Question

Should dolphins be designed in a rigid manner such as resting on several raking piles?

Answer

While designing dolphins, they are normally supported on a system of three to four raking piles. This in essence is a rigid arrangement and exhibits little flexibility as in movement against impact and berthing loads by vessels. In fact, this type of design might not be desirable in terms of maintenance since dolphins are readily susceptible to damage by high berthing vessels. To correct this situation, some power absorption devices like rubber or plastic fenders have to be installed to reduce impact load deriving from its own deflection. On other hand, by designing dolphins as supple structures capable for allowing slight deflection, it helps to reduce large forces generated during berthing of vessels. While connection, one way of designing dolphins as flexible structures are by provision of a single pile only.