Explicit rules for safety verification of open cold-formed lightweight beam-to-tubular column joints are missing in the current EC3-1-8. By developing economical detailing, with design guidance based on Eurocodes, the market share for new buildings, renovation and for additional storeys on existing buildings will increase. Within the INNO3DJOINTS project an innovative plug-and-play joint is developed, allowing for modularity and industrialization for low to mid-rise buildings. This solution will increase the competitiveness and sustainability of steel construction. The goal of this MSc thesis is to characterize the behaviour of the plug-and-play joint using the component test; T-plug bending around weak axis. The strength, stiffness and deformation capacity following the EC3-1-8 component method approach are investigated.

An experiment is designed for testing in the Stevin-II laboratory at Delft University of Technology. This work includes both the design of the set of test specimens and laboratory set-up. Secondly, a numerical study is performed to predict the experimental results and an extending parametric study is performed to derive new components, using the finite element software of ABAQUS. The influence of geometrical properties; thickness ratio (reverse channel vs. T-plug web), use of stiffeners, use of tubular sections and length of the T-plug web, is studied for a steel grade S355. The numerical study is validated for three configurations using the component test; T-plug in tension, provided by the INNO3DJOINTS project. As the parametric study is based on an elasto-plastic material model, these numerical results are directly used to derive new analytical expressions/models and characterize new components and component interactions for design verification. The numerical study resulted in the identification of seven active components for the plug-and-play joint, consisting of basic EC3-1-8 components and tubular components from the CIDECT report 16F: Component method for tubular joints. In addition, two new components are introduced namely, the reverse channel in bending and T-plug in bending. Based on a total of 127 unique joint configurations, new analytical expressions are derived to characterize the behaviour of the new components for resistance and stiffness. The component interaction is established by proposing a physical spring model and a component model suitable for Eurocode implementation. This results in the characterization of the joint behaviour for the experimental configuration C-SHS200 with a 7.5% deviation on the resistance and a 20.5% deviation on the stiffness compared to the numerical result. The accuracy of the joint stiffness can be improved if the component stiffness derivation also includes non-governing configurations and a wider range of parameters is studied, such as the position of the bolt holes along the net-section and the use of tubular section. The results, derivations and the physical spring model contribute to the INNO3DJOINTS project and could be used for implementation in the software tool, to be developed by the French Institute CTICM. Besides, the Eurocode aligned component model is recommended for practical use in design standards, but further research should be performed on the verification of the rotational stiffness on the joint level. ... Read more

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. ... Read more