CR112 - Hougang update Q3 2023

 

21 September 2023 - A view of the station box site next to the existing Hougang Central bus
interchange.

Q3 is when things started to get interesting over at Hougang station. The top slab of the tunnel boring machines' (TBMs) launch shaft was cast and excavation works commenced. King posts were being installed at the northern end of the station while diaphragm wall works continued at the south. Over at the west, works began to create the capping beam for an exit. Overall, progress is looking good and the rest of the Cross Island Line (CRL) stations will have to follow suit to catch up.

But first, before we dive into the detailed updates of the various sites, here are some landscape images of the site for your viewing pleasure. These are taken at street level and show the heavy machinery in all their glory.

2 June 2023 - A view of the station site seen from the bus interchange junction at the end of Q2.

2 June 2023 - A view of ongoing diaphragm wall works at the station's southern site.

10 July 2023 - Lovely colours in the evening with that golden hour lighting.

10 July 2023 - Machines basking in the evening sunlight.

6 August 2023 - Most days are spent toiling under the scorching heat of the sun.

6 August 2023 - The noise barriers add a pop of colour to the estate, on top of being functional.

14 September 2023 - Machines rise high and mighty, towering over the residential blocks.
Looking at that king post, can you imagine how deep the station will be?

Northern site
The northern site has been a hive of activity, especially with works commencing in earnest at the launch shaft. This shaft will facilitate tunneling works using 2 Earth Pressure Balance (EPB) TBMs that will dig and build the tunnel towards Serangoon North station. Over the course of the past quarter, the top slab of the shaft has been cast and cured, with excavation works commencing within thereafter. At the end of the quarter, rebar works were in progress for the second level slab.

Besides the work at the launch shaft, diaphragm wall works have also continued at the northern site. The works have progressed sufficiently far that one of the hydrofraise machines was decommissioned from use and removed from the site. In total, at the end of the quarter, there were only 3 machines left excavating the diaphragm walls for the station box as opposed to the 4 that were present at the beginning of the quarter.

Another key activity that took place within the quarter was the installation of king posts. King posts are long vertical piles that are used to support the excavation site. In a top-down construction, they also help to provide the vertical support for the slabs that have been cast before the next slab is constructed.

10 July 2023 - Casting works for the top slab of the launch shaft in progress.

10 July 2023 - A view of the station site with Hougang Central bus interchange and the southern
site visible in the background.

10 July 2023 - The site of the future Exit 5.

10 July 2023 - Machines at work in close proximity to the existing
buildings in the estate.

13 July 2023 - The top slab being cured after the casting process. This allows the concrete to
harden.

13 July 2023

13 July 2023 - Excavation occurring in the nearby pit.

13 July 2023 - The top layer of rebar has been exposed to create a
capping beam.

22 July 2023 - Excavation within the launch shaft has commenced after the curing process
for the top slab was completed.

22 July 2023

22 July 2023 - A close up view of the ongoing excavation work.

22 July 2023 - Remnants of the layer of covers used to help keep the concrete cool during the
curing process.

6 August 2023 - A view of the progress made at the launch shaft.

6 August 2023 - A view of the station box site with the bus interchange and southern site in the
background as well.

6 August 2023 - A close up of the excavation work in the launch shaft.

6 August 2023 - Works at the other excavation pit next to the launch shaft.

6 August 2023 - King posts on site.

2 September 2023 - Rebar work in progress for the second slab in the launch shaft. The shaft is
being built using the top-down method.

2 September 2023 - A view of the remainder of the site. Only one hydrofraise machine remains
at the northern site.

2 September 2023 - King posts & rebar cages on site.

2 September 2023 - A close up view of the king posts being prepared for installation.

14 September 2023 - Progress at the launch shaft. Rebar work is still ongoing for the second slab.

14 September 2023

14 September 2023

14 September 2023 - Capping beam completed and excavation
done at the nearby pit.

14 September 2023 - Soil investigation or improvement work being
carried out. Eventually once the shaft becomes operational, it is likely
that an acoustic shed will cover the work site.

14 September 2023 - A king post being installed.

14 September 2023 - An aerial view of the northern work site.

14 September 2023 - The king post is taller than the neighbouring
HDB block.

14 September 2023 - A view of the site of Exit 5.

Southern site
Works at the southern site are a fair bit more "bland" as the progress centres around the excavation and casting of the diaphragm walls. Beyond that, there is little else taking place at the site. It is likely to remain this way until diaphragm wall works are completed, when the king posts can then be installed.

13 July 2023 - A view of the northern site with the southern site in the background.

2 September 2023 - Ongoing concreting works at the southern site can be seen.

2 September 2023 - Diaphragm walling works in progress at the southern site.

2 September 2023

21 September 2023 - A view of works taking place at the southern site.

Staging area & Exit 6 site

The last site is the staging area for the contract which also happens to be next to the site of Exit 6. The outline of the box for Exit 6 and its connecting subway are very much visible. The top layer of the diaphragm wall has been hacked to allow for the casting of the capping beam here.

Over at the staging site, several cages of rebar can still be seen giving an indication of how much diaphragm wall work still remains. Eventually when the TBMs arrive, we expect them to be stored here before being moved over to the launch shaft.

21 September 2023 - An overview of the staging site where materials for the contract are kept.

21 September 2023 - A view of the site of Exit 6.

21 September 2023 - The outline of Exit 6 and connecting subway.

21 September 2023

As contract CR112 was one of the first civil contracts awarded for CRL1, the pace of work is one of the quickest among all the sites that are currently under construction. We anticipate that the type of work being carried out will continue on into quarter 4 of the year. With tunneling works due to commence in 2024, we should also anticipate the arrival of the TBM components and gantry cranes that will support tunnel excavation at the launch shaft soon.

Do stay tuned as we bring you updates as things progress.

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