Sokkia Singapore
Singapore now boasts of the world’s tallest Ferris wheel, the Singapore Flyer. It made its first flight in February 2008. UTOC Engineering Pte Ltd used a SOKKIA NET1200 to overcome the various challenges associated with the construction of a world record-setting structure.
The Singapore Flyer occupies a land area of 33,700 square meters along the Marina Promenade. Standing at a height of 165 meters, the Singapore Flyer features 28 air-conditioned capsules capable of holding 27 passengers each. The wheel has a diameter of 150 meters and one full rotation will take 37 minutes.
CHALLENGES IN CONSTRUCTION AND THE DECISION TO USE NET1200
The task of constructing the massive support columns and rim structure (wheel) was in the hands of the project managers and engineers from UTOC Engineering Pte Ltd.
Many challenges surfaced during the construction, the most pressing of which were the construction of the upright support columns within strict tolerances and the constant monitoring of the effects of the strong ocean winds on the rim structure.
Another challenge was presented by the conditions of the site itself. The Marina Promenade is a narrow peninsula of reclaimed land adjacent to the downtown business district of Singapore. Limited working space and the presence of the giant crank station was a challenge during construction. The tip of the support structure stands 85 meters high and the cramped work space required a steep zenith angle to perform a nearly impossible vertical measurement.
The solution to this problem started with a reference to a base line running across the base of the two support columns which required both good surveying technique and a high-precision total station. The next set of challenges was presented by the spindle which forms the axis of the giant Ferris wheel. The spindle is fitted to both sides of the support structure and has more than two thousand bolts, which required each hole to be measured in relation to the others before the actual fitting process began. This required an extreme amount of patience and a highly accurate, easy to use instrument to minimize operator fatigue. The spindle itself weighs 180 tons and holds 112 radial cables that support the rim structure and the lifting operation to attach the spindle was the most critical part of the entire construction process.
While the engineers were busy fitting the spindle, the support structure had to be constantly monitored to ensure that both ends of the spindle were level despite differences in lifting speeds of the four lifting jacks used. This required an instrument that was both fast and accurate.
To overcome the challenges in this high-precision three dimensional structural project, the construction of the Singapore Flyer required special attention to be paid to surveying techniques and a high performance instrument. The decision was made to use a SOKKIA NET1200 3D station. SOKKIA’s NET1200 is an ultra-high performance 3D station. When utilized with SDR4000 3D measurement software installed on a data collector, NET1200 can measure and compare points in three dimensions to ensure the highest precision.
This system does not require a known control point as it can establish a coordinate system by measuring two or three convenient points on site. This allows freedom of mobility so engineers can set up the instrument at any location to monitor the structure.
Using the NET1200, engineers were able to confidently measure the tip of the 165 meter tall support rim within the space constraints of the site. Using these measurements, the relation to any point along the support rim or wheel structure could be easily computed, greatly reducing working hours and operator fatigue when monitoring the entire structure.
SUCCESSFUL CONSTRUCTION STARTS WITH SUCCESSFUL PLANNING
Construction began with the assembly of the two support structures section by section. Once the supports were completed, the spindle was installed. Installing the spindle was the most important part of the entire process and was accomplished after an exhausting 12-hour operation.
Once the spindle was in place, the segments of the rim structure were installed one at a time.
The final stage of the operation was lifting the capsules to be fitted to the perimeter of the rim structure. Throughout the entire operation SOKKIA reflective sheets were used at 200 points. Working closely with structural and design engineers, UTOC surveying engineers pre-planned and attached reflective sheets to the support and rim structure components on the ground before actual construction began.
Prior to construction, SOKKIA conducted on-site training for the project team to simulate the actual working conditions and made regular visits to the site and project team.
This was done to ensure that each member was fully competent in using the system. During this process, NET1200 was only sent back once for general maintenance and cleaning as required every six months according to the service contract. Surveyors used advanced technology to make one of the most scenic tourist attractions in the world possible Construction progressed smoothly and the Singapore Flyer was completed days ahead of schedule.
NET1200 successfully accomplished the task of surveying one of the most scenic tourist attractions in the world – The Singapore Flyer.
