How long do skyscrapers take to build

The part of a skyscraper that you see above the ground is known as the superstructure. Elevators are a must-have in a skyscraper.

Imagine how long it would take to reach the th floor without travelling by elevator! Elevators make up the core of the building, which means architects pay close attention to their placement when designing a skyscraper.

As for the fastest elevator in the world? It seems bugs have a lot to teach us. Mound termites, which live in Africa, South Asia, and Australia, build mounds that are covered in tiny holes. These holes allow fresh air to enter and cool down the structure. Below each skyscraper needs to be a foundation that's strong enough to support it. Before ever building up, construction teams must build down. Found out how deep the foundations are for some of the world's tallest buildings.

The design of the foundation needs to suit the building and its site. The general rule of thumb is the taller the building is, the stronger the foundation needs to be.

For example, a skyscraper foundation is much deeper than the foundation of a residential home. However, in order for skyscrapers to achieve the heights that we know today, building design and foundation design had to evolve hand in hand.

A key development in skyscraper design occurred when buildings evolved from using load-bearing walls to steel frames to support the vertical load. With the conventional system of load-bearing walls, the wall depth of the lower stories needed to be extremely thick to anchor the height of the tower.

By using the steel frame design, the inner skeleton of the skyscraper was anchored directly into the foundation. Building skyscrapers has also evolved to be more efficient in how it manages live load-bearing capacity. For example, the Willis Tower in Chicago is eight stories taller than the Empire State Building, but its tubular design uses one-third less steel. Achieving more height with less steel means that the structural system of the foundation has less building weight to support.

The environmental factors of a site location have a significant impact on foundation construction style and depth. The foundation needs will vary from city to city, and the soil type in Dubai will influence tall structures differently than the swampy soils of Chicago. Foundation needs can even change within a relatively small area. For example, the depth to bedrock in Midtown Manhattan is only about 35 feet, but in lower Manhattan, it can be as much as feet to bedrock. This can mean foundation piers need to be drilled deeper to support tall buildings.

When designing a foundation system, structural engineers will ask questions such as:. The skyscraper site assessment will then factor into structural calculations. By including a wide set of structural design considerations, the foundation can be constructed to support the skyscraper's height and weight. Why then are so few builders in China using thermal insulation?

In a word, it is about mind-sets. Thermal insulation is outside of their conventional process and thinking. Zhang Yue: If conventional construction is a man building cars in his garage, our approach is to build cars on the assembly line. Ninety percent of the work for our prefabricated, sustainable buildings is done in the factory. Only the remaining 10 percent is done on site.

Plumbing, electric, heating and cooling vents, plus the flooring and ceiling, are fitted into a module of 60 square meters. The walls, doors, and windows are stacked on top of the module, which is then transported to the construction site as a whole. Zhang Yue: Our production process is not only fast, but it maximizes efficiency and minimizes waste—less than 1 percent construction waste, compared with the 30 percent generated by conventional methods. Because the majority of work is done in advance, our approach also speeds on-site construction.

And because our main site is the factory, our transport and logistics costs are lower. We have greater capacity in the factory to store additional materials and supplies, whereas at a conventional construction site, materials like cement and steel are often delivered daily because the site cannot accommodate extra supplies.

All in all, our construction process maximizes efficiency—in resources, labor, logistics, and transport. McKinsey: As a new entrant, you are showcasing a vastly different business model. What is the likelihood that this model can be replicated? Zhang Yue: We hope to be a model in countries like China, where the urban population is growing, existing infrastructure is incomplete, and the demand for infrastructure development is significant.

But the precondition is that we finish the job and do it well. I must build the best product with the highest efficiency, of the highest quality, at the lowest possible cost. For other builders to follow suit, the production process must be efficient and cost effective, without sacrificing quality.

If a building is expensive to develop, the market will be limited. If labor costs are too high, or the construction speed is too slow, the market will evaporate. If quality is hard to control or technicians are required to learn many new and advanced technologies, the barriers to entry will be too great.

Return on investment must also be realized fairly quickly, in two to four years; otherwise, investors will lose patience. McKinsey: When complete, Sky City will measure stories high, with 6 more stories below ground level. It could become the tallest building in the world. What does that mean to you? Zhang Yue: We are constructing the tallest building to promote the concept that urbanization need not sacrifice land or energy efficiency.

This is the real significance of Sky City. When a building is taller, it naturally uses less land. Also, Sky City is a mixed-use development and will include residential housing; commercial space for business, shopping, and entertainment; a school; a hospital; and two square kilometers of green space covered by , trees. Residents will have access to everything they need in this self-contained development.

Think of how lovely our cities could be if we all traveled to work and school and ran errands on foot. Such a lifestyle lessens energy consumption and the number of roads, cars, and traffic jams in our city.

According to our calculations, Sky City could help reduce the number of cars in Changsha by 2, and carbon emissions by , tons. We are determined that Sky City will have an impact on the people and city of Changsha, on China, and ultimately on the world.

We hope this project leads three important revolutions: one is a revolution of the construction process; two is a revolution of resource efficiency; and three is a revolution of the construction-industry business model and oversight. If we do not take action and showcase a different model that challenges conventional construction, the industry will not change.

There will be huge obstacles, many of which are beyond my imagination. But my resolve is strong. And I look forward to the day when we can reflect on those obstacles over coffee on the nd floor.