Fire Performance of Thin-Walled Steel Structures

111 Pages·2020·9.195 MB·\111

by  Yong Wang (Author), Mahen Mahendran (Author), Ashkan Shahbazian (Author)

Fire Performance
of Thin-Walled
Steel Structures

Fire Performance
of Thin-Walled
Steel Structures

Yong Wang
Mahen Mahendran
Ashkan Shahbazian
K375080_Titlepage.indd 2 2/12/2020 10:07:11 AM
CRC Press
Taylor & Francis Group
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Contents
Preface ix
Authors xi
List of notations xiii
1 Introduction: Fire Safety Requirements and Implications
for Thin-Walled Steel Construction 1
1.1 Thin-Walled Steel Structures 1
1.2 Fire Safety Requirements and Their Implications for
Thin-Walled Steel Structures 3
1.3 Determination of Fire Resistance of Thin-Walled Steel
Structures 6
1.4 Scope and Layout of This Book 8
2 Applications of Thin-Walled Steel Structures 11
2.1 Introduction 11
2.2 Recent Innovations and Advances in Cold-Formed Steel
Industry 14
2.2.1 Innovative Lightweight and Structurally Efficient
Sections 14
2.2.2 Prefabricated Structural and Modular Units 16
2.3 Fire Resistance of Thin-Walled Steel Structures and
Methods of Enhancement 18
2.3.1 Fire Protective Boards 19
2.3.2 Insulation 22
2.3.3 Steel Studs and Joists 22
2.3.4 Steel Sheathing 23
2.4 Summary 23
3 Fire Resistance Tests 25
3.1 Standard Fire Resistance Test 25
3.2 Fire Resistance Tests of Walls 28
3.2.1 General Behaviour of LSF Walls in Fire 28
3.2.2 Effects of Cavity Insulation on Fire Resistance 34
3.2.3 Effects of External Insulation on Fire Resistance 35
v
vi Contents
3.2.4 Effects of New Stud Sections on Fire Resistance 36
3.2.5 Effects of Plasterboard Joints on Fire Resistance 37
3.2.6 Effects of Other Types of Boards on Fire Resistance 39
3.2.7 Effects of Steel Sheathing on Fire Resistance 42
3.3 Fire Resistance Tests of Floors 44
3.3.1 General Behaviour of LSF Floors in Fire 44
3.3.2 Effects of New Joist Sections on Fire Resistance 46
3.4 Other Fire Resistance Tests on Thin-Walled Steel Structures 47
3.5 Final Comments 50
4 Numerical Modelling of Fire Resistance of Thin-Walled
Steel Structures 51
4.1 Fire Behaviour 51
4.1.1 Nominal Fires 53
4.1.2 Parametric Fires 54
4.1.3 Travelling Fires 55
4.1.4 Computer Programs 55
4.2 Heat Transfer Modelling 57
4.2.1 Basics of Heat Transfer 57
4.2.2 Thermal Boundary Conditions for Heat Transfer
Modelling 58
4.2.3 Computer Programs 59
4.2.4 A Simplified Heat Transfer Model for Thin-Walled
Steel Structural Panels 60
4.3 Modelling Behaviour of Thin-Walled Steel Structures at
Elevated Temperatures 63
4.4 Summary 64
5 Elevated Temperature Properties of Materials 65
5.1 Introduction 65
5.2 Mechanical Properties of Cold-Formed Steels at Elevated
Temperatures 66
5.3 Thermal Properties of Fire Protection Materials at Elevated
Temperatures 69
5.3.1 General 69
5.3.2 Gypsum 70
5.3.2.1 Density 71
5.3.2.2 Specific heat 72
5.3.2.3 Thermal conductivity 72
5.4 Additional Issues 73
5.5 Summary 74
Contents vii
6 Performance-Based Design Methods of Thin-Walled
Steel Members at Elevated Temperatures 75
6.1 Thin-Walled Steel Members with Uniform Temperature
Distribution 76
6.2 Simplified Methods for Thin-Walled Members with
Non-uniform Temperature Distribution 76
6.2.1 Limiting Temperature Method 76
6.2.2 Extension of Fire Test Results 77
6.2.2.1 Members in walls 77
6.2.2.2 Members in floors 78
6.3 Thin-Walled Steel Columns with Non-uniform
Temperature Distribution in the Cross-Section 79
6.3.1 Effective Width Method 79
6.3.2 Direct Strength Method 80
6.3.3 Simplified Effective Width/Direct Strength Method 83
6.3.3.1 Effective width method 83
6.3.3.2 Direct strength method 84
6.4 Thin-Walled Steel Beams with Non-uniform Temperature
Distribution in the Cross-Section 85
6.5 Illustrative Design Example Using Direct Strength Method 85
6.6 Summary 87
References 89
Index 95

Preface
The behaviour of thin-walled structures is complex and fire resistance of struc-
tures is a niche subject. Therefore, fire resistance of thin-walled structures has
attracted a relatively low level of interest and investment from the research
community. As a result, the current design guidance for the evaluation of fire
resistance of thin-walled structures is rudimentary, still dominated by fire
resistance testing.
However, thin-walled steel structures are increasingly used in building
construction and large numbers of thin-walled steel structure products are
developed owing to flexibility of the manufacturing methods. Research and
development of thin-walled structures by fire testing will no longer be tenable
due to prohibitive cost and limited scope of application, and methods of calcu-
lation will become essential.
Developing calculation-based methods for fire resistance of thin-walled
structures demands a thorough understanding of the fundamentals of a number
of subjects and availability of reliable input data for material properties. To
aid this process of development, this book provides a single source of infor-
mation which at present is scattered in academic articles. This book attempts
to provide an authoritative account of the latest developments in the different
aspects of the subject matter, including fire resistance requirements, behav-
iour of thin-walled structures in fire and measures of improving fire resistance
of thin-walled structures, fire behaviour, simplified heat transfer modelling to
obtain temperatures in thin-walled structures, temperature-dependent thermal
and mechanical properties of materials, and latest developments in evaluating
the load carrying capacity of thin-walled steel structures at elevated tempera-
tures by calculation.
The book is jointly written by two research groups who have had a long
and distinguished record of extensive research on fire resistance of thin-walled
steel structures and are active in developing calculation methods. The authors
hope that this book will be an indispensable reference to researchers of this
increasingly important field. We also believe that the book will be valuable
to fire protection engineers who want to optimise fire resistant design of thin-
walled steel structures through developing a firm understanding of the first
principles of the subject matter, and specialist manufacturers of thin-walled
ix