The miracle of skyscraper demolition: Making a building disappear

Demolitions always look fun but they are extremely challenging and costly projects. There is a vast number of different, yet indispensable, parameters that should be taken into account before a project like that begin. Safety and process efficiency, of course, are the top priorities.

The Japanese construction industry seems to understand this really well, given the remarkable steps forward that it has taken during the last years toward that direction. That being said, prepare yourself for a remarkable demolition spectacle as we take a closer look at the “Daruma-otoshi demolition technique” or, as it is called by its inspirers in Kajima Corporation, the “Kajima Cut and Take Down Method”. And not only that, as we will explore what other demolition practices are preparing to take over the entire industry.

But first let’s explore the more traditional demolition practices which still are very popular around the globe.

Traditional demolition techniques

For most of the people, the word demolition has to do with big fascinating explosions or humongous wrecking balls crashing against buildings. Those two are some of the most dominant demolition practices followed in the construction industry even today.

• Building Implosions:

Starting from the building implosions, it’s a very popular method for controlled demolitions. The idea behind this type of implosions is very simple and self-explanatory. A big number of explosives are strategically placed within the building structure and at the right moment they are activated in order for the building to be demolished. The goal is to achieve an explosion of such intensity that will demolish the building without causing any further damages to its surroundings. It goes without saying that, timing is key in such operations.

• Wrecking Ball Demolitions:

The use of wrecking balls in the demolition process is an older technique. Normally, wrecking balls are made out of steel and they are tied to cranes in order to get the job done. They were the number one choice during the 50’s and 60’s but they have started losing popularity as technology progresses. Nevertheless, this technique will most probably remain active for projects and tasks of smaller scale.

The daruma-otoshi method

And to the more exciting part now! Both techniques that we saw above have provided remarkable help to the construction industry, but there has to be a better way for tearing buildings down. With that thought in mind, Kajima Corporation developed a revolutionary demolition method which resembles a lot to a traditional Japanese toy with the name Daruma-otoshi. In both cases, the main concept is very similar. In order to complete your task, you have to take the tower/building down starting from its base.

It may look effortless but in practice it requires extraordinary precision and a solid plan. Regarding the demolition process, it takes place on the ground floor. Temporary offset columns are inserted in the ground level of the building structure. At the same time, computer operated jacks are installed in the basement. The structural columns gradually are replaced by the jacks and the demolition proceeds one floor at a time.

Kajima used this technique for the first time in the demolition of its former head offices. You can see on the following photos the progressive development of the project:

The benefits of the method

The Cut and Take Down technique can be applied to almost every type of building structure and it has a number of benefits both for the construction process and the environment. More analytically, we could sum them up to the following:

• Noise reduction:

Both building implosions and wrecking ball demolitions may offer impressive highlights but they are extremely noisy techniques with great impact on the environment. To the contrary, the Daruma-otoshi demolition method reduces significantly not only the intensity of the noise (20 decibels lower than before) but the radius in which the demolition work can be heard,too.

• More effective waste management:

Moreover, the Cut and Take Down method allows the better management of the demolition waste. It can increase the recycling rate of the whole process by 90%. The fact that all the demolition work takes place in the ground level helps also a lot in speeding up the whole waste management process.

Learn More: Construction project management processes: All you need to know 

• Lower impact on the surroundings:

As an extension to the previous point, this type of demolition can have a reduced impact on its surroundings. The fact that lower levels of noise and dust are resulting from it allows for a tidier demolition procedure. This can be valuable in urban environments where there isn’t enough free space for high-scale operations.

• Safety boost:

Safety always is one of the most indispensable parameters in construction. The Daruma-otoshi technique is all about it. Given the fact that less construction workers and heavy equipment has to be on site during the demolition.

The Future Of Demolition Techniques

By now, it’s safe to say that the future of demolition is already here. Messy techniques including explosives or wrecking balls have started losing ground. With the advancement of technology, it becomes easier and more cost-friendly for construction companies to experiment with new practices. The general feeling is that methods, such as the Daruma-otoshi technique, will become more and more popular.

Another example that could back this claim up is the hat technique by Taisei Corporation. The core idea of tearing down a building floor by floor remains the same. However, in this case things go the other way around. A securing “hat” covers the top three floors of the structure. This covering is able to withhold noise and dust. In its internal part, the demolition process is rapidly progressing with the help of humongous hydraulic jacks. As soon as the construction team tears down the walls and the floors, it continues to the next floor. The “hat” is moving down as soon as two of the three covered floors are completely smashed.

Another interesting fact is that another company from Italy, named Despe, is applying a similar technique for years with great success. This proves that, there is a strong interest for innovating methods that will help in a smoother incorporation of the construction process within the natural surroundings. You can have a look at the way Despe works on the video below:

In the same sense as before, those two techniques allow for a more discrete construction site with very low impact on its environment. More and more cities have started gearing their attention towards that. Especially cities with skyscrapers and old tall buildings (eg. New York) will play a very active role in the future.

Conclusion

The need for modernisation is taking over construction and demolitions could be no exception. There is a strong request for optimization of the whole construction process. Techniques like the Daruma-otoshi method or the hat practice are showing the way to a more sustainable and efficient path for construction.
Featured Image: Bluevale flats demolished using unique method via Mark Anthony