435R-95
Control of Deflection in Concrete Structures (Reapproved 2000)
1995, 77 pp.
$103.50

This report presents a consolidated treatment of initial and time-dependent deflection of reinforced and prestressed concrete elements such as simple and continuous beams and one-way and two-way slab systems. It presents the state of the art in practice on deflection as well as analytical methods for computer use in deflection evaluation. The introductory chapter and four main chapters are relatively independent in content. One or two detailed computational examples for evaluation the deflection of beams and two-way action slabs and plates are given at the end of Chapters 2, 3 and 4. These computations are in accordance with the current ACI or PCI accepted methods of design for deflection.

Includes new Appendix B which presents a general method of recalculating the strain distribution at a section considering the effects of a normal force and a moment caused by applied loads, prestressing forces, creep and shrinkage of concrete, and relaxation of prestressing steel.

Contents:
Chapter 1 - Introduction

Chapter 2 - Deflection of reinforced concrete one-way flexural members

2.1 Notation

2.2 General

2.3 Material properties

2.4 Control of deflection

2.5 Short-term deflection

2.6 Long-term deflection

2.7 Temperature-induced deflections

Appendix A2

Example A2.1 - Short and long-term deflection of 4-span beam

Example A2.2 - Temperature-induced deflections

Chapter 3 - Deflection of prestressed concrete one-way flexural members

3.1 - Notation

3.2 - General

3.3 - Prestressing Reinforcement

3.4 - Loss of prestress

3.5 - General approach to deformation considerations - Curvature and deflection

3.6 - Short-term deflection and camber evaluation in prestressed beams

3.7 - Long-term deflection and camber evaluation in prestressed beams

Appendix A3

Example A3.1 - Short and long term single-tee beam deflection

Example A3.2 - Composite double-tee cracked beam deflections

Chapter 4 - Deflection of two-way slab systems

4.1 - Notation

4.2 - Introduction

4.3 - Deflection calculation method for two-way slab systems

4.4 - Minimum thickness requirements

4.5 - Prestressed tow-way slab systems

4.6 - Loads for deflection calculation

4.7 - Variability of deflections

4.8 - Allowable deflections

Appendix A4

Example A4.1 - Deflection design example for long-term deflection of a two-way slab

Example A4.2 - Deflection calculation for a flat plate using the crossing beam method

Chapter 5 - Reducing deflection of concrete members

5.1 Introduction

5.2 Design techniques

5.3 Construction techniques

5.4 Materials selection

References