Design of Jetty Decks for Extreme Vertical Wave Loads

One of the main aspects that can govern the design of an open piled jetty platform is the wave climate. Often a better way to deal with this is to ensure that the platform deck lies above the anticipated level of the wavetops. Other considerations, however, sometimes dictate that the platform must be below this level. No clear (international) guidelines exist with respect to the vertical wave impact load on relatively large horizontal slabs such as jetty platforms. Using published results of earlier investigations into the phenomenon of wave slamming and wave entrapment under decks a practical design approach has been developed. This approach has been used in the design of two jetty platforms. Both structures have been hit by hurricane induced waves since their completion and survived both the onslaught with only minor structural damage. This paper will discuss the method with which the design waves were forecast and explain the chosen design formulae and design of the platform including the results of the lessons learned from the hurricane attacks.