Barge-Mooring-Facilities for Transshipment of Bauxite, Guyana

Client: Oldendorff Carriers GmbH & Co. KG, Lübeck, Germany Construction Costs: ca. 2.5 Mio. USD Services: Preloading Tests, Preliminary Design, Tender Design and Tender Documents, Tender Evaluation Support, Construction Supervision Period: 2006 - 2007

For the transshipment of bauxite a Barge-Resting-Area was needed in the estuary of Berbice-River. Therefore, a jetty has been constructed for mooring barges one nautical mile north of a proposed Floating-Bridge at Berbice between Rosignol and New Amsterdam.

The jetty of the Barge-Resting-Area is the main structure carrying berthing and mooring loads from the barges.
It consists of 6 straight lined segments and 2 small end-segments with a total length of approx. 308 m. One segment has a length of approx. 44 m and a width of 8 m. Each segment consists of 2 x 24 vertically driven Greenheart-piles with a truss made of timber and ropes between the adjacent piles. A floating footbridge is placed at both sides of each segment for mooring the barges at all water-levels.

Water depth at the location is between CD -3.3 m and
CD -3.8 m. Water levels are generally expected to be between CD ?0.0 m at low water and CD +3.1 m at high water. The soil consists of a 2 m – 3 m mud-layer, followed by stiffer layers of clay, which are able to carry the loads from the structure. The currents of Berbice-River are expected to be within a limit of 4 knots for ebb and 3 knots for flood.

The main construction activities were carried out as follows:

• driving Greenheart-piles
• installing timber for the truss and structural beams
• mounting stainless steel ropes for the truss
• building and fixing floating footbridges to the jetty

Main parts are 24 pair-piles (48 Greenheart-piles) with a tip diameter of min. 23 cm and a length of more then 20 m per segment which have been driven down to approximately CD 14.5 m. After driving of piles the carpenter-work started to be carried out. The horizontal truss was arranged at CD +1.5 m and measured accordingly to the distance between the piles for producing the girders which are slid in and fixed by structural beams with nails at the supporting pile. To carry tensile forces stainless steel ropes with a size between Ø 10 mm and Ø 14 mm have been mounted at the truss round the connected pair-piles.

Along both sides of the jetty, 38 floating footbridges in two different type lengths of 14.2 m respectively 15.1 m have been fixed to the jetty body. The main parts for one footbridge are four Greenheart-Piles, arranged horizontally, to carry the loads from the barge to the jetty and to distribute the forces. To ensure the floating capability 8 buoyancy elements (glass fibre reinforced floating bodies) with a length of 5.9 m and a diameter of
Ø 376 mm are placed above the laying Greenhearts. In front of the construction, 10 respectively 11 aircraft-tyres with a dimension of outer Ø 1.25 m as boat-fenders are fixed to absorb energy of the barge during berthing.

A catwalk is installed at the top of the floating bridge to enable the mooring crew to moor barges. Additional steel parts as bollard for mooring the barges and connection anchorage between the floating bridges are installed. To ensure swim-stability at each floating bridge 2 concrete-bodies are fixed at the back of the bridge.