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| Title: | Pre-stressed Concrete Structures |
| Department: | Civil Engineering |
| Author: | Prof. Devdas Menon , Prof. Amlan Kumar Sengupta |
| University: | IIT Madras |
| Type: | WebLink |
| Abstract: | Module 1: Introduction, Prestressing Systems and Material Properties (7 Hours)
Topic
Hours
Basic Concept
Early Attempts of Prestressing
Brief History
Development of Building Materials
1
Definitions
Advantages of Prestressing
Limitations of Prestressing
Types of Prestressing
• Source of prestressing force
• External or internal prestressing
• Pre-tensioning or post-tensioning
• Linear or circular prestressing
• Full, limited or partial prestressing
• Uniaxial, biaxial or multiaxial prestressing
1
Prestressing Systems and Devices
Pre-tensioning
• Introduction
• Stages
Advantages
Disadvantages
Devices
• Jacks
• Anchoring devices
• Harping devices
1
Post-tensioning
• Introduction
• Stages
Advantages
Disadvantages
Devices
• Anchoring devices
• Sequence of anchoring
• Jacks
• Couplers
• Grouting
1
Constituents of Concrete
• Introduction
• Aggregate
• Cement
• Water
• Admixtures
Hardened Concrete
• Strength of concrete
• Stiffness of concrete
• Durability of concrete
• High performance concrete
• Allowable stresses in concrete
1
Hardened Concrete
• Stress-strain curves for concrete
• Creep of concrete
• Shrinkage of concrete
Properties of Grout
Codal Provisions
1
Prestressing Steel
• Introduction
• Forms of prestressing steel
• Types of prestressing steel
• Properties of prestressing steel
• Stress-strain curves for prestressing steel
• Relaxation of steel
• Durability
• Fatigue
Codal Provisions
1
Module 2: Losses in Prestress (3 Hours)
Topic
Hours
Notations
• Geometric properties
• Load variables
Losses in Prestress
• Elastic shortening
• Pre-tensioned axial members
• Pre-tensioned bending members
• Post-tensioned axial members
• Post-tensioned bending members
1
Losses in Prestress (Part I)
• Friction
• Anchorage slip
Force Variation Diagram
1
Losses in Prestress (Part II)
• Creep of concrete
• Shrinkage of concrete
• Relaxation of steel
Total Time-dependent Loss
1
Module 3: Analysis of Members (6 Hours)
Topic
Hours
Analysis of Members Under Axial Load
• Introduction
• Analysis at transfer
• Analysis at services loads
• Analysis of ultimate strength
• Analysis of behavior
1
Analysis of Member Under Flexure (Part I)
• Introduction
Analysis at Service Loads
• Based on stress concept
• Based on force concept
• Based on load balancing concept
1
Analysis of Member Under Flexure (Part II)
• Cracking moment
• Kern point
• Pressure line
1
Analysis of Member Under Flexure (Part III)
Analysis for Ultimate Strength
• Variation of stress in steel
• Condition at ultimate limit state
Analysis of Rectangular Sections
1
Analysis of Flanged Sections
1
Analysis of Partially Prestressed Sections
Analysis of Un-bonded Post-tensioned Beams
Analysis of Behaviour
1
Module 4: Design of Members (6 Hours)
Topic
Hours
Design of Members
• Calculation of demand
Design of members for Axial Tension
• Design of prestressing force
• Analysis of ultimate strength
Design of Member for Flexure
• Calculation of moment demand.
• Preliminary design
1
Design of Sections for Flexure (Part I)
• Final design
• Final design for type 1 members
• Special case
1
Design of Sections for Flexure (Part II)
• Final design of type 2 members
1
Design of Sections for Flexure (Part III)
• Choice of sections
• Determination of limiting zone
• Post-tensioning in stages
1
Design of sections for Flexure (Part IV)
• Magnel’s graphical method
1
Detailing Requirements for Flexure
Detailing Requirements for Shear
Detailing Requirements for Torsion
1
Module 5: Analysis and Design for Shear and Torsion (6 Hours)
Topic
Hours
Analysis for Shear
• Introduction
• Stress in an uncracked beam
• Types of cracks
• Components of shear resistance
• Modes of failure
• Effect of prestressing force
1
Design for Shear (Part I)
• Limit state of collapse for shear
• Maximum permissible shear stress
• Design of transverse reinforcement
• Detailing requirement for shear
1
Design for Shear (Part II)
• General comments
• Design steps
• Design of stirrups for flange
1
Analysis for Torsion
• Introduction
• Stresses in an uncracked beam
• Crack pattern under pure torsion
• Components of resistance for pure torsion
• Modes of failure
• Effect of prestressing force
1
Design for Torsion (Part I)
• Limit state of collapse for torsion
• Design of longitudinal reinforcement
• Design of transverse reinforcement
1
Design for Torsion (Part II)
• Detailing requirements
• General comments
• Design steps
1
Module 6: Calculations of Deflection and Crack Width (1 Hour)
Topic
Hours
Calculation of Deflection
• Deflection due to gravity loads
• Deflection due to prestressing force
• Total deflection
• Limits of deflection
• Determination moment of inertia
• Limits of span-to-effective depth ratio
Calculation of Crack Width
• Method of calculation
• Limits of crack width
1
Module 7: Transmission of Prestress (2 Hours)
Topic
Hours
Transmission of Prestress (Part I)
• Introduction
• Pre-tensioned members
Transmission length
Development length
End zone reinforcement
1
Transmission of Prestress (Part II)
• Post-tensioned members
End zone reinforcement
Bearing plate
1
Module 8: Cantilever and Continuous Beams (3 Hours)
Topic
Hours
Cantilever Beams
• Introduction
• Analysis
• Determination of limiting zone
• Cable profile
1
Continuous Beams (Part I)
• Introduction
• Analysis
• Incorporation of moment due to reactions
• Pressure line due to prestressing force
1
Continuous Beams (Part II)
• Concordant cable profile
• Cable profiles
• Partially continuous beams
• Analysis at ultimate limit state
• Moment redistribution
1
Module 9: Special Topics (6 Hours)
Topic
Hours
Composite Sections
• Introduction
• Analysis of composite sections
• Design of composite sections
• Analysis for horizontal shear transfer
1
One-way Slabs
• Introduction
• Analysis and design
1
Two-way Slabs (Part I)
• Introduction
• Analysis
• Features in modeling and analysis
• Distribution of moments to strips
1
Two-way Slabs (Part II)
• Checking for shear capacity
• Spandrel beams
• Anchorage devices
• Additional aspects
1
Compression Members
• Introduction
• Analysis
• Development of interaction diagram
• Effect of prestressing force
1
Circular Prestressing
• Introduction
• General analysis and design
• Prestressed concrete pipes
• Liquid storage tanks
• Ring beams
Conclusion |
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