When it comes to constructing massive skyscrapers, battles of compromise rage: between the ideal scenario and pragmatic solution, balancing deadlines and flawless execution. Building these incredible structures requires taking severe gambles that won’t pay off for years. And nowhere are all of these forces more prevalent than in the booming financial hub of the world’s third most populous city: Shanghai.
Learn how the Shanghai tower came to be with seemingly insurmountable environmental challenges, a tight timeline, and unique building obstacles, below.
Many issues arise in a city of over 24 million people, especially when cars are involved. The Shanghai Tower project aimed to solve three problems plaguing the city: pollution, vehicle congestion, and a lack of space.
With over one billion gallons of raw sewage hitting the waters of Shanghai every day and substantial air pollution, the city lacked clean areas for people to congregate. Thus, filtering in clean air to reduce the amount of smog for tower occupants became a key project initiative.
In under a decade, the number of cars in Shanghai increased five-fold, creating the 22nd most congested roadways in the world. By planning to serve as a workplace for over 30,000 people, the Shanghai Tower would help reduce the commute of thousands and significantly curb emissions.
Lack of Space
In Shanghai, every inch of real estate is precious, and very little is set aside for public parks or green space. The green areas that do exist are so small that locals call them “postage stamps.” Fearing that poor urban planning and limited access to green spaces could affect people’s mental and physical health, and with no space available for public use, building up became the only option. With this in mind, architects intended to incorporate lush gardens and open glass areas, allowing for unpolluted views.
1. The Plan
The idea of solving three massive urban challenges through constructing one building was an ambitious goal requiring a unique plan. The architects knew they’d need a design that allowed ample light and gave the feeling of being in an outside area. Additionally, it had to be spacious enough so that people didn’t feel claustrophobic in such a tight vertical area. The building would need to accommodate residential and business clientele, along with cafeterias, spa, gyms, pools, and observation space. In other words, it needed to be immense.
Gensler, the architecture consulting firm behind the project, decided on a 121-floor building that would be divided into nine sections. A solid core one-third of a mile high would make up the main support structure. A massive glass curtain wall would encase the entire building to give occupants the feeling of being outdoors. This “second skin” of glass would provide gaps in the structure for gardens with up to 180 feet of headroom.
2. The Challenges
The Glass Skin
Problem: While the idea of building two skins of glass on a single building was an ingenious solution, there was no precedent for this design. It’s like putting one skyscraper inside of another. The first question to be tackled: how to support this outer glass wall? Ideally, a glass wall that large would be supported structurally with steel beams. However, this would ruin the aesthetic, so large and bulky beams were out of the question. If engineers tried to make the beams slimmer and less intrusive, it wouldn’t be strong enough to support itself and would collapse under its own weight. With just one floor of the curtain wall weighing 115 tons, the engineers would have to find a different way to support it.
Solution: Instead of creating one enormous stacked structure to hold all of the glass at once, the engineers decided to hang each floor of glass from the floor above. The “ring beam structure,” would extend from the bottom of the floor above to the atrium of the current floor. This solution solved the problem for the engineers, but it posed a new problem for builders. This design would require builders to start at the top floor and work their way down, but they’d need a place to stand as they worked. Traditional scaffolding, which builds upward, was out of the question. This led builders to a brilliant solution: a moving scaffold. Later termed the “flying saucer,” the 100-ton scaffold was first hoisted to the top level of the building and then slid down to each floor below.
Problem: China’s monsoon season is among the worst in the world. The building needed to withstand sustained winds from 120–170 mph and pounding rain. The building would also need to be stable enough to limit sway. While engineers concede that all buildings will sway a small amount, a force as small as one percent of a person’s body weight will be noticeable and disliked by the occupants. The architects were told that any perceived sway wouldn’t be acceptable, even for people on the 90th floor.
Solution: To reduce sway, the engineers rounded the corners of the building and shifted its edges by twisting the structure as it climbed. These tweaks could cut the wind load by up to 24 percent compared to a square building since the pressure’s dispersed more effectively. While twisting limited the building’s drag, too much twisting would make it unstable. Therefore, a balance needed to be struck. Wind tunnel experts advised that a twist of 180 degrees would be both rigid and aerodynamic. However, it would be prohibitively expensive due to the increased cost of materials to support such a structure. In the end, they decided on 120 degrees as the optimum amount of twist for rigidity, structural integrity, and budget.
Problem: The outer glass structure was optimal in theory, but there were a lot of practical challenges. For one, it needed to be able to minimize the sun’s reflection. It also had to block excessive glare that would be blinding to occupants while allowing enough sun to pass through that it still succeeded in giving people the impression that they were in an outdoor space. On top of that, it needed to be able to withstand both the winds and the rains from the typhoon season.
Solution: The end result was a special type of advanced laminated glass. While most buildings only require one layer, the double-layered glass eliminated the need for either layer to be opaque. Additionally, the extra layer was built to reduce lateral pressure loads and save energy. In Shanghai’s varied climate in which massive temperature swings aren’t uncommon, the energy-efficient glass drastically decreases heating and cooling costs.
3. The Build
“Topping out,” or placing the last beam atop the structure, was important both as a right of passage and to secure the building before the early August typhoon season. As far as the engineers and builders had come to this point, the project’s final stages looked to present very little in the way of major obstacles.
Then, on June 23rd, a rainstorm pounded Shanghai for several days. With the outer skin only partially finished, flooding in several portions of the building cost workers five precious days. Seven floors still sat unfinished, requiring the builders to hang 50 panels of glass per day to finish in time, all on wet, dangerous beams 2,000 ft up.
By July 17, the team had nearly finished the outer glass panels. It was time to install two 20-ton chiller units called “lungs.” These units, responsible for regulating temperature and air quality, must be installed at the top and bottom of the building. Each one is the size of an SUV and cost $500,000. Once installed, the lungs can never be removed, so ensuring they stay undamaged is critical.
While the first unit was lowered into the basement without issue, the second unit got stuck on the 82nd floor. The team couldn’t get it to budge. Moments later, the crane tried lowering the lung to loosen it. Instead, to the horror of onlookers, it began tilting backward away from the edge. With winds increasing, battering the crane and the building, the workers tried repositioning their winch to unstick it. Finally, after 30 minutes of tussling, the team succeeded in pulling the unit inside safely.
By August 3rd, all that’s left is one last 7-ton steel brace to be installed. To massive applause from the crowd, the final piece—festooned in flags and banners—lowers into place. The workers have somehow done it; they’ve beaten monsoon season.
The Shanghai Tower is the tallest of the world’s first triple-adjacent super-tall buildings in Pudong and the tallest building in China. Today, it houses over 30,000 workers and is a daily spectacle for locals and tourists alike.
But the real marvel is the project itself: the architects who didn’t sacrifice their designs merely to meet the project’s goals; the engineers who went to great lengths to achieve the vision of the architects; and the builders, who executed on the unprecedented design and construction method to beat the monsoon season and ensure that a costly, monumental project succeeded.
The Shanghai Tower project wasn’t a product of compromise like the vast majority of large-scale building projects are destined to become. Instead, it’s a testament to how a strong vision can unify a team and yield something truly astonishing.