More Mobility and Safety with Utracon: Jurong East Modification Project
The Jurong East Modification Project (JEMP) is part of a program by the Land Transport Authority that aims at upgrading public transportation in Singapore. After the completion of JEMP and the purchase of additional trains, the capacity of the North-South and East-West Lines will be significantly increased. In addition, during peak periods, more connections will be offered to shorten waiting times and avoid overcrowded trains.
Construction also involved building two new 2.5km long rail tracks: The North & East Bound line, and the South Bound line.
The piers of the new elevated railway were built using a combination of cast in place concrete and precast prestressed segments supported on pot bearings. The individual spans of the viaducts range in length from 29.1m to 40.5m, with all the precast segments erected using mobile cranes.
Five of the spans for the South Bound line had to be installed over existing railway lines. Because the spans in this area were large, ranging from 50.5m to 70.5m, the precast segmental construction method was used for this purpose.
Utracon Structural Systems Pte Ltd, a DSI licensee since 1998, was the Post-Tensioning specialist for this project. Bonded DYWIDAG Post-Tensioning Systems were installed in all the precast prestressed beams and in the precast segments. In addition, DYWIDAG Bar Tendons were used for stressing some cast in place crossheads. Utracon supplied 7-0.6", 12-0.6", 19-0.6" and 22-0.6" DYWIDAG Strand Tendons with MA Anchorages as well as ∅ 47mm DYWIDAG Bars for this project.
Besides carrying out the post-tensioning work, Utracon was also involved in the erection and temporary stabilization of the precast segments. Each of the 94 precast segments weighed between 35t and 55t, with the piers also built out of precast segments. In those areas where the new elevated railway spans across an operational railway line, the precast segments could only be erected between 1am and 4.30am.
In order to comply with the authority’s health and safety regulations, all precast segments were temporarily stabilized by three independent mechanisms prior to stressing. Stabilization was achieved by a combination of post-tensioning bars and steel truss supports, where each level was designed to carry the full weight of the segment independently.
To facilitate the epoxy gluing of individual segments and the execution of the post-tensioning work, an elaborate double decker steel cage was designed that was supported by the overhanging steel truss. In addition, each working platform of the steel cage was equipped with independent safety catch devices to ensure that there would be no danger for train commuters. Following the erection of each individual segment, the entire steel cage and the steel truss were moved forward using hydraulic jacks.