Wednesday 24 December 2014

'Twas the night before Christmas....



Its is Christmas Eve on the construction site and so we spent some time preparing for tonight's  anticipated visitor to the site.
Alex , with more than 15 years of  site experience, briefs the office team on what to expect based on his previous experiences with this complex site management issue.



Developing a clear understanding in such a cross cultural environment can often pose a challenge, today was no exception.

A clear understanding that Santa Claus ( or  சாண்டா in Tamil) can be lent tools and use the rest area if requested is established.

 Jasmine, our architectural coordinator clarifies the exact architectural needs of the sleigh with the the site team. 



Will his sleigh fit in the central courtyard? - Luckily we can call the surveyor to find out. How long exactly is a sleigh?
















Safety First - Ganasan from the Safety team processes the paperwork for working at height > 2 m. Not even Santa is immune from the Workplace Health and Safety Act.










There were concerns raised early in the day about the ability of the new courtyard structure to hold the weight of the laden sleight. Luckily being so close to the equator, the sleigh is likely to only be half full on arrival at UWCSEA. Just to be sure Noel and Prem, our engineers, made some detailed structural calculations.


We are currently rebuilding the road and its down to one lane. So as part of our risk management approach,  the traffic team spent some time familiarising themselves with the sleigh so as to ensure some VIP treatment in the present congested road conditions.





A distinctly local flavour to the refreshments on offer to Santa and his reindeer's on arrival at our sites. We hope he likes Mama noodles and 3 in 1 coffee as much as we do.








Finally before we go to bed we put up our stocking
Which in the middle of a tropical storm is easier said than done. I wouldn't want to be flying in this sort of weather.



 



Socking finally hung and now time to sit back and let things take their natural course.

 




“Happy Christmas to all, and to all a good night!”

Wednesday 12 November 2014

UWC Day.

(See the preparation at the earlier blog post - http://uwcsea-dover-high-school-project-blog.blogspot.com/2014/09/preparing-for-uwc-day.html ) 

Defining the people we see everyday at UWCSEA - UWC Day 2014

On UWC day, where we celebrate the day by showing our UWC values to the greater community, we sometimes forget to look internally, into the backbone of UWCSEA itself. And at this current moment, with the construction of the mega block, we have hundreds of ‘backbones’ walking around our campus. 

But unlike the staff members and even the Sodexo group, we know nothing, if not very little, when it comes to defining the construction workers, the backbones that are helping us at this moment. This UWC day, we aimed to expose at least a few of these untold stories, and to try and link the gaps between our knowledge of them and their knowledge of us. Also, to thank them for their service to us, we also provided a student-cooked lunch, accompanied by music, decor and gifts.


To start us off, we decided to talk to our peers, to see what they think about the construction workers. The construction workers are a part of our daily lives yet we have never
asked each other what we think of them and who they are to us. During the interviews, the responses were on two sides of the spectrum as the students had differing viewpoints. Half the students thought the construction workers were inspirational people as they worked tirelessly abroad in harsh conditions to provide a sustainable living for their families back home and therefore deserved a lot more respect than what’s given to them. However, there were those who felt unsafe and intimidated when walking past these workers, especially when they were in large groups. There was no correlation between the perspective of the students and their gender, nationality or age. Though these students all had different opinions, they all said that they were looking forward to getting to understand and serve the workers.

Mr. Thomas, who is currently supervising the construction of UWC Dover’s new megablock, took time out of his busy schedule to assist with the interviews and explain his impressions of the construction workers and their conditions. He said that the construction workers are treated better here than in other places that he has worked at before, and that he wanted to know more about the people who work around the campus. He mentioned the man who stands at the driveway, in rain or shine, in the morning and in the afternoon, to ensure traffic flows smoothly and we arrive to school safely. He is a person that everyone walks or drives past every day, but yet very few people know his story, and very few people know his name. Mr. Thomas wanted to know this untold story, and said that this activity was not only to give something back, but put a name on every face at UWC. Unfortunately, we could not find this man, but we found many other untold stories and names which spike the same level of intrigue.

Following an enlightening interview with Mr. Thomas, we met with Mr. Cairns. Mr. Cairns is the headmaster of UWC Dover Campus. Mr. Cairns was introduced in a very interesting manner. Mr. Thomas had informed us that a journalist who used to work for the BBC, had taken time out of his busy schedule to meet with us and help us out. All of the information provided about the guest speaker was true, but none of us expected Mr. Cairns to walk through the door. Mr. Cairns proved helpful in our video-making process, and when it came to the interview, he shared his insight with us. Since Mr. Cairns has travelled around the world, he sees a difference in how people treat construction workers in Singapore compared to other nations. He also finds many of the construction workers as warm and friendly people, who say ‘hello’ whenever he walks by. He also said that some people were slightly dismissive when talking to the construction workers.

Afterwards, we headed towards the construction sites to interview the various construciton workers. Like our student body, the construction workers themselves are diverse, from Hong Kong, China, India (various regions), but only from Asia. There are over 500 construction workers, but we treated the Indian workers on 1st October because hosting 500 workers together would be a hard task to cover. Most of the Indian workers are from the southern region, Tamil Nadu, and a few are from West Bengal. There were also a handful of workers from Bangladesh.

When we interviewed the construction workers, considering the fact that the workers need not have been genuine in their answers to the interviews they gave, we can tell that they sincerely enjoyed having students do something for them on UWC day. They have a sort of pride in them for the students studying here, coming from their own diverse countries. They have a mutual but invisible attachment with the students and that is beautiful. They all seem to be happy with the kindness and the caring nature of UWC and are looking forward to spending more time with UWC.

Through the interviews we carried out with the construction workers, we also found that all of the construction workers we interviewed have gone through further studies in university. Their qualifications ranged from Mechanical Engineering to Economics. Others, which we did not manage to interview, had special skills that allowed them to carry out certain tasks around the site, such as being able to operate the crane. Overall, everyone on the construction site had something special to offer, whether it be with or without an education.






One of the aims of the video was to uncover the untold stories, and to put a name on every face at this school. We interviewed four construction workers to find out more about them, and their interviews showed how little we knew about them. Generally, the three of them were all educated, and thought that us UWC students were hardworking and diligent students, and were proud of us. One of them even offered their help if we ever needed any help. They all had family outside Singapore, and communicated with them regularly. Throughout the entire interview, they had smiling faces and cooperated well, so it created a warm atmosphere during the interview. One of our major questions was how they communicate with each other, as some people do not speak the same language as others. The workers said that they would use hybrids of the other language and English, or just pure English. This shows that they have managed to adapt very well to this clear obstacle. Overall, after walking out of the interview, it was clear that the construction workers demonstrated optimism, determination and care towards their co-workers, staff members and the students, which is what helps build a broader UWC community.
The day was very memorable and informative for us. We were able to be a part of the entire preparation process for the day and learn more about the lives of the construction workers and the work of our our peers as the day progressed. We were also given the opportunity to be treated like real journalists as we were able to visit the construction site and observe the conditions of the workers first hand. We felt privileged that we were given the opportunity to seek advice and information from a professional journalist, Mr. Cairns. Throughout the day we were able to record and witness what each side was doing - our peers working hard to make an enjoyable experience for the workers and the workers waiting in anticipation for a traditional meal. At the end of the day we were left feeling humble, educated and fortunate. It was an amazing experience to be able to witness and record what was happening behind the curtains as the students prepared the food. It was equally amazing, if not uplifting, to serve the construction workers and receive gratitude and appreciation for our small effort. After seeing how troublesome and difficult their lives were,  we were grateful for being born into our own families. Their general optimism and upbeat behaviour also provided us with moral support, and we felt that if they could still smile when they are miles away from home, we should pay our respects to them and learn from them.

We feel that even though we have uncovered the untold stories, and we tried to help them by giving something back to them, they still managed to give something back to us, by warming our hearts with their smiles and general optimism, and we feel this is what abiding by the UWC values can give you.


Arjit Gupta, 
Aadithya Gowthaman, 
Sanah Budhraja
Sean Asahara Thio
Vignesh Srivathsan
Leila Fuerst

The Final Video...








Thursday 2 October 2014

The Potential Positive Impact of Design.


Terrapin recently released our latest publication, 14 Patterns of Biophilic Design. 



"Recall your favorite place – a scene where you felt rejuvenated, invigorated and centered.  Most likely, you’re picturing a place in nature."

This is the quote that first caught my eye and got me to read Terrapin “14 Patterns of Biophilic Design” published at the end of September.

On reflection, its content is mainly common sense (most of the best concepts usually are) but they do help join the dots and answer the "why?" on many of the isolated criticisms and successes you hear of within architecture applied to a urban build environment.  Unfortunately, these elements outlined do not seem to be consciously applied to the design of buildings that I have been involved with past the odd planter, green wall and green roof response.

I am now wondering if there is an opportunity to change that...

Download the thoughts on Biophilic Design here


Saturday 27 September 2014

Preparing for UWC Day - Meeting the construction workers and planning a lunch.

 Update: See what happened on UWC Day http://uwcsea-dover-high-school-project-blog.blogspot.com/2014/11/uwc-day.html




1 October will be a day in which the whole UWCSEA Dover Campus will focus on the UWC values, with activities ranging from working with our service clients to dragon boating to hiking to environmental projects, etc. 

As part of this day, 44 students have chosen to engage with construction workers building our new high school block to get some insight into the lives of migrant workers in Singapore and prepare a lunch and celebration as way of a thank you...This is the first of a number of blog posts about this adventure.

Blog post by Sanah Budhraja - Grade 9



Today we were given the opportunity to go to the construction site in school and interview some of the workers. They were pleased to hear that we, the students, wanted to cook a meal for them on UWC day to show our appreciation and understanding of their laborious task.
Being service oriented is a trademark of UWC and therefore all workers have been provided with a room with tables, chairs, fans, a water-fountain and a vending machine. Since most of the workers only spoke Tamil, it was important that we took students who could interact with them and speak their language. 

We asked them what they missed the most about home and the general answer was family, friends, culture and food. When we inquired about the food they wanted, most of them were open to anything as they appreciated our gesture. But once the formality died down and the workers started really enjoying our company they told us that they would prefer a traditional meal consisting of rice, mixed vegetables and a dessert called ‘paisum’. For entertainment they said they would like tamil music and simple decorations.




As we were leaving we could tell the the construction workers seemed very excited and were looking forward to this day. These workers work 7 days a week earning around $14 dollars daily so they can support their family back home. They are truly deserving of this meal and we hope that on UWC day we can reconnect and remind them of their culture as well as show our appreciation.




Additional Reporting by Leila  Fuerst

Video and Photos by Sean Asahara Thio.


To a school that honors the unsung heroes; NGO's and volunteers, we sometimes forget those who work right on our campus. This UWC day, we aim to give back a little bit to the construction workers, unsung heroes who help to shape our campus, by preparing a meal for them, accompanied by music. But before we can cook for them, we needed to ask the workers what they wanted. During the meeting, despite our sometimes slightly sketchy translations, and the fact we never worked with them before, the workers were extremely open towards us, and helped us to organise food for them. They made it very clear that they would eat anything we would offer them, as they were pleased to be recognised. We are excited to continue working with them to make this the best experience for both the students and the workers.










Thursday 25 September 2014

Post tensioned slab design - Its more interesting than it sounds (I hope!)

We have a lot to say Merci to the French for...the croissant, the baguette, the company that makes our lunch every day and the rather clever system of "post tension" construction we are using to build this building.

This system of post-tensioning was pioneered by a Mr Eugène Freyssinet  in 1933 for the foundation of a marine terminal in France and is now used extensively all over the world in bridges, elevated residential or commercial buildings, foundations, walls, and columns.

The site from above clearly showing the layout of the the metal strips...
Looking down at our construction site from above, it is possible that you may have noticed something a little unusual. The site is criss - crossed with a lines of shiny metal strips...

This strips of metal are actually hollow casings filled with wires and form part of the structural system which we use to hold up the building...This is called post tensioned construction, and is simply a method of producing prestressed concrete. 

The term prestressed is used to describe the process of introducing internal forces (or stresses) into the concrete elements during the construction process in order to counteract the external loads applied when the structure is put into actual use. This method of construction allows us to span large distances safely, whilst keeping the amount of concrete we use to a minimum.

For many of you, you can probably stop reading now as this is probably enough knowledge to anything but the most persistent of questions from the kindergarten... However if you would like to know more please continue...
.
So lets start with the basics. The materials we use.  We make most of the building from concrete, which has incredible compressive strength (it cannot be squashed easily but you are welcome to try) but unfortunately it has limited tensile strength so is not every good at resisting large forces pulling on it... This means concrete on its own can only safely really be used to span small distances. 


We would like clear open space in the building, not filled with columns so we require spans over 12m in length. Sort of like lots of little bridges. For this we use a post-tensioned contruction method, first pioneered all those years ago.

Adding post-tensioned reinforcement instead of just steel bars (rebar) alone combines the action of reinforcing the tension zones with the advantages of compressing the concrete slab

With our type of post-tensioned construction, the silver strips seen criss crossing the construction site are actually high strength steel cables which are placed inside the concrete slab from end to end. Once in place concrete is poured directly on top of them and once this concrete  has set hard, they will be pulled tight and stretched (tensioned) by a machine to impart internal forces on the concrete.



When tensioned and locked-off to the anchors, this post-tensioned system increases the load the slab can bear and reduces "sag" by lifting the slab and counteracting forces that could be pushing down on the slab and cause it to crack. This allows our concrete spans to increase to over 12 metres of clear open space and the actual slab thickness by around 30cm a floor (6 floors) to decrease overall building height.



High and low points visible on the slab
We get additional benefits by installing the  post-tensioned reinforcement in a draped profile to create high and low points instead of running in a straight line. This routes the post-tensioned reinforcement through a high point over the slab's supports, and through a low point in between those supports. Now optimum efficiency cab beobtained because the post-tensioned reinforcement is appling forces directly in the tension zones, the concrete is compressed, and the post-tensioned reinforcement is creating an uplift force in the middle of the spans where it is needed the most.


Construction process

The basic element of a post-tensioning system is called a tendon. A post-tensioning tendon is made up of one or more pieces of prestressing steel wires of a diameter of 15.2mm, housed inside a galvanised metal tube, it is these covers that you see so visibly on the site 


A tendon has anchors on each end to transmit the forces into the structure. Long tendons may have intermediate anchors along their length to allow for stressing at construction joints. (see left and right)

To get an idea of the high strength of this type of steel, a typical steel strand used for post-tensioning will fail at about 243,000 psi. In contrast, a typical piece of reinforcing bar (rebar) will fail at around 60,000 psi. To be very sure we also send samples of this steel wiaway for independent testing before we start the work.



The handling and installation of the post-tensioning tendons does require special skill and knowledge. The prestreessing team will install the empty cases in the precise locations dictated by the engineer and shown on the post-tension field placement drawings.  These have to be very accurate

 When these empty tubes have been placed  the wires are inserted in the tubes. There is often a different number of wires in each tube as the specific forces applicable in each area are calculated.

In our elevated slab construction, the tendons typically are grouped in bundles in order to increase the spacing between tendons and improve the constructability of the slab.
After the concrete is placed, it must achieve proper strength before the tendons are tensioned. On our site this is 25 n/mm3 which is about 70% of the actual eventual strength of the concrete .









 The tensioning of the tendons, also known as the stressing operation, is achieved by using a hydraulic jack. At least one end of each tendon will have been installed with a length of prestressing steel cable protruding  from the edge of the slab; this is known as the stressing tail and unlike many other types of tail, this one is designed to be pulled....
 A plastic pocket former also will have been installed at this location to create a stressing pocket 
When the edge form and pocket former are removed, the strand tail and stressing pocket are exposed to allow the construction team to use the stressing jack to apply the force in the tendon.
The forces generated when the tendons are stressed are high enough to damage the structure or even cause injury to people working on the job if the installation and stressing are not done properly. 

Safety during stressing includes making sure that no one is working in the area where the tendon is being stressed. It is possible, but rare, for the cable to snap whilst being stressed.

The tensioning is done in 2 phases, firstly it is stressed  to a force equal to 25% of a strand's tensile strength.(on our site this is 15 MPa.) At this point spray paint is applied to provide a reference line, this is then held and checked for slippage and excessive elongation of the cable, which may indicate a problem with the integrity of the cable.

If everything seems stable then the jack is re-installed and stressing is carried out to the final stressing pressure - 59.6 MPa (a lot!)

As the tensioning is occurring, the steel is being elongated, and the concrete is being compressed. When the proper tensioning force is reached, the prestressing steel is anchored in place. The anchors are designed to provide a permanent mechanical connection, keeping the steel in tension, and the concrete in compression.
The steel elongation is measured and recorded for each tendon. This measurement is reviewed to determine and verify that the proper force exists in each tendon. Once the elongation measurements have been approved, the stressing tails can be cut off just inside the edge of the concrete slab, and the stressing pocket is filled with nonshrink grout (with a material strength of 30 MPa) to provide cover and protection over the end of the prestressing steel.
The act of stressing the tendons transfers force off of the formwork and into the tendons, which carry the force over to the columns or other supports. This means that the deck forms can be removed and cycled up to the next placement as soon as it is determined that all of the tendons in the current slab have been properly stressed.


The final product....



Stamped on the underside of the slab, its pretty important we dont accidentally damage those tendons.


The edge of the slab showing the tendons and the final thickness of the slab.