Formshore Tetrapods & Dolos

Coastal erosion presents a significant challenge to the stability of harbours and shorelines, threatening infrastructure, ecosystems, and communities. Among the innovative solutions developed to mitigate this problem are concrete Tetrapods and Dolos, both of which play crucial roles in coastal defence systems.

Formshore’s Concrete Tetrapods are four-legged structures engineered to dissipate wave energy and reduce coastal erosion. Their unique shape allows them to interlock when placed in clusters, creating a porous barrier that minimises wave force without fully blocking water flow. This characteristic reduces the scouring effect at the base of the structure and enhances the stability of the coastline.

Formshore’s Dolos, feature a complex shape with interlocking arms, similar to the shape of a knuckle bone. Dolos are highly effective at absorbing and deflecting wave energy. These concrete blocks are typically used in breakwaters, jetties, and seawalls to safeguard vulnerable coastlines from the impact of strong waves.

Both Tetrapods and Dolos offer several advantages:

Wave Energy Dissipation: Their shapes allow waves to lose energy as they pass through the structures, reducing erosion and the potential for flooding.
Structural Interlock: The interlocking design enhances durability, ensuring the defence system remains effective over time.
Flexibility in Deployment: These structures can be adapted to various coastal environments, from sandy beaches to rocky shores.

Formshore can create both Tetrapods and Dolos at the Batam yard, or alternatively, transport the molds along with a concreting team to site.

Pro's & Con's

Tetrapods

Dolos

Tetrapod Pros:
Simple Manufacturing: Tetrapods have a less complex shape, making them easier and often cheaper to manufacture compared to Dolos.
Effective Energy Dissipation: Their four-legged interlocking design effectively dissipates wave energy and reduces erosion along coastal structures.
Stability: The design allows tetrapods to remain stable under extreme wave forces when placed in clusters.

Tetrapod Cons:
Limited Interlocking Efficiency: Tetrapods do not interlock as tightly as Dolos, which can lead to displacement over time.
Less Adaptability: Tetrapods are generally less flexible in handling multi-directional wave energy compared to Dolos.
Heavier Wave Scouring: The design may lead to slightly more wave scouring at the base than Dolos, depending on the placement.

Dolos Pros:
High Wave Energy Dissipation: Dolos structures have a highly effective shape for dissipating wave energy, minimising the force transferred to the coastline
Superior Interlocking: Their complex, twisting design allows for better interlocking, which increases stability even under strong currents and waves.
Durability in Harsh Conditions: They perform exceptionally well in multi-directional wave environments and over extended periods.

Dolos Cons:
Complex and Costly Production: The intricate shape of Dolos makes them more expensive and challenging to manufacture
Higher Placement Precision Required: Proper placement and interlocking require more precision during deployment, which can increase installation costs and time.
Heavier Individual Units: Dolos are often heavier (up to 20–30 tons), requiring specialised equipment for handling and placement.