Durban is the third largest city of South-Africa, located in the province of KwaZulu-Natal. The city suffers from severe floods from time to time, finding its cause in both the Indian ocean as well as the Umgeni river. The eThekwini municipality wishes a better insight in the occurrence of these floods and searches for a structural solution to protect the coastline. The eThekwini municipality has models in operation to predict the hydraulic characteristics in the ocean and the river. However, the existing models don’t represent the reality sufficiently, since the interaction between the Indian ocean and the Umgeni river is not modelled properly yet. An analysis on the area of interest has been executed. The conclusion was drawn that the Umgeni river delta was (partly) tide-dominant, meaning that the Indian ocean imposes the downstream water level. Furthermore, the wave climate was observed, as well as a look into present coastal protections. The link between the Indian ocean and the Umgeni river has been modelled using Delft3D. Since the Indian ocean imposes a downstream boundary condition (in terms of a water level) for the Umgeni river, a backwater curve might occur. First, the link is made by extending the Delft3D-model which was present for the Indian ocean only. The model has been extended all the way up to the Inanda dam. The part of the river included in the new model is approximately 32 푘푚 long. When comparing the models output at the river mouth, at the same location as a measurement point, similar behaviour can be observed. The same phase (lag) is observed, contrary to the tidal range. The tidal range in the model differs from reality, but this is due to a lack of calibration in the amplitudes of the different tidal constituents taken into account. Hence, the renewed model seems to work, but more validation still has to be done. This was not possible yet, as there is a lack of measurement stations along the river. Next to an extension of the Delft3D model, a script has been written in Python. This script is based on the empirical fit of Bresse and shows an elegant function. The results from the function in Python and the model in Delft3D are similar in a qualitative and a quantitative way. Both the models show an influence of the Indian Ocean, reaching easily to about 12 푘푚 upstream of the river mouth. This can be explained by the mild bed slope in this part. A structural solution for the flooding on the promenade at the height of North Beach was found in the form of a seawall. The most important design demand is to protect against a high water level of a 200 year return period combined with a 50 year return period wave height. These storm conditions are input for the ocean-river model, which delivers wave characteristics at the beach front, linking the structural design to the ocean-river model. After a pre-selection on design options, a Multi Criteria Analysis is carried out for the remaining eight design options. Grading is done based on criteria, representing the viewpoints of the many stakeholders involved and leading to a highest grading of a seawall in combination with an emergency barrier. Following, the water-retaining height for a vertical wall is determined. Given the the ground level height of the promenade to be 푀푆퐿 + 2.2 푚 and a total water-retaining height of 푀푆퐿 + 2.944 푚 this leads a practical construction height of 0.80 푚. Due to the limited height a reinforced concrete seawall is designed with emergency barriers for the beach entrances. The emergency barriers are designed of pinewood. Additionally, in order the fit properly in the surroundings, an integrated design is added with features like benches, thatch umbrellas and plants to disguise the construction and protect the Golden Mile in style.

Despite the increased popularity of the application of load bearing glass in the built environment, its design does rarely address sustainable or circular aspects. This Master’s Thesis analyses what the influence of connections is on the sustainable performance of structural glass and informs about the limitations and possibilities of sustainable glass design. To answer this question, sustainability has been defined from literature which resulted in ten sustainable, circular design methods. The role of load bearing glass and its connections is discussed in these methods, and it is concluded that there are two main possible design strategies for a sustainable design. First, the biggest impact in design can be made when focus is on reuse as an afterlife application to increase the lifetime of glass elements. Secondly, impact can be made by limiting the environmental footprint of the structure in the initial design by material minimization and selection. Recycling is left out of the scope since recycling on a world-wide scale barely occurs. Even in a country with a well developed recycling network like the Netherlands, just 5-10% of discarded flat glass waste ends up back in the float glass industries and the rest is downcycled to container glass or glass fibres. Besides, the sustainable impact from recycling compared to reuse is far smaller, and measures to limit contamination are out of control of the designer. At first, in order to design for reuse as an end-of-life application, demountable connections are essential and adhesive based connections should be avoided. Although demountability is a key to the circular economy, this study concludes that there are various technical barriers to overcome to make glass elements actually reusable. One important barrier is the lack of standardization in glass structures. As is shown in the redesign of "Kasteel Ruurlo", implementing standardization leads to a modular design and is integrated by using minimum size deviation and the use of a single type of connection. However, as a result of standardization, the design freedom of the architect is taken away and the mechanical connections lead to a less elegant design. Therefore, it is recommended to further development these modules and discuss elegance and design freedom in standardization. Another technical barrier to overcome is the performance and quality of glass elements which makes current reuse impossible: insulated glass units will loose their insulating performance due to failure of the edge sealant after 20 to 25 years, and laminated glass is prone to delamination over time. There is a lack of legislation which sets requirements to the quality and performance of these elements. Only for laminated glass, there is a potential reuse strategy which has been used in the redesign of "Kasteel Ruurlo". It is proposed to use a high quality interlayer as SentryGlas or Trofisol. For both interlayers, delamination problems should be further researched in order to assure a long technical lifetime. Secondly, in order to minimize the environmental impact of the structure, the impact has been quantified using Life Cycle Analysis data and Environmental Product Declarations. With the method by "Stichting Bouwkwaliteit", this data is converted to shadow costs which is used to calculate the environmental footprint of a connection. Different structural connections are considered: various facade connections, different moment rigid frame connections and various ways to connect a panel. From this calculation, the different connections are compared and it is concluded that adhesive based connections have both a smaller environmental footprint than mechanical connections, and that these result in less material use in the overall structure and thereby limiting the environmental footprint. This is also reflected in the redesign of "Kasteel Ruurlo", where due to the mechanical demountable connections, the environmental impact increases compared to the current design. With current possibilities, the relation between the connection and a sustainable design depends on the type of connection: an adhesive based connection will result in an overall low environmental impact but makes reuse unlikely. A mechanical connection could be an outcome here, but with current possibilities, reuse cannot be guaranteed either. The application of current demountable connections on the reuse possibilities can therefore be argued. In order to succeed with structural glass in the circular economy, this research emphasizes the need for legislation, standardization and to solve problems like delamination and leaking insulated glass units which now determine the lifetime of glass structures. It also shows the need for demountable connections which increase the reuse potential and which ideally do not increase the environmental footprint.