The Marina Bay Sands in Singapore is host to Bentley’s Year in Infrastructure. Its towering hotel stands out even against the “hey, look at me” architecture that has come to dominate skylines in many of Asia’s big cities. There’s nothing like it in the world, though whatever it is being subject to interpretation. Is it a ship stranded among towers? But the ship curves, so looking more like a giant silvery eel looking up. Architect Moshe Safdie was inspired by a deck of cards, which explains some of the curves in the towers and fits with owner Sands, which exists mostly to make and run casinos. Either way, it shouldn’t have palm trees 200 meters above the ground, but it does.
This most unlikely hotel, completed in 2010, has more than 2,500 rooms. But it’s not the size, or the distinctive shape of the three towers, or even the 2.5-acre park perched on top of them. What everyone can’t wait to get into–and be photographed in–are the pools. The hotel has three infinity pools on the 57th story.
Hotels in hot destinations know multiple pools are excellent draws, often with swim-up bars, but the pools in the MBS are in the sky. Infinity pools are the height of pool fashion, appearing in the millions of photos shot there, as if the subjects are basking on the edge of the sky.
To work as infinity pools, where water constantly flows evenly over the edge to create the illusion that there is no edge, they require a perfectly level wall. The water flows over the wall in a thin unbroken sheet. Should the wall be tilted, the water would flow over the lower part only, and the visible edge of the pool would destroy the illusion.
Most hotels put their pools, infinity or otherwise, close to or on the ground to support the weight of the water – and the pool itself. The MBS wanted to be different.
Keeping an edge straight and level is hard enough, but let’s make it harder by putting the pools on top of three tall towers. We know a pool this size is going to be heavy. Yes, we know the towers are going to sink over time as their foundation cause the clayey earth and landfill to shift. Each will subside at a different rate, and each tower may rotate. You can’t expect the ground under each tower to be of even density and hardness. Yes, the wind will cause the maximum deflection at the top of the towers, also differently for each tower. But you’re engineers. You’ll figure something out. That infinity pool must work.
The weight of the pool was going to be staggering. When full, the three pools held 380,000 gallons (1.44 million liters) of water. Add to that the 422,000 pounds (191,000 kgs) of stainless steel that formed the bulk of the pool structure, and then the 250.000 ceramic tiles cemented on…
Support of the stationary weight was one thing, and keeping the whole deal flat was another. Arup, the firm hired to complete structural analysis of the towers, could handle stationary weight. Since they were roof top pools, a specialist was brought in: Natare Corp., a pool manufacturer on the other side of the world in Indiana. Natare devised a system of hydraulic jacks, 500 of them, that would level the pool no matter the movement of the towers. Though the lateral movement of the towers could be almost 20 in, the jacks were able to keep the wall to within 4 mm over the entire 478 ft length (146 m).
The pool was prefabricated, which brought up the next problem. To get from Indiana to Singapore, the task took more than 30 ocean freighters.
https://www.arup.com/projects/marina-bay-sands-integrated-resort
The ship/eel/park nestled on top of the three towers was by itself a $150 million project. Construction workers had to build a faux ground floor 55 stories up in the air to create what became known as the Sky Park that crowns the towers. As soon as it was completed, MBS instantly became one of the most recognizable structure in the world, already on par with the Eiffel Tower, Taj Mahal and Golden Gate Bridge.
The ship’s prow consists of cantilevers 67 meters past tower one. It lays claim to the biggest cantilever on Earth.
The design and construction, much of which had never been attempted, and its sheer enormity have made the MBS the second most expensive building in the world. First, as you might have guessed, is the Abraj Al Bait, Mecca, Saudi Arabia, which cost $15 billion. (Source: constructionglobal.com)