162

G V P College of Engineering (Autonomous) 2016

Civil Engineering

PRESTRESSED CONCRETE(Professional Elective- II - Online)

Course Code: 15CE1125 L T P C3 0 0 3

Pre-requisites:Strength of materials, Concrete technology, Reinforced ConcreteStructures

Course Outcomes:

At the end of the Course, the Student will be able to:

CO 1 Understand the materials required and pre stressing systems.

CO 2 Calculate the loss of pre-stress and analyse stresses in pre-stressed section

CO 3 Design the section for flexure and shear.

CO 4 Design of end blocks for pre and post tensioned sections

CO 5 Calculate the short term and long term deflections in pre-stressed girders

UNIT-I (10 Lectures)INTRODUCTION :

Historic development – General principles of pre-stressing -pre-tensioning and post tensioning – Advantages and limitations of pre-stressed concrete – Materials – High strength concrete and hightensile steel and their characteristics.

PRESTRESSING METHODS :

I.S.Code provisions, Methods and Systems of Pre-stressing; Pre-tensioning and post tensioning methods – Analysis of post tensioning– Different systems of pre-stressing like Hoyer system, Magnel Blatensystem, Freyssinet system and Gifford Udall System.

Semester - V

163

G V P College of Engineering (Autonomous) 2016

Civil Engineering

UNIT-II (10 Lectures)

LOSSES OF PRESTRESS:

Loss of pre-stress in pre tensioned and post tensioned members dueto various causes like elastic shortage of concrete, shrinkage ofconcrete, creep of concrete, Relaxation of steel, slip in anchoragebending of member and frictional losses.

ANALYSIS OF SECTIONS FOR FLEXURE :

Analysis of sections for flexure; Elastic analysis of concrete beamspre-stressed with straight,Concentric, eccentric, bent and parabolictendons, kern lines.

UNIT- III (10 Lectures)

DESIGN OF SECTIONS FOR FLEXURE AND SHEAR :

Allowable stress, Design criteria as per I.S.Code – Elastic design ofsimple rectangular and I-section for flexure, shear, and principalstresses – design for shear in beams.

UNIT-IV (10 Lectures)

ANALYSIS OF END BLOCKS:

Analysis of end Blocks by Guyon’s method and Mugnel method,Anchorage zone stress – Approximate method of design – Anchoragezone reinforcement – Transfer of pre- stress in pre-tensioned members.

UNIT-V (10 Lectures)

DEFLECTIONS OF PRESTRESSED CONCRETE BEAMS:

Importance of control of deflections – factors influencing deflections– short term deflections of uncracked members, prediction of longterm deflections, stage wise prestressing.

TEXT BOOKS:

1. Krishna Raju N, “Prestressed Concrete”, Tata Mc.Graw HillPublications, 4th Edition, 2007.

2. Rajagopalan. N, “Prestressed Concrete”, Narosa publications,2nd Edition, 2006.

Semester - V

164

G V P College of Engineering (Autonomous) 2016

Civil Engineering

REFERENCES:1. Ramamrutham S., Prestressed Concrete, Dhanpatrai

Publications, 4th Edition, 2006.

2. Lin T.Y. & Ned H. Burns, “Design of Prestressed ConcreteStructures”, John Wiley & Sons, 3rd Edition, 2004.

3. All the relevant codes.

Semester - V