JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Pre-requisites

Reinforced Concrete Design & Structural Analysis.

Course Objectives:

• 1. To critically review the techniques of pre-stressing both Pre-tensioning and Post-tensioning
• 2. To design the pre-stressed concrete members for ultimate limit state and limit state of serviceability
• 3. To realize the importance of the Statically Indeterminate structures and Load Balancing •
• 4. To analyze and design continuous pre-stressed concrete beams with bent cables having straight and parabolic profiles

Course Outcomes

After completion of the course, students should be able to

• 1. Realize the importance of pre-stressing the long span structures and heavily loaded members
• 2. Acquire the knowledge of various pre-stressing techniques; their merits and demerits
• 3. Develop skills in planning, analysis and design of pre-stressed concrete beams, and slabs
• 4. Develop skills to satisfy the serviceability and strength provisions of the Indian Standards (IS:1343-2012)

UNIT - I

Introduction – Prestressing Systems – Pre-tensioning Systems – Post-tensioning Systems – High Strength Steel and Concrete - Analysis of Prestress - Resultant Stresses at a Section – Pressure Line or Thrust Line – Concept of Load Balancing. Losses of Prestress – Loss Due to Elastic Deformation of Concrete – Shrinkage of Concrete – Creep – Relaxation of Stress in Steel – Friction – Anchorage Slip.

UNIT - II

Deflections of Prestressed Concrete Members: Importance of Control of Deflections – Factors Influencing Deflection – Short-term Deflections of Uncracked Members – Prediction of Long-time Deflections – Deflections of Cracked Members – Requirements of IS 1343-2012. Ultimate Flexural Strength of Beams: Introduction, Flexural theory using first principles – Simplified Methods – Ultimate Moment of Resistance of untensioned Steel.

UNIT - III

Composite Constructions: Introduction, Advantages, Types of Composite Construction, Analysis of Composite beams- Differential shrinkage- Ultimate Flexural and shear strength of composite sections- Deflection of Composite Beams. Design of Composite sections.

UNIT - IV

Prestressed Concrete Slabs: Types Of Prestressed Concrete Floor Slabs- Design of Prestressed Concrete One Way and Two Way Slabs. Prestressed Concrete Pipes: Circular prestressing- Types of Prestressed Concrete Pipes- Design of Prestressed Concrete Pipes.

UNIT - V

Continuous Beams: Advantage of Continuous Members – Effect of Prestressing Indeterminate Structures – Methods of Achieving Continuity – Methods of Analysis of Secondary Moments – Concordant Cable Profile – Guyon’s Theorem, Redistribution of moments in a continuous beam. Anchorage Zone Stresses in Beams: Introduction, Stress distribution in End Block – Anchorage zone stresses –Magnel’s method- Guyon’s Method - Anchorage zone Reinforcement as per IS1343-2012.

REFERENCES:

• 1. Prestressed concrete, Krishnanraju N., Tata Mc Graw Hill, New Delhi.
• 2. Prestressed concrete by K.U. Muthu, PHI Learning Pvt. Ltd
• 3. Design of prestressed concrete structure, Lin T. Yand Burns, Asia Publication house, 1995.
• 4. Limit state design of prestressed concrete, Gutan Y, Applied science publishers, 1972.
• 5. IS:1343-2012-code of practice for Prestressed concrete M. Tech in COMPUTER AIDED STRUCTURAL ENGINEERING I YEAR II – SEMESTER