Project works and theses

Notes
The topics listed here are generally appropriate for both Master's Theses and Project Works. Each task will be customized according to the requirements of the respective module. If you're interested, please reach out to the contact persons provided. You're also welcome to discuss your own topic ideas with us.
The guide for preparing and defending Diplomarbeiten at the Professorship for Timber Engineering is available for download here.

1.Experimental Analysis of Springback in wood Bending 

Hardwood, especially in construction, presents unique challenges due to its mechanical properties. One key challenge is managing the springback effect that occurs after bending, which affects the final shape of the material. This research aims to replace traditional tension bands, commonly used in wood bending, with flexible laminate materials to enable spatial plastic deformation while minimizing springback. The objective is to conduct a thorough analysis of the material behavior during bending and develop an experimental setup to measure and control springback effects.

As part of the thesis, the student will review the mechanical properties of hardwood, design an experimental program to simulate different bending scenarios and conduct tests to assess deformation and springback under various conditions. The focus will be on understanding the factors that influence both the bending process and springback, with the goal of identifying more efficient and flexible methods for bending wood in construction.

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

Siavash Namari

2. Design of timber structures assisted by FEM

The finite element method is used today to a growing extent in the design of structures. This has also been recognized on standardization level where complementary rules for design using FEM are emerging to cover the design of steel, concrete and timber structures. Often though, design based on FE-analysis involves certain complexities and problems that need to be considered and treated adequately in order to arrive at an accurate and safe design. Some guidelines and recommendations on the design of steel, concrete and timber structures based on FEM are already available. There is still a need, however, for more comprehensive and detailed studies in many areas in this field, and this topic has been promoted often by our colleagues in practice. Examples of topics to be further studied are:

• Inclusion of the hygro-mechanic and time dependent behaviour of wood in material models: How to consider k_mod and k_def in FEM based design
• Considering non-linear load-deformation behaviour of connections in design of timber structures: How can the slip modulus and ductility be adequately represented in a model and are the given values reliable?
• Influence of the variability and orthotropy of timber on the FEM based design: Is the characteristic value always safe or are further evaluations of variability needed?
• Criteria for parametric design of timber structures: How can the specific properties and characteristics of wood be considered in the optimisation of parametric design?

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

3. Hybrid timber structures

The combination of different materials offers the potential to benefit from the individual strengths and potentials of each material. Timber concrete composite is one of the combinations that allows the development of new, powerful hybrid structures, e.g. for prefabricated floors in buildings or for or in-situ cast road bridges. Nevertheless, there are several challenges that need to be considered in the design, construction and over the service life of the structure, e.g. the adequate shear connection between both materials, the impact of the moisture during construction phase and beyond, or the long-term deformation behaviour under individual ambient conditions. In all of this also the costs and sustainability benefits have to be considered.

Examples of topic proposals in this area

• Impact of moisture and humidity during the entire lifetime of timber concrete composite structures
• Deformation behaviour of timber concrete composites structures
• Concepts for durable and high-performance timber concrete composite bridges

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

4. Design and Testing of Adhesive-Free Connection Methods for Bent Wood Structures

As part of ongoing efforts to enhance resource efficiency and sustainability in wood construction, there is a need to explore alternatives to adhesive-based joints in bent wood structures. This research will focus on the design and testing of innovative mechanical joints, such as dowels and wedges, for use in curved wood elements. The goal is to develop connection methods that can accommodate the high tolerances found in bent wood while maintaining structural integrity and flexibility.

The thesis will involve designing several mechanical connection prototypes, followed by experimental testing under different load scenarios to evaluate their performance. The student will analyze the strengths and weaknesses of each joint, paying attention to manufacturing constraints and the specific challenges posed by bent wood construction. The results will contribute to the development of more efficient and sustainable construction practices using hardwood.

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

Siavash Namari

5. Connections in timber structures

Connections play a fundamental role in the design and construction of timber structures. The stress concentrations around the fasteners in connections, the induced multiaxial stress states and the reduced cross-sections in the connection area, in addition to the anisotropic and brittle behaviour and the high variability of wood, make connections a critical component for the overall structural behaviour, which play a fundamental role regarding the structural safety and economy of timber structures. This complex connection behaviour is so far not fully reflected in the existing design standards. In addition, the global structural design and reliability analysis of entire timber structures often does not account for the impact of the complex behaviour of connections, such as its non-linearity, brittleness and ductility, cyclic and vibrational performance, etc.

Examples of topic proposals in this area

• Durable and reliable connections - how to avoid brittle failure?
• Cyclic and fatigue performance of connections in timber structures
• Combined loading of fasteners in lateral and axial direction – are current design rules safe and economic?

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

6. Assessment of existing timber structures

The surge of modern timber structures of higher consequence class in recent decades demands an increased effort regarding maintenance of their structural reliability. Monitoring, assessment and rehabilitation are measures to deliver this. Drivers for the maintenance of these structures are often the extension of service life and assessment is often needed in case of changes in use.

The criteria for maintencance are commonly economic. Instead of pure damage detection, as it is often done for the preservation of historic structures, for modern high performance timber structures it should be additionally aimed at an reliable characterisation of the effective (material) properties of the existing structure in order to make a judgement of its structural safety and behaviour in the future. Due to the inherent large variability of the material properties of timber and the necessary conservatism in the design assumptions (for new structures) resulting from that, updating of the effective material properties of the elements in a structure offers a huge potential for a more realistic prediction of load-carrying capacity.

Examples of topic proposals in this area

• Assessment and determination of material properties in existing structures
• Basis of design of existing structures: Probabilistic modelling, updating, and specification of partial factors to guarantee the safety of existing structures
• Efficient rehabilitation and reinforcement interventions for existing timber structures

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer

7. Design for adaptation, re-use, and circularity of timber structures

The planning and design of timber buildings should consider holistic sustainability and reliability aspects from the very beginning of the process. This should consider the demands and benefits of all stakeholders in the building design process. In the future timber buildings need to fulfil not only the basic design code requirements, but also be prepared for potential future changing demands and requirements. Hence, the design must provide robustness and facilitate adaptation, repair and reuse of the building and its components. Adaptation is the process of considering the changing demands and needs of the prospective users in the actual building, both in a short-term perspective or for long term use, including the adaptation of both load-bearing and non-load-bearing elements. Repair will implement the possibility that damaged load-bearing components meaning that parts of the structure can be easily restored or exchanged, which allows to react to unforeseen and accidental cases of e.g. water leakage, compartment fire, etc.

Examples of topic proposals in this area

• Enabling and facilitating repair of timber structures
• Adaptability as a means of extending the service life of timber structures
• Design for deconstruction – development of concepts for reusable connections
• Safe or sustainable? Potential of risk-informed decision making for timber structures

Details of the tasks will be specified prior to commencement.

Contact person:
Prof. Dr. Jockwer