Abu Dhabi's leaning tower

The Capital Gate or the so-called “Leaning Tower of Abu Dhabi” is the most tilted building in the world.

The 35-story skyscraper is one of the tallest buildings in Abu Dhabi. However, its size or height are not one of the factors that make it unique. Instead, engineers challenged common design and created a building with an inclination of 18 degrees to the west. As an indicative example, the leaning tower of Pisa currently leans by about 5 degrees.

The skyscraper hosts a hotel, offices, restaurants and bars. "Because of the shape of the building, every room in the hotel is different," Julia Gimadyeva, Andaz hotel employee, said.

The construction of the building began in 2007 and was completed in 4 years. Currently, 9 years have passed since the completion of the project and it still constitutes the "farthest man-made leaning building" worldwide. Maintaining the structural stability of the building was extremely challenging since it "defies" gravitational forces. The ultimate goal of the project was to "challenge the rules of architecture and to build a structure that would put Abu Dhabi on the world map", Ahmed Al Mansoori, a lead engineer for Capital Gate and Director of Engineering at Abu Dhabi National Exhibitions Company, stated. "Nature wants it to collapse. Everything about the tower makes it want to fall over, but it has been designed to stop," Al Mansoori added.

Conventional skyscrapers utilize a framework that is vertical to the surface of the ground. The framework transfers the weight of the building to the ground and bears the loads caused by winds or earthquakes. The Capital Gate's framework was constructed using an innovative design known as "Pre-cambered core‟. The framework of the building was deliberately constructed slightly off-center but straightened as the skyscraper's height increased. 15,000 m³ of concrete reinforced with 10,000 tons of steel were utilized to form the building's core.

Designers used a pile foundation. About 6000 m³ of sand were excavated before 400 piles were driven into the subsurface of the ground. The piles were divided into two 2 sets:

• Set 1: Piles are shorter and their function is to drive the overhanging forces into the ground
• Set 2: Piles are longer and are anchored deep into the bedrock

A platform suspended on the edge of the building was also constructed. The endeavor was a difficult puzzle that engineers tackled. "The solution was a curving mesh skin that 'splashes' against the building, culminating in the platform," Al Mansoori, stated.

To learn more about the Innovative Structural Design of Capital Gate, download the file below.