American Copper Buildings is an engineering marvel built on 6.4 acres of land that developed by JDS Development company and designed by Shop Architects in the Manhattan District of Murray Hill, New York. But why is this building considered an engineering marvel?

Although it is thought that this building, which resembles a dancing couple when viewed from the outside, has a romantic aspect, there are many different reasons for the design of the building in this way. The 6.4-acre estate was home to the Consolidated Edison power plant. The remaining area had to be built in accordance with the conditions set by New York zoning laws. The conditions allowed for two separate buildings to be built with 48 floors. But, the project owners wanted to build a single structure. The aim of the project was to ensure that people do not need to go anywhere other than the area they live in to meet their social needs. That’s why the architects designed two living spaces with 48 floors, but came up with the idea of connecting these two skyscrapers to fit their purpose.

Building the city’s first sky bridge

The problems didn’t end here either. The sky bridge that they planned to build to connect the two buildings violated the boundaries of the existing Consolidated Edison power plant on the site. With a joint decision, the architects and engineers in the project came up with the idea of tilting the buildings towards each other so that the sky bridge would not neglect the area of the power plant, and they advanced the project in this direction. So how did they do this?

Building a Leaning Building

How did they construct a building that was planned to be slanted, when bending can occur other than those calculated in reinforced concrete, including in the construction of a building planned to be straight? Due to the sloping structure of the building, they fixed each floor to the curtain wall. Even if the building is tilted, the elevator shaft and curtain walls will remain upright and act as the backbone of the building. In this case, they will reduce the pressure on the ground when building slanted skyscrapers.

 

What is Curtain Wall?

Vertical carrier elements with a ratio of at least 6 to the short side of the long side are called curtains. Curtains are used effectively to carry horizontal loads in high-rise buildings. Curtains significantly reduce the relative storey drifts that cause significant damage to multi-storey buildings in severe earthquakes. The moments of inertia in the long side direction are much larger and they effectively carry the horizontal loads in the long side direction. As the height of the carrier systems increases, the importance of the curtains increases in direct proportion. Curtains are preferred in high-rise buildings in terms of limiting lateral displacement as well as strength.  The use of reinforced concrete curtains in high-rise buildings is beneficial and even mandatory under some conditions for various reasons. In fact, reinforced concrete shear walls are recommended for structures of all heights as a safety element due to their large bending stiffness and shear area.

After all these planning, the land started to be prepared for construction in 2012. The land was located on one of the river’s most flood-prone banks, which was affected by Hurricane Sandy in 2012. The foundation was very important as the water level was high. The foundation was excavated to a depth of 15 meters, but due to the water level 1.5 meters below the surface, they placed massive concrete on the surface to prevent the area from being flooded. The foundation excavation took 1.5 years.

After the foundation, the floors were started to be built. As each floor rises, the buildings are bent, slightly moving towards each other and then further apart. Each of the buildings has 4º curves. The structure of the buildings is constructed with steel beams and concrete slabs. After the buildings were built, it was time to combine the two buildings. Construction of a sky bridge to connect two structures at 90 meters above ground level.

Skyscrapers are built to withstand strong winds. Its highest points can tilt up to 1 meter in all directions. How can they ensure that a bridge remains intact in this state of mobility? The total mobility between the two buildings is 30 cm. This is a movement enough to shatter the bridge in the middle under the influence of a strong wind. As a solution, they fixed the bridge to one building and had it tilt towards the other. They created a movement area of 70 cm in all directions.  Thus, in the event of a wind, one of the buildings will move outwards and the other inwards. In this way, they have solved every obstacle they encountered by using an ingenious engineering.

Frontispiece

The facades of the towers are covered with copper and glass plates. The bridge is covered with crystals and aluminum frames. The project team aimed to create a facade that uses texture and variation to emphasize the shape of the building. They considered many metal alloys but chose copper because of its transition from a shiny material to a darker brown finish and eventually a green patina. These sheets will have a characteristic copper patina over time. Officials say that in about 10 years, the facades will appear the same color as the Statue of Liberty. The copper panels that give the buildings their name are made with a copper compound that includes a flame retardant middle layer and a stainless steel backing. As a result of all this, the American Copper Building took its place on the horizons of New York as an ingenious engineering marvel. This design offers impressive living space in one of the world’s most populated cities.

Credit: Ece Kayakci / www.sanalsantiye.com 

Published On: Haziran 15th, 2021 / Categories: Blog / Tags: , , , , , /