Given the importance of modularity in structural design, understanding the performance of modular shell structures is essential for improving both circularity and construction efficiency in spatial structures. To enhance sustainability and aesthetics, timber gridshells can be used to integrate sustainable building materials with complex pattern topologies. Modularity not only contributes to circularity of building materials, but also eases assembly, reducing both cost and construction time. By investigating different segmentation strategies, their impact on structural behaviour and buildability can be identified. This knowledge supports the optimisation of modular gridshells, leading to more efficient construction solutions.

This research aims to explore optimal segmentation strategies for timber gridshells, considering structural behaviour, element reusability and the efficiency of production, assembly and transport. A timber geodesic gridshell dome serves as a case study, but the findings contribute to modularity of gridshells in general. The main research question is: How can the modular segmentation of timber gridshells be designed to optimise their structural and construction efficiency?

For this research a method is developed to generate modular gridshells and optimise their design by evaluating both structural performance and construction efficiency. The modular designs consist of pinned splice joints that longitudinally connect two beams of different modules. Various modular designs are created by defining the location of these intermodular joints, thereby determining the overall modular geometry in the structure. A structural analysis gives understanding of the structural behaviour and the required material use. A construction analysis provides insight into reusability and efficiency of production, assembly and transport. A multi-objective comparative analysis is conducted to identify the most favourable designs based on project goals and stakeholder preferences.

Findings show that this modular approach improves assembly efficiency and the reusability of elements. It is particularly advantageous to choose a modular gridshell over a classic one when the primary design objective is reusability. However, the modular segmentation method negatively affects structural performance and increases material usage, primarily due to the use of pinned splice joints, which reduce overall stability. Additionally, applying modularity results in lower production and transport efficiency.

The results further indicate that larger modules improve structural stability and reduce the required material, due to fewer splice joints. Larger modules also result in higher assembly efficiency and reusability. However, increasing module sizes may exceed maximum transport size limits. It could also lead to a higher number of module types, reducing production and assembly efficiency. Furthermore, the module shape significantly influences the number of splice joints, underlining the importance of careful geometric consideration to minimise joint quantity. Additionally, increasing the rotational stiffness of splice joints could improve the structural performance.

In conclusion, it is crucial to consider project objectives and stakeholder interests in the structural design of a gridshell. Moreover, this research concludes that modular gridshell designs perform best when:
• Module sizes are maximised within transport constraints;
• Module shapes are designed to minimise the number of splice joints;
• An increase in module size comes with a minimisation of number of module types. ... Read more

In many places in Uganda, people do not have a connection to the drinking water supply system and there is a lack of treated water supply, meaning that people only have access to water a certain part of the day. As a result many people rely on springs, handpumps, rivers or lakes, of which the quality cannot be monitored or controlled.

During this multi-disciplinary project, we worked together with the National Water & Sewerage Corporation (NWSC) and the Ministry of Water and Environment (MWE) to research the possibilities of extending the water supply system of two project areas, Bugiri District and Hoima City. The current water supply in both areas use groundwater as a source and the possibilities for the extension also consider using surface water besides groundwater.

The different alternatives for the extension of the water supply in Hoima City and Bugiri District are evaluated using a multi-criteria analysis (MCA), consisting of a financial analysis, a performance analysis and a risk analysis. By evaluating the different options using an MCA, the decision-making process can become less complicated.

The MCA-tool that is set up in this research can be used by engineers to study different areas in Uganda and make it easier to compare different options for the extension of a drinking water supply system in an early design stage. The tool is for the two project areas as examples, after which it is also tested during a case study with engineers from both NWSC and MWE. Useful feedback came out of this session which will be used to finalize the tool and elaborate on it.

To design the different alternatives for the project areas and to get insight into the drinking water supply of Uganda, Hoima and Bugiri are visited at the beginning of the project.

For both project areas, it is recommended to improve the operational performance of the already existing groundwater supply system as a short-term (5 years) solution. The long-term (25 years) solutions consider groundwater options as well as surface water options, using for example Lake Victoria, Lake Albert and River Nile as water sources.


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