A tale of two bridges: Padma Bridge construction costs highest in the world

[Mustang06]

Now I know that battered (inclined) piles are being driven under each of the Piers. Some are straight but some are inclined.

The inclined ones are meant for resisting the strong force due to the high river current during the rainy season. A 100 kph current is quite strong. Without adequate inclined piles, the current will cause vibration of the bridge. It is a great job done by the Chinese company!!
@Mustang06, @GeraltofRivia

Why am I tagged?

 

[Nilgiri]

Now I know that battered (inclined) piles are being driven under each of the Piers. Some are straight but some are inclined.

The inclined ones are meant for resisting the strong force due to the high river current during the rainy season. A 100 kph current is quite strong. Without adequate inclined piles, the current will cause vibration of the bridge. It is a great job done by the Chinese company!!
@Mustang06, @GeraltofRivia

Nice thread resurrection bruh.

Why am I tagged?

You must have impressed him somewhere lol.

 

[nahtanbob]

I do not think that the cost of any one bridge construction project can be compared directly with others unless both have similar features and soil, and the piles and piers have the same features, say, the same diameter and length (depth) were used.

The water flow in the Padma is about 100 km/hour (2.7 m/sec) during rainy season. So, the piling system is built to withstand this strong current. The pile dia. has been kept 2.5 m and the depth of piling is about 100 m from the river bed. To compare, we need data from the Bhupen Bridge. But, we just do not have them. So, we cannot compare.

People should understand that the bridge piles must withstand vertical as well as the heavy lateral force due to water current. So, a stronger pile system is needed. The cost of construction increased in Padma because a huge quantity of concrete was poured to fill the 2.5 m dia pile casing. My question is what is the pile dia. in the Bhupen?

Why so large pile in Padma? If the pile casing dia. is lowered to, say, 1.5 m instead of the design dia. of 2.5 m, it could have decreased the cost. But, it would have resulted in the vibration of the pile/pier system during rainy season due to fast current. Will you accept a bridge that vibrates when you pass over it? Certainly, no.

There are hundred other factors that were considered during the computerized design procedure or stress analysis, and finally, the Padma bridge is being constructed based on those design analysis. However, I have heard the piles in Padma are driven straight vertical instead of battered ones as in Jamuna. Batter pile means a pile driven at "an angle with the vertical" to resist a lateral force.

Please note that battered piles are not used in Padma, but were used in the Jamuna bridge: 6 vertical to 1 horizontal. In Jamuna, the velocity of water is about 144 km/hr, though.

144 kmph - that is extremely fast moving. are the units right ?

 

[Nilgiri]

144 kmph - that is extremely fast moving. are the units right ?

Well pointed out. 2.7 m/sec = 10 km/hr.

I think bluesky confused few units:

http://en.banglapedia.org/index.php?title=Ganges-Padma_River_System

The recorded highest flow of the Ganges was 76,000 cumec in 1981, and the maximum velocity ranging from 4-5 m/sec

Taking 5 m/sec to be the absolute maximum in the system....that is about 18 km/hr.

 

[nahtanbob]

Well pointed out. 2.7 m/sec = 10 km/hr.

I think bluesky confused few units:

http://en.banglapedia.org/index.php?title=Ganges-Padma_River_System

The recorded highest flow of the Ganges was 76,000 cumec in 1981, and the maximum velocity ranging from 4-5 m/sec

Taking 5 m/sec to be the absolute maximum in the system....that is about 18 km/hr.

I am pretty tough swimmer. I doubt I will try to swim in such fast waters

 

[Nilgiri]

I am pretty tough swimmer. I doubt I will try to swim in such fast waters

Well yeah, water is 1000 times more dense than air .

For every equivalent velocity, it is thus 1000 times more the kinetic energy.

In fact this is why its often useful to model things in water at slower speeds, even if we intend to use them in air at higher speeds....given the equivalent energies represented are the same and both are newtonian fluids....but slow moving water = cheap to produce compared to fast moving air. One would have to concern oneself with other parameters like viscosity differences (if they are relevant) in the dimensional analysis.

 

[nahtanbob]

Well yeah, water is 1000 times more dense than air .

For every equivalent velocity, it is thus 1000 times more the kinetic energy.

In fact this is why its often useful to model things in water at slower speeds, even if we intend to use them in air at higher speeds....given the equivalent energies represented are the same and both are newtonian fluids....but slow moving water = cheap to produce compared to fast moving air. One would have to concern oneself with other parameters like viscosity differences (if they are relevant) in the dimensional analysis.

even water moving at 20 kmph can be deadly

 

[bluesky]

144 kmph - that is extremely fast moving. are the units right ?

Could it be 14.4 kph? Sorry for the mistake. 14.4 kph makes it 4.0m per second. It is in Jamuna/Brahmaputra. In the Padma, the design velocity is 10.0 kph or 2.7 m/sec.

@Nilgiri

 

[Michael Corleone]

Parma bridges design and technique is like going against god and giving a middle finger to Mother Nature. The river is pretty wild and not some average river. No wonder the cost are high

Good Business for Chinese Banks and Money lenders- and Even better business for Chinese steel, cement and construction companies-



No steel and cement production could be a reason- They could ask cheap cement from Pakistan and steel from India- But the Bengali ego is too much- they will buy Cement and Steel from abroad- even If they have to pay 20 times the amount-

Our cement and ceramics meet the local demand and are exported to Middle East and surrounding countries including India. Look up crown cement alone for example. What you’re on about.

Interestingly when china builds bridges or anything in china its amazingly cheap. but same built in any other country its cost is astronomical.

BBangladesh hope not face the same fate srilanka has faced.

That’s because China is in a building spree. They have cut down cost. Where as other countries are developing from zero and taking up one project at a time with foreign help.

I am pretty tough swimmer. I doubt I will try to swim in such fast waters

Nobody swims in padma. It would be like daring to swim in the Bay of Bengal. These waters are pretty rough on average and deadly in mansoon season

 

[Nilgiri]

even water moving at 20 kmph can be deadly

Yes, this is why the same speed in a boat feels so much more powerful than a vehicle on land.

30 mph on land is no big deal...meh etc

30 knots (on water) is like OHMERGERD....because energy needed to get thru water is 1000 times more.

Could it be 14.4 kph? Sorry for the mistake. 14.4 kph makes it 4.0m per second. It is in Jamuna/Brahmaputra. In the Padma, the design velocity is 10.0 kph or 2.7 m/sec.

@Nilgiri

Yeah I guess you just put an extra factor of 10...its no biggie.

Normally having system water velocity higher than 10 m/s (so roughly 36 kmph) won't be modelled because of cavitation onset (in say most pipe or channel sizes). Nature generally has a number of speed barriers for water well before that....given the tremendous energy intensities needed for a fluid that weighs 1 tonne for just a cubic metre.

144 kmph water would be absolutely crazy. You might approach that speed in the most extreme hurricanes at the surface shear level of the ocean.

 

[Bilal9]

How competitive is whatever you have of steel and cement production units in Bangladesh ? Are there any coal, iron ore mines in Bangladesh too feed these production units or you buy them from abroad ? What about Lime for cement production ?

Bhai Google is your friend....please use it.

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Bangladesh boasts the world's largest vertical roller mill (VRM) with a 8.1m grinding table, supplied by Denmark’s FLSmidth, at Shah Cement Muktarpur plant in Munshiganj. VRM is ultramodern clinker grinding technology and only in use at newer plants.

Bangladesh cement production is import dependent and it is one of the largest importers of clinkers globally.

More below.
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23 January 2019

The Bangladeshi cement industry has been busy over the last month. Both Vietnam and Iran have marked up the country as a major destination for their exports. No change there, but Saudi Arabia has also started to join them as its producers have started announcing clinker export deals to the country. Alongside this there have also been production upgrades announced from MI Cement, Chhatak Cement and a Saudi-led partnership.

Md Shahidullah, vice president of the Bangladesh Cement Manufacturers Association (BCMA), described 2018 as a good year for the local industry to local media. Cement sales rose to 33Mt and consumption grew by 12% year-on-year.

Bangladesh has an integrated production capacity of 8.4Mt/yr from eight plants according to Global Cement Directory data. The main plants are Chhatak Cement and Lafarge Surma Cement. Locally produced clinker accounts for about 20% of the country’s needs, with the other 80% imported from abroad. Hence, the action is really with the grinding plants and the country has over 30 of them. A market report by EBL Securities in mid-2017 reckoned that local cement production capacity was 40Mt/yr but that actual production was around 32Mt in the 2016 - 2017 reporting year due to problems with power supplies and so on. Given the focus on grinding it’s interesting to note imports of clinker. These rose by 9% year-on-year to a value of US$518m in 2017 - 2018, the highest figure since 2014 - 2015. Not all of this may be consumption related since the local currency, the Taka, depreciated against the US dollar in 2017 and 2018.

Back in 2016 the market leaders were Shah Cement, LafargeHolcim Bangladesh, Bashundhara Group, Seven Rings Cement and HeidelbergCement. They accounted for about half of the market share. Of these LafargeHolcim Bangladesh saw its revenue nearly double year-on-year to US$101m from US$58m in the first half of 2018. Its profit did double to US$6.3m from US$2.7m. The company is a joint venture between LafargeHolcim, Spain’s Cementos Molins and other partners.

Bangladesh suits a grinding-based industry due to its high level of navigable waterways and low levels of limestone. In some respects though the country is a glimpse of what future cement markets might look like. Its lack of raw materials means it focuses on grinding and a clinker-rich world plays right into this. This creates an oversaturated market full of lots of companies due to the lower cost of setting up a grinding business or cement trading. In theory this should be great for end consumers and the general development of the country. After all Bangladesh has a high population, of 164 million, and a low gross domestic product (GDP) per capita, US$4561, and similarly low per capita consumption of cement. The downside though is that reliance on external raw materials. Any changes to exchange rates or material supply puts the entire industry at risk or puts prices in flux. In the meantime though the interest by Saudi exporters adds an interesting dynamic to a crowded market.

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http://www.eblsecurities.com/AM_Res... Review of the Bangladesh Cement Industry.pdf