J106 - Boon Lay update Q2 2023

 

29 June 2023 - A view of the station work site seen from block 661B.

Okay, this one is going to be a big update as there has been a lot of progress since our last update. For a more condensed update, do check out our Instagram or Facebook posts. Work has progressed fairly quickly within the last quarter over at contract J106 for the construction of Boon Lay Jurong Region Line (JRL) station and associated viaducts along Jurong West Street 64. Most of the viaduct piers have since been cast with approximately 4 to 5 left, whose columns have yet to be cast. The remaining viaduct piers are at various stages of completion, with some viaduct spans completed. The station area has progressed a little slower given its complexity but the first few pier supports there are beginning to take shape as well.

10 June 2023 - Zone segregation by contractor.
Source: LTA & Contractor

Contract orientation
The contractor - China Communication Construction Co - has been producing very clear public relations materials to keep residents updated on the progress & upcoming construction works. For the benefit of this update, we'll be referring to the various zones as demarcated by the contractor. Zone 1 covers the over run viaducts up to the contract boundary with contract J111, the station and viaducts up to the junction with Jurong West Central 3. Zone 2 then begins at the junction with Jurong West Central 3 and continues up to the junction with Jurong West Central 1. Finally, Zone 3 commences at the junction with Jurong West Central 1 and ends at the contract boundary with contract J105 at the junction with Jurong West Street 65.

2 June 2023 - A view of the viaduct pier cast & the rebar of a station pier column emerging.

2 June 2023 - A close up view of the station pier column rebar.

2 June 2023 - Sheet piles in place and form work visible at the station work site.

2 June 2023 - Another view of the southern half of the station work site.

2 June 2023

2 June 2023 - Rebar in place for a station pier column along the side of Jurong West Street 64.

15 June 2023 - Southern half of the station site.

15 June 2023 - Northern half of the station site. The viaduct pier is visible just before the station.

15 June 2023 - Viaduct pier north of the station under construction.

15 June 2023 - Foundation works ongoing for several more station piers.

29 June 2023 - The base of the station pier column has since been cast.

29 June 2023 - One of the first station pier columns cast at the northern half of the site.

29 June 2023 - Ongoing foundation works.

29 June 2023 - The paid transfer linkway will be located between the EWL tracks.

29 June 2023 - Another view of the cast station pier column at the southern half of the site.

Station (Zone 1)
Over the past quarter, the piers supporting the station structure have begun emerging. The station will be located along Jurong West Street 64, roughly 2 stories above the existing East-West Line (EWL) platform level. The JRL station will also straddle both the road and the EWL which undercrosses the JRL below its concourse level. As such, the expected levels in the station are as follows:

1st storey - EWL concourse
2nd storey - EWL platforms, paid transfer linkway
3rd storey - JRL concourse, paid transfer linkway
4th storey - JRL platforms

In order to straddle the road, several station pier columns need to be built on either side of Jurong West Street 64. To facilitate this work, along with utility detection and diversion, the roadway was diverted above the canal running parallel to the street. With this diversion, work can proceed without having to be concerned about multiple traffic diversions and the columns located at either the sides of the road or in the road median can be built in a quicker manner. Within the last quarter, at least 2 station pier columns have been noted to begin casting work, signifying that the station is close to becoming much more visible after months of foundation work.

8 April 2023 - Viaduct piers within Zone 2, a very short stretch.

8 April 2023

8 April 2023 - Towards the northern end of Zone 2 and the beginning of Zone 3.

8 April 2023

7 May 2023 - Viaduct piers within Zone 2.

18 May 2023 - A view of Zone 2 from the south at the junction with
Jurong West Central 3.

18 May 2023 - Utility diversion works for sewer lines in the way of
the last remaining pier within Zone 2.

18 May 2023 - The junction with Jurong West Central 1.

20 May 2023 - The piers within Zone 2 have had their columns cast. All that remains is the
crosshead to be constructed.

20 May 2023 - The 3 piers within Zone 2, the last pier here has not yet
commenced column construction.

2 June 2023 - An aerial view of both Zone 2 and Zone 3 piers.

2 June 2023

2 June 2023

15 June 2023

15 June 2023

15 June 2023

Viaduct zone 2
Zone 2 is a rather short stretch of piers, consisting of a total of 4 piers between the junctions with Jurong West Central 1 and Jurong West Central 3. Over the past quarter, the pier columns have begun popping up with 3 of the 4 piers being completed to the crown level. The last remaining pier will take some time due to the diversion works required for the sewers that were in the way of the pier's construction. Following this, crosshead construction is required to top out the remaining piers as it has yet to begin as of Q2 of 2023.

8 April 2023 - The southern end of Zone 3 at the junction with
Jurong West Central 1.

8 April 2023 - A viaduct pier with crosshead casting completed.

8 April 2023 - Hanger beams with the first viaduct segments installed
on the viaduct pier.

8 April 2023 - A view of a viaduct pier with lifting frames being trialed. Interestingly enough, this
pier would not have any further work for the remainder of the quarter and the lifting frames would
be relocated without any segments being lifted here.

7 May 2023 - A newly cast viaduct pier column.

7 May 2023 - Crosshead construction underway.

7 May 2023 - Typically after the first set of segments are lifted using the hanger beams, they
are swapped out with the lifter beam which can lift segments up on its own. However, this pier was
only left with a single segment on all 4 sides lifted.

7 May 2023 - Another view of the pier with only 4 segments lifted while the lifter frame was
transferred to another pier.

7 May 2023 - Progress of segment launching further south.

7 May 2023 - Lifter frames and hanger beams on two separate piers.

7 May 2023 - An aerial view of hanger beams.

7 May 2023 - An aerial view of lifter frames. The winch used for
lifting segments is visible.

7 May 2023 - Lifter frames at the other end of the span.

7 May 2023 - A view of the remaining piers to the north of Zone 3.

7 May 2023 - Progress of span construction seen from the street level.

15 May 2023 - A view of viaduct construction seen from the south.

15 May 2023

15 May 2023 - Piers with crosshead casting completed.

15 May 2023 - Formwork from crosshead casting.

20 May 2023 - The hanger beams and lifter frames have been relocated to other piers now.

20 May 2023 - A view of the movement expansion joint pier crosshead under construction.

20 May 2023 Completed viaduct piers with crosshead and segments to the north of Zone 3.

20 May 2023 - A view of the suspended viaduct span. An equal number of segments are
lifted on all 4 sides to balance the load.

20 May 2023 - Lifter frame in place to complete the span.

20 May 2023

20 May 2023 - The southern end of Zone 3 and northern end of Zone 2.

20 May 2023 - A view of the heavy equipment and viaduct construction from street level.

2 June 2023 - The span between the first two piers was completed and the lifter frame again
relocated to the junction pier.

2 June 2023 - A view of the completed sections of viaduct. The two sections have yet to be joined
together officially.

2 June 2023 - An aerial view of the viaduct deck. The crossover before Boon Lay station will be
located roughly around here. It is possible to see the difference in segment design across the
two areas - the normal trackway to the left and the crossover area to the middle and right.

2 June 2023 - The gap between the two trackways will be slabbed over to facilitate trains switching
tracks before pulling in to Boon Lay station.

2 June 2023 - Remaining piers to the north of Zone 3.

2 June 2023 - For some reason, the hanger beams are back at the initial
pier that they first launched segments at on this contract.

2 June 2023

2 June 2023

29 June 2023 - The spans completed up to the junction with Jurong West Central 1.

29 June 2023 - A view of the piers to the north of Zone 3. Several movement expansion joint piers
are visible forming a T-shape. The lifter frames are back at work on the first pier where segments
were originally launched for the contract.

Viaduct zone 3
This quarter saw the completion of 3 viaduct spans at the southern end of the zone - potentially due to more time required to slab over the space between each viaduct to allow for the construction of a crossover here. A crossover is where trains switch from one track to another and allow them to change directions - an essential role given that Boon Lay is the terminal station for this sector of the journey when the JRL opens its first phase.

The quarter also saw the completion of nearly all the remaining pier crossheads within the zone, including at least 2 movement expansion joint piers. These have a slightly differing design than that of the typical fixed pier. In a fixed pier, the viaduct segments are directly affixed to the pier whereas in a movement joint pier the viaduct segments are supported on bearings. This allows the viaduct to expand and move slightly as the viaduct expands and contracts under different weather conditions.

It will be interesting to see how the viaducts are constructed over the movement expansion joint piers. In a typical rigid pier, the hanger beam is affixed atop the crosshead and segments are lifted. However in a movement expansion joint, this is not possible as the crosshead supports the bearings upon which the viaduct segments sit. There is no space to anchor the hanger beam for the segment launching, nor will the load be balanced as each movement expansion joint supports the ends of two spans for a single trackway and the ends of four separate spans for a double trackway.

8 April 2023 - A view of the northern-most 2 piers of Zone 3.

8 April 2023 - The area being cleared for the construction of the remaining pier columns for the
portal piers.

7 May 2023 - A view of the remaining piers of Zone 3 at the north.

7 May 2023 - More equipment in place for the construction of the remaining columns.

7 May 2023

18 May 2023 - Foundation work in progress for the remaining pier columns.

2 June 2023 - Auger machine digging bored piles for the pile foundations of the portal pier column.

29 June 2023 - A view of the construction progress for the portal piers from the north.

Portal piers
The 2 northernmost piers of the contract are portal piers to allow the tracks to diverge ahead of Bahar Junction station. The pier columns need to be built sequentially owing to limited space for road diversions. The columns that sit in the road median were constructed first by pushing the roadway further apart to create a suitable work space. Upon the completion of the pier columns, the roadway was again shifted closer to the completed pier so that work on its twin column could commence. It will be some time yet before the pier column is completed, after which work on the portal beam to bridge the two columns can commence.

This post will also be available on Instagram & Facebook from 5 July 2023.