Samenvatting

This thesis aims to evaluate the potential of an aluminum extension to improve the operational service level of the Zeelandbrug, in terms of capacity and safety. This encompasses assessing the bridge's current performance, investigating evolving regional transport demands, defining improvement priorities, and comparatively analyzing materials like aluminum and steel.

Key findings indicate that while the Zeelandbrug currently operates within its traffic capacity, it demonstrates poor road safety as evidenced by a history of accidents. Projections also show that by 2040, traffic growth will push the bridge's intensity-to capacity ratio to nearly 97%, rendering its current 2x1 configuration unsustainable for stable, uncongested flows and necessitating substantial redesign to meet future "zerovictims" safety ambitions.

The conclusions drawn indicate that to achieve the province’s long-term “zero victims” safety ambition and accommodate projected traffic volumes, the Zeelandbrug will require widening. While capacity expansion is not immediately urgent, proactive planning is essential given the bridge’s approaching end-of-life.

Design variants were developed by integrating stakeholder priorities with cross-section design theory to define lane configurations, safety features, and structural concepts, followed by comparative modelling of aluminium and steel options. Winning variants featured emergency lanes and physical directional separation. These variants were then assessed through feasibility analyses, including shear, moment, and deflection checks, which were measured against the Zeelandbrug’s known structural limits. Structural feasibility analyses revealed that a simple cantilevered aluminium deck extension is not viable due to excessive fixation moments and shear forces on the existing concrete box
girder, which lacks the necessary reinforcement. However, alternative frame and girdersupported designs using aluminium were found to be structurally feasible, meeting deflection and frequency requirements while reducing critical stresses. Aluminium offers advantages in weight reduction, corrosion resistance, and installation speed compared to steel, though cost and thermal expansion behaviour must be carefully managed.

The aluminium extension concept, when implemented with vertical frame supports and girders rather than a cantilever fixation, was found to be technically feasible and therefore recommended for further research and development.