Verify Account

UNIT-I

Introduction

Historic development – General principles of prestressing pretensioning and post tensioning – Advantages and limitations of prestressed concrete – General principles of PSC – Classification and types of prestressing – Materials – High strength concrete and high tensile steel their characteristics.

UNIT-II

Methods and Systems of Prestressing

Pretensioning and posttensioning methods and systems of prestressing like Hoyer system, Magnel Blaton system, Freyssinet system and Gifford – Udall system – Lee McCall system. Losses of Prestress :Loss of prestress in pretensioned and post-tensioned members due to various causes like elastic shortage of concrete, shrinkage of concrete, creep of concrete, relaxation of stress in steel, slip in anchorage, frictional losses. IS 1343 - 2012 code provisions.

UNIT-III

Flexure

Analysis of sections for flexure - beams prestressed with straight, concentric, eccentric, bent and parabolic tendons – stress diagrams – Elastic design of PSC slabs and beams of rectangular and I sections – Kern line – Cable profile and cable layout.

Shear

General considerations – principal tension and compression – Improving shear resistance of concrete by horizontal and vertical prestressing and by using inclined or parabolic cable – Analysis of rectangular and I beams for shear – Design of shear reinforcements – IS code provisions.

UNIT-IV

Transfer of Prestress in Prtensioned Members

Transmission of prestressing force by bond – Transmission length – Flexural bond stresses – IS code provisions – Anchorage zone stresses in post tensioned members – stress distribution in End block – Analysis by Guyon, Magnel, Zielinski and Rowe’s methods – Anchorage zone reinforcement – IS 1343-2012 code provisions.

UNIT-V

Composite Beams

Different Types – Propped and Unpropped – stress distribution – Differential shrinkage – Analysis of composite beams – General design considerations.

Deflections

Importance of control of deflections – Factors influencing deflections – Short term deflections of uncracked beams – prediction of long time deflections – IS code requirements.