This award is for a ground engineering scheme, as a standalone project or part of a larger development, with a contract value of between £500k and £1M that stands out in terms of its credentials in innovation, sustainability, health and safety and value engineering.

AKT II, Vinci Construction & Bachy Soletanche: UCL Pool Street

This project introduces two 16 to 20 storey towers directly above two UK Power Networks (UKPN) and National Grid (NG) extra-high-voltage tunnels at 20m to 30m under the proposed development, as part of the regeneration of a formerly industrial area in Stratford, east London.

AKT II worked closely with the client, University College London, the principal contractor Vinci, the piling contractor Bachy Soletanche, UKPN and NG. Following a performance-based approach, and with advanced finite element modelling, AKT II has value engineered the original, conventional proposal into a sustainable design solution of continuous flight augered piles, avoiding the use of costly wet rotary piling, permanent sleeving and base-grouting. This allows smaller diameter piles, less embodied carbon, and there is no need for support fluid.

Altogether, this geotechnical solution enhances the project’s site logistics and construction timeframe, with over 30 weeks of construction programme savings. It also made working safer, better for the environment and saved approximately £7M for the client.

Bachy Soletanche & Vibro Menard: Eco Park South, North London Heat and Power Project

Bachy Soletanche and Vibro Menard delivered the geotechnical works for the first phase of Eco Park South. The project was delivered in three visits, implementing four different construction methods. The team developed an environmentally friendly solution that contributed to an overall reduction of between 10-16% of the total embodied carbon in the ground engineering element of the works.

The key drivers were the usage of controlled modulus columns, which enabled the client to use a thinner slab with less reinforcement, and the use of the Trenchmix method to construct a cut off wall instead of using a traditional sheet piled solution.

Adopting these two processes reduced the amount of vehicles for spoil removal and the number of deliveries to site for cages and sheet pile panels.

Bam Ritchies: Kergord substation - drilling and blasting

In 2020, Bam Ritchies wwas awarded a contract for the drilling and blasting of 150,000m3 of rock as part of Scottish and Southern Electricity Networks Kergord HVDC Substation project on the Shetland Islands.

There were many challenges to overcome in delivering this project in such a remote, geologically challenging and environmentally sensitive location. They included difficult topography and thin blast layers which challenged the blast design, minimal explosive facilities on the islands, close proximity of aged buildings and close co-ordination to enable concurrent site activities to continue throughout the activities.

To achieve this aim, Bam Ritchies became involved in the project from an early stage. Having the right team on the project, working in close collaboration with its customer, coupled with early planning of an efficient explosives supply and correct drill rig selection, allowed the team to accelerate and safely blast 265,000m3 of rock, some 75% more than originally planned.

The development at 191 Old Marylebone Road comprised demolition of an existing nine storey office and basement, and the construction of a new 14 storey building. CGL investigated the feasibility for reusing existing 1990s piles within a piled assisted raft, following BRE Rufus protocols.

CGL conducted a targeted SI, along with parallel seismic testing, to better understand geotechnical consolidated soil strengths and de-risk uncertainty on the pile lengths, strength, quality, durability and reliability.

The results informed a Plaxis 3D FE model, allowing complex soil-structure interaction of the proposed piled assisted raft to be assessed and the feasibility of the scheme verified. This model further informed ground movement assessments for surrounding assets and temporary works design. A robust post-demolition pile testing strategy validated CGL’s initial assumptions and sensitivity analysis.

This pragmatic reuse of foundations supported sustainable development, achieving significant carbon-savings through lower concrete, steel and haulage when compared to an alternative replacement foundation scheme.

Concept Engineering Consultants: HS2 S1 Area East ground investigation work

Since summer 2021, Concept has completed more than 24 individual ground investigation packages for SCS Area East as part of its ongoing HS2 main works contract.

Concept completed ground investigations across a diverse variety of challenging work environments, while being flexible and adaptive to achieve the aims of the investigation as conditions and requirements changed on a daily and hourly basis.

Investigations required involvement from all areas of Concept’s business structure, from specialist and skilled teams on the ground, to experienced geotechnical logging geologists, to laboratory and reporting staff, technical advisors, QS and commercial experts, and site level and senior project management.

Throughout the process, the investigation has required Concept’s staff to invest heavily in training schemes including SMSTS, PASMA, NRSWA, BDA, FORS and NVQs, among others. It also invested in R&D to develop new articulated sampling equipment. By completing the work packages in a timely and cost-effective manner, and by working collaboratively, Concept has contributed to the geotechnical and structural data bank of London.

Curtins Consulting, Vinci Building South & Socotec: Kingston Community School

This project was conceived to provide a much needed primary school for a part of Kingston that had no nearby school to serve the community. The scheme was a partnership between developer City Hart and educational facility provider Located.

The site required that the school facilities were kept above ground with the MUGA pitch on top of the residential tower with a gym and other mechanical facilities in a basement two storeys below ground. The site was exceptionally tight with roads on two sides and a rail line embankment adjacent to the long edge of the site.

Geotechnically Curtins acted as the designer for Vinci Building South on the project, as well as the contractor’s engineering manager and contractor’s responsible engineer with direct liaison to Network Rail for engineering assurance. Network Rail viewed the project as high risk due to the basement being next to the rail embankment. Curtins designed a slope monitoring system with the help of Socotec, which consisted of prisms, sleeper monitors and precise levelling. The system worked well and there were no unforeseen slope movements within modelled parameters.

Gloucestershire County Council, Atkins & Walters: A46 Cooper's Hill Southern Corner

The A46 Coopers Hill Southern Corner site is located near Gloucester and runs along the side of the Cotswolds escarpment.

Complex global and local slope movements have caused deterioration of the A46 carriageway and the erosion of the VRS and kerb foundations, compromising its impact capacity. Atkins was commissioned by GCC to undertake the remedial design of the carriageway and VRS.

Atkins designed a medium-term solution comprising a bored pile remedial structure, which provided support for the VRS, while addressing the movement within the landslip deposits and the carriageway embankment and providing an element of improvement to the global stability. GCC considered that this medium-term remedial structure provided the best cost-benefit solution.

The geotechnical elements of the construction at the A46 Southern Corner were undertaken between January and March 2021. During construction, Walters was the principal contractor and Atkins provided technical supervision as the principal designer.

Mott MacDonald & Story Contracting: Medge Hall (CP6 earthworks)

The project was to investigate the track faults on a strategic rail embankment running over 3.2km of peat. Constraints included limited financial and track access, and a need to reduce maintenance at the transition zones to a 500m long piled slab.

Something more robust than the existing ballast ramps and geocell layer was required, but ground improvement or bearing piles would simply move the problem along, and there was no previous case history to provide the answer.

Mott MacDonald devised a solution of tied sheet piled walls, followed by cantilever sheet piles that would deflect further under loading and smooth the transition. This enabled full lateral confinement of the ballast, sub ballast and underlying peat such that tamping and heavy traffic would not result in lateral spreading of the embankment and excessive differential settlement.

Soil Engineering Geoservices & The Coal Authority: Mitchell Street mine shaft, Coatbridge

The Coal Authority and Soil Engineering successfully delivered the stabilisation of a 302m deep mine shaft in the middle of a suburban street. Using both an iterative and collaborative approach, the team undertook phased investigation, design and treatment works, while engaging with the supply chain to provide specialist support.

Through the drilling of over 150 holes, employment of a 37m long shaft platform, injecting almost 700t of grout and completing Soil Engineering’s deepest ever borehole, the area was made safe, then remediated and handed back to the local authority and residents.

United Utilities, Costain, Eric Wright & GHD: Birds Park Impounding Reservoir improvements

Birds Park upper reservoir was constructed around 1850 as a water supply to Kendal, Cumbria. Assessment deemed it to be one of UU’s highest risk dams and works were required to mitigate this risk. Due to its proximity to Kendal with potential to mitigate flood impact the EA was keen to retain the asset for flood mitigation. These discussions meant the required works were delayed by nearly 10 years.

Due to its location in a small valley in the hills access to the site meant that limited ground investigation could be undertaken. This meant that the design of the new spillway and weir structure was based on best assumptions. The project team worked collaboratively to modify and redesign the structure to suit encountered ground. This was set against environmental challenges and the need to ensure the stability of the aging dam.

WSP & Balfour Beatty Jones Bros JV: A487 Caernarfon & Bontnewydd Bypass

The A487 Caernarfon and Bontnewydd Bypass is a new 9.8km highway through predominantly greenfield land to the southeast of Caernarfon in North Wales.

A design and build partnership between WSP and the Balfour Beatty Jones Bros (BBJB) construction JV delivered the scheme for the Welsh Government. It opened to traffic in March 2022, ahead of programme and within budget.

The project features three reinforced soil integral structures, two multi-span viaducts up to 260m long and 25 earthworks including embankments up to 20m high and cuttings up to 25m deep. One key challenge was to develop an efficient mass haulage scheme for bulk volumes of 1.3M.m3 along the route, providing the required fills to feed construction as and when needed. WSP worked collaboratively with BBJB to maximise the use of site-won materials to reduce haulage and inherent carbon footprint.

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Tagged with: GE Awards 2022 GE Awards 2022 shortlist

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