Prestressed Concrete Course

Lesson 1 • Basic Concepts of Prestress

Defines prestress, precompression, and the load-balancing concept. Connects these ideas to the chapter's goal of building a solid theoretical base.

Lesson 2 • Types of Prestressing Systems

Distinguishes pre-tensioning from post-tensioning and internal from external prestressing. Students identify the appropriate system for given structural conditions.

Lesson 3 • Materials Used in Prestressed Concrete

Covers high-strength concrete and steel properties essential for prestressing. Material selection directly affects prestress losses and structural performance.

Lesson 4 • Advantages and Limitations of Prestressing

Evaluates structural, economic, and durability benefits alongside practical constraints. Prepares students to make informed decisions about when to apply prestressing.

Lesson 1 • Relaxation of Prestressing Steel

Explains stress relaxation in low-relaxation and normal-relaxation strands over time. Students apply relaxation factors to compute total time-dependent losses.

Lesson 2 • Elastic Shortening of Concrete

Derives the elastic shortening loss formula for pre-tensioned and post-tensioned members. Students calculate loss values for single and multiple tendon systems.

Lesson 3 • Creep and Shrinkage Losses

Quantifies long-term concrete deformation losses using creep coefficients and shrinkage strains. Accurate estimation prevents serviceability failures over the structure's life.

Lesson 4 • Friction and Wobble Losses

Applies the exponential friction equation to curved and straight tendon profiles. Connects friction losses to tendon layout decisions made in later design chapters.

Lesson 1 • Concept of Load Balancing

Uses equivalent loads from tendon curvature to simplify analysis of continuous members. Demonstrates how balanced load reduces net bending and simplifies calculations.

Lesson 2 • Analysis of Cracked Prestressed Sections

Applies cracked section analysis to post-cracking service conditions using compatibility. Prepares students for ultimate strength analysis in the following chapter.

Lesson 3 • Stress Analysis at Transfer

Computes concrete stresses immediately after prestress transfer using the transformed section. Identifies critical stress conditions that govern initial tendon force selection.

Lesson 4 • Cracking Moment and Decompression

Defines decompression moment and cracking moment for prestressed sections. These values set the boundary between uncracked and cracked section behaviour.

Lesson 1 • Ultimate Flexural Strength Concepts

Introduces the rectangular stress block and strain compatibility for prestressed sections. Establishes the theoretical basis for all flexural strength calculations in this chapter.

Lesson 2 • Ductility and Reinforcement Limits

Evaluates section ductility through reinforcement index and strain limits. Ensures designs provide adequate warning before failure through ductile behaviour.

Lesson 3 • Partial Prestressing Design

Designs sections with combined prestressed and non-prestressed reinforcement for controlled cracking. Balances serviceability and strength objectives in a single design approach.

Lesson 4 • Flexural Design of Rectangular Sections

Applies strength equations to rectangular prestressed sections with bonded tendons. Students size sections and verify strength against factored moment demands.

Lesson 1 • Shear Behaviour of Prestressed Members

Explains how prestress modifies diagonal tension and shear crack formation. Understanding this behaviour is essential before applying design equations.

Lesson 2 • Shear Strength and Stirrup Design

Calculates concrete shear contribution and designs transverse reinforcement for prestressed beams. Stirrup spacing and minimum requirements are derived and verified.

Lesson 3 • Bond and Development of Prestressing Steel

Quantifies transfer length and development length for pre-tensioned strands. Proper bond design prevents anchorage failure at member ends.

Lesson 4 • Torsion in Prestressed Members

Applies space truss analogy to torsion design of prestressed box and solid sections. Torsion interaction with shear and flexure is addressed for combined loading.

Lesson 1 • Camber Prediction and Control

Calculates initial camber from prestress and self-weight for pre-tensioned members. Camber control is critical for composite deck construction and architectural tolerances.

Lesson 2 • Deflection Calculation Methods

Applies moment-area, conjugate-beam, and direct integration methods to prestressed beams. Accurate deflection prediction is the foundation of serviceability compliance.

Lesson 3 • Vibration and Dynamic Serviceability

Evaluates natural frequency and acceleration response of prestressed floors and bridges. Dynamic serviceability is increasingly critical in long-span lightweight structures.

Lesson 4 • Long-Term Deflection Due to Creep

Estimates time-dependent deflection growth using creep multipliers and sustained load ratios. Long-term deflection often governs serviceability in lightly loaded members.

Lesson 1 • Slab Edge and Opening Details

Addresses tendon deviation, edge beams, and reinforcement around slab openings. Proper detailing prevents stress concentrations and local failures at discontinuities.

Lesson 2 • Yield-Line Analysis for Slabs

Uses yield-line theory to determine ultimate load capacity of two-way prestressed slabs. Provides an alternative to elastic methods for irregular slab geometries.

Lesson 3 • One-Way Prestressed Slab Design

Designs one-way slabs with uniform tendon profiles using elastic stress and strength checks. Provides a straightforward entry point before addressing two-way behaviour.

Lesson 4 • Punching Shear in Prestressed Slabs

Calculates punching shear capacity at column-slab connections including prestress enhancement. Shear reinforcement and drop panels are designed to meet strength demands.

Lesson 1 • Moment Redistribution in Prestressed Frames

Applies plastic moment redistribution to reduce peak negative moments at supports. Redistribution limits are tied to section ductility established in Chapter 4.

Lesson 2 • Tendon Layout in Continuous Beams

Selects tendon profiles that minimise secondary moments and satisfy stress limits throughout. Profile optimisation reduces losses and simplifies construction.

Lesson 3 • Analysis of Prestressed Frames

Extends continuous beam analysis to portal and multi-storey prestressed frames. Column-beam interaction and lateral load effects are incorporated into the analysis.

Lesson 4 • Secondary Moments in Continuous Beams

Derives secondary (hyperstatic) moments arising from prestress in indeterminate structures. Understanding secondary moments is essential before designing continuous members.