3 RCD_Chapter 1 Introduction.pdf
- 1. CE 322 PRINCIPLES OF REINFORCED CONCRETE DESIGN INSTRUCTOR: KRISTINE MAY MATURAN, CE COR JESU COLLEGE, INC. COLLEGE OF ENGINEERING AND TECHNOLOGY
- 2. Reference: CASTRO, M. J. B. (2022). SIMPLIFIED REINFORCED CONCRETE DESIGN: BASED ON THE NATIONAL STRUCTURAL CODE OF THE PHILIPPINES 2015. GILLESANIA, D. I. T. (2013). SIMPLIFIED REINFORCED CONCRETE DESIGN: 2010 NSCP.
- 3. Course Outline 1. Introduction to reinforced concrete 2. Analysis and design of beams for flexure (Strength design method) 3. Analysis and design of T-beams and doubly-reinforced beams 4. Serviceability requirements 5. Shear in beams 6. Torsion 7. Short columns 8. Long/slender columns 9. Special provisions for seismic design and detailing (NSCP 2015 Section 418) 10. Bond, development length, hooks, and splicing of reinforcement 11. Analysis and design of one-way slabs 12. Analysis and design of two-way slabs 13. Alternate design method (Working stress design)
- 4. Chapter 1 - Introduction to Reinforced Concrete
- 5. 1. Introduction to Reinforced Concrete •Concrete and Reinforced Concrete Components ◦ Cement ◦ Concrete ◦ Reinforced concrete ◦ Aggregates ◦ Water ◦ Reinforcing Steel Bars
- 6. 1. Introduction to Reinforced Concrete •Concrete is a mixture of sand, gravel, crushed rock, or other aggregates held together in a rocklike mass with a paste of cement and water. Sometimes one or more admixtures are added to change certain characteristics of the concrete such as its workability, durability, and time of hardening. •Reinforced concrete is a combination of concrete and steel wherein the steel reinforcement provides the tensile strength lacking in the concrete. •CEMENT AND WATER ◦ Used in binding aggregates (sand and gravel) ◦ Water/cement ratio greatly affects the strength of concrete •CURING OF CONCRETE ◦ Curing is performed by submerging the specimen underwater. This is done in order to prevent moisture loss. Rapid moisture loss leads to cracking and loss of strength of the concrete specimen •Note : Ideally, the maximum strength of concrete is attained at the 28th day of curing.
- 7. 1. Introduction to Reinforced Concrete •Advantages of using Concrete 1. Strong in compression 2. High resistance to actions of fire and water 3. Very rigid 4. Requires less maintenance 5. Very long service life 6. Very widely available 7. Castable to any shape and dimensions •Disadvantages of using Concrete 1. Very low tensile strength 2. Requires forms and shoring 3. Relatively low strength per unit weight or volume 4. Properties of concrete vary
- 8. 1. Introduction to Reinforced Concrete •Design code and specification ◦ Design codes provide detailed technical standards and are used to establish the requirements for the actual structural design. It should be realized, however, that codes provide only a general guide for design. •Notations and Symbols
- 9. 1. Introduction to Reinforced Concrete •Concrete design properties ◦ Specified compressive strength
- 10. 1. Introduction to Reinforced Concrete ◦ Minimum spacing of reinforcement ◦ Bundled reinforcement (refer to Section 425.6) 25 mm in ACI 318
- 11. 1. Introduction to Reinforced Concrete •Section 425.6
- 12. 1. Introduction to Reinforced Concrete
- 13. 1. Introduction to Reinforced Concrete
- 14. 1. Introduction to Reinforced Concrete ◦ Specified concrete cover requirements
- 15. 1. Introduction to Reinforced Concrete
- 16. ◦ Strength reduction factors 1. Introduction to Reinforced Concrete
- 17. 1. Introduction to Reinforced Concrete •Loads and load combinations 1. Dead loads 2. Live loads 3. Environmental loads
- 18. 1. Introduction to Reinforced Concrete •Arrangement of reinforcing bars for most efficient rectangular beam section bmin = 2cc + 2ds + ndb + n − 1 sc where: cc= concrete cover ds=diameter of stirrup db= bar diameter sc = clear spacing between the longitudinal bars n = number of longitudinal bars
- 19. Example •1. Draw the details of the most efficient beam in terms of flexure if the beam is cast in place, non- prestressed and not exposed to weather or in contact with the ground. Beam section: 250 mm x 360 mm reinforced with 10 mm stirrups and 6- 16 mm longitudinal bottom bars.
- 20. Example •2. Draw the details of the most efficient beam in terms of flexure if the beam is cast in place, non- prestressed and not exposed to weather or in contact with the ground. Beam section: 280 mm x 480 mm reinforced with 10 mm ϕ stirrups, area of required steel reinforcement, As = 3122 mm2. Bending moment is negative. Used 20 mm ϕ longitudinal bars. Vertical spacing between the layers of bars should be 25 mm minimum.
- 21. End of Chapter 1