Sunday, November 9, 2014

Woodlands Avenue 1 Diverts

The third traffic diversion under T205 has been implemented over at Woodlands South this morning. This diversion shifts the existing southbound Avenue 1 closer to Christchurch Secondary, alongside the already-diverted northbound road which had been earlier implemented on Oct 6.

With both carriageways of Avenue 1 fully diverted, D-walling works for the north perimeter of the station will commence in full swing from now. A subsequent diversion of Avenue 1 to the north can be expected in 6 months for the d-walling works on the south perimeter. Upon completion of the ERSS we expect excavation works to begin by the first half of 2016.



New southbound carriageway diverted to the left. The station box will be located beneath the former road.

Thursday, October 16, 2014

POB Launches @ Napier

The temporary Pedestrian Overhead Bridge is successfully up at Napier Road following 2 nights of beam launching. The segment over the carriageway bound for Orchard was first launched up on Tuesday morning. The second segment of steel was then launched earlier this morning over the westbound road. The temporary bus bay and shelter along the eastbound road is almost completed, and would open anytime soon.

M&E works to the temporary bridge would take place together with the construction of the bridge's staircase from now. The new temporary bridge could possibly be operational by year end, following which the existing bridge would be demolished. This is the second POB to be demolished along the line.

Completion of beam launching along Napier Road this morning

The photos below show the progress of the beam launching throughout the week.

Wednesday, October 15, 2014

Gardens By The Bay

Concluding the final update for Q3 at the Marina Channel, preliminary site clearing and ground investigation works have commenced by the contractor at the Gardens by the Bay site. I will begin the 4th Quarter updates from mid-December; however occasional updates on recent developments will still be written over the next 2 months.

Contract T228 is for the construction of GRB station and twin tunnels across the channel to Marina East. Serving the other corner of the new downtown at Marina South, Gardens by the Bay station will be built beneath a future 2 lane dual carriageway road that will connect Marina Boulevard and Marina Gardens Drive. The road has yet to be named by the URA. With a fairly simple layout, the station will have a concourse and platform basement levels. Entrances A and B will be located on either sides of the new road. Entrance C to be linked by a subway will be located on a reserved portion of land between the Marina Barrage and Gardens by the Bay.

Entrance C to be built between the Marina Barrage and GBTB 

Tunnelling to Marina East
2 EPB Machines will be procured for this contract. The TBMs will be driven from a launch shaft east of GRB across the channel. A circular retrieval shaft - named Gardens by the Bay Marina East (GBME) will be built at the edge of Bay East under the contract. The GBME shaft will complement the docking of both the TBMs from GRB as well as the future E1 Marina East station under the Eastern Region Line project. T228 will handover the GBME shaft to the future ERL contractor throughout the whole of 2018 for the docking of the ERL TBMs before receiving possession of the shaft once again.  An escape shaft will then be constructed within the GBME shaft before it gets backfilled.

The tunnels will be driven straight down across the channel from the GRB launch shaft to GBME (foreground)
GBME Retrieval Shaft

Monday, October 13, 2014

Marina South Hoards Up

Contract T227 is for the construction of Marina South station, twin bored tunnels north to Marina Bay and a section of cut and cover tunnels from Marina South to Gardens By the Bay. Designed to serve a corner of the future development at Marina South, the station is located at an angle parallel to the MCE under the proposed extension of Marina Mall (road). The design takes into consideration the future Singapore Underground Road System (SURS) which will run beneath Marina Mall such that the concourse & platform level would not be obstructing the future road tunnel.

The station will be 20m deep with 4 basements - UPN linkway (B1), Concourse (B2), Mezzanine (B3) and Platform (B4). Entrances A,B and C will be located along Central Boulevard whilst Entrances D and E will be along Marina Boulevard. 5 vent structures will be built for the station.

Hoardings partially hoarded up around an empty field where the station will be
Bored tunnels
2 EPB TBMs will be driven from a launch shaft at Marina South 850m to Marina Bay. The tunnels will be in a semi-stack configuration when it undercrosses part of a designed pile-free zone of the Common Service Tunnel (CST) Phase 3B that has been specially catered for the tunnels to be bored through. 1 semi-stacked cross passage will be built south of the CST intersection. This is the 48th and final CP to be built within the TSL tunnels.

Cut and Cover tunnels
The tunnels connecting Marina South to Gardens by the Bay (GRB) will be constructed fully by open cut. This is for the construction of a cripple siding and crossover track between both stations. 650m long, the C&C portion is also the 5th and final Temporary Staging Area (TSA) site along the line.

Curvature in the site clearing can be seen for the future Cut and Cover tunnels to GRB
Ccontract boundary between T227 and T228
Update Progress
Being under the last batch of contracts to be awarded, minimal site clearing and hoarding works can only be seen at this point in time. Yongnam had also recently been awarded the subcontract for shoring works under T227.

Saturday, October 11, 2014

Marina Bay Encloses

Contract T226 is for the construction of the new Marina Bay station. The excavated portion will be predominantly divided into 2 sections segregated by the existing North South and Circle Line tunnels. The excavated portion in the south will be for the main station box; the north portion would be for the TBM launch shaft for T225 and an access shaft to facilitate mining activities to link the 2 open cut areas. Extensive underpinning works to the existing RTS is required for the mined section. This is where the ground freezing is designed to be executed.

The new TSL Marina Bay station will have 3 new entrances and 5 basement levels with a formation level 38m deep. Entrance A (integrated with vent shaft 1) and Entrance C will be opposite the existing CCL entrance along Bayfront Avenue and Park Street respectively. Entrance B is located at the future intersection of Sheares Avenue and Park Street.

Existing RTS in Orange/Red, Existing site boundary in yellow, Proposed station box in cyan (Mined tunnels in blue)

Transfers and A&A to Existing RTS
In simplicity, 2 new dedicated connections will be made to the TSL from the existing NSL and CCL stations. The NSL linkage will be an open cut section parallel and west of the NSL station box along the former Marina Station Road. This linkage will be on the level as the NSL concourse B1.

The CCL linkage to be located east of the existing CCL station  along Bayfront Avenue will offer an unpaid and paid section. Located on the same level as the CCL concourse, the design makes use of existing knock out panel provisions made into the CCL station. The south knock out panel will feature the paid link (hence a reconfiguration of faregates within the CCL station). The north panel will feature the unpaid link.

T226 Taisei's site office and LTA's TSL Civil Team 4 project office completed to the west at 20A Park Street
Update Progress
The last 3 months have been spent on site clearing, as well as minor ground improvement works around the site area. 2 clusters of silos have been hoisted up south and west of the proposed station box. 4 crawler cranes, 2 trench cutters and a piling rig has been assembled on the site however no excavation has been taken by the d-wall machines yet.

With the recent closure of the former Marina Street and Marina Station Road, the site area has now been fully enclosed with the old roads cleared of traffic. The site office has been completed around 2 months back. The same building will house the project office of LTA's Thomson Line Civil Team 4. Here's a timeline of progress over the 3rd Quarter.

Thursday, October 9, 2014

Shenton Way Begins

Contract T225 is for the construction of Shenton Way station and 2 adjacent twin bored tunnels connecting Maxwell to Marina Bay. The station is located along Park Street on state land south of Asia Square Tower 2.

Shenton Way Station
The station will have 5 levels with formation at about 40m below ground level. The levels are - Subway Linkway (B1), Concourse (B2), Plant Rooms (B3), Upper and Lower platforms (B4/B5). There will be 3 entrances. The main entrance A with vent shafts integrated will be located south of Park Street. Entrances B and C will be located along the future Central Linear Park - empty patches of reserved land for recreational activities to be extended south from the existing Lawn@Marina Bay.

The station will also be directly connected to neighbouring developments such as Asia Sqaure, V on Shenton and the Marina One through the subway link to be part of the future Underground Pedestrian Network (UPN).

Existing site hoarding (yellow), proposed station box (blue)
Tunnelling
2 EPB machines will be self manufactured by STEC under this contract. The 2 TBMs will do an initial launch from Shenton Way towards Maxwell before dismantling and relaunching back for the second drives from Marina Bay to Shenton Way. The launch shaft at Shenton Way will be integral to the station box due to space constraints. The launch shaft at Marina Bay will be constructed by T226 and will require a handover process.

Both tunnel drives are in a stacked configuration. For the drives to Maxwell, the Golden Bridge across Shenton Way will be demolished for the extraction of piles along the tunnel route. Further down McCallum St, 2 temporary access shafts will be built for the installation of protection works to the existing EWL tunnels running under Robinson Road. Temporary closure of McCallum St can be expected during the construction.

T225 Site Office along the future Central Linear Park
Update Progress
The structure of the site office is completed and fit out works are underway. Casting of the surface slab is taking place. A hydrofraise, piling rig and 2 crawler cranes currently sit on the site. The bentonite plant and silos are located south of the site.

Tuesday, October 7, 2014

Maxwell - It's Beginning

The Maxwell station under T223 will have 3 levels. The formation level is proposed to be 31m beneath the surface of Neil Road. The station will have 3 entrances. Entrance A will be built infront of Kreta Ayer Heights; Entrance B will be at Maxwell Food Centre and Entrance C will be located at the Chinese temple.

Following the closure of Dickenson Hill, the bentonite silos have been erected and a treatment plant has been assembled. A hydrofraise trench cutter has been brought to the site. The site office is currently being built in the center of the site. Several traffic diversions for Neil Road has been planned and will be executed in phases.

Bentonite plant and silos
T223 Site office in the midst of construction

Sunday, October 5, 2014

Outram Park Assembles

Contract T222 is for the construction of Outram Park station and 2 twin bored tunnels to Havelock and Maxwell. The station is situated on an empty plot of state land north of the existing East West Line. The contract was awarded to Daelim Industrial. They have previously worked under Contract 487 of the Marina Coastal Expressway and this is their second project for the Client.

Site overview
Proposed TSL box parallel to the existing East West line (left)
Outram Park Station
The new station will have a very similar layout to its EWL counterpart. There will be 3 levels - a Concourse, Platform and Transfer level. An additional 2 entrances will be built along Outram Road to complement the existing interchange. Entrance A will be located near Pearl Bank, while Entrance B provide doorstep connectivity to the Health Sciences Authority. The station will be constructed top-down.

A&A to existing RTS
There will be an overhaul in the linkage design within the existing interchange. The new changes include:
- 1 new dedicated NEL-EWL paid link with 4 travellators
- 1 new dedicated NEL-TSL paid link to be extended from the existing NEL-EWL linkage
- 1 new EWL-TSL paid link to be constructed beneath both platforms on the transfer level. 2 new escalators will be installed down from the west end of the existing EWL platform for this linkage.
- 1 new unpaid link between all 3 lines to be constructed on the concourse level with 4 travellators

Outram Road which would see intensive phased traffic diversions to build the new linkages
New Entrance B to be built infront of HSA and enhance connectivity to the interchange station
Tunnelling
2 launch shafts will be constructed on either ends of the station box. 2 EPB TBMs will be procured under this contract. The TBMs will do an initial north drive to Havelock station before docking, dismantling and reassembling for the second drives to Maxwell at the south. The alignment of the TSL tunnels to Havelock run directly beneath the existing EWL tunnels for a good 500 meters. A cross passage will be located here. Similar to contract T212 at Upper Thomson, this will be the first time excavation of a tunnel parallel and beneath and existing operational MRT tunnel is being executed here.

Tunnels to Maxwell will go beneath the existing footings of shophouses near Kreta Ayer
Use of SFRC segments in tunnelling
A new type of tunnel rings have recently been experimented for the first time in Asia under C933 of the Downtown Line. Steel Fiber Reinforced Concrete, or SFRC in short, contains fibrous material and are precast in a (7+1) segment arrangement that distinguishes itself from the conventional RC (5+1) tunnel segments. The fiber reinforcement segment uses less steel, and is much more durable and crack resistant. The segments are made in Singapore and production time and cost is also lowered.

Moving forward, LTA continues to expand the use of these rings in the construction of new lines. Contract T206 and T222 were identified contracts to be considered for the usage of the SFRC rings. At the Underground Singapore 2014 conference held last month, the LTA confirmed that 2 TSL contracts will be using the new fibrous segments, doubling the use from 4.7km on the DTL3 to 10km for the new Thomson Line.

Update Progress
The site office has just been completed and is located behind the soon to be demolished Pearls Centre. Works are midway to surface the slab on the site ground. On areas with the completed slab, the bentonite plant and silos have been erected. Trench Cutters are also being assembled on the site.

T222 Site office at 102A Eu Tong Sen St
Pre-assembled trench cutters and erected bentonite silos

Friday, October 3, 2014

Havelock Clears

The proposed Havelock Station sits directly beneath a large portion of the Bukit Timah Granite along Zion Road. The volume of rock to be excavated is tremendous; about 180,000 cubic meter of rock is envisioned to be blasted during the excavation of the station - 80% more than that at Woodlands North and 20 times the amount that at Woodlands. As such, we will expect the excavation of the station to be very slow. Similar to Great World, the station will have 3 levels and 5 entrances. Entrances D and E will be linked by an underpass and are located on either sides of Havelock Road. The remaining 3 entrances are located along Zion Road to serve the Bukit Ho Swee estate.

Progress Update
The site office for T221 has recently been completed, and is located at 51A Kim Seng Road. The site is also home to LTA's Thomson Line Civil Team 3's project office. Slope treatments and the felling of trees around the site are underway. 12m high hoardings have also gone up around certain portions of the site.

Northern section of Havelock Station

Wednesday, October 1, 2014

Great World - It's Beginning

Contract T220 is for the construction of the Great World station and 2 twin bored tunnels to Orchard and Havelock stations. The station is sited on an empty plot of state land once occupied by ERC Institute and the Ministry of Manpower. The buildings have since been demolished and works have begun at the site. The contract has been awarded to a joint venture between Tiong Seng and Dongah at a 65% to 35% stake ratio. These 2 companies have had common working experiences together while tunnelling under C913 of the Downtown Line.

Stamford Diversion Canal Contract 1
This is a civil contract by the Public Utilities Board (PUB) to divert water flow from the existing Stamford Canal by constructing a 2km drainage diversion tunnel to the Singapore River in an effort to alleviate flooding along Orchard Road. Contract 1 was awarded in May just 6 days before T220. Works have started on this contract and the Great World site is currently being shared between the two different projects from PUB and LTA.

Stamford Diversion Canal Phase 1
PUB and LTA project at the Great World site
Great World Station
The station will have 3 levels - An upper concourse, concourse and platform level. The upper concourse is a common subway level which will link all 5 entrances of the station. The station will be constructed top-down. Upon completion of the project, a new 400m long dual carriageway road connecting River Valley Road and River Valley Green will be built above the station.

Entrances C and E will be located on either sides of Kim Seng Road. The subway leading from the station to these 2 exits will be underneath the access road leading to The Trillium and Centennia Suites. As such, a 100m long pipe roof for trenchless construction of the subway will be adopted here. The subway leading to Entrance D on the opposite side of River Valley Road will be constructed using sheet piles.

A&A to existing POBs
2 Pedestrian Overhead Bridges will be altered under this project. The existing bridge located north of the station along River Valley Road will see one of its staircase being reconstructed whilst the bridge across Kim Seng Road to Great World City will integrate with Entrance C and have 2 new lifts added.

T220 Tunnel Chart
Tunnelling
2 Launch shafts will be built on either ends of the Great World Station. 1 TBM will launch out of the north launch shaft for a 650m double drive to the cripple siding at Orchard. The authority has given the contractor a choice of either an EPB or Slurry TBM to be used in this sector; and to justify for the chosen type. A cross passage will be constructed between GRW and ORC.

A slurry TBM will launch out of the south launch shaft for a 550m double drive to Havelock station. The tunnel alignment to Havelock runs beneath the recently completed Centennia Suites. The authority has imposed a no-pile zone during the construction of the apartment where the twin tunnels will cut under.

Gantry Crane over the mined shaft under Contract T2123, the first of such installed along the Thomson Line
Shaft at T2123 in proximity to the Alexandra Canal and Centennia Suites
Contract T2123
This is a civil contract awarded to Presscrete Engineering for the advanced works at the Great World site. The works involve constructing a small shaft, for the removal of abandoned piles (by mining) near Centennia Suites along the tunnelling route to Havelock. The demolishment of the 3 ERC and 8 MOM blocks were under this contract as well. Additionally, River Valley Green has been extended for site access to the Great World site.

Update Progress
Within 4 months of the award of contract, the Great World site has seen tremendous progress as compared to other contracts over a similar span of time, with the help of site clearing completed by the advanced works under T2123. Trench cutters and hydraulic grabs have arrived on the site. Guide walls for the d-wall excavation have been constructed at the south launch shaft. Silos have also been erected in the middle of the site and 12m high hoardings have been erected along the perimeter of the site.

Guide walls for the D-wall excavation of the launch shaft
Cross reference of the guide walls installed. Also shown is the mined shaft for T2123.