The Vange Amateur Radio Society

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Demolition of a Multi-Storey Office block.
(Time Lapse Video)
By: Steve Adams. G0KVZ
As presented to the Vange Amateur Radio Society 24th Jan 2013

Introduction.
In the second half of 2012, Demolition started on a multi-storey office block near where I work.
I decided that it would be a good idea to monitor one-days progress and to create a time-lapse video of the work.

Method.
In order to produce this video, I would use a simple computer webcam, parthered with standard image capture software and a video creation package.
The webcam would be mounted in a simple clamp and fastened to a window frame using bulldog clips to maintain a fixed position throughout the sequence.

Hardware.
My choice of hardware was limited, as my regular webcam is best suited to indoor use, as it is unable to cope with the brightness of outside scenes, so I was forced to use my MiniDV Video Camera as demonstrated at an earlier evening. This device can be used as a webcam with a resolution of 320 x 240 pixels.

Software.
Having performed some analysis of a number of available packages, I finally opted for the following software that appeared to be best suited and capable achieving the required results:
MyCamMD1 - To capture images
Microsoft Live Movie Maker - To create video

General Considerations and Calculations.

Video length.
Having looked at similar videos on YouTube, I determined that the ideal length of such a video would be around five minutes, any more than this, and it would be too long.

Number of frames.
To determine the number of frames (photographs) required, I used the following calculation:
Number of frames per second to generate a flicker free video = 25
Video length (in seconds) x Number of frames per second.
5 x 60 x 25 = 7200 Frames

Delay between photographs.
In order to determine the required delay between frames, I used the following calculations:
As the workers on this site work from just before 9 until around 17:00, so:
Working hours 9-5 = 8 Hours (28800 seconds)
28800/7200 = 4 seconds

Storage requirements.
Having checked the typical size of a 320 x 240 image file compressed and stored as a jpg, the file size was found to be around 20k.
Therefore the space taken on the HDD by these images would be 20k x 7200 = Approx 150MB
As there was adequate storage available on my netbook, this would not be an issue.

Order of images.
As the Video Camera (Webcam) names each image with a name that is constructed of the date/time of the image, it follows that the images are easily sorted by filename to ensure that they appear in the correct sequence.
Fortunately, when the list of files was imported to the Video Studio software, the order was maintained.

Finishing touches.
Once the main video content had been generated, all that was left was to add a suitable audio soundtrack, and to add a title sequence.

The Result:
The final version of the video can be seen here:

Demolition technique.
Due to the close proximity of other office blocks, the demolition company were unable to use explosives or a wrecking ball to bring down the structure. Therefore they were limited to two strategies:

From floor 14 to 8.
Pneumatic hammer action chisels mounted on mini-diggers were used to pulverise the concrete floor whilst leaving an area of each floor untouched to allow the diggers to continue working from above.
Gas axes were then used to cut through the steel re-inforcing of the concrete floor.
After each floor was demolished, the walls and windows were then pulled inward.
All of the rubble is then dropped down to the ground level via a previously decommissioned lift shaft.
From Floor 7 to the ground.
At this level it was possible to use a crane mounted hydraulic jaw, that bit through the concrete without the careful drilling/pulverising that was necessary on the lower floors.
This was only an option on the half of the building that was furthest from the occupied building, but using this technique saved weeks of effort.
And the remaining structure was demolished using the above technique. with all of the rubble simply bulldozered over the side of the building.

In the following video one half of the building has been demolished to the ground level, and only four floors remain of the other half.
The mini diggers can be clearly seen breaking up the floor while on a small island left of the floor, and the rubble ramp can be seen just left of the centre of the picture.
And a better view of the work area gives a clearer view of the proceedings:

The information contained upon this page is supplied in good faith, and to the best of my knowledge is accurate.
However, I accept no responsibility for damage or injury, however caused, due to the use of this data.