By Team Mangalorean

MANGALORE, February 15, 2010: The National Highway Mangalore division is in a fix, it can’t find contractors to repair the NH 48 stretch in the Shirady ghat. Contractors who have carried out the repair and relaying work on this stretch are unsure of giving warranty to the longevity of the road. They want the government to control the overloading of trucks that carry iron and manganese fines to the New Mangalore Port.

The Shirady ghat section was closed for traffic in October 2007 following the complete erosion of the road due to heavy movement of overloaded trucks.

Speaking to Mangalorean.com one of the contractors who carried out a part of the work on the stretch last time Ramesh Kumar Kottari told that he and two other contractors were ready to give warranty to the road provided the government adheres to the recommendations of the Indian Road Congress on over loading. “According to the recommendations a truck with 6 wheels can carry up to 10 tonnes and truck with 10 wheels can carry up to 16 tonnes. But the Transport authorities were allowing them to carry 40 tonnes”.

“Overloading is a universal problem; all roads in the state were being eroded due to the overloading. The only way it could be stopped was by strictly enforcing the loading discipline. The PWD has issued circulars to all the deputy commissioners of all the districts in the state to adopt zero tolerance stands towards overloading” says an official at NH Mangalore.

A paper by Balabhaskara Reddy, senior structural engineer, and A.Veeraraghavan of Bangalore University, which has been entitled "Effects of overloading and introduction of tandem-axle trucks on pavement life", highlights the structural damage to a pavement system caused by overloaded commercial vehicles.

The paper says overloading of trucks has assumed menacing proportions in the country. The structural adequacy of the pavement on National Highways is inadequate to withstand the increased magnitude of axle loads. The multi-axle vehicles reduce the impact of motion on the road and distribute the weight of the vehicle and the load evenly.

 Executive Engineer of State National Highways S. Gopal says to minimise the intensity of damage, the National Highways, has recommended to the Government that weighbridges be constructed along the highways to bind the operators to conform to the rules and Registered Laden Weight (RLW) norms. The life of the roads with three layers of metal is three to five years depending on the volume of traffic. The lifespan is calculated on the basis of 10,000 passenger car units (PCU). One bus is equated to eight PCUs. The thickness of the road is determined on the basis of the California bearing ratio which is based on the potential load-carrying capacity.

The National Highways reports show that the percentage of vehicles moving on National Highway 48 with single rear axles (exceeding the prescribed 10.2 tonnes of load) was 55.3. Tandem-axle vehicles exceeding the prescribed 18 tonnes form 42.9 percent. The last review of the situation was made in 2003 which showed that the percentage would increase at 2.5 per cent a year.

The excessive wear and tear of National Highways, particularly at the curves, has been attributed to single-axle overloaded trucks.