Utracon Overseas Pte Ltd snags SBR National Business Awards for Heavy Civil Construction
Its use of the digital control system for synchronous incremental launching of long-span bridge girders overcame the inaccessibility issue to perform girder launching works from underneath the bridge.
Incorporated in Singapore in 1998, Utracon was then a locally-registered company that was set up to compete in the highly competitive post-tensioning and bridge specialist-work sectors against the mainly established European specialists. In 2007, a spinoff namely Utracon Overseas was formed to embark on an internationalisation journey for the Group. To date, the Group has reached out to and established strong market presence in 10 countries with multiple projects in the pipeline.
Its tie-up with DYWIDAG through a license agreement and the company’s in-house R&D propelled the company to deliver quality post-tensioning products on site. Through sheer hard work and good work ethics, Utracon won over many clients and by the turn of the millennium, had emerged as the largest post-tensioning contractor in Singapore. Utracon has also excelled in the areas of bridge specialist works and system formwork, offering cost-effective and engineering-driven solutions for its clients.
Utracon was invited by its Japanese client to design, supply and operate specialised bridge launching equipment for the construction of two steel box girder bridges across Shitalakshya River and Gumti River in Bangladesh, namely the Kanchpur Second Bridge and the Gumti Second Bridge.
The bridge superstructure was made up of steel-concrete composite slabs and was supported underneath by three rows of steel box girders in the longitudinal direction. In particular, the steel superstructure of the Gumti Second Bridge weighed more than 6,700 tons over nine spans.
Utracon proposed the use of Incremental Launching Method for the erection of these bridges. The steel box girders were assembled in segments on one side of the river and pushed across the river in stages with special heavy-duty devices. After every push, the subsequent segment was connected to the rear of the preceding segment before the next launching cycle. This process was repeated until the entire steel bridge girders making up the whole length of the bridge were launched across the river into its final position.
This method overcame the inaccessibility issue to perform steel girder launching works from underneath the bridge. It is also safer because it does not use heavy lifting equipment to straddle from pier to pier. Moreover, the pushing force is only a small fraction of the weight of the steel girders, which makes the incremental launching equipment to be lighter and more economical than the normal launching gantry that typically comprises massive trusses to straddle the long bridge span.
The bridge’s steel box girders were pushed forward synchronously by incremental launching devices located at fixed locations on the river’s bank and piers. Each launching device consists of hydraulic jacks and pumps that allow movement in longitudinal, vertical, and transverse directions. In this project, Utracon came across the longest pier-to-pier span length of a bridge (i.e.,97.6m) for which the Incremental Launching Method was utilised in Utracon's work history.
Utracon designed and incorporated digital controls into the launching devices to enable remote measuring and central control over every launching location and cycle. The loadings and movements of each launching device were measured by pressure transducers and position sensors respectively. Data generated from these measuring devices was transmitted digitally to the central control unit and displayed on a touch screen. By tapping the buttons on the screen, the engineer was able to control the speed and movement of all or selected jacks and pumps, as well as to halt the entire launching operation under emergency circumstance.
Incorporating digital control technology to an otherwise traditionally operated method of incremental bridge launching has greatly improved the efficiency and safety of the construction work. By monitoring and controlling all the movements and loadings of each launching device at once, engineers are able to ensure that all the launching devices were working synchronously, which is crucial for the smooth launching of the bridge and overall workplace safety. Also, the central controller is able to quickly spot any anomalies from the screen readouts and give instructions to the operators on the ground to do troubleshooting. Consequently, the bridge launching was completed three months ahead of the given construction schedule with the company’s digitally controlled devices.
As the equipment is compact and robust, Utracon is looking forward to reusing the same equipment and technology for future incremental launching bridge construction works. Through this experience, Utracon will further seek to harness digital technology in their future construction works.
Watch the interview below to know more about their winning project: