Question to civil engineers here

[shadowdragon]

Well I am no civil engineer and unqualified to comment. But I heard from my CE friends that you need to have a foundation depth below ground of at least one third or one fourth of the height above ground, of which part of it can be basement parking....

For super-talls like the 111 story tower planned in Dhaka's suburbs, the foundation supposedly will need to be at least 15 or 20 stories deep, maybe more.

Please correct me if I'm wrong.

Yep you are correct.. the more high rise a building the more load it has.. which has to be transmitted below ground and those layers of foundation are given to it depending on the load and type of soil.. but these type cost very much and I think Dhaka lies on the seismic activity lines... So it would be unwise to construct it in such a manner....

 

[serenity]

I did not know Dhaka is mostly silt. Silt is very unstable and hard to build on. Unpredictable and water saturation behavior makes it harder. But there is no bedrock? Usually just deep pile down to bedrock and have foundation floors designed to suit with many stories underground. If bedrock is not accessible then forget about really tall buildings. Especially if wind is another big factor.

 

[Michael Corleone]

Is it even possible to build iconic tower in bd?

 

[bluesky]

I did not know Dhaka is mostly silt. Silt is very unstable and hard to build on. Unpredictable and water saturation behavior makes it harder. But there is no bedrock? Usually just deep pile down to bedrock and have foundation floors designed to suit with many stories underground. If bedrock is not accessible then forget about really tall buildings. Especially if wind is another big factor.

I am not sure maybe in some places in the north there are subsoil bedrocks in the shallow depth of 100m because it is near the Himalayas but not in Dhaka.

So, only the Friction Piles can be used in or near Dhaka. But, even the silts, clays, or sands are also very loose in BD because it is a delta created by soils from the Himalayas that will not give the needed upward frictional resistance to the piles needed to withstand the imposed Dead, Live, Wind, and/ or Seismic Loads.

So, high-rise structures may not be feasible in BD/ Dhaka.

 

[SpaceMan18]

Is it even possible to build iconic tower in bd?

Idek lol , but apparently they’re still going with the project.

 

[bluesky]

Idek lol , but apparently they’re still going with the project.

I could not find a video where that initiator (I forgot his name, a Hindu) was lamenting that he went to BD 39 times but the govt did not respond.

By the way, how do you guys expect Dhaka's weak subsoil without bedrocks can take such a heavy load? Civil engineering design is not an Aladin technology.

Is it possible to build a structure in the sky without a base? It is similar also when the soil is weak.

 

[Paul2]

I could not find a video where that initiator (I forgot his name, a Hindu) was lamenting that he went to BD 39 times but the govt did not respond.

By the way, how do you guys expect Dhaka's weak subsoil without bedrocks can take such a heavy load? Civil engineering design is not an Aladin technology.

Is it possible to build a structure in the sky without a base? It is similar also when the soil is weak.

Can they brute force the issue, and just build the base slab to be big, and heavy enough?

By the way, Walton wants to build another tower in Bashundhara. They already spent $20.5M for the land. So you can imagine, it almost certainly must be a 100m+ project. They will not be buying premium land to build something smaller than what they have already.

 

[Michael Corleone]

I could not find a video where that initiator (I forgot his name, a Hindu) was lamenting that he went to BD 39 times but the govt did not respond.

By the way, how do you guys expect Dhaka's weak subsoil without bedrocks can take such a heavy load? Civil engineering design is not an Aladin technology.

Is it possible to build a structure in the sky without a base? It is similar also when the soil is weak.

The same way burj khalifa was raised in soft desert sand

 

[Bilal9]

Yep you are correct.. the more high rise a building the more load it has.. which has to be transmitted below ground and those layers of foundation are given to it depending on the load and type of soil.. but these type cost very much and I think Dhaka lies on the seismic activity lines... So it would be unwise to construct it in such a manner....

I hear now that the tallest tower under planning in Dhaka's suburb in question will be no more than 96 stories, which is still unprecedented locally, we have nothing more than about 45 stories tall (half a dozen under construction and recently built), due to higher than normal piling and foundation costs.

I saw that Malaysia's Merdeka PNB 118 story tower under construction in KL had to have the piles for the building core driven down to 300 feet. That is 1/3rd of the building height at least.

The Padma Bridge pier footer pilings driven in Bangladesh went down to 366 feet.

The piling tubes look like this, before filling with cement.

 

[Bilal9]

I hear now that the tallest tower under planning in Dhaka's suburb in question will be no more than 96 stories, which is still unprecedented locally, we have nothing more than about 45 stories tall (half a dozen under construction and recently built), due to higher than normal piling and foundation costs.

I saw that Malaysia's Merdeka PNB 118 story tower under construction in KL had to have the piles for the building core driven down to 300 feet. That is 1/3rd of the building height at least.

The Padma Bridge pier footer pilings driven in Bangladesh went down to 366 feet.

The piling tubes look like this, before filling with cement.

Here is the construction video, very detailed story...if you watch this on a 4K screen exceeding 75 inches, looks phenomenal.