Tuesday, 19 March 2019, Sibu: The construction of the Batang Rajang Bridge or more popularly known as Durin Bridge will be seeing the completion of its first closing segment or “stitching process”, tentatively in April this year.
With the stitching process underway, it means that the construction work on this 1.708km bridge, the longest in the whole of Pan Borneo Highway Sarawak project, has reached another significant milestone!
Half of the bridge from the mid-point towards Durin is now substantially completed and is ahead of schedule. At the other end, the other half of the bridge from the mid-point towards Sibu is progressing smoothly, and is also similarly ahead of schedule. The closing segments will be achieved by the early fourth quarter of this year.
“Five out of 17 spans of this box girder bridge need to undergo the stitching process to close the segment in between two adjoining piers.
“The process literally is a designated construction sequence to close the last segment, or gap, between the edges of two opposite cantilever segments (or between the end of an incremental girder and the end of a cantilever segment) to form a complete continuous span.
"This current closing segment (No. 1) will help connect or join (stitch) together the cantilever segment at the far end of Pier No. 12 (River Pier) and the far end of incremental girder at Pier No. 13 (Land Pier), thus forming a continuous span (or bridge deck) between the two Piers 12 and 13. Once this is done, we will have a two-lane highway on this brand new bridge deck!
“When the process is completed, then we can move on to do the parapet wall and the road furniture,” said LBU Construction Manager for Batang Rajang Section Wesley Chong.
The construction of this Durin Bridge comes under Batang Rajang Section of Bintangor Junction- Julau Junction & Sibu Airport-Sungai Kua Bridge works package (Works Package 07). The other two Sections are Julau Section and Sibu Section.
Four stages will be involved in the process of completing the casting of each one of the five closing segments (stitching). The first stage, according to Wesley, is to install and stress the horizontal cross bracings.
“And this will be followed by Stage 2 process, which is to adjust the vertical alignment between the ends of the two opposing cantilever segments, by using clamping trusses and carefully pulling them to match the level at the top.
“Obviously, a lot of similar fine adjustments have been carried out earlier too during the stressing process of each of the completed segment (a total of 34 segments at Pier No. 12) before we arrive at this stage of closing segment, indicating that a lot of meticulous, careful and painstaking engineering work have already gone into the works during the construction process, which is a distinctive characteristic of this type of intricate and precision construction.
“Once this is done to the satisfaction of the Supervision Consultants, it is time to move on to Stage 3, which is to install the closing segment formwork to fix the closing segment in its rightful place, along with other necessary reinforcement etc.
“Finally, it is all set to get on to Stage 4, that is the casting (using very high strength concrete) of the closing segment. It will of course be followed by the stressing of the bottom tendons of this closing segment upon the concrete maturing to the required strength,” Wesley elaborated.
As for the configuration of the bridge in consideration of its navigational capabilities underneath, the bridge will see two navigational clearances, each with a horizontal width of 110m and a vertical clearance of 20m under the bridge soffit created. This is mandated by the Sarawak Rivers Board, making it truly challenging to create this large span width over the mighty Batang Rajang.
When completed, Batang Rajang Bridge will rise up to about 22m from the approach ground. It will mirror the existing bridge with two navigation channels as noted above.
The main contractor for Works Package 07 is Hock Seng Lee Berhad-Dhaya Maju Infrastructure (Asia) JV Sdn Bhd