A

u cg

n

c g

P fAP

f A

=

Read Calculate required


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6. If dimensions are significantly different from estimated (step 3), recalculate ( e / h ) and redo steps 4 & 5. Revise Ag if necessary.

7. Select steel gst AA =

8. Using actual dimensions & bar sizes to check all load combinations ( use charts or exact: interaction diagram).9. Design lateral reinforcement.



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StrunetReinforced Concrete, Mechanics and Design ( Fourth Edition )

( James MacGregor, James K. Wight)Fundamentals of Reinforced Concrete ( Gillesania )books.google.com.ph/www.tcd.ie/civileng/Staff/Biswajit.Basu/3A2/3A2LEC16.pdfwww.philjol.info/index.php/JRSCE/article/viewPDFInterstitial/.../580www.tpub.com/content/NAVFAC/.../dm2_080107.htm


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reinforced concrete design column interaction diagram

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