Supply Chain - Site Preparation
5
results
Related Content
Case Studies
- Don Regulators (2024)
- Keadby Terminal Assisted Outfall Pumping Station (2024)
- Hampton Loade WTW (2023)
- Don Regulators (2023)
- Queensferry WwTW (2024)
- Kerse Treated Water Storage Tank (2024)
- Niagara Weir Stabilisation & Fish Pass (2023)
- Bourn Reservoir (2023)
- Ise Valley Sewer Rehabilitation (2024)
- Derrycrin WwTW (2024)
(left) location of the regulator gates and (right) the new Meadowgate top-down vertical control gate[/caption]
Precast concrete ‘fish tiles’ from Craven Concrete Ltd positioned in the channel - Courtesy of JBA-Bentley[/caption]
(left) The dewatered channel and (right) ‘fish tile’ installation - Courtesy of JBA-Bentley[/caption]
Syphon outlet - Courtesy of JBA-Bentley[/caption]
(top left) the existing Canklow regulator gate (bottom left) 3D model of the new Canklow Regulator and (right) bathymetry of Woodhouse Mill Washland - Courtesy of JBA-Bentley[/caption]
The power supply to the gate will be a three-phase supply routed via a new MCC, which will contain the control modules, centralised drive units, and the telemetry system for remote monitoring and operation of the gate. The operation of the gate will be from on-site or via telemetry, with some semi-automated functions. The facility for future full automation of the site has been incorporated into the design. The MCC and electrical components will all be located within a kiosk mounted on a raised steelwork platform to lift the electrical components above the 0.1% AEP flood level. Also on this raised platform will be the DNO kiosk bringing power onto the site from the national grid, and a standby generator to provide resilience in case of power failure.
Overhead power exclusion zones within model - Courtesy of JBA-Bentley[/caption]
Outfall construction (November 2021) - Courtesy of GBJV Ltd[/caption]
Outfall construction constraints - Courtesy of GBJV Ltd[/caption]
Aerial view of final pour - Courtesy of GBJV Ltd[/caption]
Pump hall - Courtesy of GBJV Ltd[/caption]
Outfall structure including fenders - Courtesy of GBJV Ltd[/caption]
Google Maps image of Hampton Loade WTW - Courtesy of Ross-shire Engineering[/caption]
Dirty washwater from the 18 filters is received in four dirty wash water storage tanks. These tanks are sequentially operated with one tank receiving flows, one tank settling washwater, one tank decanting settled washwater, and one tank desludging at any one time. Settled washwater is decanted via a floating arm fitted with an actuated valve. The decanted water then flows to the river via two discharge balance tanks. The resulting washwater sludge is pumped to two sludge balancing tanks via two desludge pumps. In addition to flows from the four dirty washwater storage tanks, the two balancing tanks also receive sludge from the two Accentifloc clarifiers and the two Superpulsators. The sludge from the sludge balancing tanks is then continuously fed to the two sludge thickeners. The sludge is dosed with polymer at the inlet to the thickeners. Supernatant from the thickeners flows to the two discharge balance tanks by gravity. Thickened sludge from the bottom of the thickeners is then pumped to the two hydraulically linked sludge holding tanks for storage. Thickened sludge is dewatered by two centrifuges, each fed by a dedicated feeder pump drawing from the sludge holding tanks. Sludge cake from the centrifuges is deposited into sludge skips outside of the centrifuge building by two screw conveyors. When the skips are full, the cake is transferred to land where it is stored on site before disposal to agricultural land near to the Chelmarsh Reservoir.
3D render of Hampton Loade WTW CeraMac® filtration stage - Courtesy of Ross-shire Engineering[/caption]
(left) Render of the Hampton Loade WTW CeraMac® plant and (right) construction progress to date (February 2023) - Courtesy of Ross-shire Engineering[/caption]
Dedicated feed pumps for each of the CeraMac® units will be located within the basement of each CeraMac® building. These will pump forward water from the existing clarifier units onto the CeraMac® membranes, delivering back to existing GAC filters and situated at a level to ensure safe and reliable operation.
An extensive cleaning and neutralisation process is included to ensure that the membranes can be kept clean and allow for maximum production requirements. This involves the provision of new storage and processing equipment.
Progress at Hampton Loade CeraMac® membrane plant (October 2023) - Courtesy of Ross-shire Engineering[/caption]
The existing Canklow regulator gate - Courtesy of JBA-Bentley[/caption]
Canklow is currently in the detailed design phase of works. Alongside the gate design some additional civil engineering works are required. This includes some remedial works to the existing sheet piled channel walls including new anchors, a new crane pad to be utilised during construction and to facilitate future gate maintenance as well as the substructure for the new motor control centre (MCC). One of the key constraints of the site are high voltage overheads; therefore, the crane pad location and the siting of the EA’s compound with MCC had to carefully considered.
To assist in undertaking the design and developing the business case for the project, 3D survey was undertaken to create a 3D Matterport tour of the site. It allows the user to quickly navigate around the site and view all the infrastructure remotely. This proved particularly useful during the pandemic when restrictions were in place and site visits were limited.
The existing Woodhouse Mill regulator gate - Courtesy of JBA-Bentley[/caption]
Model of the new Meadowgate regulator - Courtesy of JBA-Bentley[/caption]
(left) Screenshot of fish pass model - Courtesy of JBA-Bentley, (top right) fish tile mould - Courtesy of Craven Concrete Ltd, and (bottom right) the Meadowgate site - Courtesy of JBA-Bentley[/caption]
To refine the design and prove passability for a range of species, the proposed arrangement was modelled using CFD. This allowed the upstand heights to be adjusted to provide the optimum depth and velocities through the range of design flows.
Precast fish pass tiles - Courtesy of Craven Concrete Ltd[/caption]
Hydrogen sulphide attacks: (left) to the existing isolation penstocks, and (right) to the existing inlet channel walls - Courtesy of Morgan Sindall Infrastructure[/caption]
3D model of the existing and new structures – Courtesy of Arcadis[/caption]
3-D model showing all pipelines rising from ground and entering reception tank – Courtesy of Arcadis[/caption]
Installed reception chamber and rising mains - Courtesy of Morgan Sindall Infrastructure[/caption]
(left) DfMA installation of new inlet screens and chambers, (top right) the screenings skip canopy, and, (bottom right) internal photograph of bellmouth discharge points in reception tank - Courtesy of Morgan Sindall Infrastructure[/caption]
Overpumping manifold to isolate existing inlet works and grit plant - Courtesy of Morgan Sindall Infrastructure[/caption]
View of tank with backfill almost completed. Pedestrian crane on the left - Courtesy of ESD JV[/caption]
(top left) Groundworks nearing completion, (bottom left) tank construction underway, and (right) view of tank interior - Courtesy of ESD JV[/caption]
The almost completed structure before backfill operations - Courtesy of ESD JV[/caption]
(top) Collapsed left bank and masonry weir, (left) left hand cofferdam dewatered, exposing the extent of the undermining to the weir foundations, and (right) sewer pipes diverted through a temporary bridge (PortaDam and cofferdam installed on the left hand side of the river) - Courtesy of Ward & Burke[/caption]
(top left) Left bank foundation RC slab and wall built, excavator grab positioning reclaimed stone wall, (top right) left half of weir stabilised, shutter for right hand cofferdam installed, river bed graded ready for flooding, (bottom left) with the weir stabilisation complete the existing fish pass and part of the weir are demolished to make room for the new fish pass, and (bottom right) sewer pipes reconnected through the fish pass walls - Courtesy of Ward & Burke[/caption]
During construction, large stones from the collapsed downstream weir and left bank were recovered from the river. The design was altered to reuse these stones and incorporate them into the structure, avoiding embodied carbon associated with the original proposed concrete structures and imported aggregate. The stones were used to rebuild the left bank, installed as scour protection on the right bank, and used to landscape canoe landings. The stones helped the structure blend harmoniously with the surrounding environment.
Before flooding the left bank downstream cofferdam, a steel shutter was designed and installed on the new concrete slab to seal the proposed right bank cofferdam to the weir face. This enabled part of the right bank cofferdam to be constructed within the left bank cofferdam, ensuring a better seal and reducing risks associated with piling in the river.
Once the left bank was complete and the left half of the weir stable, the cofferdams were flooded and removed.
A similar process was followed on the right bank to stabilise the weir. Sheet pile cofferdams were installed upstream and downstream of the weir. Temporary pumps kept the cofferdams dewatered.
(top left) Propped cofferdam for upstream section of fish pass, preparing for blinding, (bottom left) fish pass wall rebar, upstream section, and (right) upstream baffles, penstock, and access metalwork installed in fish pass - Courtesy of Ward & Burke[/caption]
Midland Valves supplied a penstock upstream and stop logs downstream to isolate the fish pass for maintenance. The penstock and stop log frames were cast into the fish pass walls, flush with the base of the fish pass. This avoids grit being caught in the frame, preventing a tight seal.
The fish pass was constructed in two halves; upstream and downstream of the weir. The two sewer pipes were cast into the walls of the downstream section. The downstream section was constructed first so that the sewer pipes could be re-energised and the temporary pumping station decommissioned before the end of the whole project.
To construct the downstream section of the fish pass, a section of the weir and sewer pipes were removed. Then the ground was formed and blinded with a 8.53° slope. The base steel was fixed and the base poured. Next the wall steel was tied, shutters erected and the walls poured. The walls were constructed with a tolerance of +-5mm to ensure the baffles could fit and there wasn’t excessive space for debris to get caught. For the construction of the walls, the formwork panels had to be stepped to tie in with the run of the slope. The on-site joiners made relevant angled shutter bases to integrate with the main wall shutters so each wall could be poured in one go.
To construct the upstream section of the fish pass, a new cofferdam was installed. The cofferdam was initially propped with MGF frames. The blinding was designed strong enough so that the MGF frames could be removed once it reached strength. It was important that the MGF props were removed because they would have clashed with the fish pass wall, and limited lifting operations in the cofferdam. The construction process was repeated and the fish pass base and walls were poured.
Surveys and inspections of the fish pass by Yorkshire Water and the Environment Agency confirmed that the overall design and construction of the structure was satisfactory and within the design specification. On confirmation of this, the dewatering pumps were decommissioned and the sheet piles removed from the river to allow flows through the new pass.
A 160t crane was employed to remove the sheet piles upstream of the weir. The excavator that had driven them in could not reach over the new fish pass.
[caption id="" align="alignnone" width="1200"]
(left) right bank cofferdam, looking at the rebuilt left bank masonry wall (and right) 160 ton crane and vibro hammer removing the upstream cofferdam - Courtesy of Ward & Burke[/caption]
View of tank under construction with newly painted exterior walls - Courtesy of Stonbury[/caption]
Tank under construction, showing precast concrete slabs being maneuvered into place by a crane - Courtesy of Stonbury[/caption]
Demolition of the disused circular tank prior to construction - Courtesy of Stonbury[/caption]
Addressing the drive to build assets with lower embodied carbon and to reduce the length of the programme, the design incorporated the use of precast concrete roof slabs in addition to conventional in-situ pour concrete. This was preferred to a fully precast solution due to the risk of perennial ingress issues at precast joints. This would help to reduce embodied carbon by approximately 10% compared with a traditional build and make the 48-week programme possible.
The structural elements of the reservoir and pipework were to have a minimum design life of 50+ years, and 20+ years for all other elements. All structural and geotechnical design was in accordance with the relevant section of the Eurocodes, and all concrete elements were designed with a water-tightness classification of 1. All work was designed to be carried out in accordance with the latest CESWI, WIMES and Cambridge Water Company general engineering specifications and to meet DWI requirements for potable water storage units and the current SEMD guidance.
Construction workers building reinforcement cage for walls - Courtesy of Stonbury[/caption]
The site for the new reservoir after demolition of the previous tank - Courtesy of Stonbury[/caption]
Formwork panels - (left) outside view during construction of the upper wall, and (right) inside view during construction of walls and columns – Courtesy of Stonbury[/caption]
Construction workers guiding precast concrete roof slabs into place - Courtesy of Stonbury[/caption]
(left) Construction worker using the newly installed exterior staircase, and (right) the completed tank undergoing an integrity inspection - Courtesy of Stonbury[/caption]
Temporary pipeline ready for assembly - Courtesy of @one Alliance[/caption]
Road closures were necessary while installing the pipe bridges - Courtesy of @one Alliance[/caption]
Installing the temporary overpumping solution - Courtesy of @one Alliance[/caption]
Re-lining rig - Courtesy of @one Alliance[/caption]
Rehabilitation of the existing mains using specialist pressure-rated cured in place pipe (CIPP) liners was selected. Framework supplier OnSite Central Ltd installed the liners using a combination of ultraviolet and water cure techniques to suit the challenging pipe conditions. Aware of the time constraints, OnSite Central Ltd worked with the project team to ensure the liners were delivered promptly from IMPREG GmBH in Germany, and that installation gangs were available to work extended shifts to ensure the challenging programme was delivered.
Overpumping termination point - Courtesy of @one Alliance[/caption]
The existing Derrycrin WwTW located near the Ballinderry River - Courtesy of NI Water[/caption]
Derrycrin during construction (August 2023) - Courtesy of NI Water[/caption]
Temporary treatment plant used at Derrycrin - Courtesy of DLJ Water Ltd[/caption]
Derrycrin WwTW inlet works - Courtesy of DLJ Water Ltd[/caption]
The new rotating biological contactors - Courtesy of NI Water[/caption]
Flow split chamber - Courtesy of DLJ Water Ltd[/caption]
MCert chamber - Courtesy of DLJ Water Ltd[/caption]
Desludge valves - Courtesy of DLJ Water Ltd[/caption]
NI Water Capital Delivery and Operations personnel pictured with the contract team from DLJ Water and RPS - Courtesy of NI Water[/caption]
Mini CS & Company News
- Frydd Wood, Elan Valley Aqueduct
Frydd Wood, Elan Valley AqueductThe BNM Alliance (a joint venture between Barhale and North Midland Construction) awarded Aarsleff the contract to design, supply and install a soil nailed slope to allow, with associated works, the launching of a tunnel boring machine for the Severn Trent Elan Valley Aqueduct Rehabilitation project in Wales. The original aqueduct was built between 1893 and 1904. Fast forward over 100 years and the aqueduct still provides drinking water from the Elan Valley to Severn Trent’s customers in Birmingham. The aqueduct transports high quality water entirely by gravity. Having supplied water for over 100 years, the aqueduct is beginning to tire in three key locations and offline replacements are necessary. 8 (No.) test nails were installed on the 17th July. These were tested to destruction to confirm the design prior to production works starting. With its Klemm 806 rig, Aarsleff will then installed 670 (No.) 100mm diameter fully galvanised R32 -280 self-drilling soil nails of 6-16m in length. [caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
In addition to the soil nails, approximately 670 (No.) head plate and nut were supplied and fixed. The soil nailed wall has an estimated 1250m2 area to which Aarsleff has supplied and fixed a steel mesh and geotextile facing. Aarsleff were on site from 24th July with completion 15th September 2017. Aarsleff showcased its previous work in soil nail projects of similar size to the main contractor before winning the contract to demonstrate its technical capabilities and expertise whilst simultaneously, assuring the client of cost, time and quality. Aarsleff has sought value engineering primarily through optimisation of the soil nail layout and facing mesh.
The self-drilling soil nails were procured from Barnsley-based Minova and possess a hollow bar, which is used for drilling ether with water flush, air flush or cement grout flush and are extended by using couplers. The standard couplers have a design which ensures end-to-end bearing of the hollow bars to transfer percussive energy from the top hammer to the drill bit whilst a sealing ring in the centre stop, minimised flush spillage during drilling. The soil nails also possesses a sacrificial drill bit.
[caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
The rig we employed is designed for the use of powerful double head drilling units, hydrualic drifters or rotary heads. It can also be equipped with drill masts either with feed gear or cylinder feed systems, with the option of fitting lattice mast extensions, the modularity of which, allows the adaption of a variety of options, which makes the drill rig ideal for anchoring, micro piling, jet grouting and even geothermal drilling. After completion, two percent of all working nails will be ‘Acceptance’ tested to validate the design and provide confidence as to the quality of the installation.
[caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
Scope of works
- 670 (No.) 100mm soil nails
- 670 (No.) head plate and nut
- 1250m2 steel mesh and geotextile facing
For more information: Aarsleff Ground Engineering: +44 (0)1636 611140 | www.aarsleff.co.uk
- Double Slide Rail Installation at SmartParc Development, Derby
Double Slide Rail Installation at Sm...NTS UK were first contacted by KPM Contracting in February 2023 with regards to providing a ground support system for a 13m x 3m foul pump tank to be installed at 5.5m below ground level. NTS UK provided a ground support system utilizing their Double Slide Rail tie-back system to provide a clear internal opening of 14.2m x 4.2m. Since the successful installation of the first foul pump tank NTS UK have gone on to provide the ground support solutions for an additional nine tank installations undertaken by KPM across the site. These excavations ranged from double tank installations at 20m x 15m plan dimensions to manhole installations 3.5m x 3.5m in plan with incoming services on three sides accommodated by the NTS UK pile chamber solution. The ground support systems utilized at the site incurred a number of challenges including high and variable groundwater, varying ground conditions, tight programme, unknown existing infrastructure and the neighbouring River Derwent. NTS UK were able to provide a design solution using their Slide Rail System. Many of the tank excavations were designed to allow for the re-use of components between different excavations, cutting down on transport, therefore reducing the carbon footprint attributed to each excavation. Fewer components than traditional shoring systems are used with the NTS UK Slide Rail system, this ensures fewer lifting operations and a much quicker and safer installation method. The system was installed using the dig & push method of installation which allows for no eccentric vibration and a no-toe solution, ensuring the risk of impacting any unknown services was mitigated. [caption id="attachment_1914" align="alignnone" width="1200"]
(left) First tank being lifted into the open excavation and (right) twin tank Slide Rail excavation 20m x 15m x 4.5m - Courtesy of NTS UK Ltd[/caption]
One of the larger 20m x 5m x 4.5m excavations at the site was close enough to the River Derwent for a sheet and frame solution to be considered. NTS UK’s temporary works designers deemed that an excavation this size at the site required 85 (No.) 7m Long Larssen Piles with two levels of the NTS UK System 80 frame. In contrast the NTS UK Slide Rail System utilized for the construction of the ground support system consisted of fewer than 50 components. The absence of any frames has also resulted in concrete/material, and therefore environmental and cost, savings for KPM Contracting. The components from this excavation were then utilized on two other excavations at the site. KPM Contracting were able to excavate, install & backfill the 20m x 5m x 4.5m excavation in seven working days – far quicker than would have been possible when using traditional methods, highlighting the environmental & commercial benefits of the system.
NTS UK’s Slide Rail is becoming ever popular in temporary works circles as the preferred method for fast, safe, cost-effective temporary excavation solutions.
Martin Munnelly, director of KPM Contracting.
“The system is so easy to use, far quicker, much safer and reduces our material costs significantly. It will definitely be explored for all future excavations,”
Geoff Bates, Area Sales Manager NTS UK.“The guys on site have been brilliant, and have all fully embraced the system.”
For more information contact National Trench Safety: 03332 076 007 | https://www.ntsafety.co.uk/
- Newark Waste and Water Improvement Project
Newark Waste and Water Improvement P...Aarsleff has completed the CFA and Sheet piling works for a major new scheme that will protect homes in Newark from sewer flooding and provide a reliable water supply for decades to come. In 2016, Nick Wallace from Severn Trent explained that £60 million would be spent to replace more than 12 miles of old pipes with new, larger ones. Aarsleff worked on Queens Road to facilitate the replacement of a tunnel with a 1.5 metre diameter one. We employed an ABI TM13 /16SL with a Hydropress to pre-auger,and further installed 28 (No.) PU22- 12m long sheet piles. Due to being in a residential and restricted area, Aarsleff employed a Silent Hydropress to drive in the sheet piles to reduce the vibration. Scope of works- CFA - 28 (No.) sheets
- ABI TM13/16SL with Hydropress
- 10th May 2017 - 25th May 2017
For more information: Aarsleff Ground Engineering: +44 (0)1636 611140 | www.aarsleff.co.uk
- River Humber Pipeline Replacement
River Humber Pipeline ReplacementScope of works
National Grid, working with North Lincolnshire Council and East Riding of Yorkshire Council, developed a plan to construct a tunnel under the River Humber to replace the existing pipeline. The three-year project will provide National Grid with a 5km long, 3.65m diameter tunnel bored 30m under the river bed. A single 1200mm concrete-weight coated steel pipe will be inserted into the tunnel in a single string, making it the longest gas pipeline insertion of this kind in the world.Issues and solutions
The River Humber pipeline is an important pipeline - connecting an import location for gas at Easington, on the East Yorkshire coast, to the national network – delivering gas supplies to millions of households throughout the UK. The original pipeline, Feeder 9, is buried in a cut-and-cover trench under the river bed where tidal patterns have eroded the river bed uncovering the pipeline. Remedial work was undertaken to provide a short-term solution while a long-term solution was developed. Working with the joint venture consisting of Skanska, PORR Bau GmbH and A.Hak, MGF’s in-house design engineers developed and manufactured a bespoke temporary works propping solution for the tunnel boring machine (TBM) launch pit excavation. The contractor required the design to allow for the following key factors:- Use of a load monitoring system.
- Design of bespoke connection details to sheet piles or capping beams where steel walers were not used.
- Design of bespoke 'headwall' beam to eliminate knee bracing at the end of the tunnel portal to increase working space.
- Design of prop connections to withstand 10 tonne accidental load.
"This project was particularly challenging due to the multiple levels of framing, high loads and strict robustness criteria. As the design was required to survive the loss or damage of a prop and withstand a 10-tonne impact load more props were required, however we had to balance this with ensuring that the contractor had sufficient space to excavate efficiently. The design of the headwall beam contributed significantly to this as it removed the requirement of having knee bracing at the end of the excavation, opening space and making bulk excavation easier."
The project will take approximately two years to complete and top level of the temporary works will stay in place during this time. In an adjoining field, the pipework is being welded in top strings in readiness for insertion. The tunnelling is currently underway with a slurry TBM.
For more information: MGF Ltd | +44 (0)1942 402700 | www.mgf.co.uk
- Derby Hydro Power House
Derby Hydro Power HouseScope of works
The purpose of the job was to design and supply temporary and permanent support for a hydro power house and turbine chamber (plus associated inlet channel and tailrace) constructed at the side of an existing weir on the banks of the River Derwent in the centre of Derby.Issues & solutions
The design incorporated a single level of modular 406UC Hydraulic Brace system in conjunction with Larssen piles up to 10m in length, toed in mudstone, covering a perimeter of over 150m. MGF's design allowed early removal of the brace by using a permanent concrete base slab as a low propped cantilever. The design had to take into consideration the complicated construction sequence; and the location of a large crane during installation and removal of the river piles. During the project Balfour Beatty and MGF collaborated to develop the Stairsafe system (the UK's first temporary steel stair system designed specifically for excavations). The system proved a great success in providing rapid and safe access into excavations leading to greater site productivity. The system is now being used throughout the UK on excavations up to 6.5m in depth. [caption id="" align="alignnone" width="1200"]
Courtesy of MGF Ltd[/caption]
Project details
- Sector: Energy & Waste
- Client: Derby County Council
- Contractor: Balfour Beatty
- Consulting engineer: Atkins
- MGF Depot: Midlands - Rugeley
- Product hired: 406UC Hydraulic Brace, 10M Larssen Piles
From early in the tender process MGF have been heavily involved with Balfour Beatty to develop an innovative, cost effective and highly complicated cofferdam design; which helped make Balfour Beatty's tender attractive to the client, Derby City Council. Michael Rummens, Balfour Beatty Site Agent, commented:The verdict
"MGF were brought in at tender stage to assist in the value engineering of the cofferdam and support frames. Upon contract award, MGF's technical team were extremely proactive in producing a workable design in line with the projects requirements. The professional, amenable and expedient attitude continued throughout the process from design, technical support, plant hire and delivery and site assistance."
For more information: MGF Ltd | +44 (0)1942 402700 | www.mgf.co.uk
- Alleviating Flooding at Beaumaris Castle
Alleviating Flooding at Beaumaris Ca...The project required the contractor to excavate within 25m of Beaumaris Castle – a UNESCO World Heritage site and one of the best examples of 13th and 14th century architecture in Europe attracting over 100,000 visitors last year. Faced with the challenge of installing 600m of 1.5m diameter polypipe in 6m sections between existing manholes, John Kelly Construction spent time researching the products available on the market, before finding that MGF’s High Clearance Trench Boxes were ideal for the job. [caption id="" align="alignnone" width="1200"]
Courtesy of MGF Ltd[/caption]
The 7m x 2.9m wide High Clearance Trench Boxes coupled with Top Boxes saved time and money to the contractor when compared to sheets and frames. The strength of the box allows suitability and capability of going to 5m depth and having high clearance struts on both ends of the box allows access at both sides – ideal for installing larger diameter pipes.
[caption id="" align="alignnone" width="1200"]
Courtesy of MGF Ltd[/caption]
Paul Cowen, Technical Sales for MGF commented:
“Beaumaris’ most recent floods in 2017 was the catalyst that something needed to be done regarding the surface water drainage system. MGF became involved to supply the excavation support equipment to alleviate the threat of flooding to protect the natural beauty and tourism trade in the area”.
MGF’s stock logistics team confirmed availability of the kit at our Dartford depot and coordinated transfer to the Astley depot before delivery to site with three 40ft articulated vehicles and two 15t wagons to ensure the order was met. [caption id="" align="alignnone" width="1200"]
Courtesy of MGF Ltd[/caption]
John Kelly, Managing Director of John Kelly Construction, stated:
"I was very impressed with MGF as a company as they were very quick to respond to our queries, provided designs and all equipment ordered arrived on site with no delays."
- Sector: Water & Utilities
- Client: Isle of Anglesey County Council
- Contractor: John Kelly Construction
- MGF depot: North West - Astley
- Products hired: High clearance trench box, top boxes & titan manhole box
For more information: MGF Ltd | +44 (0)1942 402700 | www.mgf.co.uk
- Major Supply Grid Upgrades, Somerset
Major Supply Grid Upgrades, SomersetScope of works
Excavation works began in 2017 at the Dancing Hill Reservoir site as part of a £6 million project to upgrade the Water Supply GRID for Bridgwater and the surrounding areas. Major upgrades are required due to large-scale developments in the area.Issues & solutions
The design was particularly challenging due to the complicated nature of the ground surrounding the reservoir tank. A sizeable berm was built on the ground profile around Cofferdam 4 to ensure a safe and stable excavation. This exaction also had to accept other loadings from Cofferdams 1, 2 and 3. Multiple 203UC tank brace frames were used due to the strict lift plan limit of 1 tonne. Larger or heavier brace systems could risk the collapse of existing foundations. Vibration pile driving was not permitted due to the detrimental effect it could have on the high-pressure water mains that supplies customers. There was also a HV cable running through the site that had to be avoided. The exact location of other services created additional challenges and ongoing surveys had to be monitored throughout the duration of works. As of 2017 there are four connected cofferdams in place allowing safe working space to combine new pipeworks to the main reservoir tank. Multiple back-to-back 203UC tank braces with special alignment of bracing has been key in the design, combined with KKD 600 sheets to secure the trench. Several Lightweight DavitSafe systems allow safe access into the 10m deep cofferdams.- Sector: Water & Utilities
- Client: Wessex Water
- Location: Bridgewater, Somerset
- Scheme: Water Supply GRID Upgrade
- MGF depot: Bristol
- Products hired: Multiple 203UC brace, KKD 600 sheets, lightweight davit
Dancing Hill - Courtesy of MGF Ltd[/caption]
For more information: MGF Ltd | +44 (0)1942 402700 | www.mgf.co.uk
- Newark Waste and Water Improvement Project - Shaft 26
Newark Waste and Water Improvement P...Severn Trent is investing £60 million to upgrade Newark’s sewerage and water system to help protect homes from sewer flooding. The scheme will provide a reliable water source for decades to come. In 2016, Nick Wallace from Severn Trent explained that more than 12 miles of old piles will be replaced with new, larger ones. In May 2017, Aarsleff worked on Queens Road in Newark, to facilitate the replacement of a tunnel with one at 1.5m diameter. Here, 28 (No.) sheet piles were installed. As part of the same scheme, and for the same client, Aarsleff was awarded the contract to construct a sheet piled cofferdam on Harcourt Street. Aarsleff installed 46 (No.) sacrificial steel sheet piles, with pile width 600mm and 12.0m in length. There was a retained height of 10.2m, forming the overall cofferdam. Again, Aarsleff’s work will facilitate the replacement of an old water course. [caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
As Aarsleff was piling in the middle of a residential street, it drove the sheet piles using an ABI leader rig with pre-augering taking place in advance of main works where it utilised a Silent Hydro pile press to reduce the noise and vibration. A 50-tonne capacity crawler crane was employed, operating at a maximum 6m radius to unload and handle piles and hammer.
Aarsleff’s Senior Technical Estimator Ashley Carter said:
“It is a great endorsement of Aarsleff’s work that we have been awarded our second contract for the same scheme in Newark, just 7 months later. There are around 400 homes in Newark that are currently at risk of flooding, demonstrating just how important sheet piling projects like this are in future-proofing our infrastructure and communities."
[caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
- Scope of works
- 46 (No.) steel sheet piles
- Pre-auger
- Equipment
- ABI rig
- Silent hydro pile press
- Contractor
- BNM Alliance (an nmcn PLC and Barhale joint venture)
- Construction period
- 11th December 2017 - 20th February 2018
For more information: Aarsleff Ground Engineering: +44 (0)1636 611140 | www.aarsleff.co.uk
- Scope of works
- Sustainable Vegetation Management
- Stourport Cofferdam
Stourport CofferdamJ Murphy Group awarded Aarsleff the contract to install a temporary sheet piled cofferdam on the River Severn, as part of the £300 million Birmingham Resilience Project. The scheme is one of Severn Trent’s largest ever infrastructure projects, specifically to develop an alternative water supply for Birmingham to complement the Elan Valley Aqueduct (EVA). The Birmingham Resilience Project will create a new abstraction point and pumping station on the River Severn, at Lickhill Quarry near Stourport, to which water will then be pumped along a new 25km pipeline, through pipes with a 1.0m diameter, to the water treatment works in Birmingham. Aarsleff’s sheet piling works allowed a dry working area for J Murphy to construct the secant piling to the intake structure. Sheet piles will then be subsequently removed and the entire structure submerged. Water is to be taken from the River Severn which will provide a new source for the aqueduct, while maintenance takes place on the original EVA. When the resilience plan is in operation, the city of Birmingham will be drawing water from at least four sources, rather than just one. Early contractor engagement between J Murphy and Aarsleff identified significant technical deficiencies in the early engineering proposals for the temporary works cofferdam. Aarsleff’s proposed design was safer, quicker and cheaper with significantly less risk to the environment, their clients program and operatives. Aarsleff installed the bespoke temporary sheet piled cofferdam which comprised 154 (No.) AZ26-700 steel sheet piles, with an integral enhanced toe support system comprising of 53 (No.) H-Section piles. These were required due to the very shallow underlying bedrock, which only allowed for a limited sheet pile penetration. Access was provided by a temporary access works platform allowing safe working over water. Aarsleff employed a high frequency vibratory hammer and an impact hammer to drive its piles (using panel driving techniques) and employed a 110-tonne capacity mobile crane operating at a maximum 25m radius to unload and handle piles and hammers. [caption id="" align="alignnone" width="1200"]
Courtesy of Aarsleff Ground Engineering Ltd[/caption]
Senior technical estimator Ashley Carter said:
“This was a technically challenging scheme to be involved with requiring a lateral thinking approach to resolving the challenging problems. The prestigious project demonstrates the high level of experience and expertise Aarsleff’s sheet piling department can offer to its clients”.
Aside from delivering the project on time and within budget, Aarsleff were also able to reduce risk and environmental damage. Risk reduction through application of practical construction methodology, and Reduction in Environmental impact, (as the original scheme involved drilling underwater and spoil flushed directly into the watercourse). Steel sheet piles will also be recovered for re-use making this element of the scheme carbon neutral. Aarsleff took the technical challenge and applied sense and reason to develop a practical, constructible and engineered solution, which benefitted all parties for the aforementioned Environmental, Commercial and Safety aspects. Meeting a tight construction programme at the front end of a long complex scheme gives Aarsleff great satisfaction. Scope of works- 154 (No.) AZ26 steel sheet piles (section modulus 2600cm3/m of max length 8.0m)
- Integral enhanced toe support system comprising of 53 (No.) 254/254/132 S355 JO H-Section piles
- Prefabricated box section connection detailing at 1.26m centre to centre
- 21st July 2017 - 13th Sep 2017
For more information: Aarsleff Ground Engineering: +44 (0)1636 611140 | www.aarsleff.co.uk
The Strelley to Redhill site compound showing the TBM being lowered into the shaft and the pipes ready to be laid - Courtesy of Avove[/caption]
Courtesy of Avove[/caption]
To overcome these challenges, the Vegetation Management team worked alongside other Avove teams involved with the project to develop solutions that reflected best practices. Being able to leverage the existing expertise of colleagues ensured that bespoke solutions could be developed, representing simplicity, innovation and cost efficiency for Severn Trent.
Courtesy of Avove[/caption]