• • • • • • 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): • • • • • • • • • 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 4 Course Outline • • • • • • • • • • • • • • • • • • • • • • • • 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 • • • • • • • • • • • • • • • • • • • • • 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 Only 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 • • • • • • • • • • • • • • • • • • • • • • • • 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 • • • • • • • • • • • • • • 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 7 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 • • • • • 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 15 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 16 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 21