Robust Scour Protection for Berth Deepening
Project Need and Scope
A berth deepening project at one of the container terminals at Jeddah Port, Saudi Arabia, formed part of a major expansion to increase capacity from 1.8 million TEU to 2.5 million TEU. The works enabled the feeder quay to accommodate New Panamax class vessels with drafts of up to 14.0 m. The quay comprised 330 m of existing construction and 45 m of new quay wall, both requiring enhanced scour protection to suit the increased depth and more demanding vessel operations. The project was completed in 2016.
The existing quay wall had previously been protected using traditional rock armour. In addition, the underlying coral bed had shown evidence of scour, posing a risk to the stability of the quay structure. A more efficient and sealed protection solution was required to safeguard both the structure and its foundation under the increased hydraulic loading.
Key Design Elements
Proserve developed a scour protection system based on in-situ concrete mattress technology. A constant thickness apron, with an average thickness of 300 mm, was designed to prevent underscour of the precast block quay wall and to offer reliable resistance to propeller-induced flow.
For precast block wall structures, the key to long-term performance lies in preventing the loss of the bedding stone beneath the blocks. Once this bedding layer is compromised, the wall structure becomes vulnerable to settlement and instability. Therefore, the concrete mattress was designed and positioned to cover only the extent necessary to protect the bedding stone layer — providing targeted, efficient protection without excessive material use.
The total length of constant thickness concrete mattress scour protection is 269m, consisting 62N° 4.4m wide panels, each zipped together and filled in-situ to form reliable ball & socket joints. The scour apron provides robust and reliable protection to the quay wall structure from scour due to the powerful vessel propeller action and bow thrusters.
The system covered a total of 269 m along the quay wall, using 62 concrete mattress panels. Each panel was 4.4 m wide once filled. The panels were zipped together and filled in-situ with micro-concrete to form secure ball-and-socket joints, resulting in a continuous, robust apron across the full protected length.
To address the risk of toe scour, a flexible falling rock edge apron was incorporated at the seaward edge of the mattress. This toe detail was designed to manage any ongoing erosion of the coral bed while ensuring the edge of the concrete apron remained protected.
Installation Detail
The concrete mattress system was installed using pump-filled formwork panels placed on the seabed by divers. Once in position, the panels were filled from the surface using micro-concrete pumped through hoses, allowing the formwork to bleed excess water while consolidating a dense and durable concrete apron.
Installation had to be carefully managed within the confines of a busy operational port, with vessels actively berthing and unberthing nearby throughout the works. The in-situ approach provided excellent control over placement and progress while minimising disruption to ongoing port activities.
On-Site Training
Summary of Advantages
The concrete mattress system delivered a robust, sealed scour protection solution that offered several advantages over traditional methods:
- Continuous, sealed apron: Eliminates the risk of settlement and displacement associated with rock armour, particularly under thruster flows.
- Targeted protection footprint: By protecting only the bedding stone beneath the quay wall, the system avoided unnecessary material use and reduced installation time.
- Reduced thickness and material volume: At just 300 mm thick, the mattress significantly reduced the footprint of protection — ideal where clearance beneath vessels is limited.
- Efficient construction: The in-situ approach enabled rapid and controlled installation, even within an active port setting.
- Proven long-term performance: The protection system provided durable, reliable defence against scour in a critical berth location.
This project at Jeddah Port demonstrates how in-situ concrete mattresses can provide an effective and economical solution for quay wall protection — particularly where deepening, structural integrity, and vessel clearance are key priorities.