The construction of the 1.7km long landmark bridge with 500m main span cable-stayed across Sg. Johor is lead by Design & Build Contractor, Ranhill Engineers & Constructors Sdn Bhd. The two main pylon structures for this bridge each have a height of 150m.
-- SALIENT TECHNICAL FEATURES --
The construction works for this bridge is both technically and environmentally challenging. The engineering works for this major cable-stayed bridge is being undertaken by Ranhill Cowi (Denmark) Joint Venture. This bridge, when completed, will be one of the longest single plane cable –stayed bridges in the world. For Ranhill, this will be the second cable stayed bridge that it has successfully completed, the first being the 640m long Sg. Muar Cable Stayed Bridge under the Muar Bypass Project completed in the year 2005.
A 740m long span composite steel and concrete box girder is used for the main span and side spans of the cable-stayed portion of the structure. The remaining 968m of approach deck (484 m on each side) are structured using an all concrete multi-cell box girder section.
The foundation for the two main pylons utilise 2,000 mm diameter bored piles encased in 19mm thick steel casing with 5.5 m thick cast in-situ reinforced concrete pile caps. The abutments and the 10 piers on either side of the river for the approach spans are founded on 600 mm and 1000mm diameter spun piles with 2.5 m thick cast in-situ reinforced concrete piles. The height of the cast-in situ reinforced concrete piers ranges from 3 m to 17 m. The piers are spaced at 48 m centres.
A jump form system is used for the construction of the two main pylons utilizing a 6 m jump. After casting each 6 m segment, the form is advanced and set for the placing of rebar and concrete in the next segment. A tower crane is used to deliver reinforcement and concrete from the material delivery barges to the working platform of the jump form.
The construction of the main span is accomplished using a Balanced Cantilever Method Starting at each of the main pylons with Derrick Cranes lifting the composite Steel Girder off a delivery barge and supporting it while it is attached to the rest of the structure. The components of the Composite Steel Girder Sections will be fabricated in Jiujang, Chine before being shipped to Malaysia where they will be assembled to the individual deck segments at the storage/casting yard at Tanjong Penyabong on the east riverbank of Sg. Johor.
This is where the majority of the welding, painting and erection works will be carried out. A temporary jetty will be constructed near the storage/casting yard to load each of the 61 deck segments that make up the composite deck onto the marine delivery barge for transportation to the erection site.
For the approach span, an Incremental Launching Method will be used in which the completed portion of the structure is “pushed” forward to permit casting of the subsequent segments. In order to achieve this special purpose, Incremental Launching Yards are constructed at each at each abutment bridge. The yards will be the working area for the preparation of formwork, reinforcement, casting, stressing and launching of the approach span concrete box girder. The approach spans will be cast in 12m long sections and will be moved out into their final position in 24 m stages. A specially designed steel launching nose will be removed upon successful completion of the launching.