Linking expressways with major roads:

Colombo Outer Circular expressway first phase opens next month

By Ranil Wijayapala

Minister Nirmala Kothalawala

Project Engineer Wimal Kandambi

The Outer Circular Expressway to link major expressway projects such as the Southern Expressway, Northern and Kandy expressways and other major roads such as Colombo - Avissawella, Colombo - Kandy and Colombo - Negombo roads through an outer ring of Colombo city is now progressing with the completion of its first phase from Kottawa to Kaduwela.

It was decades ago that the idea of reducing the huge traffic congestion within the Colombo metropolitan area was highlighted to make easier and comfortable the visits to the commercial capital for the general public. Hence constructing the outer circular road to facilitate the vehicles to bypass the routes within the Colombo city limits when travelling to outstations was considered the most appropriate and effective way of achieving this task.

The 3.3 Km viaduct of the Outer Circular expressway going through a marshy land near Kaduwela. Pix: Tilak Perera

Overpasses constructed across the expressway

Kottawa entry point

The Kottawa interchange to link the Southern expressway and the Outers Circular expressway

Side view of the 3.3 km viaduct

Temporary interchange at Kothalawala, Kaduwela under construction

Though the concept was available for a long period, the implementation of that concept was delayed due to various reasons. But today that concept is becoming a reality in a step-by-step process along with other mega expressways that are being constructed to provide speedy access to various parts of the country.

"The first phase of the Outer Circular Expressway as an extension of the southern expressway is due to be open for the motorists on March 8 making yet another leap forward in the road development sector", Project Minister of Ports, Shipping and Highways Nirmala Kothalawala said.

"Through this expressway we are trying to minimise the traffic congestion within the Colombo city and also to encourage the development of Colombo suburbs as major townships", the Minister said.

"We are hoping to develop the Colombo suburban cities such as Kottawa, Kaduwela and Kadawatha along with this project, he said.

He said all these endeavours are becoming successful due to the leadership of President Mahinda Rajapaksa to give a brighter future for the people in this country.

"Before opening for the motorists by President Mahinda Rajapaksa on March 8 we are opening the expressway for public view on March 4 and 5 . We are inviting people to walk along and see the longest bridge-like viaduct in the country during this period", the Minister said.

Explaining the details of the project and its construction aspect Project Engineer of the Outer Circular Expressway project Wimal Kandambi said the expressway starts from end point of the Southern Expressway and runs upto Kerawalapitiya once all the phases of the project are completed.

The total length of the expressway is 29.1 kilometres and it is divided into three phases. The first 11 kilometres run from Kottawa to Kaduwela. The second phase from Kaduwela to Kadawatha (8.9 kilometres) while the third phase runs from Kadawatha to Kerawalapitiya. The length of that section will be 9.3 kilometres.

"The phase one of the project from Kottawa to Kaduwela is now getting ready for the opening with the completion of the construction work by February 28", he said.

The cost involved for the first phase is Rs.24.9 billion and it is funded by the Japanese International Cooperation Agency. The China Harbour Engineering Corporation is the main contractor of the project and the Oriental Consultant Ltd is acting as the constancy agency for the project.

This phase was started in December 2009 and it was due to be completed on May 31, 2013. "But due to various reasons it could not be completed but now the road is going to be open very soon", Kandambi said.

There will be three interchanges for the first phase of the project, one will be at Kottawa at the end point of the Southern expressway, the other at Kothalawala, Kaduwela to connect the expressway with Malabe - Kaduwela road or the new Kandy Road. In between there will be another interchange at Pore' Athurugiriya to connect the expressway with Malabe - Godagama Road.

"But we have not started the construction work at Pore' and work will commence only after the opening of the expressway", he said.

"Though we are having an interchange at Kothalawala, Kaduwela to open the first phase of the project, the permanent structure for the Kaduwela interchange also comes under the phase II of the project. It is scheduled to be completed in another year. Therefore, a temporary interchange has been constructed at Kothalawala, Kaduwela to facilitate the opening of the first phase of the project on March 8", he said.

Within the first phase of the project there are eight overpasses and two underpasses. "The two underpasses will be for the Kelani Valley railway line and for the Homagama hospital road at Homagama area.

The eight overpasses will be for Colombo - Avissawella road, Kottawa - Athurugiriya road, Balika Nivasa road, Nugemulla road, Horahena road, Suhada Mawatha, Malabe - Godagama road and for Malabe - Kaduwela road. There are also 78 box culverts and pipe culverts to facilitate the road", he said.

Viaduct

One of the prominent features of this expressway is the 3.3 kilometre long viaduct constructed to have this expressway on elevated form across the marshy land in Mahawela between Pore' and Kothalawala. "This will be the longest viaduct or the bridge in Sri Lanka", Kandambi said.

"If we fill the marshy land, the retention capacity of the marshy land will be drastically reduced creating huge flood in the area. To prevent that we built the expressway on viaduct. If we compare the cost, the viaduct construction cost is a little high compared to the embankment construction. But environmentally that is a very big saving as it reduced the environmental impact", Kandambi said.

"This is a very good concept that we adopted for the Outer Circular expressway, and for all the phases of the project we adopted the same concept especially when the expressway is going through the marshy lands and paddy lands", he said.

Construction of the 3.3 kilometre viaduct was a challenging task and it was constructed on pile foundation. There are 756 piles, 92 pile caps, 92 pier stems, and 930 beams to complete the viaduct. It took more than two years to construct this viaduct.

"Chinese mechanism was used in this construction to remove the beam placing equipment from one stand to the other without dismantling it. That mechanism saved a lot of time," he said.

For the embankment construction soil treatment was done to enhance soil strength to suit the construction purpose, he said.

"Initially we planned this road for vehicle speed of 80 kilometres per hour. But later it was planned as a Southern expressway continuation. So the design speed was increased to 100 kilometres per hour. But since the viaduct section was completed by that time it was difficult to change design speed in the viaduct area. So for a section of the viaduct we limited the speed to 80 kilometres per hour and installed variable speed limits", he said.

Environmental aspect

"We considered the entire environment surrounding the project and we received environmental clearance and guidelines from the Central Environment Authority.

The contractor was required to provide all the information at the bidding stage.

We have to make sure that the contractor is adopting the environmental management plan at the implementing stage", he said.

Mechanisms were also adopted to measure the damages to the houses lying within 50 metres distance either side of the road. There are 480 houses and buildings which lie within this periphery.

We have a big file for every house within that periphery and we have all the details of the house before the construction commenced. If they have a crack in the walls we measure the crack from time to time. Likewise we have a big file for each house.

"Before the start we did the precondition survey and marked all the damages in those buildings. If there are any cracks developing in those buildings based on the public complaints we will have an intermediate survey to ascertain whether the cracks are severe. If cracks are severe and the building is not safe for the people to live we take people out and they will be paid a monthly rent for the new place", explaining the measures taken to measure the damages to nearby houses during the construction period, he said.

Once the project is completed a final condition survey will be done and the damages will be estimated by comparing the pre-condition survey and the final survey.

"We selected the National Building Research Organisation to estimate whatever the damage. Then that damage will be compensated", he said.

Explaining the measures taken to ensure more environmental friendly measures, Kandambi said animal underpasses have also been established where the paddy lands are separated due to road construction.

He said measures have also been taken to implement the project as quality assurance project by checking all the material used by the contractor for the construction before using it for any construction work.

"We were strict on quality and we ensured 100 percent quality of the material used for the project", he said.