Bangladesh Bridge Authority (BBA) is going to enforce a reduced weight limit for goods-laden vehicles on the Bangabandhu Bridge from today to enhance its durability. But the new limit is still not consistent with the recommendations made by experts over a decade ago.
In an office order issued on October 31, the BBA set a maximum weight limit of 22 tonnes for two-axle vehicles (six wheels), 30 tonnes for three-axle (10 wheels), 40 tonnes for four-axle (14 wheels) and 49 tonnes for five-axle vehicles.
Previously, there was no maximum weight limit for two-axle vehicles. The limit was 33 tonnes for three-axle vehicles, 45 to 49 tonnes for four-axle and 61.8-96 tonnes for five-axle vehicles, a BBA official said.
Experts consider overloading of vehicles as a major cause for early damage to roads and bridges. This increases the maintenance cost of roads and bridges, they said.
The 4.8-kilometre bridge on the Jamuna river, which was opened to traffic in 1998, is a vital strategic economic road, rail, energy and telecommunication link between the northern and southern parts of the country.
The enforcement of standard weight limit for vehicles, trucks in particular, on this important bridge has been overlooked for years even after a five-member committee of the Buet’s civil engineering department recommended in 2006 that international standard weight limit should be followed.
The BBA had formed the committee, comprising five Buet professors, in July 2006 after the deck of the bridge devolved cracks. According to its documents, the government never followed the recommended weight limit. It enforced a much higher limit in 2011 although a dedicated weighbridge was built simultaneously with the super structure.
The Buet committee recommended a maximum weight of 20 tonnes for two-axle truck, 25 tonnes for three-axle and a maximum 12 tonnes for each additional axle after that, subject to a minimum axle distance of 1.5 metre along the length of the vehicle.
BBA statistics show that the movement of traffic on Bangabandhu Bridge has increased manifold over the years since its inauguration in June 1998. As many as 59 lakh vehicles used the bridge in the last fiscal year, up from 8.92 lakh in 1998-99 fiscal year.
NEW WEIGHT LIMIT
The new weight limit is consistent with that in place for vehicles on other roads and bridges under the Roads and Highways Department since 2017.
After five-axle, each of the axle load would be 10 tonnes, according to the October 31 BBA order.
The authority also fixed 17 tonnes as maximum weight for second axle. For the first time, it has set a maximum weight of 5 tonnes for the front axle.
“No vehicles beyond the weight limit will be allowed to cross the bridge for the sake of durability and safety of Bangabandhu Bridge,” reads the order.
The BBA also requested all truck owners and drivers to comply with the new weight limit considering the Jamuna Bridge as a very important national infrastructure.
TRUCKERS CALL THE SHOTS?
The government has failed to enforce the international standard weight limit following protests by truck owners and drives.
In May 2005, the then communication ministry, now road transport and bridges ministry, through a gazette notification had set a maximum permissible axle load limit for motor vehicles for the first time. It fixed 13 to 15 tonnes for two axles, 22 to 25 tonnes for three axles, 25 to 33 tonnes for four axles and 35 to 38 tonnes for five axles. In June 2012, the ministry prepared a guideline on Axle Load Control Centre.
In August 2016, the authorities tried to impose fines for overloading under the guideline, but transport owners and workers damaged weighbridges in Manikganj and Chattogram on the very first day of their protest.
The government was then forced to increase the maximum weight limit for goods-laden vehicles through a November 2017 order, which states that two-axle vehicle can carry maximum 22 tonnes, three-axle maximum 30 tonnes and four-axle maximum 40 tonnes.
The Buet report in 2006 said Bangladesh had no standard for loading trucks and the government had limited control on the shape, size and weight of trucks which were using the Bangabandhu Bridge.
Unfortunately, the situation still remains unchanged, experts said.
Regarding the cracks on the bridge’s deck, five Buet professors in their report said “those developed as thermal cracks which were not considered in the design and the cracks widened as temperature had an effect on those.”
They had recommended taking immediate measures immediately to seal the cracks and impose restrictions on the weight of vehicles.
“Then the authorities repaired it [bridge] and we advised them to set a weight limit,” Prof KM Amanat, one of the five Buet professors, told The Daily Star on November 20.
Asked what impact overloading of vehicles might have on the bridge if their recommendations were not followed, he said it would cause damages to the bridge and reduce its lifespan.
Prof Amanat, a structural engineering expert, said they design a bridge and measure its load capacity following the international standard.
Regarding violation of standard weight limit, he said, “If a two-axle vehicle is allowed to carry 22 tonnes of goods instead of 15 tonnes [standard], it would cause four times more damage than the normal.”
Apart from the one at Bangabandhu Bridge, there are only three more weighbridges on the country’s two national highways -- Dhaka-Chattogram and Dhaka-Aricha.
The government has taken up a project to build 21 axle load control centres at a cost of Tk 1,630.28 crore at the entrances to different highways within June 2022.
WHAT THE BBA SAYS?
Quazi Muhammad Ferdous, chief engineer of BBA, said they didn’t set any weight limit for front axle in the existing rules for Bangabandhu Bridge.
For this reason, truckers often run overload vehicles on the bridge by loading more goods on the front axle, causing damage to the bridge, he added.
“So we were going to introduce the new weight limit, with a fixed limit for the front axle [5 tonnes],” he told The Daily Star on November 25.
Asked why they didn’t impose restrictions as per recommendations of the Buet expert committee, he said they strengthened the bridge after receiving the recommendations.
He hoped the new weight limit would prevent damage to the bridge.