SIBU: The 1.708km-long Durin Twinbridge across the Rajang River here is by far the longest bridge to be constructed in the Pan Borneo Highway project.
Lebuhraya Borneo Utara (LBU) Sdn Bhd, the project delivery partner for the Pan Borneo Highway in Sarawak, said works on the bridge were about one-third completed and progressing well as of June.
The Pan Borneo Highway project has no fewer than 115 bridges in Phase 1 from Telok Melano in Lundu to Miri, it said.
Construction works on the Durin Twin-Bridge come under Package 4 of the project which covers a 76km stretch from Bintangor junction in Meradong District to Sungai Kua in Selangau District.
“Foundation works on the bridge were completed in June this year.
“Driving along the bridge today one can see that both the abutments and 16 piers are at varying degrees of completion,” LBU said in its website.
An abutment is a structure built to support the lateral pressure of earth embankment on both ends of the bridge.
A pier, meanwhile, is an upright support for a structure or superstructure to raise the bridge deck to the required level above the original existing grade, serving to create head room for traffic underneath or navigational flow.
However, the hallmark of the Durin Bridge is its intricate construction technique adopted to cater to the free navigational flow underneath.
“A navigational clearance as wide as 150m underneath is mandated by Sarawak Rivers Board, making it extremely challenging to create this large span over the river.
“To overcome this challenge, the balanced cantilever bridge construction method is being used for the Durin Bridge.
“Such construction method is typically recognised by the segments of construction springing out both ways from the pier top (hammer heads), one after the other incrementally, till they meet in the middle to be joined into the span,” it said.
When completed, the Durin Bridge will rise up to about 22m from the ground.
It will mirror the existing bridge with three navigation channels, one of them 150m wide, and a height clearance of 20m.
The Borneo Post
02 August 2018