Civil Construction 2015

Weekly site updates for the 2015 calendar year.
Civil Construction & Technical Installation 2017 Civil Construction 2016Early Works & Civil Construction 2014Aerial Views

Week 52 — 21 December 2015
At this time last year, the first walls of the Accelerator tunnel were being prepared for casting, work had not yet begun on any of the permanent buildings, and excavation of the Target Station area was still a month away. Construction of the tunnel is now less than 50 meters from the Front End Building, several permanent buildings are in progress, with some now as far along as HVAC and facade work, and the complex piling of the Target Station is well advanced. The number of site workers has increased from around 40 to more than 200. 
Below are two aerial photographs of the ESS construction site separated by one year's time. The first photograph is from December 2014, and the second from December 2015. Click each photograph to enlarge.
The European Spallation Source site, December 2014. PHOTO: Perry Nordeng
The European Spallation Source site, December 2015. PHOTO: Perry Nordeng
Week 51 — 14 December 2015
The final aerial photographs of the site from 2015, taken on 15 December. Click each one to see it in high-resolution.
The Target Station and Experimental Hall areas. Large-diameter bored piles are being installed at the center area to support the Target Monolith. PHOTO: Perry Nordeng
The completed sections of the Accelerator tunnel flanked by the Gallery Building (above) and the HEBT Loading Bay (below). PHOTO: Perry Nordeng
Overview of the area within Circular Road. Excavation and piling for the Experimental Halls can be seen in the foreground above the drainage ponds. PHOTO: Perry Nordeng
The Accelerator tunnel emergency exit (bottom left) and the HEBT Loading Bay (top right) in progress. PHOTO: Perry Nordeng
Week 50 — 7 December 2015
More than two dozen towering concrete pillars were installed, outlining the structure of the 3,000-square-metre main hall of the Central Utility Building (H01). These will be supported by trusses and prefab concrete walls. The groundworks for the Cryo-Compressor Building (G04) were completed, setting the stage for its construction. The four-storey high Gallery Building (G02) ‘cold box’ is now nearly enclosed by its walls, and backfill along the Accelerator tunnel walls continues. The Accelerator tunnel’s dog-leg approach to the Target Station has been fitted with a concrete ramp that rises 10 meters from the Accelerator to the Target. Accelerator tunnel walls have been cast through section E22, with vaults progressing into section E20
Concrete pillars being set by a crane for the 3,000-square-meter Central Utility Building main hall. PHOTO: ESS
Walls being erected on the Accelerator tunnel dog-leg section, which rises 10 meters to its interface with the Target Station. PHOTO: ESS
Week 49 — 30 November 2015
An assessment of the extensive piling of the Target area reveals that one-third of the 356 steel core piles are in place, 43% of the nearly 6,000 concrete piles are set, and 25% of the piles for the Experimental Halls are completed. The casting of the Accelerator tunnel is extending toward completion on both ends, with the first vault on the Dog Leg area cast last week and vaults for section E19 completed. This leaves about 120 meters to the Front End Building. The extensive utility tunnels giving underground access to the Target Station are now being prepared for casting, and prefab walls, including some of the facade, continue to be installed on the Gallery Building (G02) "cold box".
A surveyor in front of a large-diameter bored pile that will help support the Target monolith. PHOTO: ESS
A November 20 overhead view of the piling and tunnel works in the Target area. PHOTO: Perry Nordeng
The Accelerator tunnel (foreground) and Gallery Building "cold box" structure, which is receiving exterior walls and a facade. PHOTO: ESS
Week 48 — 23 November 2015
A milestone was reached in the Target area as earthworks on the installation galleries were completed. These are tunnels that connect the Target Station to the D03 Instrument Halls, and concrete works will begin this week. The vault for the Front End Building was completed and backfill around the basement level of the building has already begun. Scaffolding and winter protection has been erected around electrical substation H06 in preparation to install the facade and paint the building. The connection between the completed Cryo-Transfer Line tunnel and the Cryo Building is being cast, as are more walls and vaults at both ends of the Accelerator tunnel. Eight of the 63 large-diameter bored piles for the Target Station monolith are now cast.
The steel sheet piling outlines the Target Station area. In the foreground are the excavated Installation Gallery tunnels serving the Target Station and D03 Instrument Hall. PHOTO: ESS
The top slab of the Server Hall for the Central Utility Building in the foreground, and scaffolding and winter protection being erected around electrical substation H06 in the background. H06 will soon receive a facade and will be painted. PHOTO: ESS
Week 47 — 16 November 2015
Backfill of the Accelerator tunnel began. Beginning in the vicinity of the HEBT Loading Bay, the backfill will eventually reach 5-7 meters above the tunnel’s top slab, changing the face of the site considerably. Casting of the tunnel itself continues to progress at both ends with walls cast in the Dog Leg section leading to the Target Station and as far as section E21, roughly 80 meters shy of the Front End Building. Corresponding stubs, vaults, emergency exits and retaining wall castings have progressed accordingly. The steel frame for the Cold Box section of the Gallery Building (G02) is complete and concrete works inside and out have progressed. The first large-diameter bored pile for the Target monolith was completed this week and the large vault for the Central Utility Building’s (H01) server hall was cast.
The top of the Accelerator tunnel near the front end. Backfill of the tunnel began this week near the far end and will ultimately reach 5-7 meters above the top slab.
The Gallery Building taking shape. The steel structure is now complete with interior and exterior concrete works continuing.
Week 46 — 9 November 2015
The installation of concrete piles for the long-range experimental halls, Experimental Hall 3, began, while the large-diameter bored piling for the Target Station monolith has successfully moved forward. Concrete works on several buildings are moving quickly, with reinforcement work nearly complete at the top slab of the Central Utility Building’s (H01) server hall as well as the remaining top slabs for the Front End Building. The HEBT Loading Bay has received another set of walls and a vault, and the Dog Leg section (E01-E03) of the Accelerator tunnel, which brings the beam up to the Target Station, has also received a pair of wall sections. High-voltage electrical cables have been laid for distributing power from electrical substation H05, which now has switchgear installed, some of the first interior installations for the facility as a whole. 
Looking down the spine of the ESS Accelerator and Target Station (foreground) on October 27, 2015. Click for the full-size image. PHOTO: Perry Nordeng
View from above the Front End Building on October 27, 2015. The ion source will be located in the uncovered section, where thick concrete vaults are now being installed. Click for the full-size photo. PHOTO: Perry Nordeng
Week 45 — 2 November 2015
Installation of large-diameter bored piles for the Target monolith began. There are 63 of them and completion is scheduled for March 2016. Excavation and piling for the Target installation tunnels has also begun. The steel for the four-storey cold box area of the Gallery Building (G02) is in place with precast concrete walls attached on the tunnel side. The second level of the cast-in-place Central Utility Building (CUB) walls are being cast in preparation for the steel and pre-cast concrete upper floors. Prep work and documentation was completed for the underground process piping to be installed in the Gallery Building, ABB switchgear is ready for cable connections in the electrical substation H05, and casting of the Accelerator tunnel continues steadily forward.
The UK-based very large piling machine in operation at ESS. There are 63 large-diameter bored piles to be installed for the Target Station monolith foundation.
The first completed roof on an ESS building, electrical substation H06.
Week 44 — 26 October 2015
A very large piling machine has arrived from the UK to install large-diameter bored piles for the Target monolith foundation. It was delivered in four parts and is now being assembled. The total length of covered Accelerator tunnel has reached 294 metres, as walls have been cast in E19b and vaults in E17b. Half of the top slabs for the Front End Building (FEB) were cast, some 2,000 cubic meters of concrete. The build-up for the structure and form for the top slabs above the ion source part of the FEB has begun, where an additional 4,000 cubic meters of concrete will be placed, at twice the thickness. A metal roof has been installed on the cold box steel structure for the Gallery Building, and all roofing is substantially complete on the H06 substation building.
The cold box part of the Gallery Building in progress as seen from the top of the Accelerator tunnel.
The top slab of the Front End Building in progress.
Week 43 — 19 October 2015
Tunnel works through 20 October 2015. Click to enlarge.
Preparation of the monolith area of the Target Station was completed, allowing for installation of the 1.6-meter-diameter bored piles to begin. A large piling machine will arrive from the UK next week for the purpose. The Accelerator tunnel approached 60% completion as more concrete was cast throughout the site, including the top slab through section E17a, and walls through E19a. The HEBT loading bay has likewise received more walls and vaults, and concrete work for the Stubs and Front End Building have moved forward as well. The high voltage switchgear for one power substation was delivered this week from the Czech Republic, and roofing work continues on another.
The Gallery Building 'cold box' under construction, with a steel frame and precast concrete panels.
Preparations for the monolith foundation piles, which will be bored into the concrete rings. The cast-in-place concrete piles are 1.6 meters in diameter.
Week 42 — 12 October 2015
Numerous concrete castings across many of the active areas of the project site were made this week: walls and vaults continue to go up on the Accelerator tunnel (G01); more of the seven-part stub castings have been completed, creating the numerous large interfaces between the RF Gallery Building (G02) and the Linac tunnel; the first vault of the HEBT Loading Bay on the south side of the tunnel was cast; blinding has been set for the two tunnel emergency exits; and the dog-leg area of the tunnel has seen its first walls go up; base slabs are being cast in the Cryo-Compressor Building (G04); and cable pits are being cast in concrete for the Central Utility Building (H01) infrastructure. Steel work is ongoing for the 4-storey section of the Gallery Building known as the ‘Cold Box’, and precast walls are following close behind. High-voltage cabling and grounding works continue throughout the G and H buildings. And at the Target Station the pile drivers continue to pound the pilings down to the bedrock. 
The Front End Building under construction. Protons exit to the left.
The Accelerator tunnel is undergoing floor polishing and painting of the walls and vault.
The HEBT Loading Bay ramp received its first vault this week (not shown). Components and service equipment will be loaded into the Accelerator tunnel via this ramp, which will be serviced by an elevator from ground level several meters above.
Week 41 — 5 October 2015
An important milestone was achieved this week: the final section of the 537 meters of the Accelerator tunnel base slab was cast, providing a walkable path from the Front End Building to the so-called “beam dump” area at the Target Station. The full tunnel, with walls and vaults, is now more than 50% complete. Assembly of the 12-meter-high steel frame for part of the Gallery Building (G02) began, taking the whole site into a new vertical realm. The Target area is now prepped to receive the large steel pilings that will support the 6,000-tonne monolith. Excavation of the Experiment Halls also began, which will include tunnels for access from the Target Station to other parts of the facility. A 100-tonne transformer unit has been delivered to the site, one of the two that will provide power to ESS. Cabling and grounding works are ongoing for the high-voltage transfer that will be needed between power stations H05 and H06, and then onto the Cryo-Compressor Building (G04), where inbound process pipes have been set in preparation for concrete casting.
September 30 orthographic photo of the ESS construction site. 
Click for high-resolution version.
The Accelerator tunnel bottom slab reached the Target Station beam dump this week.
The steel beam structure for the 12-meter-high section of the Gallery Building.
Week 40 — 28 September 2015
Three of the four walls have been cast on the Front End Building, where the ion source for the Accelerator will be located, and the formwork for the building's vaults is being prepared. The Accelerator tunnel itself continues to expand with the full 537 meters of base slab expected to be completed this week. The floor is being polished inside the tunnel. Sheet piling along the southwestern segment of Circular Road, the main ring road around the Target end of the facility, has been completed from the main entrance to building H05. Around 30 concrete rings have been installed in the monolith area of the Target Station, within which large-diameter piles will be sunk. Grounding and electrical trunking in bottom slabs is in progress in all G buildings, and high voltage cabling is being installed between electrical substations H05 and H06. Kraftringen is also finalising the district heating pipes connecting the Central Utility Building (H01) with the Lund district heating grid. 
The Front End Building on 18 September 2015, where the ion source for the ESS Accelerator will be located. The Accelerator tunnel begins to the left. Click for a full-size image. PHOTO: Perry Nordeng
Sheet piling works along the southwest section of Circular Road on 18 September 2015. Click to enlarge. PHOTO: Perry Nordeng
Week 39 — 21 September 2015
The painting of the interior walls of the Accelerator tunnel began, and the ongoing concrete works have brought the total length of the covered tunnel to 46% completion (248 meters, from E04-E15a). The tunnel’s base slab is about to reach the beam dump area of the Target Station, where excavation of the 4-meter-deep monolith area is preparing the way for the installation of the monolith’s concrete and steel ringed foundation, expected to begin next week. Preparations for the 12-meter-high steel structure that will mark the Gallery Building (G02) are finished and delivery of the steel is expected next week, which will give a new vertical dimension to the site. Walls also continue to go up on the Front End Building and the HEBT Loading Bay. In building works, the Central Utility Building (H01) saw more walls cast, electrical ducting is being installed in one substation (H05) and roofing work continues on the other (H06)
Interior works in the Accelerator tunnel. Installation of components will begin in 2017.
The roof installation for the HEBT Loading Bay on the north side of the Accelerator tunnel.
Week 38 — 14 September 2015
The Central Utility Building (H01), the Gallery Building (G02), and the Cryo-Compressor Building (G04) have all seen significant progress in their respective concrete works, including the first castings of the latter’s base slab. Roofing and facade work have begun on the two power station buildings, H05 and H06. Apart from the usual weekly progress on the Accelerator tunnel castings, significant concrete work has also transpired on its periphery. The retaining wall connecting the stubs to the Gallery Building is progressing quickly, and is now 60 meters long with three stubs fully integrated and backfill following close behind.
The retaining wall and two stubs as seen from the roof of the Accelerator tunnel. The stubs are the interface halls between the Gallery Building and the Accelerator tunnel.
Roofing work on the Distribution Substation (H06) for the Central Utility Building.
Week 37 — 7 September 2015
The 10th of the 25 linear sections of the Accelerator tunnel has received a concrete roof, bringing the total length of covered tunnel to 226 meters (Sections E4-E14). Backfill along both the north and south sides of the tunnel is also progressing alongside steel work on the Gallery Building (G02) running parallel to the tunnel. Other building works include completion of the basement walls of the Central Utility Building (H01) and the use of the structurally complete substation building H05 to test mockups for other building facades. High-voltage electrical cables are being run between the two substations, H05 and H06. Piling for the Target Station foundation is around one-quarter complete, with 1101 of 3958 concrete piles and 84 of 364 steelcore piles installed.
Concrete works at the Accelerator tunnel dogleg section (Target end). To the right can be seen the tunnel backfill progress as the ground-level is brought to the top of the tunnel. 
Ductwork being installed by the MEP contractor inside building H05.
Week 36 — 31 August 2015
The process of BREEAM certification at ESS has begun. The Gallery Building (G02) will contain permanent offices and a control room, making the planning of its construction the first to be evaluated against BREEAM criteria. Additionally, the first MEP installations on site have taken place in building H05, including ventilation ducts. In the field, the Accelerator tunnel has received another wall and another top slab. The blinding has been cast in the dogleg section at the Target end of the tunnel, and the base slab of the HEBT loading bay is nearly complete. Reinforcement for the walls of the Front End Building continues to be built up in preparation for casting those, and Stubs continue to be cast alongside the Accelerator tunnel.
An August 18 aerial photo of the HEBT loading bay area. Click to see full-size image. PHOTO: Perry Nordeng
An August 28 orthophoto of the ESS site, created by Skanska's surveyors. IMAGE: Skanska ESS Construction
Week 35 — 24 August 2015
The first wall of the Front End Building has been cast and blinding of the Accelerator tunnel dog-leg section (E01-E03) has been completed, bringing the tunnel’s footprint right to the doorstep of the Target Station. Excavation for the foundation of the Cryo-Compressor Building (G04) has also advanced. Building H05, ESS’s primary electrical substation, and the first to be constructed on the site, has now moved to interior work, including painting. Backfill along the north and south sides of the Accelerator tunnel is moving forward, and 17 castings on the tunnel alone were completed this week.
The two ends of the Accelerator tunnel. On the left is the foundation of the Accelerator dog-leg that takes the beam into the Target Station; on the right is the Front End Building, where the proton beam originates.
An August 18 aerial photograph, showing the extensive piling at the Target Station and the end of the enclosed section of the Accelerator tunnel. Click to see full size.
Week 34 — 17 August 2015
The total length of the covered section of the Accelerator tunnel was extended to 191 meters, and the base slab for the Accelerator’s Front End Building was completed, with the casting of its first wall scheduled for next week. Backfill along the north side of the tunnel continues in conjunction with the build-up of the stubs, and the HEBT area has had its first wall cast. The drilled foundations for the Cryo-Compressor Building (G04) are complete and fine excavation is in progress. In the Target Station area, preparations for deeper excavation for the monolith foundation have begun. And at the Central Utility Building (H01), the basement walls are being cast.
Work in progress at the Accelerator's Front End Building.
A July 2 aerial view of work at the Central Utility Building (foreground) and it's electrical substation (back). Precast elements of the substation are now all in place, and casting of the basement walls of the CUB has begun. Click to enlarge.
Target Station foundation works.
Week 33 — 10 August 2015
As the piling of the Target Station continues into another week, the construction site has seen building works moving forward across the facility. Formwork for the walls of the Front End Building is being installed; walls and slabs have been cast in different areas of the large Central Utility Building (CUB); the Primary Substation (H05) has been prepped for interior painting; more precast elements have been installed at the Distribution Substation (H06); foundation works have continued for the Gallery Building (G02); and detailed excavation—along with drilled foundations—of the Cryo-Compressor Building (G04) has commenced. Backfill continues along the north side of the Accelerator tunnel, and the weekly casting regimen of a top slab, walls, and a bottom slab was completed as expected. Excavation of more Accelerator tunnel stubs along with the dogleg section has begun.
Building H06, the Distribution Substation for the Central Utility Building being fitted with precast concrete.
Week 32 — 3 August 2015
Backfill along the cryo-transfer line tunnel was completed over the summer holiday, setting the stage for excavation of the cryo-compressor building. Backfill along the Accelerator tunnel, as well as piling efforts in the Target area, also continued over the holiday. Casting of the Accelerator tunnel resumed this week and will proceed at a rate of one section of walls and top slab weekly, with full coverage of the tunnel expected by next summer. Preparations have been completed for concrete casting to begin at the Front End Building (FEB) and HEBT area, while the base slab of the large Central Utility Building (CUB) has been cast, with a mix of precast and cast-in-place walls soon to follow. Foundation works for the Gallery Building (G02), including drilled foundations, have begun. This will be a steel frame building to be erected in the coming months. 
Backfill complete at the cryo-transfer line tunnel. The remaining visible part of the tunnel is now covered with waterproofing. In the background is building H06, the power station for the Central Utility Building.
Two aerial views from July 2, 2015. On the left are the Target Station piling works, and on the right the Accelerator tunnel. Click for high-resolution photos. PHOTOS: Perry Nordeng
Weeks 27 through 31 — 29 June 2015
Progress in concrete works for the HEBT loading bay, Accelerator tunnel, and Front End Building (FEB) have progressed reliably, including two base slabs for the FEB. The layered backfilling process continues alongside the Cryo-Transfer Line tunnel, the Accelerator tunnel, and stubs. Target piling will continue through the summer break period (weeks 29-31), along with some civil works, including backfill and road works. Skanska Installations has signed on as the first Mechanical, Electrical & Plumbing (MEP) contractor on the site, signalling that building works will soon be moving inside.
View of the Accelerator tunnel, looking toward the Front End Building. 
Further excavation, sheet piling, and core piling at the Target Station.
Week 26 — 22 June 2015
The base slab for the Accelerator tunnel reached the Front End Building this week. This leaves only sections E01-03—the dogleg linking the linac to the Target Station—before the entire tunnel’s base slab is complete. Casting of the walls and vaults follows on predictably. Swedish subcontractor Intergrund was on site to begin the complex foundation work for the Klystron Gallery (G02), which will include 134 concrete and steel plinths installed at a depth of 1.5 meters. The extensive piling work for the Target Station is progressing. Over 200 concrete piles have now been sunk for the Target Station foundation, with another 3,700 to go. In preparation for the delivery of steelcore pilings this week, six casings have been installed in the bedrock, with 450 remaining. Sheet piling around the monolith area has also progressed, which will soon allow for deeper excavation of that ground. Building works continue as per last week.
Backfill in progress along the Cryo-Transfer Line tunnel, which connects the Accelerator tunnel to 
the Cryo-Compressor Building (G04).
Week 25 — 15 June 2015
Accelerator tunnel progress schematic, 18 June 2015. Click to enlarge.
Work on the Accelerator tunnel approached a key milestone, with only one base slab (E25) remaining to be cast to make the connection to the Front End Building (FEB). Casting of the base slab of the FEB itself is expected to begin next week in parallel with ongoing formwork and reinforcement preparations on other areas of the FEB slab. Backfill continues along the CTL tunnel and several stubs—the connection halls between the klystron gallery (building G02) and the accelerator tunnel, which run adjacent to one another. The foundation work for the Gallery Building (G02) is well underway, with some concrete already cast, and the Central Utility Building (H01) foundation is also taking shape. Building H05 is complete pending installation of the facade, and installation of the prefab walls and roof for H06 is in progress. Installation of concrete and steel core piles, along with additional sheet piling, continues in the Target Station area. Over five thousand pilings will be installed for the Target Station and Instrument Halls. 
Steel reinforcement for the Central Utility Building (H01) basement.
Concrete works at the HEBT Loading Bay, adjacent to the Accelerator tunnel.
Week 24 — 8 June 2015
Sheet piling for the Target Station and Experimental Halls 1 & 2 is moving quickly and expected to be completed before the summer holiday. Steel core piles are being hammered into the bedrock for the Target Station and concrete piles are now being installed for the Experimental Halls, which flank the Target Station on both sides. The casting of the CTL tunnel has been completed and backfilling is in progress. The basement of the 3,000-square-meter Central Utility Building (CUB) is being cast in concrete, and the CUB’s electrical substation, building H06, now has prefab concrete walls. The Accelerator tunnel received another bottom slab, a set of walls, and a top slab this week, as scheduled. And formwork has begun on the chicane-shaped HEBT loading bay on the south side of the Accelerator tunnel.
Members of the ESS Accelerator Division inspecting the Accelerator tunnel.
Piling progress in the Target Station area.
Week 23 — 1 June 2015
On the construction site, casting continued last week with one base slab and a top slab in the Accelerator Tunnel. The front end building has been equipped with blinding and reinforcement works is ongoing in the lift pit. The CTL tunnel is expected to be completed for filling mid-June, after which the big crane on rails can be moved past CTL and works continue in the direction of the front end building. The base slab for a cable trench and lift pit was cast for the first gallery substation last Thursday. The works on the Circular Road continue, now with the piping for water and sewage. Soil modification is ongoing in the experimental halls area.
June 5 aerial view of soil and foundation works at the Target Station and Instrument Halls area. Click for full-size image. PHOTO: Perry Nordeng
Tunnel overview and casting of the top slab. 
Week 22 — 25 May 2015
Last week the Skanska Safety week took place at the ESS construction site. During the week several workshops were held at the site, about for example working close to cranes and heavy machines, and members of Skanska's management team attended. At the moment there is a lot of activity in the Linac tunnel as the front end building is being cast with blinding, the dog-leg is being excavated, and concrete castings have been performed in base slab E20, top slab E06a and wall E04a. The last wall section for the CTL tunnel was cast last week. Two more top slabs remain, then the CTL will be subject to finishing and repair works, before being filled with soil in the first half of June. In the target area piling works continues and the first pre-cast walls are now being installed in the 192 m2 primary substation.
The last walls are being cast in the CTL tunnel.
Week 19 — 4 May 2015
Preparations to install steelcore piles for the Target Station foundation are progressing, and holes have been drilled for this purpose in the A2T section of the Target area. Excavation of the Front End Building site for the Accelerator has begun, and concrete works continue as scheduled for the Accelerator tunnel, HEBT loading bay, and cryo-transfer line tunnel. Excavation has also commenced for the RF Gallery Building, while building works for the Central Utility Building (CUB) and the Secondary Substation (H06) continue as planned. The Experimental Halls area is undergoing soil modification works prior to excavation beginning in that area as well.
Target area foundation works.Foundation works in the Target Station area. Steelcore piles will soon be installed in the A2T section, shown here with concrete blinding in place. Click the image to enlarge. PHOTO: Perry Nordeng
Week 18 — 27 April 2015
The Accelerator tunnel has now been excavated from E04 all the way to the front end building, the excavation of which will begin this week. There are 70 meters of enclosed tunnel now, and vaults are being cast for the cryo-transfer line tunnel as well. Excavation of the largest of the auxiliary buildings—the more than 4,000 square-meter Central Utility Building (CUB)—is well underway, with concrete blinding partially complete. The Target site foundation is undergoing parallel sheet piling and blinding, with 10% of the area complete in this respect. The foundation for the Primary Substation, H05, has been cast.
Site workers drilling holes in the concrete blinding of the Target site. Piles for the Target Station foundation will be installed at the locations of the holes. Corrugated steel sheet piling can be seen in the background.
Week 17 — 20 April 2015
Concrete works for the Accelerator tunnel moved reliably forward, with excavation and blinding completed through section E23, about 40 meters shy of the Accelerator front end. Blinding of the HEBT Loading Bay excavation site adjacent to the south side of the tunnel has been completed, setting the stage for structural works. On the Target site, which is about 650 m2, blinding will now commence area-by-area as preliminary sheet piling is completed, preparing the surface for the installation of foundation piles next month. Building works at the electrical substations continue, and the site for the large Central Utility Building is now being excavated. 
Concrete works at the HEBT Loading Bay site adjacent to the Accelerator tunnel.
The Target Station foundation taking shape. The site will soon be ready for pilings.
Week 16 — 13 April 2015
The High-Energy Beam Transport (HEBT) Loading Bay—the principle access point for installation and maintenance of Accelerator tunnel components, located on the south flank of the tunnel—has been excavated and is being prepared for concrete works. Progress has also been made on the large concrete stubs, which serve as the multiple interface points between the RF Gallery building and the Accelerator tunnel. The tunnel itself has reached 50 meters of completed concrete works, including base slab, walls, and vault. Concrete works on the CTL tunnel connecting the future cryoplant to the Accelerator tunnel are nearing completion, with backfill expected next month. In building works, excavation of the large Central Utility Building (H01) began, and concrete works on H05 and H06 continue. The long process of sheet piling the target area continues.
Interior of the Accelerator tunnel at the interface with Stub 7, one of the many access points between the RF Gallery building and the Accelerator.
The cryo-transfer line tunnel nearing completion. Backfill is expected in mid-May.
The enclosed area of the Accelerator tunnel has reached 50 meters in length.
Week 15 — 6 April 2015
Spring is here and the ESS construction site is humming. Casting of the Accelerator tunnel concrete is progressing at a rate of one bottom slab, one wall, and one vault per week. Excavation of Accelerator tunnel sections E19 to E25 has been completed, meaning the tunnel is now excavated from E04 all the way through to the front end. E07a walls are cast, extending the Accelerator tunnel walls now to a length of 80 meters. At building H05, the Primary Substation, the inner walls have been cast. At H06, the Distribution Substation, formwork and reinforcement are being prepared for casting of the first cable trenches next week. And finally, excavations for H01, the large Central Utility Building on the north side of the Accelerator tunnel, is also expected to begin next week.
Overview of Accelerator tunnel works, photographed 10 April 2015. Click for full-size image. Photo: Perry Nordeng
Week 14 — 30 March 2015
The excavation for the High-Energy Beam Transport (HEBT) loading bay began this week. This will be the main access point for the installation and maintenance of the components inside the Accelerator tunnel. The first walls for building H05 have been cast, and detailed excavation and fill has been complete for building H06, the large secondary electrical substation. The steady reinforcement and casting of base slabs, walls, vaults, and stubs continues on the Accelerator tunnel, and sheet piling for the Target area foundation continues. A 7-meter-high noise barrier has been built along Odarslövsvägen, and a second earth barrier to protect neighbours from the noise of the pile drivers is being built. There are now over 150 people working on the ESS construction site, in the site office, and in production.
Test piling on the ESS Target Station site.
Week 13 — 23 March 2015
This week at the construction site saw the beginning of sheet piling works in the Target area to allow for deeper excavations, both over a larger area and with variable depths. As piling will continue for a long time, two 5- to 7-meter-high noise barriers are being built up along Odarslövsvägen for noise mitigation. Concrete works on the Accelerator tunnel continue, with base slabs cast up to section E16. Walls are complete from E10 to E07b. Casting of stubs 7 and 8 is ongoing.
E09, the HEBT Loading Bay bend.
3D model of building H05, the primary electrical substation for ESS.
Week 12 — 16 March 2015
It is a modest beginning, but the complex construction of the ESS Target Station is ready to move forward. First-level excavation, drainage, and other ground works have prepared the site for sheet piling, deeper excavation, drilling, and concrete and steel core piling in the months to come. Concrete casting has begun at building H05, the first permanent building to be erected on site. The Accelerator tunnel and cryo-transfer line continue to grow, with more base slabs and walls cast in concrete this week. A new prefab site establishment for the site workers is also in progress to accommodate the increasing workforce.
A modest beginning: the ESS Target Station is ready for sheet piling. The Max IV synchrotron can be seen on the horizon.
Week 11 — 9 March 2015
There were three concrete castings on the construction site this week: one 20-meter base slab in section E14, one 10-meter wall in section E08b, and the third wall section out of seven in the CTL tunnel. Stubs 8 and 7 in the Accelerator tunnel have been excavated and are being reinforced for casting. Reinforcement and formwork is being prepared at building H05, with casting scheduled for next week. Excavation for the sheet piles in the Target area continues. Excavation for the second site establishment is ongoing, and the modular buildings should arrive next week. Excavation for building H06 is also ongoing, as is reinforcement in the CTL tunnel.
Reinforcement and formwork at Building H05, the primary electrical substation. This is the first permanent ESS building to be erected on site.
Week 10 — 2 March 2015
The March 6 update of the schematic overview of the tunnel works. The length of the Accelerator tunnel is 536.5 meters. Blinding is completed in sections E04 to E18 (315 meters). The base slab has been cast from sections E04 to E13 (214 meters). Walls are ready in E10 and E09 (39.2 meters) and vaults are cast at E10a and b (19.6 meters).
The second vault section was cast at E10a, which means there is now a 19.6-meter-long roof on the Accelerator tunnel. More walls are rising as well, with nearly 40 meters cast, including the bulge for the HEBT loading bay connection. While excavating section E18 of the tunnel, an area of sand and silt was discovered, which caused a temporary excavation stoppage. A trench has been dug through the section, connecting to the drainage on the north side and a pump has been installed to lower the water level. Excavation will continue following clearance from geotechnical engineers. There are now 85 staff based in the site office and 65 site operatives, bringing the total staff on site to 150.
Two views of the vault cast at section E10 of the Accelerator tunnel.
Aerial overview of Accelerator tunnel and CTL tunnel from 9 March 2015. Click to see full-size image. Photo: Perry Nordeng
Week 9 — 23 February 2015
Excavations are moving forward rapidly on the construction site. The Target area has been excavated to a depth where sheet piles will now be installed along the slopes, like interlocking walls, enabling deeper excavation. The Accelerator tunnel excavation continues in the direction of the front-end building, with 50 meters completed this week. The foundation for building H05, the 192 square meter primary substation in close proximity to the Eon power station, has been completed this week, setting the stage for the first of the Building Works to begin next week. Reinforcement and concrete works on the Accelerator tunnel continue to progress daily. 
Excavation site for the ESS Target Station. Sheeting will be installed on the slopes, allowing for deeper excavation.
Week 8 — 16 February 2015
On the construction site, the first Accelerator tunnel vault has been cast this week, at E10, marking the first enclosed section of the tunnel. New excavation work for the Accelerator tunnel is now progressing in the direction of the front-end building. This will be executed in two phases, with the first phase covering approximately 150 meters. The casting of the E11 base slab on Wednesday morning brings the total length of tunnel base slab cast to around 168 meters, from E04 to E11, and the slab for the cryo-transfer line tunnel has been completed. Excavation for building H05 also began this week.
A revised Construction Layout Plan was issued this week. 
Week 7 — 09 February 2015
New excavation work has ramped up at the construction site, bringing with it a flurry of activity. An additional 150 meters of the accelerator tunnel excavation has begun (sections E14 to E20), and the foundations of building H05 will be dug out next week. Reinforcement work in the accelerator tunnel is moving from section E04 to section E11, with casting of the base slab at E04 to follow. The walls at E10 are complete (about 20 meters in length on each side), and the support structure for the first section of the tunnel vault is being erected. With the base slab for the cryo-transfer line (CTL) nearly complete, the first walls along the CTL tunnel have also been cast. 
Work at section E10 of the accelerator tunnel 12 February, including the support structure for the vault (yellow stands).
Week 6 — 02 February 2015
Steady progress on the reinforcement and formwork for the accelerator tunnel continued at the site in preparation for further concrete casting next week. Other preparations continue around the site in anticipation of the start of building works next month. Substations H05 and H06 will be the first to rise, followed by G02 (the gallery building running alongside the accelerator tunnel, including the cold box and test facility), and the auxiliary buildings along Northern Gallery Road.
Click the image for high-resolution photo.
Aerial view of accelerator tunnel (horizontal) and cryo-transfer line tunnel (vertical), taken 5 February 2015. 
Click for high-resolution photo. Photo: Perry Nordeng
Week 5 — 26 January 2015
A construction milestone was reached this week. The first 10-meter-long concrete walls of the accelerator tunnel were cast on both sides at section E10. The walls are 3.5 meters high and half a meter thick. Other progress included the completion of the casting of the cryo-transfer line tunnel base slab as well as the base slab at E05. Reinforcement continues at section E04. Procurement of building materials, facades, and foundations for the first buildings, H05 (Primary Substation) and H06 (Distribution Substation), are in progress. Excavations should be completed within the next month and building works are scheduled to begin mid-March. 
Casting of the first 10 meters of the accelerator tunnel walls.
Week 4 — 19 January 2015
The casting of the accelerator tunnel base slab at sections E06 and E07 was completed this week, meaning that 98 meters of the base slab have been cast since December 1. Reinforcement work is ongoing on further sections of the tunnel slab, and removal of moulding and concrete polishing is ongoing on sections already cast. Reinforcement, formwork, and shoring for the two 3.5-meter-high tunnel walls at section E10 have moved forward in preparation for casting next week. 
Week 3 — 12 January 2015
The accelerator tunnel walls are beginning to rise at the construction site. Following a week focused on installing concrete reinforcement for the tunnel, it is expected that next week E10 will be the first section of the accelerator tunnel wall to be cast. Additionally, base slab sections E07, E05, and the remainder of the cryo-transfer line tunnel are also scheduled for concrete next week. A new permanent asphalt road is being prepared at the northeast corner of the site: Northern Gallery Road will receive water and sewage connections to Pond 1. Permanent lighting is being installed along Delivery Entrance Road. Walkways around Circular Road (Target) are under way. And a new logistics area is being prepared for operation in the Spring when the workforce is expected to expand.
Poor weather at the construction site has recently run the full gamut of snow, rain, gale-force winds, thunder, lightning, and hail. A tent on rails is being installed along the tunnel to protect the new surfaces and the workers from further harsh conditions, meaning that future concrete casting will be able to progress through inclement weather. To better track this meteorological excitement, a weather station has been installed atop the site offices. Those interested can now monitor conditions on site directly through Weather Underground. The location ID is ISKNELNS15. 

Formwork and shoring for accelerator tunnel wall at section E10. 
Week 2 — 5 January 2015
Tunnel works have resumed. Reinforcement of section E07 is now under way, and preparations for casting the remaining section of the CTL tunnel have begun.
Welders working on the concrete reinforcement for the accelerator tunnel base slab and walls.
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