structural stress grading of selected sarawak timber using non-destructive tests alik anak duju

51 Pages·2014·0.45 MB·English

STRUCTURAL STRESS GRADING OF
SELECTED SARAWAK TIMBER USING
NON-DESTRUCTIVE TESTS

ALIK ANAK DUJU

DOCTOR OF PHILOSOPHY
UNIVERSITI SAINS MALAYSIA

2009

STRUCTURAL STRESS GRADING OF SELECTED
SARAWAK TIMBER USING NON-DESTRUCTIVE TESTS

by

ALIK ANAK DUJU

Thesis submitted in fulfilment of the requirements
for the degree of
Doctor of Philosophy

May 2009

ACKNOWLEDGEMENTS

I wish to express my sincere gratitude and appreciation to my supervisors
Associate Professor Dr. Badorul Hisham Abu Bakar and Senior Lecturer Dr. Megat
Azmi Megat Johari of School of Civil Engineering, Engineering Campus, Universiti
Sains Malaysia (USM), Pulau Pinang, Malaysia for their invaluable guidance,
suggestions and constructive criticisms that lead to the completion of the research
project for Doctor of Philosophy (PhD).

Sincere thanks are due to the Managing Director/Chief Executive Officer of
Sarawak Forestry Corporation Sdn. Bhd. (SFCSB), Datu Haji Len Talif Salleh, General
Manager of Applied Forest Science and Industry Development (AFSID), SFCSB, Mr.
Nigel Lim Poon Teck and Senior Assistant Director (Research and Development) of
Forest Department, Sarawak, Tuan Haji Abang Mohamad Moktar Abang Pawozan for
giving me the opportunity to use the research equipment and testing facilities.

Acknowledgements are due to Dr. Takashi Nakai, ex-JICA Team Leader, Dr.
Naohiro Kuroda, Dr. Toshinari Tanaka and Dr. Hirofumi Nagao of Forestry and Forest
Products Research Institute (FFPRI), Tsukuba, Japan, Professor Dr. Mohd. Hamami
Sahri and Associate Professor Dr. Paridah Md. Tahir of Faculty of Forestry, Universiti
Putra Malaysia (UPM), Serdang, Associate Professor Dr. Mohd. Ariff Jamaludin of
Faculty of Applied Science, Universiti Teknologi Mara (UiTM), Shah Alam, Associate
Professor Dr. Taksiah Abdul Majid and Lecturer Dr. J. Jayaprakash of School of Civil
Engineering, Engineering Campus, SM and Manager Mr. Kandau Jenang, of Testing and
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Consultancies, AFSID, SFCSB, for their comments and suggestions on the write-up of
this thesis.

Thank you very much goes to the staff of Basic Wood Study of Forest Products
of SFCSB particularly Development Executive Mr. Andrew Nyorik Nibu, Laboratory
Technicians namely, Mr. Nungah Liang, and Mrs. Yeo Hui Choo for assisting in the
preparation and testing of timber samples. Thanks also to Development Executive Mr.
Lai Jiew Kok on assisting in the analysis of data using SPSS and Laboratory Technician
Mr. Tan Jui Liah for his assistance in providing the data on drying of timber species. To
all the staff of Wood Anatomy Section especially to Development Executive Mr. Yang
Min Chin, Laboratory Technicians viz., Mr. Voon Shin Lee and Mr. Charles Diyom for
assisting in identification of timber species are very much appreciated. Once again, I
would like to express my profound thanks to all of them.

Finally, I like to convey my very special gratitude to my beloved wife, Dumang
Dullah, my son Lawrence Insol who is currently pursuing his Bachelor of Science
Degree in Timber Technology at UPM, daughters Delphanie Lonnie and Valarie Ching
for their patience, love and encouragement. To my beloved mother Noi Insol, brother
Ujoh Duju, sisters viz., Urie Duju, Gansau Duju, Tanai Duju, Choawan Duju and Runtie
Duju, brother in-laws, sister in-laws, friends and colleagues for their encouragement,
concern and moral support throughout the course of this study.

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TABLE OF CONTENTS

Page

Acknowledgments ii
Table of Contents iv
List of Tables x
List of Figures xi
List of Plates xix
List of Abbreviations xxi
Abstrak xxiii
Abstract xxiv
CHAPTER 1 - INTRODUCTION 1
1.1 Background 1
1.2 Problem Statement 5
1.3 Objectives of Study 6
1.4 Scope of Works 6
1.5 Outline of the Thesis 7
CHAPTER 2 - LITERATURE REVIEW 11
2.1 Forestry of Sarawak 11
2.2 Forest Industry Sector of Sarawak 15
2.3 Utilization of Timber in Construction 18
2.4 Properties of Selected Timber Species 21
2.4.1 Selangan batu bukit (Shorea foxworthyi) 22
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2.4.2 Menggris (Koompassia malaccensis) 23
2.4.3 Penyau (Upuna borneensis) 24

2.4.4 Kapur paya (Dryobalanops rappa) 25

2.4.5 Alan batu (Shorea albida) 27
2.4.6 Jongkong (Dactyloclados stenostachys) 28
2.4.7 Geronggang (Cratoxylum arborescens) 29
2.5 Grading of Timber 31
2.5.1 Visual Grading of Timber 34
2.5.2 Mechanical Grading of Timber 36
2.5.3 Limitations of Timber Grading 37
2.5.4 Grade Stresses of Timber 39
2.6 Destructive Evaluation of Timber 40
2.7 Non-Destructive Evaluation of Timber 41
2.7.1 Frequency Vibration Method 43
2.7.2 Bending Deflection Method 44
2.7.3 Penetration Depth of Pin Method 45
2.8 Strength Properties 45
2.8.1 Timber Species 46
2.8.2 Density 48
2.8.3 Moisture Content 50
2.8.4 Wood Defects 51
2.8.4.1 Knots 51
2.8.4.2 Sloping Grain 53
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2.8.4.3 Other Factors 55
2.9 Summary 57
CHAPTER 3 - MATERIALS AND TEST METHODS 58
3.1 Introduction 58
3.2 Materials 58
3.2.1 Sampling of Timber Samples 59
3.2.2 Preparation of Timber Samples 63
3.2.3 Seasoning and Conditioning of Timber Samples 63
3.3 Test Methods 65
3.3.1 Non-Destructive Testing 65
3.3.1.1 Longitudinal Vibration Frequency Method 65

3.3.1.2 Dead Weights Loading Method 67

3.3.2 Destructive Testing 69
3.3.2.1 Static Bending Test for Full Size Structural 69
Samples

3.3.2.2 Static Bending Test for Small Clear Specimens 71

3.3.2.3 Compression Parallel to Grain for Small Clear 72
Specimens

3.3.2.4 Pilodyn Penetration Depth 73
3.3.3 Physical Properties 74
3.3.3.1 Moisture Content Determination 74
3.3.3.2 Density Determination 75
3.2.3.3 Grain Angle Determination 76
3.3.3.4 Knot Size Ratio Determination 77
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3.3.4 Statistical Analysis 77

3.4 Summary 78

CHAPTER 4 - RESULTS AND DISCUSSION 79
4.1 Introduction 79
4.2 Physical and Mechanical Properties of Structural Timber 80
4.2.1 Moduli of Elasticity of Structural Timber 82
4.2.2 Bending Strength of Structural Timber 85
4.2.3 Air-Dried Density of Structural Timber 87
4.2.4 Moisture Content of Structural Timber 88
4.2.5 Strength Properties of Small Clear Specimens 90
4.2.6 Compressive Strength Parallel to Grain for Small Clear 92
Specimens

4.3 Results of Visual Parameters and Pilodyn Penetration of Structural 93
Timber

4.4 Comparison of Grade Stresses of Strength Properties of Timber 95
4.4.1 Comparison of Grade Stresses of Moduli of Elasticity and 96
Timber Species

4.4.2 Comparison of Grade Stresses of Bending Strength of 99
Timber Species

4.5 Rupture Pattern of Static Bending Test of Structural Timber 102
4.6 Summary 105
CHAPTER 5 – RELATIONSHIP OF NDT WITH OTHER 106
PARAMETERS

5.1 Introduction 106
5.2 Relationship between Strength Properties of Structural Timber 106
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