The size of the building will surpass your imagination. It has to be at least 31km or 101706 feet tall. The basic footprint of the building, considering an aspect ratio of 10 will be approximate: 3.1*3.1=9.62km2 Which is equal to 2377 acres. The aspect ratio means the ratio between height and width. Where 10 is the height.
This building will have much larger base than the most of the universities of the world. The size of this structure will be beyond our imagination. The shape of the building has to be considered as that of a pyramid. The volume occupied by this structure will be approx. 3.33 trillion cubic foot or 94.3 billion cubic meters. The capacity of the Three George dams is 40 billion cubic meters. That means the capacity of the structure we are going to build will have 2.36 times the volume of the Three George dams.
The material which will be required to build such an enormous superstructure would be very much in quantity. Generally, the volume density of the material used in the construction of building ranges from 10% – 15% of total building volume. Consider 15% of the building volume that is 14.14 billion cubic meter. That is 35.4% of the total volume of the water in the Three George dam. This means to dig a hole in the earth that is 2.42 km x 2.42km wide x 2.42 km deep.
The weight of the structure will be approx. 34.02 billion metric tons on the basis of the density of concrete. Which is 85% the weight of the water stored in the three George dams. A 31km building will have approx. 9000-9500 stories. And the number of subterranean levels will be close to 100–150. Some of these levels may end up being a solid concrete block just to resist foundation pressures, water pressure submerged in the soil, soil pressure and an uplift from the groundwater table. We may need deep piles approximately another 500m deep to release pressure from soil or the building might start sinking.
Similarly, we can estimate the amount by which this particular building will sink into the ground. This particular building, when topped out, will sink approximately 4–6 feet into the ground considering excellent soil conditions. Now, the amount of stress in different materials will definitely exceed their capacities. In order to reduce these stresses, we will use the “Pulleys”. Let say 1 column can take the load from 150 stories. Then we can transfer a load of this single column to two adjacent columns using a transfer beam. Thus each column will have the load of 1/2 the column and it can go on for another few stories. This way we can form a network of columns which will transfer loads and thus we can work with materials from today’s generation and work on something that is way far out in future.
Now, we have to change the material, either a high strength concrete or steel or even carbon fibers. So that when we reach the bottom we have the strongest possible material stressed to meet maximum demands. Because the material that we have today will definitely not work for this building. The reason being – towards the base, for every square foot of the building 20% of the area has to be filled with concrete to transfer these loads. It will look much denser than this. This is more than a volume of concrete than we originally discussed in our calculations. Which means it would increase the weight of the structure.
So, we have a limitation in terms of strength of the material. But we can go around it and use other materials. The other issue will be maintaining the cabin pressure towards the top. The difference in atmospheric pressure inside as compared to outside will gradually increase as we go up to the top of the building. This difference will be enormous but we can build glass and façade to resist these forces and to make sure air does not go out and create small blasts in the building.
Another concern is earthquakes. We will have to make sure that this building is not located in an earthquake zone. Well, even if it is, the response of the building will be so long that it may hardly react to the earthquake frequencies to cause significant demands. We will have to see, if it shows a significant response, we may have to choose another location for the building.
Also, pumping concrete to heights 50 times taller than the Burj Khalifa, that is a whole new issue. Still, I believe we can do some precast and lift it up the building.
From the point of view of the structural engineer, the challenges will be overwhelming and quite difficult to solve, but it may be possible to design such a building. Although, constructing a building of this kind will be worthless and less efficient, considering we can building many smaller structures with less weight and complexity which fits different people’s needs. But just for academic purposes or just for fun, it will be a pretty awesome idea, maybe we’ll be able to think of ways to solve the problems and let’s see if our results converge.
What do you think about it? Share your views in the comment section.