There is no limit to human fantasies. Or it can be said that humans are humans because they have fantasies. Architecture is also untouched by these. First, we went multistory then we built skyscrapers, we built on mountains, deserts, in jungles, then how could underwater construction have been left? From the ancient lost city of Atlantis to Singapore’s Resort World Sensota and Dubai’s Ossiano, underwater construction has always been thought of by humans. Underwater architecture could also be the need of the hour keeping in mind the present climate scenarios. Today, underwater architecture is not only limited to buildings but underwater transport is also gaining popularity. Nowadays, underwater construction is such a known term that even developing nations are attempting to do it. For instance, the Underwater train in Kolkata would be India’s first underwater construction project. There is also a plan to make an underwater toll road in Jakarta, Indonesia. When the structures on land deal with dampness and water logging problems every now and then, underwater structures are undoubtedly a technological feat.

Materials

Concrete, Steel, Acrylic Sheet

With the advancement in technology, multiple options for building materials are there. For underwater construction, such materials are needed that can withstand the pressure of the water, do not corrode, and are transparent to provide visibility for aesthetic purposes. Therefore, a type of concrete is used that sets quickly. Excessive energy steel is used as it provides reinforcement and because of its corrosion resistance. Acrylic sheet is also highly considered as it can provide transparency (for aesthetic purposes) and can take loads better than glass. These are some of the most preferable materials for underwater construction.

Underwater tunnels

Brunel’s Tunnel Shield, Tunnel Boring Machine 

The technological advancements have come a long way. Almost two centuries ago, to make a 1200-foot tunnel, it took a time of 9 years. This very tunnel is the famous tunnel under the Thames River in London. This was the first underwater tunnel in the world. At that time, it was used using ‘Brunel’s Tunnel Shield,’ which was a rectangular iron wall having many shutters. One shutter was opened at a time to dig that much area of soil and the machine used to move forward.

Role of Technology in Underwater Architecture - SHeet1
Brunel’s Tunneling Shield_©sciencephoto.com

Today, Tunnel boring machines are used which can create a 1200-foot-long tunnel in just 24 days! India’s upcoming Mumbai Ahmedabad undersea rail project will use a TBM with a cutter head having a diameter of 13.1 meters, to create a tunnel 21 km in length.

Role of Technology in Underwater Architecture - SHeet2
Tunnel Boring Machine_©youtube.com

Another advanced method to make a tunnel underwater is the cut-and-cover method. In this, a trench is dug in the riverbed. Then, prefabricated tubes (of steel or concrete) are inserted. Once, the tubes are surrounded by rocks, tube sections are connected, and water is pumped out.

Underwater buildings

Cofferdam, Caisson

Generally, the process of making a building underwater involves constructing it off-site and then placing it under the water. To make an underwater foundation, huge drills are dug using machines. These drills are then inserted with hollow pipes which then are filled by concrete. Once the concrete dries and sets, it gets hardened and gives a very strong foundation. Then, the construction of building pieces takes place off-site. The modular pieces are transported to the site. Again, machinery is used to lower down these pieces and fasten them to the foundation at their right places. The water is then pumped out from the building.

Another technique is by using the cofferdams. A cofferdam is a temporary structure built by the workers on the site. It is made by using the rocks and dirt available on the site, or steel. After this structure is made, water is pumped out and the workers start the construction work of the building in the dry area. Once the construction work is completed, the cofferdam is dismantled. Cofferdams are also used to do the repair work of underwater structures such as the piers of bridges, dams, ships, etc.

Role of Technology in Underwater Architecture - SHeet3
A Cofferdam_©theconstructor.org

Unlike cofferdams, which are built on the site, caissons are already made water-tight structures. These are lowered down into the water. Sometimes their bottom is open and sometimes not. In the case of open caissons, workers keep on digging the soil below until they reach the solid rock surface. This stage serves as the foundation of the building, and the caisson becomes the foundation itself. The air pressure makes sure that the water does not enter the open caisson from below.

Role of Technology in Underwater Architecture - SHeet4
A Caisson_©civilology.com

Upcoming Projects

China, Dubai, Istanbul, Mumbai

Technology will keep on enhancing day by day. Starting from submarines to underwater hotels and resorts, underwater construction technology has come a long way. This is not the end but just the beginning. Even many more advanced underwater projects are in the pipeline. China’s Bohai Street Tunnel Project, Dubai’s underwater floating mosque, and an Underwater train connecting Dubai and Mumbai, The Great Istanbul Tunnel, are some upcoming extraordinary underwater projects to name a few.

Proposal for The Great Istanbul Project_©yukselproje.com
References :

Kurian, C., GAndhi, M.D. and Selvi, P.V. (2021). A STUDY ON ADVANCED UNDERWATER CONSTRUCTION AND IT’S CHALLENGES. International Research Journal of Engineering and Technology (IRJET) , [online] 08(04), pp.576–580. Available at: https://www.irjet.net/archives/V8/i4/IRJET-V8I4115.pdf [Accessed 20 Sep. 2023]

Newton, E. (2023). How Does Underwater Construction Work? [online] Revolutionized. Available at: https://revolutionized.com/how-does-construction-underwater-work/#:~:text=To%20build%20underwater%20foundations%2C%20engineers [Accessed 24 Sep. 2023]

Outlook. (2022). India’s First Underwater Train and Deepest Metro Station To Be Operational By 2023. [online] Available at: https://www.outlookindia.com/travel/india-s-first-underwater-train-and-deepest-metro-station-to-be-operational-by-2023-news-211839 [Accessed 22 Sep. 2023]

The Indian Express. (2023). Largest tunnel boring machine to be used for Mumbai-Ahmedabad bullet train project. [online] Available at: https://indianexpress.com/article/cities/mumbai/mumbai-coastal-road-project-tunnel-boring-machine-bullet-train-project-8659648/#:~:text=A%20tunnel%20boring%20machine%20(TBM [Accessed 24 Sep. 2023]

www.wonderopolis.org. (n.d.). How Do You Build a Tunnel Underwater? | Wonderopolis. [online] Available at: https://www.wonderopolis.org/wonder/how-do-you-build-a-tunnel-underwater/#:~:text=Today%2C%20underwater%20tunnels%20are%20often [Accessed 24 Sep. 2023]

Author

Vani is a young Agra based architect, graduated from Dayalbagh Educational Institute in 2023. She has a keen interest in traveling, mythology and animated movies. She loves simple architecture with minimum ornamentation and is always fascinated to see how culture, society and beliefs shape the architecture of a place.