Combined glued laminated timber using hardwood and softwood lamellas

Inhaltsverzeichnis (Table of Contents)

• 1 Introduction
  • 1.1 Background
  • 1.2 Aim and purpose
  • 1.3 Limitations
  • 1.4 Reliability, validity and objectivity
• 2 Literature Review
  • 2.1 Glulam history
  • 2.2 Research and developments on glulam
  • 2.3 Research on combined Glulam hybrid (GL hyb)
  • 2.4 Clear wood properties of selected wood species
• 3 Theory
  • 3.1 Wood
  • 3.2 Mechanical properties of wood
  • 3.3 Glulam
    • 3.3.1 Softwood glulam
    • 3.3.2 Hardwood glulam
    • 3.3.3 Glulam made from different species
• 4 Method
  • 4.1 Experiments
    • 4.1.1 Modulus of elasticity of single boards
    • 4.1.2 4-point bending test
    • 4.1.3 Optical deformation measurement system (Aramis)
    • 4.1.4 Local Modulus of Elasticity
    • 4.1.5 Global Modulus of Elasticity
  • 4.2 Analytical calculation
  • 4.3 Finite-Element calculation
• 5 Results
  • 5.1 Dynamic modulus of elasticity (Edyn) of single boards
  • 5.2 4-point-bending tests
    • 5.2.1 Bending strength
    • 5.2.2 Local Modulus of Elasticity
    • 5.2.3 Global Modulus of Elasticity
    • 5.2.4 Optical deformation measurement
  • 5.3 Analytical results
    • 5.3.1 Section forces
    • 5.3.2 Modulus of elasticity
    • 5.3.3 Bending capacity
  • 5.4 FEM-Results
• 6 Analysis
  • 6.1 Stiffness
  • 6.2 Bending capacity
  • 6.3 Type of failure
• 7 Discussion
• 8 Conclusion

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis investigates the behavior of glued laminated timber (GLT) combining hardwood and softwood lamellae. The main objective is to evaluate the influence of hardwood on the strength and stiffness of GLT beams, considering its placement in the tension and compression zones and varying its quantity. This will be achieved through experimental and analytical methods, comparing the results to assess the effectiveness of incorporating hardwood into GLT construction.

• Strength and stiffness of combined hardwood and softwood GLT
• Influence of hardwood placement (tension and/or compression zones)
• Impact of varying hardwood proportions on GLT performance
• Comparison of experimental and analytical results
• Analysis of failure types in combined GLT beams

Zusammenfassung der Kapitel (Chapter Summaries)

1 Introduction: This chapter introduces the background of glued laminated timber (GLT) and the motivation behind this research, specifically focusing on the use of both hardwood and softwood lamellae. It clearly defines the aim and purpose of the study, outlining the scope of the investigation. The limitations of the study are also addressed, acknowledging potential constraints and their impact on the results. Finally, it establishes the methodology's reliability, validity, and objectivity.

2 Literature Review: This chapter provides a comprehensive overview of existing research on glulam, tracing its historical development and highlighting key advancements. It delves into specific research on combined glulam hybrids (GL hyb), examining previous studies that incorporated both hardwood and softwood. The review also explores the clear wood properties of selected species, establishing a foundation for understanding the material behavior relevant to the study's objectives.

3 Theory: This chapter lays out the theoretical foundation for understanding wood and glulam behavior. It explores the mechanical properties of wood and delves into the specifics of softwood and hardwood glulam. It provides the theoretical framework necessary for interpreting the experimental and analytical results presented in later chapters, emphasizing the differences and similarities between using different wood types in the GLT manufacturing process.

4 Method: This chapter details the experimental and analytical methods used in the study. The experimental procedures, including the methods for determining the modulus of elasticity of individual boards and the four-point bending tests, are described in detail. The use of an optical deformation measurement system (Aramis) is also explained. Additionally, the chapter outlines the analytical calculations and finite-element calculations performed to support the experimental findings, providing a complete overview of the methodology employed.

5 Results: This chapter presents the findings obtained from both experimental and analytical approaches. Results from dynamic modulus of elasticity tests on single boards are presented, followed by the results from four-point bending tests, including bending strength, local and global moduli of elasticity, and optical deformation measurements. Finally, analytical and finite element method results such as section forces, modulus of elasticity, and bending capacity are presented, providing a thorough overview of the quantitative data obtained.

6 Analysis: This chapter presents an in-depth analysis of the results presented in Chapter 5. It focuses on the stiffness and bending capacity of the combined hardwood and softwood GLT beams, relating these findings back to the theoretical framework established in Chapter 3. A critical evaluation of different failure types observed in the experiments is also provided. This chapter serves as a bridge between the experimental results and the broader discussion presented in the subsequent chapter.

Schlüsselwörter (Keywords)

Glued-laminated-timber, GLT, hardwood, oak, combined glulam, timber, timber engineering, strength, stiffness, bending strength, modulus of elasticity, finite element analysis, experimental testing.

Häufig gestellte Fragen

What is the focus of the study outlined in this document about glued laminated timber (GLT)?

This study investigates the behavior of glued laminated timber (GLT) that combines hardwood and softwood lamellae. The primary focus is to evaluate how hardwood influences the strength and stiffness of GLT beams, specifically considering its placement within the tension and compression zones, as well as varying the proportion of hardwood used.

What are the main objectives of the GLT study?

The main objective is to evaluate the influence of hardwood on the strength and stiffness of GLT beams, considering its placement in the tension and compression zones and varying its quantity. This will be achieved through experimental and analytical methods, comparing the results to assess the effectiveness of incorporating hardwood into GLT construction.

What are the key themes addressed in this GLT research?

The key themes are: strength and stiffness of combined hardwood and softwood GLT; the influence of hardwood placement in tension and compression zones; the impact of varying hardwood proportions on GLT performance; comparison of experimental and analytical results; and analysis of failure types in combined GLT beams.

What does Chapter 1 (Introduction) cover?

Chapter 1 introduces the background of glued laminated timber (GLT) and the motivation behind the research, focusing on the use of both hardwood and softwood lamellae. It defines the aim and purpose of the study, outlines its scope, addresses limitations, and establishes the methodology's reliability, validity, and objectivity.

What does Chapter 2 (Literature Review) cover?

Chapter 2 provides an overview of existing research on glulam, tracing its historical development and highlighting key advancements. It examines research on combined glulam hybrids (GL hyb) incorporating both hardwood and softwood, and explores the clear wood properties of selected species.

What does Chapter 3 (Theory) cover?

Chapter 3 lays out the theoretical foundation for understanding wood and glulam behavior. It explores the mechanical properties of wood and delves into the specifics of softwood and hardwood glulam, providing a framework for interpreting the experimental and analytical results.

What does Chapter 4 (Method) cover?

Chapter 4 details the experimental and analytical methods used in the study. It describes the methods for determining the modulus of elasticity of individual boards, the four-point bending tests, and the use of an optical deformation measurement system (Aramis). It also outlines the analytical calculations and finite-element calculations performed.

What does Chapter 5 (Results) cover?

Chapter 5 presents the findings from both experimental and analytical approaches. It presents results from dynamic modulus of elasticity tests on single boards, followed by results from four-point bending tests (bending strength, moduli of elasticity, optical deformation measurements). Finally, analytical and finite element method results such as section forces, modulus of elasticity, and bending capacity are presented.

What does Chapter 6 (Analysis) cover?

Chapter 6 presents an in-depth analysis of the results from Chapter 5. It focuses on the stiffness and bending capacity of the combined GLT beams, relating these findings back to the theoretical framework. It also provides a critical evaluation of different failure types observed in the experiments.

What are the keywords associated with this GLT research?

The keywords are: Glued-laminated-timber, GLT, hardwood, oak, combined glulam, timber, timber engineering, strength, stiffness, bending strength, modulus of elasticity, finite element analysis, experimental testing.