Step 2 - Excavation - Preparing the foundations

Preparing the foundations...Digging a hole....

In the last step we decided to build a raft foundation, a big "raft" of concrete that is going to support the building, the first step to this is to dig out the existing soil...

Part of this building is an extension of the current basement carpark which is semi - underground (at the very front it is a ground level).

The site excavation size is about 67m x 81m with the depth ranges from 2.55m to 5.95m ( at the tent plaza end)

 This means we need to excavate about 16500 m3 of earth to get down to the start of the level of the foundations.

Each big earth moving truck that you see in Singapore can carry between 6 - 9 m3 of earth, depending on how well the earth is compacted when it is dropped in by the excavator.

So this means we need to remove around 2532 individual truck loads of soil from the site.......

Our soil goes to an earth dumping ground at Marina South and might be used for reclaiming more land around Singapore..More information on earth dumping in Singapore




Once the soil is removed and we have got to the final level that will form the foundations, we then compact the ground with 10,000 Kg vibrating roller. You can feel everything shake when this is working...

Step 1 - Making the foundations - Designing foundations.

Foundations, actually one of the most important parts of the building, for I hope obvious reasons..

There are many choices on which foundation system to use in a building like this and in many cases it can be a difficult decision to make...

To make it a little easier we approach it scientifically and to start this process off The first thing we need to do is assess the quality of the soil that is going to be under the building as this will be taking some of the load of the building.



When you see one of these appear in your neighbourhood, it might just be time to leave for a few months :) It means someone is collecting information for an imminent building project!

The pipes on the floor are for the soil samples which collect in the middle of the pipes as they are driven into the earth.

In our case we took around 10 drill holes all over the site and take core samples of the soil. We drill down around 30 metres from the existing level

Our engineer studies these stratas - If you are wondering the use of these physical geography lessons, here it is...

These are copies of some of our soil reports and you can see what the composition of the soil is underneath the building. Unfortunately no gold, diamonds or oil...

The soil is very different all over the island.

There are many idioms out there related to the building of things on sand, you can see from these reports, that in the real world of building you can quite build a house on sand and be perfectly happy that it will be there for a very, very long time..

From analysis of these soil reports we decided to construct the foundations as a "raft". This is as it sounds, it is a big raft of concrete on which the building rests. This has a number of advantages, but one of the reasons for choosing this system was to minimise the disruption on the workings of the school and our residential neighbour...

A more detailed explanation of these different foundation systems can be found here or if you are short of time take a look at this condensed version......



Go to the next step - Preparing the foundations

Does it look like a building site yet?

Our interactions with the kindergarten left us battling against a number of clear expectations from these little but very astute ones. Quite clearly from their perspective a building site in Singapore is not really a building site without a suitably large crane being visible. Bowing to this pressure we have now got on and installed one on the site.

I hope we have gone up just slightly in the eyes of some our most important customers. 

This crane is a called a "Luffing crane" which is different from many of the cranes that you see in Singapore that have a fixed horizontal beam with the hook moving up and down this beam. The main problem with that traditional type of crane is that it would oversail occupied areas of the school. For pretty obvious safety reasons this is unacceptable to us. 

However the choice of crane does influence various elements of construction and planning, when we are lifting loads at the full extension of the crane, we will be  down to a very low capacity, perhaps just a few tonnes (around 2 and a half cars!) . The heavier loads will  have to be lifted close to the tower or broken into smaller pieces. This is influencing the design of the steel for the roof structures for the theater and the exam hall which will now need to be designed into "bite sized chunks" and then welded together once they have been craned onto the roof...

Assembled like a very large lego set..

The finished product at some 40 metres above the ground and positioned in the middle of our new building.

The crane is operated by a man (or women) sitting in the small cab sitting on top of the crane, these individuals need to be very brave and quite tough as there is no air conditioning up in that glass box and the tower itself moves back and forth as it picks up and drops off heavy loads or if the wind is strong.

You also need to be rather patient as you cant just come down if you forget something! Lunch is usually delivered to the crane operator by him dangling a long rope with a hook down to his team on the ground.

K1 have a go on a "digger"

Continuing the K1 unit of inquiry about construction we organised a quick go on the "baby digger"

One for the pedals and one for the controls..

How many students can fit in the bucket...

Progress of Site - early March 2014

Current Progress on site - March 2014

Well the excavation has now started in earnest, we are averaging around 100 truck loads of soil from the site every day and we will need to do this non- stop for at least 60 days to get to the final level of the basement (as this is a school project I will let you work out how many truck loads of soil this will be!) 

You can now see a strange cage of steel in the middle of the site, to correct some misinformation in the Primary School I can confirm this is not for the builders at night, the guard dog or naughty children but it is in fact the foundations for the tower crane which will soon be rising from the ground. This cage will be lowered in the hole in the ground and is support by the 12 pieces of steel that can be seen poking from the ground.

This will be interesting as everyone knows that the building site is not a building site with a big crane but also because it will give all that are watching carefully an idea of the final level of the car park as this huge lump of concrete will eventually be left under the car park floor.

For the sake of future generations that may be reading this blog in 2224, I will be embedding a number of coins from 2014 in this block of concrete so please get digging if the school is now short of funds....

ETH Future Cities Lab and UWCSEA Collaboration

As part of our efforts to ensure as efficient building as possible we have been working  with our friends at the ETH future cities lab.

We have been collaborating with them for a number of years as their real world experience in sustainable design and building can offer project experience to our students and drive our individual buildings to be leaders in high performance "green" architecture and mechanical and electrical design.

Take a look and bookmark the project blog to find out what we are doing:

 Beyond Efficiency Collaboration Blog  (http://beyondefficiency.blogspot.sg/)

Project Team Visit to Sports Hub

The board facilities committee, the project team and UWCSEA Facilities team had the opportunity to visit the Singapore Sports Hub project.  Although on a totally awe inspiring scale, there are always things to learn that we could apply to our building projects. The most applicable was the approach to safety with so many workers from different companies on site. Impressive.

We are now going for a fully retractable roof over the exam hall in the new building (only joking!)