Reinforced Concrete Design

What makes Unique of RC…?

It is a COMPOSITE MATERIAL…

  • It requires APPLICATION of more involved Principles of Mechanics…
  • Structural Design is iterative requiring both ANALYSIS and DESIGN DECISIONS aided by judgment and EXPERIENCE.
  • ACI 318 -the model code in the United States of America for guiding the design of RC members, look at Chapter 8.
  • NSCP Code -the code in the Philippines..conforms to the provisions of ACI 318 Code!!!

Important Material Properties…

Concrete Strength and Steel Strength…

  • 28-day Compressive Strength, f’c: ACI 318 Code 2011 edition, Chapter 5.
  • Modulus of Elasticity of Concrete, Ec: ACI 318 Code 2011 edition, Chapter 8.5
  • Strength property or yield strength, fy..
  • Modulus of Elasticity of Steel, Es: 29,000,000 psi –ACI 318 Code 2011 edition.

1. –Procedures on how to Design Reinforced Concrete Beams!!!

Concrete Beam Sizing..!

Beam Section Diagram

Beam Section Diagram

Determination of Beam Size (b x h)—USE Spreadsheet or Hand Calculation!!!

Concrete Beam Size (b x h) or (b x d), FORMULA:

Beam Size Formula

Beam Size Formula

Beam Section, Strain and Force Diagram

Beam Section, Strain and Force Diagram

Equilibrium Equation orm Neutral Axis Distance, c --- Quadratic Equation for c

Equilibrium Equation orm Neutral Axis Distance, c — Quadratic Equation for c

Rebars Determination..

Area of Steel (As) determination!!!

Strength Formula

Strength Formula

As

Rho

The ACI Code 10.3.3 to 10.3.5 limits on the Steel Ratio (rho):

1.1 Minimum Beam Size for which Deflections are NOT LIKELY to be a Problem.

1.1.1 Set Neutral Axis distance, c = 0.375cb….

Beam Size NOT LIKELY TO HAVE DEFLECTIONS

Smallest Beam Size NOT LIKELY TO HAVE DEFLECTION PROBLEM

1.2 Arrangement of Rebars, Splicing points and splice length, development length, hooks requirement, and required Stirrups.

Stirrup Spacing Requirements per ACI

Stirrup Spacing Requirements per ACI

Stirrup Maximum Spacing

Stirrup Maximum Spacing

ACI Bottom Bar Splice Requirements

ACI Bottom Bar Splice Requirements

ACI Standards for Top and Bottom Splice Requirements

ACI Standards for Top and Bottom Splice Requirements

ACI Standards for Beams Reinforcements

ACI Standards for Beams Reinforcements

2. –Procedures on how to Design Reinforced Concrete Columns!!!

Tie Design Standards

Tie Design Standards

ACI Standards Columns Bars Details

ACI Standards Columns Bars Details

ACI Column Splice Details

ACI Column Splice Details

ACI Bar Bending Details

ACI Bar Bending Details

ACI Bar Bending Details

ACI Bar Bending Details

ACI Column Ties Requirements

ACI Column Ties Requirements

2.A. –Structural Design for column using Interaction Diagram!!!

Interaction Diagram

Interaction Diagram plot using Column design software and MS Excel Spreadsheet

 2.B. –Example of ACI Interaction Diagram.

Interaction Diagram-Rectangular Section-Courtesy of ACI

Interaction Diagram-Rectangular Section-Courtesy of ACI

Interaction Diagram-Spiral Column-Courtesy of ACI

Interaction Diagram-Spiral Column-Courtesy of ACI

2.C. –Summary of Column Design Requirements!!!

Column Design Requirements

Column Design Requirements

2.1 Strength Reduction Factor, phi =0.70 -applicable up through ACI 318-1999; they have been changed to phi =0.65, for compression controlled members (columns and beams under compression controls) beginning with ACI 318-2002 Code, and continuing with the ACI 318-05 and 2008 up to present.

3.–Example: Design of Concrete Members, i.e. Frame Analysis, Beams, Columns, Footings using MS Spreadsheet.

FRAME ANALYSIS-My own Spreadsheet Program

FRAME ANALYSIS-My own Spreadsheet Program

MS Excel Spreadsheet for Column

MS Excel Spreadsheet for Column

Column Excel Spreadsheet

Column Excel Spreadsheet

RC BEAMS

RC BEAMS

1-Footing

RC FOOTING1

 

RC FOOTING2

RC FOOTING2

REFERENCES:

  1. Design of Reinforced Concrete by Jack. C. McCormc, 3rd edition-1993, 7th edition-2005, 9th edition-2011;
  2. Design of Concrete Structures by Arthur H. Nilson, 12th edition -1997, International edition;
  3. Design of Concrete Structures by Arthur H. Nilson, 14th edition -2010, International edition;
  4. Reinforced Concrete (A Fundamental Approach), by Edward G. Nawy, 6th edition -2008,
  5. Reinforced Concrete, Mechanics and Design, by James K. Wight and  James G. MacGregor, 6th edition -2012,
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2 thoughts on “Reinforced Concrete Design

  1. Pingback: The Vinton Street elevator was Tillotson Construction’s 1950 hometown showcase « Our Grandfathers' Grain Elevators

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