Precast and Prestressed Concrete

Week 1: Introduction to Precast Concrete and Prestressed Concrete

• Introduction to precast and prestressed systems – Overview, history and evolution.

• Advantages and disadvantages of precast concrete members & broad applications.

• Overview of relevant BIS specifications

Week 2: Non-Structural and Structural Precast Elements

• Non-structural elements: paver blocks, fencing poles, transmission poles, manhole covers, hollow and solid blocks, kerb stones

• Structural precast elements: tunnel linings, canal lining, box culverts, bridge panels, foundations, sheet piles

• Testing of precast components according to BIS standards

Week 3: Precast Building Components and Material Characteristics

• Precast structural building components: slab panels, beams, columns, footings, walls, lintels, chajjas, staircase elements

• Prefabricated buildings with load-bearing and non-load-bearing wall panels and floor systems

• Material characteristics, plans, and standard specifications

Week 4: Prefabricated Building Systems and Joint Design

• Classification and design considerations of prefabricated building systems

• Manufacturing, storage, curing, transportation, erection, and related equipment

• Study of Joint design: requirements, structural behaviour and detailing of various joint types.

Week 5: Introduction to Prestressed Concrete and Materials

• Principles and basic terminology of prestressed concrete

• Applications, advantages, and disadvantages

• Materials used and need for high-grade materials

Week 6: Types of Prestressing Steel

• Types of prestressing steel: wire, cable, tendon

• Merits, demerits, and typical applications of different prestressing steels

• Overview of relevant BIS specifications.

Week 7: Methods of Prestressing and Pretensioning Systems

• Methods of prestressing: internal/external, pre-tensioning, post-tensioning

• Applications, merits, and demerits

• Pretensioning systems and processes, including Hoyer system.

Week 8: Post-Tensioning Systems & Introduction to Losses.

• Post-tensioning systems: Freyssinet, Magnel Blaton, Gifford Udall systems

• Processes, applications, merits, and demerits

• Understanding the loss of prestress.

Week 9: Losses of Prestress and BIS Recommendations

• Prestressing force in cables

• Loss of prestress due to friction, length effect, wobbling, curvature (with simple numerical problems)

• Losses at anchoring stage and from shrinkage, creep, elastic shortening, and steel creep (with numerical problems)

• BIS recommendations for percentage loss in pre- and post-tensioning.

Week 10: Analysis of Prestressed Beams and Cable Profiles

• Basic assumptions in prestressed beam analysis

• Analysis of rectangular prestressed beam sections.

• cable profiles (concentric, eccentric straight, parabolic), and their effect on stresses at different beam locations

Week 11: Effect of Cable Profiles on Beam Stresses

• Effect of cable profile on maximum stresses at midspan and supports

• Numerical problems on determining maximum stresses with linear cable profiles (Concentric and eccentric profiles).

Week 12: Design of Prestressed Beams and Course Review

• Introduction to Design – Overview & BIS recommendations.

• Designing simply supported rectangular prestressed beam sections (without complex numerical)

• Course recap, practical engineering implications, final assessment, and feedback