The Benjamin Sheares Bridge

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NET monitor perfectly even in the harshest of conditions

sin01.jpgOpened in 1981, the Benjamin Sheares Bridge is the longest bridge in Singapore, spanning 1.8km. It is also the tallest, at 20m. The bridge was named to honor Dr. Benjamin Henry Sheares, the second president of the Republic. Built over reclaimed land, the bridge is made of pre-stressed concrete and links East Coast Parkway on to Marina Bay on the west coast.

The Marina Bay Bridge across Marina Bay was officially opened on April 24, 2010. There are two components to the new bridge – a six-lane roadway for vehicle sand a six-meter-wide curved pedestrian connection that overlooks Marina Bay. The spiral-shaped pedestrian bridge, called the Helix Bridge, is 280m long, while the Bayfront Bridge, spanning 303m, was picked for the parallel bridge for vehicles.

The Bayfront Bridge provides a direct connection between Marina Centre and Marina South. The opening of this new road network will provide vehicular access to the upcoming developments in the Marina Bay area, such as the Marina Bay Sands Integrated Resort Gardens by the Bay and the Marina Bay Financial Centre.

Monitoring Solution Providers Pte Ltd, (MSP), was involved in monitoring the movement of the Benjamin Sheares Bridge and later, the Bayfront Bridge under Land Transport Authority Contract 905.*sin05.jpg

*Contract 905 is for the design, construction and completion of tunnels between Promenade Station and Marina Bay.

To carry on the project, MSP was requested to overcome severe conditions: the monitoring instruments must have high ratings in dust and water protection since the instruments are placed on the pile cap that sat on the water of Singapore River; plus, power consumption of all equipment used must be kept to a bare minimum due to the lack of constant power supply.

This project was the first use of NET for bridge movement monitoring in severe environmental conditions. They have few worries about the lifespan of the instrument and how often it will break down, to troubleshoot the instruments. To reach the instruments, workers had to hire a boat to reach the pile cap where the instruments are installed. It was also important to make sure the instruments would not rust and stay durable an entire year.

sin04.jpgAnother major challenge for the NET system was the fact there were no continue power supply on the pile cap; this was the first time for the NET system to constantly monitor a job site without continuous power. MSP Engineer came up with a solution to take the public lighting power which operates only form 7p.m. to 7a.m. The engineer visited the monitor site every two weeks with a control box that included PDA, battery charger, power converter, sin03.jpgtimer, four car batteries with which the PDA can last for two weeks.

There, software linked the PDA and server together for downloading data and updating the software from the instruments.

Kenny Lim, Managing Director of MSP, said, “For the design of the instrument stand, we need to consider the vibration created by the vehicles that travel on the bridge, the heat, the sunlight and the rain. To reduce the vibration, they place a 5mm rubber mat underneath the instruments. To avoid the direct sunlight heat, they install additional sleeves outside the stand with 20mm gaps to allow the heat to escape. To be honest, we feel easy on rain damage because the instruments are environmentally rated to IP64.

After the installations, he said, “Our confidence in the durability of the instruments increased because the data processing team examined the data closely for the next six months to ensure the accuracy was constant.

“A year later, we continue to observe the raw data to make sure it still maintains the highest accuracy. Even during periods of heavy rain the instrument were still monitoring perfectly. After year of monitoring, we can attest that NET is a good and reliable product,” Lim said.

“MSP owns more than 80 NET instruments now. On our customer concerns were whether MSP are able to deliver and complete in time, with the NET 1m red laser guide and Auto lock center, it gave us a lot faster without looking into the instrument during teaching the prisms.”

Lim said: “With the combination of instruments and customized software, we have a decided edge over our competitors.”

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The Benjamin Sheares Bridge PDF icon [3,940KB]

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