The Building That Was Built From Top to Bottom

At Plaza de Colón in Madrid, Spain, there is a twin building that is known locally as "El Enchufe" or "The Plug" for it is said to resemble a giant electrical plug. Its formal name is “Torres de Colón” or the Columbus Towers. Some say it is the ugliest building in Madrid. Its green art deco-style top, and copper and smoked glass façade doesn’t inspire much pride among the city’s inhabitants. Nevertheless, Torres de Colón has been an icon of Madrid’s skyline since it went up in 1976. It harbored great curiosity while it was being built, for Torres de Colón was built from top to bottom.

Torres-de-Colon-composite

Construction stages of Torres de Colón.

The first thing that rose was the two central pillars on concrete footings. Then the top-most floor was raised and hung with steel cables. The rest of the floors followed from top to bottom. Only the bottom three floors including the basements were built from bottom up. The glass facades are covered with maroon and green and the plug-like structure was added later to the top.

The top-down construction method is said to provide significant savings in cost and time, as they allow the floors to be constructed at the basement level and hoisted to the top, rather than moving workers, construction material and equipment from floor to floor.

torres-de-colon-1

Construction of Torres de Colón

torres-de-colon-2

The central towers of Torres de Colón without the floors.

Although an uncommon construction technique, Torres de Colón isn’t the only building to be built this way. The Central Bank of Ireland, in Dublin, and the Standard Bank Centre in Johannesburg, South Africa, were both built from top to bottom.

There are at least three buildings in Poland built top to bottom. The Trzonolinowiec, built in 1961-1967, is sometimes referred to as "hanging man". It stands in Wrocław. The other two stands in city of Gdansk, and Katowice.

The Bulgarian city of Sofia also has such a building, built in the 1970s.

sofia-building

Photo credit: Reddit

In 1959, a different experimental technique was employed to build a residential building in the industrial city of Magnitogorsk, Russia. Rather than have floors suspended from cables, pre-fabricated floors were jacked up in place and fixed to the floors above.

A variation of this technique was developed in The Netherlands. It’s called the Jackblock.

The website of the American Society of Civil Engineers explains how it works:

The top story of a building is constructed at ground level on a large number of jacks. It is then jacked up an amount equal to its exact height and another is built underneath it. What is now a two story block is jacked up another level and the third floor and walls built underneath. These three floors are jacked up and so it goes until the building has reached its exact height. It is then anchored to the foundations.

top-down-house-russia-1