ABSTRACT

After soil, concrete is probably the most widely used construction material. Since the beginning of the twentieth century the use of concrete has assumed enormous proportions. Today it is hardly conceivable that innumerable infrastructure works could be constructed without concrete, and quay walls are no exception. The reasons for the use of concrete can vary greatly. At the beginning of the twentieth century when concrete was first used to build quays, this was because they could be built more quickly. Before that time quay walls were built up from a fascine dam, wooden piles and a masonry superstructure (Chapter 2). First, the caisson concept was chosen for concrete quay walls; after that, at least in the port of Rotterdam, in many cases a change was made to quay walls with a high foundation. For these the superstructure can be designed as an L-shape, a box girder or a variant of these.

In addition to the development of structural concepts in concrete, it was also possible to detect developments in the concrete itself. These developments were not specifically designed for quay walls and were primarily driven by experience and increasing insight into the general behaviour of concrete. Still, there are also aspects relating to the nature of concrete technology that are especially important for hydraulic structures; it must be remembered that these structures often have relatively large dimensions. From the points of view of concrete technology and construction, one is dealing with mass concrete, or in other words concrete structures of such dimensions that during the hardening phase special measures are required to prevent large temperature differentials and the associated cracking. The limit for mass concrete is a thickness of about half a metre for the elements. Furthermore, it is necessary to take into account that concrete is often exposed to a very aggressive environment. Sulphates may cause the deterioration of quay walls on the coast and the penetration of chloride ions may lead to corrosion of the reinforcement. It is also necessary to take into account very heavy mechanical loads, such as highly concentrated loads caused by cranes and other heavy equipment, and high friction forces generated by manoeuvring vehicles.