Overview

The new 220,000-square-foot addition to the Scientific Center of Kuwait includes a seawater aquarium, interactive exhibits, Imax Theatre and Dhow Harbor. Located in the Salmiya district along the waterfront, the new expansion involves removal, demolition, restoration, land reclamation and new shore protection. Additional land area will be created by reclamation and extending the current promenade. 

Challenge

Located along the waterfront, the new addition required the renovation and reinforcement of the existing seawall and the relocation of intake and outfall sea water pipelines – in just six months.

The dredging contractor, Gulf Dredging & General Contracting Co. KSC, was tasked with constructing a new sea wall of armor rocks. Using wire cranes loaded on a floating barge, operators place rocks and lay pipes in alignment with existing construction. Accuracy of rocks and pipes must be sub-centimeter.

The conventional method would have required dropping buoys along the wall to guide the crane operator as well as a diver to help maintain accurate positioning. As well, all work would have to be performed in daylight for safety and visual referencing.

Gulf Dredging sought machine guidance system to help manage the process and provide visual and documented verification

Technology

• Trimble 5700 RTK base station on site
• HYDROpro Software and SPS461 GNSS on the survey boat to track underwater dredge head progress relative to the design shape
• Trimble Marine Construction (TMC) software and MPS865 Marine GNSS Receiver on the wire crane with UHF Radio from TDL 450 H connected to Trimble 5700 Base to develop and deliver accurate 3D visualization of the bucket/dredge head relative to the design in 3D to assist the operator with underwater construction work
• Proximity switch and multi-turn sensors for cable drums and slew ring monitoring

Solution

Surveyors generated the new sea wall design in layers. Each layer is uploaded to Trimble Marine Construction software on the wire crane’s computer, thus allowing the operator to place rocks and pipes to sub-centimeter accuracy. The operator can visualize each layer as its completed.

Further, the as-built surface is continually mapped and visible to the survey team to update the work progress and to calculate bill of quantities.

This solution has provided:

• Improved productivity and reduced rework and over-dredge where daily progress has increased to 50–75% than before
• Precise tolerances in 3D positioning of steel pipeline on the seabed; contract divers are no longer required
• Safety for surveyors and divers, who don’t have to be on or in the water while the crane is placing rocks or laying pipes

Moving Forward

As the new Trimble Marine Construction systems have gained client confidence and met their expectations, there is an ongoing discussion about installing more crane systems and unifying the Trimble Marine Construction packages on survey boats and cutter suction dredgers providing a common user interface and streamlined data flow between design engineers, surveyors and dredge operators.