Jetty type platform for shallow water - uses prefabricated grillage decks spanning piers of triple column form with head and tow beams

摘要

Land-fabricated triple column piers and simply-supported grillage decks are used to build a shallow sea platform or jetty, the columns being connected by transverse beams at the head and foot, and the decks receiving a battle-deck floor or similar. The piers may be floated out form the shore with the head beams fixed by a temporary connection and may be lowered for the foot beam to rest on a previously prepared foundation. Special barges may be utilised, having a trough section, and being ballasted to partially submerge and leave the pier in an elevated position on floats. Decks units may also be floated into position, utilising pontoons which are again ballasted to lower the deck onto its supporting piers. The temporary head beam connections are made good after setting the beam accurately to level. Used in offshore oil exploration.