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Week 1 Lec 1-Introduction to Reinforced Concrete-PPT

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CE305 Reinforced Concrete Design I
Course Duration: One Semester
Credit Units: 3-0
Level: 6th Semester, 3rd Year
Prerequisites: None
Instructor: Dr. Shahid Iqbal (Email: shahid.civil@suit.edu.pk)
• Course Objectives:
• To develop understanding among students to the fundamental concepts of
Reinforced Concrete Design, properties of hardened concrete, design
philosophies, codes of practice, loads, & safety provisions.
• To enable students to comprehend the analysis & design of rectangular, T,
& L shaped sections, one-way slabs, axially loaded columns, shear &
diagonal tension, deflection, & control of Cracking.
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
1
Course Learning Outcomes (CLOs)
• Demonstrate concepts of Reinforced Concrete
Design, design philosophies, loads, & safety
provisions. (C4) (PLO1) (PLO2)
• Analyze and Design rectangular, T, and L shaped
sections in bending. (C6) (PLO1) (PLO2) (PLO3)
• Analyze and Design one-way slabs and axially
loaded columns. (C6) (PLO1) (PLO2) (PLO3)
• Analyze and Design for shear and calculate
deflections and crack widths accurately. (C6) (PLO1)
(PLO2) (PLO3)
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
2
Teaching & Learning Activities (TLAs):
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Video presentations
Solved examples
In-class activities
Classroom discussions
Homework assignments
Quizzes
Take-home tests
Mid-term major examination
Final comprehensive examination
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
3
Assessment
• Quizzes, homework assignments, and take-home
tests = 25 %
• Mid-term major examination = 25 %
• Final comprehensive examination= 50 %
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
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Course Outline
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1. Introduction
Structural Concrete
Advantages & Disadvantages of Reinforced Concrete
Codes of Practice
Design Philosophy & Concepts
Loads & Safety Provisions
Structural Concrete Elements
Structural Reinforced Concrete Design
2. Properties of Concrete
Factors Affecting Strength of Concrete
Compressive Strength
Stress–Strain Curves of Concrete
Tensile Strength of Concrete
Flexural Strength (Modulus of Rupture) of Concrete
Shear Strength & Modulus of Elasticity of Concrete
Poisson’s Ratio & Shear Modulus
Modular Ratio & Volume Changes of Concrete
Creep & Shrinkage of Concrete
Unit Weight of Concrete
Fire Resistance of Concrete
High-Performance Concrete
Lightweight Concrete & Fibrous Concrete
Steel Reinforcement
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3. Flexural Analysis of Reinforced Concrete Beams
Introduction & Assumptions
Behavior of Simply Supported Reinforced Concrete
Beam Loaded to Failure
Types of Flexural Failure & Strain Limits
Load Factors & Strength Reduction Factor 𝜙
Significance of Analysis & Design Expressions
Equivalent Compressive Stress Distribution
Singly Reinforced Rectangular Section in Bending
Lower Limit or Minimum Percentage of Steel
Adequacy of Sections
Sections in the Transition Region (𝜙 < 0.9)
Rectangular Sections with Compression
Reinforcement
Analysis of T Sections
Dimensions of Isolated T-Shaped Sections
Inverted L-Shaped Sections
4. Flexural Design of Reinforced Concrete Beams
Rectangular Sections with Tension Reinforcement
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Spacing of Reinforcement & Concrete Cover
Rectangular Sections with Compression
Reinforcement
Design of T-Sections
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
5
Course Outline
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5. Shear & Diagonal Tension
Shear Stresses in Concrete Beams
Behavior of Beams without Shear Reinforcement
Moment Effect on Shear Strength
Beams with Shear Reinforcement
ACI Code Shear Design Requirements
Design of Vertical Stirrups
6. Deflection & Control of Cracking
Deflection of Structural Concrete Members
Instantaneous Deflection
Long-Time Deflection
Allowable Deflection
Deflection Due to Combinations of Loads
Cracks in Flexural Members
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8. One-Way Slabs
Types of Slabs
Design of One-Way Solid Slabs
Design Limitations According to ACI Code
Temperature & Shrinkage Reinforcement
Reinforcement Details
Distribution of Loads from One-Way Slabs to
Supporting Beams
9. Axially Loaded Columns
Types of Columns
Behavior of Axially Loaded Columns
ACI Code Limitations
Spiral Reinforcement
Design Equations
7. Development Length of Reinforcing Bars
Development of Bond Stresses
Development Length in Tension
Development Length in Compression
Critical Sections in Flexural Members
Standard Hooks (ACI Code, Sections 25.3 & 25.4)
Splices of Reinforcement
Moment–Resistance Diagram (Bar Cutoff Points)
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
6
Recommended books
• M. Nadim Hassoun & Akthem Al-Manaseer, Structural
Concrete: Theory & Design, 6/e, 2015, ISBN
9781118767818, John Wiley & Sons (required)
• James K. Wight, Reinforced Concrete: Mechanics &
Design, 7/e, 2015, ISBN 013348596X, ISBN
9780133485967, Pearson Prentice Hall
• Jack C. McCormac & Russell H. Brown, Design of
Reinforced Concrete, 10/e, 2015, ISBN 978
1118879108, ISBN 1118879104, John Wiley & Sons
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
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Introduction to Reinforced Concrete
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
8
Concrete and Reinforced Concrete
• Concrete – a mixture of fine aggregate (sand), coarse
aggregate, cement, water and admixtures.
• Admixtures are materials, other than cement,
aggregate and water, that are added to concrete
either before or during its mixing to alter its
properties, such as workability, curing temperature
range, set time or color.
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
9
Concrete and Reinforced Concrete
• Concrete has high compressive strength and low
tensile strength
• Reinforced concrete is a combination of concrete and
steel. The reinforcing steel is used to resist tension
• Reinforcing steel can also be used to resist
compression (columns)
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
10
Advantages of Reinforced Concrete
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High compressive strength relative to unit cost
High resistance to effects of fire and water
Reinforced concrete structures have high stiffness
Low maintenance cost
Reinforced concrete structures have a long service
life
• Reinforced concrete is often the only economical
material for footings, floor slabs, basement walls and
piers
• Reinforced concrete offers architectural flexibility
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
11
Advantages of Reinforced Concrete
• Reinforced concrete uses local materials for
aggregate, and only small amounts of cement and
steel, which are items that may not be available
locally
• Labor skills are not as high for reinforced concrete
construction, when compared to some other
common materials, such as structural steel
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
12
Disadvantages of Reinforced Concrete
• Concrete has a low tensile strength, requiring use of
reinforcing steel
• Forms are required to hold the concrete until it
hardens. In addition, falsework may be necessary.
Formwork and falsework are expensive
• Concrete has relatively low strength when compared
to its unit weight
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
13
Disadvantages of Reinforced Concrete
• High unit weight translates into large dead load and
corresponding increase in bending moment
• Concrete beams are relatively large, which leads to,
for example, larger story heights and taller buildings
• Concrete properties can vary widely depending on
proportioning, mixing and curing
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
14
Codes
• Building Code Requirements for Structural Concrete
(ACI 318-08)
• ASCE/SEI 7-10
• Eurocode and DIN
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
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Portland Cement
• Type I – common, all-purpose cement
• Type II – low heat of hydration and some resistance
to sulfates
• Type III – high, early strength; high heat of hydration
• Type IV – low heat of hydration
• Type V – used for concrete with exposure to high
concentration of sulfates
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
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Air-Entraining Admixtures
• Air-entraining admixtures produce small air bubbles
in the concrete
• On freezing water expands without creating internal
pressure in the concrete
• Concrete without entrained air will deteriorate due
to freeze-thaw cycles
• Important for bridge decks and other concrete
members exposed to freeze-thaw cycles
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
17
Accelerators
• Accelerating admixtures, such as calcium chloride,
reduce curing time
• Calcium chloride can cause corrosion in reinforcing
steel, aluminum and other materials
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
18
Set Retarders
• Retarding admixtures slow the rate of set of concrete
and reduce temperature increase
• Retarding admixtures are useful when a large
amount of concrete is to be placed and it is
important to reduce temperature
• Retarding admixtures prolong the plasticity of the
concrete, increasing the bond between successive
pours
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
19
Water Reducers
• Plasticizers and Superplasticizers
• Superplasticizers are made from organic sulfates
• Superplasticizers maintain workability with reduced
water/cement ratio (usually using less cement)
• Superplasticizers are used to produce selfconsolidating concrete (SCC)
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
20
Thank You
Reinforced Concrete Design –I by Dr. Shahid Iqbal, Department of Civil Engineering,
Sarhad University of Science and IT, Peshawar, Pakistan
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