Fun fact: You will find more than 100,000 active tower cranes in the world today. These huge building machines are scattered in urban landscapes around the world, acting as temporary landmarks in which urban cities are growing and changing. While travelling you will undoubtedly encounter a crane or two, if not more.
Dubai, United Arab Emirates is known to be home to a lot of those building cranes, where they push and help in the building of international city’s skyscrapers and high tech buildings. In reality, Dubai has significantly more active tower cranes than every other city on the planet. The true count in Dubai, however, is up for dispute. Some have even claimed that the town comprises near 25% of the world’s active tower cranes, housing some of the largest cranes in operation, although some have put this amount at a significantly reduced 5%.
Regrettably, these estimates are based off an assumption, plus they don’t reflect any comprehensive count of the tower cranes in Dubai. In reality, many experts note that the alleged large proportion of tower cranes in Dubai is a part of a myth which continues to be disputed and has been debunked. A while ago, an article printed in the Wall Street Journal more correctly reported that there to be near 1000 active tower cranes at Dubai, giving the city about one percent of their whole world’s crane share count.
A town which has a specific count of its many tower cranes is Sydney, Australia. Sydney, as of late 2015, had 220 active tower cranes, which makes it next after Dubai. This amount is credited to current growth and curiosity about high-rise residences, and 170 from those 220 tower cranes are for work on high-rise home jobs.
In terms of the USA, the city with the highest number of tower cranes is of surprise. It is not New York, not Los Angeles, but Seattle. Seattle is your tower crane capital of America, and as of October 2016, it has 58 active ones in use. Many factors are prompting the use of numerous cranes in Seattle, such as numerous high-rise, mixed-use buildings adjoining to Amazon’s headquarters, the town’s flourishing Denny Triangle area, along with many other downtown urban improvements. In reality, Seattle’s crane count has increased so much from the past year (by 38 percentage) that there’s a lack of available operators. Cranes can vary in nature from skyscraper building cranes to bubble crane and frannas.
The number of tower cranes in almost any city skyline isn’t directly attributed to that city, but marks an expansion in local businesses and population. The shift caused cities to adapt space for both of these items is nearly always good, as it enables these booming businesses to continue to prosper and for towns to re-establish themselves.
What often gets overlooked, and one thing I found fascinating on my travels is how cranes manage to get on top of buildings. After observation and then further research I found that this is done through using their own hoisting capability to make themselves taller. While that is the most frequent strategy, there are actually three ways:
1) The outside climbing method, where the crane, the arm and its tower, extends upward along the exterior of this construction.
2) The inner scaling method, where the crane assembles a couple of flooring at one time from the interior and then “jumps” into a higher place.
3) The “skycrane” process of airlifting at a crane onto a helicopter.
In the outside climbing method, the bottom of the crane is fixed to a concrete slab on the floor, and the crane tower is built beside the building with smaller, portable cranes. When the construction is all about 180 ft tall (15 stories), the crane has been secured into the construction with metal collars, and new sections are put into the crane’s back. To add sections to itself, the crane has a particular climbing segment, a major metallic sheath that extends the exterior of the crane tower. This sheath increases the arm over the previous vertebra and briefly supports it, then takes in a brand new tower section from the arm. The sheath holds that section set up while employees bolt it in. They repeat this procedure every 180 ft or so: the crane constructs the building, then it is fastened to the construction, then it receives fresh vertebras to grow taller. Although this is general crane practice when building skyscrapers it is a dangerous practice and unlike technology that has cloud backup services, this process has a limited backup if an error occurs.
The next way is the inner climbing method. The crane stands within the middle of the construction, in a sort of makeshift courtyard, in which it constructs the skyscraper around itself around a hundred feet at a time. A hydraulic cylinder in the crane’s bottom elevates it via the hollow centre of this building to a higher ground. Subsequently, employees slip steel beams beneath the crane to provide it a hardy new floor, then the crane starts building again.
The next technique is to get a heavy-lift helicopter (or even “skycrane”) fly into the peak of the building site. This has to be done piece by piece one section of a crane’s tower may weigh between 3,000 and 20,000 lbs. But due to the price, and since flying a load-bearing helicopter on a populated region is logistically very difficult, this way is the rarest, used just a few times per year nationally. It support solutions and the growth in technology has seen cranes expand in what they can achieve.