Cable Bridge over Kelani River – major engineering feat
By Aditya Abeysinghe
Sri Lanka’s first Cable Bridge, a great engineering achievement is planned to be opened to public in July, 2021. Funding for the project is provided as a loan by the Japan International Cooperation Agency (JICA) with a financial assistance of 35,020 million Japanese Yen.
Due to the high volume of traffic entering Colombo City, the need for a new link bridge to reduce the traffic over the current bridge and its urban surroundings were planned over a long period. Hence, the Government of Sri Lanka began constructing a new elevated road project in 2014 running parallel to the current bridge (above *Kelani River) and extending to urban areas in Colombo by the river such as *Dematagoda and *Baseline road.
The new bridge is built as a cable suspension bridge to withstand harsh environmental conditions and wear out of the bridge over time. It is the first state of the art cable bridge that will be opened for traffic in Sri Lanka. The road will be composed of six lanes with access roads and interchanges. The project has been allocated 12.9 hectares of land and will also connect the Colombo-Katunayake Expressway (the expressway that links Colombo City with Colombo International Airport, a significant engineering achievement linking a highway network in Sri Lanka). The new bridge will start from the *Peliyagoda exit of the Colombo-Katunayake Expressway and divide towards the Port Access Road and the *Baseline Road. Baseline Road traffic will be covered by the traffic entering from Negombo Road and Kandy Road. The project is constructed in two phases: the steel bridge section and the extradosed bridge section. The construction of the steel bridge section started on 19th December 2017 and the construction of the extradosed bridge section started on 18th October 2017. Over 80% of the project composed of two phases is completed as of this writing.
The steel bridge section is a 2329 m long section and consists of 922 m of steel bridge and 1407 m of interchanges and ramps. It is 20.5 m wide and covers areas like Baseline road, i.e. Orugodawatta junction to Kelanitissa junction, Kelanitissa ramp area, Kelanitissa junction, Port Access road, i.e. Kelanitissa junction to Ingurukade junction and Ingurukade junction to Port, and Avissawella road, i.e. Orugudawatta junction to Stace road. The extradosed bridge section is a 1185 m long and 28.4 m wide section and spans over the Kelani river.
This road will have box-girders 5.6 m high at the pylon locations and box-girders 3.3 m high at the midspan and the two ends. Two U-shaped pylon structures have been used for a twin tower configuration to support the 24-stay cable structure stemming from each tower. Each tower is 29 meters high and supports the box-girders and rise of the piers. Each stay cable structure is attached to a 30.4 meter wide bridge deck and is composed of Expanded Lineup Epoxy Coated and Filled (ECF) cables.
After construction the new road will connect the Katunayake Expressway with the *Rajagiriya-*Battaramulla Outer Circular Highway. The entire length of the proposed highway is 8.1 kilometers and is composed of two components – a 6.9 kilometers road from the new Kelani Bridge to Rajagiriya and a 1.2 km road from *Baseline Road to *Dematagoda. The road from the new Kelani Bridge to *Rajagiriya will be built with on and off ramps.
Kelani River is the widest river in Sri Lanka and since British Colonial Era constructing bridges over this river at Peliyagoda has been considered as a major engineering feat. Hence, several bridges have been constructed over Kelani River at Peliyagoda joining Colombo and *Gampaha Districts with the first bridge being constructed in 1822. Since then, the Victoria Bridge (Kelani Bridge) constructed in 1895 and the current bridge have replaced the first bridge, easing the traffic congestion entering Colombo from the North.
- Baseline Road – A road in Colombo, Baseline Road passes through Dematagoda. Baseline Road is about 4.5 kilometers from Colombo Fort.
- Battaramulla – Situated about five kilometers from Colombo City, Battaramulla is situated near the Parliament of Sri Lanka.
- Dematagoda – A suburb in Colombo, Dematagoda is represented by Divisional Code 9 (Colombo 9).
- Gampaha – Situated north-east of Colombo City, Gampaha is a major town in Gampaha District of Western Province.
- Kelani River – Ranking as the foruth longest river in Sri Lanka, Kelani River is 145 kilometers long.
- Peliyagoda – Situated on the north shore of Kelani River, Peliyagoda is the entry point to Airport Expressway.
- Rajagiriya – A large suburb bordering Colombo, Rajagiriya is part of Sri Lanka’s administrative capital Sri Jayawardenapura.