Abstract
This study explores alternative structural designs for mooring and berthing dolphins specifically for Berth A100 at the Port of Ngqura. Traditionally, mooring and berthing dolphins are constructed using concrete pile foundations due to their high durability and low maintenance in marine environments. However, recent advances in construction materials and the rising cost of traditional solutions- driven by factors such as increased cement prices, higher transportation costs for heavy precast elements, and extended lead times for specialised marine-grade concrete-highlight the need to evaluate alternative materials, specifically hollow steel piles, for potential cost-effectiveness, constructability, and structural performance.
The primary objective of this research is to conduct a detailed comparative structural analysis of concrete pile foundations and hollow steel pile foundations, assessing their load-bearing capacity, durability, installation requirements, and lifecycle costs, to determine which option offers the greatest efficiency and cost-effectiveness for the operational and environmental conditions at the Port of Ngqura. The study employs Prokon structural analysis software to model and simulate the load-bearing capacities of both concrete and steel pile dolphins under a variety of environmental loads, including berthing, mooring, wind, wave, and current forces. A Multi-Criteria Analysis (MCA) is used to evaluate each design based on several criteria: health and safety, environmental impact, constructability, maintainability, and cost.
The results show hollow steel piles, due to their flexibility, are better suited for high impact berthing loads, providing enhanced energy absorption compared to concrete piles. Steel piles have approximately 36.47% higher average moment capacity compared to concrete piles, indicating significantly better performance under berthing load However, their susceptibility to corrosion in saline environments necessitates robust protective measures. Conversely, concrete piles exhibit greater durability and lower maintenance requirements, making them favorable for long-term applications in less dynamic conditions. These findings align with existing literature, such as Abdelaziz et al. (2021), which highlights the lateral capacity and resilience of steel piles in dynamic marine environments, and studies by Roubos et al. (2018), emphasizing the importance of conservatively designed berthing factors for durability. This research extends these insights by integrating a broader evaluation framework, including environmental and economic considerations.
The conclusions emphasize the suitability of hollow steel piles for dynamic, high-load applications, while concrete piles remain an optimal choice for scenarios prioritizing durability
and minimal maintenance. The findings provide a comprehensive decision-making framework for optimizing pile foundations in marine infrastructure, with recommendations for hybrid solutions and advanced corrosion protection for enhanced sustainability.