Padma Bridge Rail Link: Tweak rail design to let tall vehicles pass

In a major setback, Padma Bridge Rail Link Project authorities have been asked to change its viaduct designs as the poor clearance of bridges would impede large lorries on approach roads.

The Cabinet Division gave the directives recently after the Padma Multipurpose Bridge Project (PMBP) authorities expressed serious concerns because the designed viaducts for rail use have left too little clearance for tall vehicles that might use the roads underneath.

Viaduct designs for both ends of the bridge have the same issues.

Judging by the international standards for national highways, both the vertical and horizontal clearances are too small, and hence the faulty design should be amended, PMBP authorities said.

Padma Bridge Rail Link Project (PBRLP) designed the viaducts.

PMBP officials said construction of viaducts with the existing vertical limit will hamper movement of heavy lorries or loaded vehicles and the existing horizontal limit will shrink the width of the connecting roads of the country's longest bridge.

Rail link authorities claimed that the problem regarding vertical clearance actually arose over pier -25(1) and -25(2), and their contractor is redesigning it now. The task would not take more than a month, officials said.

Besides, the officials are now consulting with Buet experts to find alternative solutions to the problem regarding horizontal limits.

The PBRLP authorities stopped the construction work of the pier in question in mid-July, amid opposition from the BMBP authorities.

However, this will have no effect on the overall cost and duration of the project, PBRLP authorities claimed.

"The Cabinet Division has given us some instructions for redesigning and we are following those," PBRLP Director Golam Fakhruddin Ahmed Chowdhury told The Daily Star on Wednesday.

Both PMBP and PBRLP are fast-track projects.

Bangladesh Bridge Authority (BBA) is implementing the much-hyped PMBP at a cost of Tk 30,193 crore to connect the country's southwestern region with the capital via road and rail lines.

On the other hand, Bangladesh Railway is implementing "Padma Bridge Rail Link Project" to connect the capital with Jashore with a 169km rail line over the under-construction Padma bridge at a cost of Tk 39,246-crore.

The trains will use the lower deck of the 6.15km double-deck bridge and vehicles would use the road above.

But because rail tracks require much longer slopes than roads do, the rail lines will pass over the connecting roads on either side of the bridge. 

And at the points, where the rail viaducts would be constructed over the roads, the standard clearance between the road and the lowest part of the viaduct should be 5.7 metres, so that all types of vehicles can operate smoothly.

Besides, a national highway needs to have a standard horizontal limit of 15.50 metres, officials said.

"But, thier [PBRLP] vertical and horizontal limits are shorter than what is needed on the national highway on both sides of the bridge," PMBP Director Shafiqul Islam told The Daily Star on Tuesday.

"They have deviated from the standard. I have informed the authorities about it," he said.

BBA Executive Director Belayet Hossain said if railway viaducts are built according to the current design, large lorries will not be able to use the bridge.

"The cabinet secretary sir has asked them [PBRLP] to redesign it," he told this correspondent.

The PBRLP held a meeting on August 19 to resolve the issue and a letter it sent to the authorities concerned shows some details of the problem.

The connecting road of the Padma bridge goes underneath the pier no 25(1) and 25(2) of railway viaduct at the Janjira end of the bridge.

When the contractor of PBRLP, upon informing PMBP authority, dug the road to install pile caps of the piers, PMBP on July 19 asked the contractor to stop the work and also sought documents about the vertical and horizontal clearance of the piers and the design of the crossing point, reads the letter.

The contractor stopped the work and the PBRLP sent those documents. The vertical limit between the bottom of the piers and connecting road is 5.51 metres and horizontal clearance between the two piers would be 9.65 metres, the letter mentioned.

The letter, however, mentioned the width of the connecting road as 9.36 metres.

But, the PMBP authority said the vertical and horizontal limit is not enough and those should be 6 metres and 15.5 metres respectively.

The letter mentioned that the design of the PBRLP was prepared taking the opinion from BBA in 2015 and the issue was discussed at the meetings of the interface committee of the both the projects.

Besides, construction of all piles of piers 25(1) and 25(2) and pier no 27 to 47 have already been completed. So it's not possible to change the level of the rail lines, reads the letter.

The PBRLP authority, rather, suggested lowering the level of the connecting road to maintain the expected vertical limit and they would do it from their project.

But, the PMBP authority said the design is not acceptable at all.

WHAT PD'S OF PBRLP AND PMBP SAYS

Golam Fakhruddin Ahmed Chowdhury said, "This is not a problem. We have received a requirement proposal, which we are adjusting now."

Replying to a question he said, "Deviation has occurred only regarding pier no 25, which is being fixed now."

Asked about Fakhruddin's claim, PMBP's Director Shafiqul Islam said, "No. This is not correct. Our objection is over the design of viaducts on both sides of the bridge and regarding both the vertical and horizontal limits."

Asked whether they have to change the design of all 21 piers (No 27 to 47) and reconstruct those, Fakhruddin said no. "We have to change only the pier no 25. There is no problem regarding the other piers."

The contractor has already been instructed to redesign the piers and it may take a maximum one month to do that, he added.

Regarding BBA and PMBP authorities' objection over horizontal clearance, Fakhruddin said, "We will try to divert the road."

Asked whether PMBP will accept the proposal, he said, "We will discuss the matter. We are talking with the BUET experts in this regard and will definitely find a solution."

He claimed it would not have any impact on the cost and duration of the total project as works are going on at the other parts of the project.

BBA Executive Director Belayet Hossain and Railways Ministry Secretary Salim Reza and top officials of both projects will visit the project site today.

"Directives have already been given to solve the problem. We will go and see how to implement those," Belayet said.