Recent History, Types, and Future of Modern Caisson Technology: The Way to More Sustainable Practices

The construction of caisson breakwaters dates from ancient times (Brindisi battle and Caesarea Maritima , Roman Empire) of yore but has evolved with regards to technology and the materials available at all times (wood, gravel, and rubble mound). The growth in draught in vessels searching for deep water depths for berthing plus environmental problems have led to the 20th century facilitating the boom in vertical types and concrete caissons built in different ways (dry and floating techniques). Furthermore, structural criteria gave way to functional, environmental, and aesthetic criteria. The search for new, more efficient forms led to the construction of increasingly more complex elements including many that still require an economically viable construction system. To where will this search for new materials and forms take us? The use of composite materials could be considered, at the moment, as too expensive, but analyzing the cost with a wider approach, as Life Cycle Assessment, shows us that caissons in composite materials are cost effective and could be a solution. Furthermore, the possibility of using recyclable composites opens up big opportunities of using these materials at affordable costs. Caissons in composites or recycled composites are then a real alternative to concrete caissons. In Spain, two examples can be observed: a berthing area in Canary Island (Puerto del Rosario, South Atlantic Ocean) and a crown wall in Cartagena using polyester fiber bars (Mediterranean Sea). European policy in matters of sustainability promotes the circular economy, which means not only consider construction of caissons in recycled composites should be considered but also the comparison of all materials and construction procedures. Lastly, the calculation of the Environmental Product Declaration (EPD) should be promoted.