Frail Valley bridges pose a bottleneck in road expansion efforts
KATHMANDU, Feb 14: While the government has widened the encroached roads in the Kathmandu Valley, it is finding the task of constructing new bridges and maintaining the old ones quite challenging.
The Department of Roads has enlisted 26 bridges as important for expanding the road networks of the Valley.
However, bridges with just two lanes have proven incapable to ease the flow of increasing number of vehicles in the capital.
The DoR officials say that the government must carry out a detailed survey before expanding the bridges. According to Madhav Karki, chief at the Bridge section of DoR, some 17 bridges, which are already in dire need of maintenance, may get weaker if constructions are undertaken without proper survey.
“The lifespan of existing infrastructures may get shortened if we begin constructions without consulting internationally recognized experts,” said Karki.
Chief of the Kathmandu Development Authority Bhai Kaji Tiwari said that the two lane bridges have become a bottleneck at a time when the roads are expanded to six lanes to adjust to the increase in vehicular movement.
He added that the DoR has proposed the Kathmandu Valley Town Development Authority to expand the Bagmati Bridge and Dhobikhola Bridge along the Koteshwar-Maitighar road section. However, the deal is yet to get finalized.
In 2009, the DoR and the Kathmandu Road Division Office launched a joint survey to check the status of the bridges in the Valley. The survey found the bridges at Balkhu Ring Road, Tribhuvan Rajpath, Bishnumati, Balaju, Sinamangal, Dhobi Khola, Seto Pul and Shobha Bhagawati in a dire need of attention.
The office had also completed the tender process for the maintenance of the bridges at an estimated cost of Rs 35 million. Building cut off walls, check dams, abutments and filling the sand-extracted areas were major works the office aimed to carry out.
However, the project could not be implemented as the Ministry of Finance failed to allocate the necessary budget to the DoR. “In lack of budget it has become impossible to undertake periodic maintenance of bridges,” said Karki, adding, “Though the government has shown some seriousness after the collapse of the Sinamangal bridge, repairing bridges still does not fall under priority because the problems with bridges are not as readily visible as that of roads.”
´Bridges constructed before the 80s may not last a 100 years as is expected´
Former Secretary of the Ministry of Physical Planning and Works
Bridge construction is an important part of the effort to expand transportation network. The technical aspects cannot be compromised if we want to build strong bridges.
While laying the foundation, technicians must go through a detailed survey of soil quality. It is hard to guarantee that the bridges built in Nepal until 1980 were constructed keeping all aspects in mind as there was dearth of both skilled manpower and equipments at the time.
Today, the foundation of many bridges are exposed. It is a bad sign for their stability. The Sankhamul bridge is its perfect example. In such situation, expanding bridges becomes a sensitive task as their foundations need to be made stronger before the expansion.
The problem of traffic rules violations is another serious aspect that contributes to weakening of the bridges. The standard criteria for the Valley bridges is that a vehicle traveling on one side of the bridge must not weigh more than 10 tons. But at present, even the heavy lorries of 50 to 60 tons capacity are seen crossing the bridges.
Besides, the government lacks the resources to monitor the status of the bridges and reports are prepared based on naked-eye observations.
Excessive scour can cause unequal settlement of foundation or leave part of the structure unsupported causing structural failure. Bridges at Balaju, Seto Pul, Gopikrishna, Gongabu Buspark and Balkhu Ring Road are among those which have developed cracks at the foundation.
The ground under these bridges has sunk few meters due to sand mining. Though the Self Governance Act 1999 authorizes the District Development Committees and the Village Development Committees to control illegal sand extraction, the local administration itself is involved in extraction of sand and crushed pebbles from rivers as they receive huge amount of revenue by exporting the minerals to India.
The bridges at Balkhu and Dhobi Khola are also facing embankment slope failure. Rapid and unplanned development in the city has also encroached on the territory of rivers, which leads to deepening of riverbed level.
People´s tendency to urinate at bridges leads the iron bar and railings to rust.
These issues must be dealt with seriously as constructing a bridge can cost Rs 60 million to billions.