Delivering resilience and value while mitigating risks from the ground up
One of UK’s Top 50 Geotechnical Consultancy Firms
At Ayesa, we understand that the interaction of construction projects with their surrounding environment and ground conditions often presents the most significant risks and uncertainties. Recognized as a leader in this field, we specialize in analysing and devising solutions for challenging ground conditions on both undeveloped (greenfield) and previously developed (brownfield) sites, often in complex urban areas. Our expertise lies in tackling diverse geotechnical issues, offering robust and practical solutions for a variety of development projects, regardless of their size or scale. Our deep basement/underground spaces expertise are combined with our broad pool of expertise to add value to the numerous infrastructure projects we help deliver.
Notably, Ayesa is ranked #11 among the top 50 ground engineering consultants in the UK. (1)
Our geotechnical engineering skills are versatile and can be effectively applied across a wide range of project types, including water, marine, energy, civil infrastructure, buildings, rail, and conservation. This versatility and expertise enable us to successfully navigate and mitigate the complexities inherent in ground engineering, ensuring the success and safety of diverse construction projects.
Employer of Choice: In Ireland, we are a platinum Deloitte Best Managed Company and, in the UK, a Top 10 Ground Engineering consultant. (1)
Frameworks: We sit on several frameworks (18+) that deliver critical infrastructure, including Irish Water, The National Trust, and the Office of Public Works (OPW).
We have been present in the Middle East since 2009 with offices in KSA, UAE and Bahrain. Since then, we have completed over 1000 projects for leading public and private clients such as Qiddiya, Cruise Saudi, SWCC, Saudi Aramco, Diriyah Gate Development Authority, Amaala, Neom, Red Sea.
Technical Excellence: With a reputation for technical excellence, our highly skilled engineers take a complex problem and use critical thinking to navigate a path past any obstacles.
Multidisciplinary: Our multidisciplinary teams comprise over 70 different skillsets, with the expertise necessary to tackle the most challenging assignments, presented by each project. We collaborate across disciplines to provide solutions at the frontline of industry best practice.
Connected networks
Through our connected network of 14, 000 professionals in 23 countries, we provide high quality, timely and cost-effective engineering, consulting and project management, saving clients considerable amounts of money and time by delivering value-driven solutions.
A global leader of engineering and technology consulting services
Established in 1966, Ayesa is a leading global provider of engineering and technology consulting services.
Ayesa is ranked #45 in the Top 225 International engineering design firms of the world and ranked #16 in Global Water supply, and #24 in transportation. (2024: ENR World Top 225, ENR Global Sourcebook)
(1) Ranked #11 by revenue in GEPLUS.co.uk Top 50 Ground Engineering Consultants Survey 2025
Multidisciplinary Expertise
Geoscience
Transportation
Water
Buildings
Conservation >
6 a global leader
A trusted global partner delivering excellence in major projects for the private and public sectors
#45 International Engineering Design Firms (1) #8 Top 10 By Region (1)
#16 Global Water Supply: 2023 Global ENR Sourcebook (by revenue) #24 Transportation: 2023 Global ENR Sourcebook (by revenue)
(1) (1)
Consulting Firms #2
(1)
(1) ENR Ranking: Top 225 International Engineering Design Firms 2024 (according to revenue) and 2024 Global Sourcebook #3 Top International Engineering Design Firms
#11 Top 50 UK Geotechnical Consultants (2) (2) (Geplus.co.uk) 2024 Ground Engineering Magazine’s top UK Geotechnical Consultants ranked according to UK revenue
(3) Ranked #1 by 285 clients in Spain according to Eraneos & Whitelane report 2024 Top 25 IT providers.
We promise to keep delivering outstanding work, as an end-to-end lifetime partner
2
LASTING POSITIVE IMPACTS
3
1 PEOPLE CENTRIC
AN END-TO-END PARTNER
SOLUTIONS-DRIVEN
Best in class engineering, innovative solutions with global best practice and a focus on sustainability
OUR PILLARS
CLIENT-FOCUSED INNOVATION
We build long-lasting relationships with clients to add value and return on investment. Ayesa sits on several critical infrastructure frameworks in Ireland and the UK and the Middle East
A workplace where innovation is encouraged where skills, diversity, and continuous development is a priority
As leaders in the new economy, we are responsible for driving change that prioritises people, planet, and good governance.
Our goal is not just to just protect the planet, but to improve it.
What lies beneath
The Full Range of Geotechnical Engineering Services across the Entire Project Lifecycle
When working on a project, how construction interacts with its surrounding ecosystems and ground conditions is often the source of the most significant risks and uncertainties. Ayesa has become an acknowledged leader within this sector, analysing difficult ground conditions on both greenfield and brownfield land, solving complex geotechnical challenges by providing robust and practical solutions for various development projects, whatever the size or scale. Our geotechnical expertise can be applied effectively to projects, whether water, marine, energy, civil, buildings, rail and conservation.
Our international experts in geotechnical engineering identify and mitigate groundrelated risks through rigorous investigation, analysis and design. We have completed large scale schemes across all construction sectors, providing designs including foundations, retaining walls, tunnels, shafts, earthworks and slopes. We form integrated geotechnical and structural design teams capable of providing fully coordinated solutions, maximising the reliability and efficiency of our projects. We assist with determining the optimal construction sequencing and provide practical and valuedriven geotechnical solutions, such as ground movement assessments, contaminated land remediation and soil-structure interaction.
We are equipped to manage the geotechnical inputs on projects from the initial investigation phase to on-site monitoring during construction. Our experienced engineers and geologists are industry leaders in specifying and managing geotechnical investigations and interpretative reporting. Numerical modelling has developed rapidly over the past decade, and often the quality of geotechnical investigative data is the limiting aspect for developing intricate models and assessments. We undertake complex 3D modelling for projects to investigate any impact on surrounding assets due to ground and structural movements. The use of ground engineering will help improve the design of structures and can reduce asset-lifecycle costs by using the latest methods and technologies. Our staff will ensure the necessary data is captured during the investigation phase to offer clear benefits to the design and modelling phase – whether this is a city centre basement development or a large linear infrastructure project.
TOP 15 GROUND CONSULTANT IN THE UK
Red Line - Doha Metro, Qatar
Geoscience - Expertise
Urban Geotechnics
Engineering Geology
Site Investigation
Surface Water & Groundwater Risk Assessments
Infrastructure Geotechnics
Underground Spaces
Land Quality & Regeneration
Urban Geotechnics
Maximising constricted urban spaces with innovative underground solutions
For over 20 years, Ayesa has successfully worked on urban projects across various ground conditions by supplying geotechnical engineering and below-ground design services. Our team consists of geotechnical engineers, civil engineers and engineering geologists who deliver tailored solutions to meet individual urban project and client requirements. We have extensive experience in design and construction in various ground conditions throughout cities in Ireland, the UK and the Middle East.
Advising Innovative Solutions
Cities worldwide are struggling with a myriad of environmental and social problems with air, water and soil pollution and crowded, ageing infrastructure. Innovative solutions are essential to combat these problems by utilising underground solutions and maximising space.
Our geotechnical engineers contribute to exciting and challenging projects, many of which are major national and international schemes built within densely populated areas. In the buildings sector, we have provided foundation and basement designs for The Shard in London, the New Children’s Hospital in Dublin and the visitor centre at Titanic Belfast.
Often, we apply complex 3D modelling on projects to understand the impact on surrounding assets due to potential ground and structural movements. We provide detailed earthworks and sub-structure solutions for large urban infrastructure schemes such as the Crossrail line extension in London, the Doha Metro scheme in Qatar and the M50 widening in Dublin.
Our expertise covers all aspects of geotechnical and geological engineering, from planning, investigation and feasibility studies to design, construction surveillance and operations and maintenance.
60 Dawson Street, Dublin, Ireland
University College London Hospitals (UCLH), UK
PROJECT FOCUS: An Architectural Icon and Western Europe’s tallest building
THE SHARD
OVERVIEW
One of London’s most iconic landmarks, The Shard is a striking silhouette in the skyline. As one of the tallest buildings in Europe, The Shard reflects the ambition and vision of the City. With its location in the heart of London, any works on The Shard risked a considerable impact on its neighbours; most notably the adjacent London Bridge station, a Victorian structure and integral transport hub for the city.
PRIMARY ROLE
Ayesa was appointed as the detailed designer for the substructure, including a top down construction sequence for the triple level basement. As the project is adjacent to London Bridge station, a central hub on London’s rail network, the rail authority (Network Rail) required detailed analysis of the effect of the basement excavation on the Victorian station structure. Ayesa undertook a detailed Ground Movement Assessment and successfully satisfied Network Rail and their technical advisors, gaining approval for our design.
INNOVATION / VALUE ADD
The solution designed by Ayesa included a secant piled wall to allow for the deep excavation, piled foundations, and plunge columns. The original foundation concept involved the piles being base grouted. Following a successful preliminary pile test to record settlements and strains, Ayesa argued that base grouting was not necessary and provided a value-based alternative. The final solution comprised 60m deep, 1.8m diameter, bored piles founded in the underlying Thanet Sand.
Location: London, UK
Capital Value: £350m
Project Name: The Shard Country: UK
Client: Balfour Beatty Ground Engineering
PROJECT FOCUS: Designing a Mega Excavation
(23,000m 3) in Dublin’s capital city
60 DAWSON
OVERVIEW
Project Kells (later rebranded as 60 Dawson) is a large retail and office development in Dublin City Centre at Dawson and Nassau Street. The proposed works includes the construction of a new, four to six-story high mixed-use building. As part of the redevelopment, it is proposed to complete a bulk excavation for a two level below ground deep basement.
Two sides of the proposed basement are parallel to the LUAS Cross City Line, at the junction between Nassau Street and Dawson Street. The basement is approximately 3.4m to 7.1m from the nearest LUAS running rail. In the temporary case, excavations of 10.15m to 10.75m bgl are required.
PRIMARY ROLE
Ayesa worked closely with the clients (PJ Edwards) from the tender stage providing consultancy services covering design methodology, monitoring, and detailed design of the secant pile wall and temporary support to the wall during construction.
To facilitate installation of drainage and services, excavation depths up to 10m and 11m bgl have been accounted for in the temporary case. The designs had to meet tight movement criteria and we proposed a real time instrumentation system, to ensure that the works had no adverse impact on adjacent sensitive structures and the live LUAS light rail line.
Ayesa also completed the design of permanent works foundation piles. The installation of foundation piles was required to accommodate large compression loads where the top of bedrock was well below the basement formation level.
Ayesa also completed the design of the capping beam for the temporary works to distribute the support from the temporary propping and tie back anchors along the secant pile wall.
Extensive studies were also done on the possible construction methods for constructing the pile caps and piers in the marine environment. Both bridges were designed using post-tensioned concrete box girders of uniform depth – each carrying 2 lanes of traffic, with inclined piers supporting the spans over water and vertical piers for spans over mud flats.
Location: Dubin, Ireland
Capital Value: €58m
Project Name: 60 Dawson Street
Country: Ireland
Client: PJ Edwards & Co. Ltd.
PROJECT FOCUS: ESB
Flagship Headquarters in the capital
PROJECT FITZWILLIAM
OVERVIEW
The ESB head office building on Fitzwilliam Street Lower is a stunning new commercial building in the heart of Dublin city centre. The 45,000m² development comprises two commercial office buildings with the protected historic Georgian houses on Mount Street that were restored and refurbished into modern, high-quality residential properties, maintaining their protected status. The 45,000 sqm space will feature sustainable technologies to reduce carbon emissions and energy costs, resulting in a near-zero energy building. With an excellent BREEAM rating, the project is one of Dublin’s most sustainable and efficient office developments.
PRIMARY ROLE
This was a complex construction project in an extremely busy city centre environment, so stakeholder management was crucial. Ayesa served as a specialist designer for P.J. Edwards, focusing on the detailed design of the perimeter secant pile wall. The secant wall consisted of approximately 400 linear meters and required the installation of over 650 piles. To ensure stability, the wall was reinforced using pre-stressed glass fiber-reinforced polymer (GFRP) anchors, strategically placed under streetscapes. The use of GFRP anchors was chosen in collaboration with (Dublin County Council) DCC to prevent any future obstruction of service installation beneath the adjacent streets.
Additionally, Ayesa was responsible for the detailed design of 450 foundation-bearing piles and 150 anti-flotation anchors for the substructure.
Throughout the project, Ayesa also acted as a temporary works designer for PJ Hegarty, providing assistance across various on-site elements.
The Project won the award for Large Commercial Project of the year at the ICIA Irish Construction Industry Awards 2022.
Location: Dublin
Capital Value: €58m
Project Name: ESB Head Quarters
Country: Ireland
Client: PJ Edwards & Co. Ltd.
PROJECT FOCUS:
A landmark development redefining Dublin’s footprint from a brownfield site
CHARLEMOUNT SQUARE
OVERVIEW
Dublin’s Charlemont Square project marks the second phase of the Charlemont Street revitalization initiative, aiming to rejuvenate the urban landscape of Dublin 2. This ambitious €210 million mixed-use development encompassed the transformation of approximately 13,000m2 of constricted space in the city center. The project was completed between January 2018 to December 2022 and has created a vibrant central hub for the local community.
To pave the way for progress, four outdated residential blocks were cleared, making room for six new multi-story blocks that now house 96 top-tier apartments. The ambitious undertaking engaged a total of 203 subcontractors and became the most extensive excavation project within Dublin’s canal area.
OUR ROLE
Ayesa provided a detailed design package for the construction of a contiguous pile retaining wall and a secant pile retaining wall to support the excavation of a single and double level basement for the proposed Charlemont Street development in Dublin. The retaining walls were designed to be installed using continuous flight auger (CFA) piles, with various sections of the walls being temporarily supported by propping during the short-term condition. The pile design requirements were determined in accordance with relevant codes and guidelines, and the walls were assumed to be supported by the basement and ground floor slabs in the longterm condition.
The design was completed at the request of the client P.J. Edwards & Co. Ltd.
Location: Dublin
Capital Value: £210m
Project Name: Charlemount Square
Country: Ireland
Client: PJ Edwards
PROJECT FOCUS:
Earslfort Terrace, Dublin
CADENZA BUILDING
OVERVIEW
Cadenza, Earlsfort Terrace is a 13,000 m² flagship office development built for leading pension and investment company Irish Life. The Cadenza project consists of a modern office development over 8 floors with bespoke facades and sustainability deliverables of BER A3, NZEB compliance, LEED Platinum V3, WELL Gold V1, WiredScore and enhanced Smart building metering & monitoring.The building comprises six office floors above a lower ground floor and a single-level basement. Its construction includes an RC concrete frame with post-tensioned slabs, while the facade boasts a unique structural glass wall with an external tapered stone veil.
PRIMARY ROLE
Ayesa completed the secant pile wall design and temporary works support measures as part of the enabling works contract for the redevelopment of Davitt House, Earlsfort Terrace, Dublin 2 into its new incarnation as Cadenza Earlsfort Terrace.
The contractor submitted a comprehensive report outlining a detailed design and certification proposal for the permanent works secant pile. The project involved several key stakeholders, including Walls Construction Ltd as the main contractor, Waterman Moylan Consulting Engineers (WM) as the engineering team, PJ Edwards & Co. Ltd (PJE) as the piling contractor appointed by the main contractor, and Ayesa acting as the pile designer on behalf of PJE.
In order to facilitate the excavation of a twolevel below-ground basement, a secant pile wall was installed to provide structural support. Additionally, temporary support measures were implemented in specific areas to minimize lateral movement of the wall during the excavation stage.
Location: Dublin
Capital Value: Undisclosed
Project Name: Davitt House (now Cadenza Earlsfort Terrace
Country: Ireland
Client: PJ Edwards & Co. Ltd. and Walls Construction
Previously Davitt House
Infrastructure Geotechnics
Breaking New Ground
At Ayesa, our expertise lies in delivering innovative and cost-efficient geotechnical solutions. We cater to a wide range of infrastructure sectors, including transportation (roads, rail, metro) and marine projects. Our services encompass earthworks, earth retaining systems, foundation engineering, and asset management.
Increasing urban population and the need for enhanced connectivity and sustainability highlight the importance of understanding geotechnical risks in major transportation infrastructure projects. Our role is crucial in this scenario, where we offer endto-end project management from design through construction. As a multidisciplinary consultancy, our goal is to equip our clients with crucial insights to address and reduce geotechnical risks, thereby minimising uncertainties and offering remedial solutions.
Our team at Ayesa, adept in handling diverse sectors, geographical areas, and project scales, assesses ground risks and recommends mitigation strategies throughout the project lifecycle, including feasibility studies, planning, conceptual and detailed design, and implementation. We are particularly adept in the Design and Build sector, where our knowledge of construction methods and emphasis on practical buildability has been a significant advantage to our clients.
Our international and local project experience is vast and varied, encompassing challenges like designing road schemes on Ireland’s soft grounds, tackling mountainous terrains in Kosovo and Albania, and addressing seismic conditions in the US$5 billion New Aqaba Port project. Our portfolio also includes consulting on rail earthworks and slope remediation for London’s Crossrail, and major metro projects in Doha and Jeddah. In Ireland, we consult across a multitude of complex urban projects including Lidl distribution centre, and iconic city buildings with deep basements
Our consultancy spans a broad spectrum of essential services for project success. This includes site inspections, geotechnical investigation management, geological mapping, monitoring and instrumentation, hydrogeological assessments, design and reporting in geotechnical engineering, emergency assessments and repair strategies, asset management, maintenance planning, temporary works design, independent checks, expert witness, and construction services.
Royal Commission Bridges, Jubail, KSA
Route 7 Motorway - Kosovo
A32 Cherrymount Link, Enniskillen, UK
PROJECT FOCUS: A
Tale of Two Bridgesdelivering efficiencies through collaboration
ROYAL COMMISSION BRIDGES
OVERVIEW
The Royal Commission in Jubail (RCJ) plans to construct two new bridges: one from Jalmudah to Al-Batinah Island (Battinah)and the other from Dareen to a nearby unnamed island (Dareen). Batinah is a 4-lane bridge proposed to replace an existing causeway to allow increased access to Abu Ali Island. Darren is a 2-lane bridge designed to replace a smaller existing bridge to link the mainland to an island with oil production facilities. Both bridges have been designed with a 60m main span to clear a 40m navigational channel to allow safe navigation of vessels up to 15m in length.
PRIMARY ROLE
Ayesa in association with FAEC was commissioned by the RCJ to undertake the detailed design of both bridges, the approach causeways, the marine works including lining the channel, protection for the piers and navigation aids. Detailed assessments included carrying out a detailed study for the form, shape and location of both bridges. The location and height of each bridge was determined considering the existing causeway and bridge remaining in operation until each was opened. Extensive geotechnical investigations were carried out to ensure the optimum piling solution was found for all piers in varying ground conditions. The long-term settlements of the approach embankments were also taken into consideration.
Extensive studies were also done on the possible construction methods for constructing the pile caps and piers in the marine environment. Both bridges were designed using post-tensioned concrete box girders of uniform depth – each carrying 2 lanes of traffic, with inclined piers supporting the spans over water and vertical piers for spans over mud flats.
INNOVATION / VALUE ADD
Ayesa utilised our multidisciplinary team to supervise the ground investigation works, as well as providing a range of specialised expertise. The bridges were designed around a principle of ‘balanced aesthetics”, combining striking design that blends seamlessly with surroundings and delivers constructability and cost-efficiency.
Location: Jubail, KSA
Capital Value: Undisclosed
Project Name: Royal commission Bridges
Country: KSA
Client: Royal Commission of Jubail (RJC)
PROJECT FOCUS: New transport links on soft ground
A32 CHERRYMOUNT LINK
OUR ROLE
Ayesa played a pivotal role as the civil and geotechnical designer for the contractor-designed elements (CDE) in the £13 million scheme to develop a Class A trunk road in Enniskillen, Northern Ireland.
Spanning a distance of 2 kilometers, the route presented unique challenges due to its passage through areas characterized by deep, very soft ground, including peat and lacustrine clays. A key aspect of our involvement was to devise costeffective solutions to enhance the ground’s stability, ensuring the successful construction of the trunk road.
SOLUTION
In tackling the soft ground challenges, Ayesa employed the ‘excavate and replace’ technique, a proven method for ground improvement. Our role involved meticulous supervision of the soft ground replacement, using engineered fill in a carefully phased manner. This approach was pivotal in preventing potential instability in the adjacent lands, ensuring both safety and project integrity.
Our engagement spanned from the initial tender phase right through to construction, marking our deep involvement in the project. A testament to our innovative thinking was the development of a valueengineered soil nail solution. This creative approach was an alternative to the originally conceptualized reinforced concrete retaining structure. The result? Significant savings for our client in both time and resources.
Beyond ground improvement, Ayesa’s expertise extended to the detailed design of key infrastructural components. This included a public and a private footbridge, along with their approach ramps and bank seat abutments. These structures were supported on reinforced earth embankments, showcasing our capacity to integrate aesthetic, functional, and structural elements seamlessly.
Location: Enniskillen, UK
Capital Value: £13m
Project Name: A32 Cherrymount Link
Country: UK
Client: P.T McWilliams/Mclaughlin & Harvey JV
PROJECT FOCUS: one of the largest engineering projects in the world
SILVERTOWN TUNNEL
The ambitious Silvertown Tunnel, a new 1.4 km twin bore tunnel under London’s River Thames, is a testament to modern engineering. Spearheaded by the Riverlinx CJV, a consortium of BAM Nuttall, Ferrovial Construction, and SK ecoplant, this project represents a significant advancement in urban infrastructure. Among the high-caliber team of specialists assembled by Riverlinx CJV is Ayesa, appointed as the underground structural designer. Ayesa’s responsibility spans the spectrum of temporary and permanent works, including cut and cover tunnels, TBM shafts, and other critical structures. This tunnel, linking Silvertown to Greenwich, aims to alleviate congestion from the 122-year-old Blackwall Tunnel and revitalise the surrounding areas. Adhering to the Tunnel Code of Cosstruction Practice (CoCP), the project emphasises sustainable construction practices, including river transport for materials and low-emission machinery usage.
Our role: Ayesa’s role in this monumental project is multifaceted. As the underground structural designer, our expertise covers cut and cover tunnels, three complex TBM shafts, portal structures, open-cut structures, damage assessment, and instrumentation and monitoring. The excavation combines TBM and Cut and Cover methods, showcasing our adaptability in tunnel construction techniques.
Value Addition through Innovation: Ayesa worked for the Riverlinx CJV, closely with Ferrovial’s Engineering Services department and BAM Wayss & Freytag, to develop the “peanut shaft” which would launch the largest TBM in the UK. This design was developed in response to the need to avoid anchors to the ground due to land right constraints in the project location. The design allowed the shaft to be built using secant piles which is the first time in the UK for a peanut shaft. Other alternatives such as D-walls were incompatible with the existing obstructions for the project or with the available supply chain (hydro mill not available in the UK). As part of the innovative implementation, the team conducted a feasibility assessment in conjunction with the existing concept design, looking at various worldwide solutions and investigating their viability in the UK. The solution found was unique to previous UK constructions as it combined four shafts of 21.2m diameter connected through the key T-shaped counterfort structures. This structure required no external ground treatment or ground anchors. In March 2023, after the successful completion of the first tunnel, Ayesa’s helped develop the design of an oval-shaped chamber which facilitated a 180˚ rotation of the TBM in sections, a strategic move by Ferrovial to expedite the process and avoid a six-month dismantling and rebuilding phase.
Collaboration and Advanced Techniques: Our collaborative efforts extended beyond contractual obligations, particularly with COWI, the lead geotechnical designer. This synergy, involving shared expertise and optimized workflows, was crucial in minimising pandemic-related delays. In terms of technical prowess, Ayesa utilised advanced tools like 3D modeling and Plaxis 3D for shaft construction simulations, alongside 2D
Location: London
Capital Value: £2b
Project Name: Silvertown
Country: UK
Client: Riverlinx CJV, BAM Nuttall, Wayss & Freytag, Ferrovial Agroman and SK E&C
Plaxis for the Cut and Cover North construction. Our comprehensive approach included designing temporary supports and developing dewatering plans for the shafts, showcasing our commitment to delivering efficient, innovative solutions in complex, multi-stakeholder environments.
Through this project, Ayesa reaffirms its dedication to innovation, collaboration, and providing exceptional value in challenging urban infrastructure projects.
Breaking new ground with the first London tunnel in three decades
TThe Silvertown Tunnel project is not just about constructing a new tunnel; it’s a transformative initiative for the 62-acre Silvertown site. This ambitious endeavor includes the restoration of the historic 1930s Millennium Mills, building a bridge to connect Silvertown Quays with Custom House Crossrail station, and establishing the Roundhouse East as a dynamic music and education event space. These developments are set to revitalize Silvertown, turning it into a thriving community hub within London. The tunnel itself will significantly reduce traffic pollution and congestion, improving connectivity across the city.
Ayesa’s Integral Role in Underground Structural Design
Ayesa plays a leading role in this project as the principal underground structural designer, working alongside the Riverlinx CJV consortium (comprising Ferrovial, BAM Nuttall Ltd PPP PGGM, and SK Engineering & Construction Co. Ltd). This 1.4km twin-bore road tunnel under the Thames is breaking new ground in engineering, The CJV has been instrumental in introducing several firsts in this project, such as the award-winning “Peanut” launch chamber, a “rotation chamber,” and a “retrieval” chamber, facilitating the operation of the UK’s largest Tunnel Boring Machine (TBM).
Addressing Challenges with Eco-Friendly Practices
The project team, including Ayesa, prioritizes ecofriendly practices by using low-emission machinery and transporting materials by river. Remarkably, 780,000 tonnes of spoil from the recently completed second tunnel were removed via barge. The early stages of the project faced challenges from remnants of old industrial structures and maintaining a 4% vertical gradient for the tunnel under the Thames riverbed. The COVID-19 pandemic further complicated matters, but Ayesa collaborated effectively with the geotechnical designer COWI, overcoming hurdles like dispersed teams and site delays. This collaboration led to workflow optimization, reduced review times, and cost savings for the client, earning them a spot as finalists in the GE Geotechnical Team of the Year 2022.
Ayesa’s Comprehensive Design Contributions
Ayesa’s responsibilities encompass designing various components, such as temporary and permanent structures in cut and cover areas, TBM shafts, and portal structures, along with overseeing damage assessment and instrumentation and monitoring. The project employs both TBM and Cut and Cover excavation methods.
In detail, Ayesa is responsible for the design of critical elements like the Cut and Cover North and South sections,
which act as access ramps for the Silvertown and Greenwich districts. The firm is also leading the design of several control shafts, including the Rotation Shaft linking the Silvertown Tunnel to Cut and Cover South. The cut and cover sections’ walls are constructed using secant piles. Ayesa has employed advanced techniques such as 3D modeling and Plaxis 3D for shaft construction simulations, and 2D Plaxis for the Cut and Cover North construction. They also designed temporary support for the shafts and developed a comprehensive dewatering plan for the construction of the rotation, launch, and retrieval shafts.
Innovations in Shaft Design: The Peanut, Rotation, and Retrieval Shafts
Ayesa played a key role in designing the award-winning “Peanut Shaft,” which successfully launched the UK’s largest TBM. This NCE award-winning design features four 21.2-meter diameter shafts connected through T-shaped counterforts, curving to align with the road without needing external ground treatment or anchors. The TBM, named Jill, 82 meters long with an 11.91-meter cutter face and weighing 1,800 tonnes, completed the first tunnel drive by February 2023, advancing at an impressive pace of 10 meters per day.
For the second tunnel drive, Ayesa helped design the “rotation chamber,” an oval-shaped structure allowing the TBM to rotate 180 degrees in sections, avoiding existing utilities. The chamber measures 18 meters deep, 40 meters long, and 39 meters wide, featuring two openings for the TBM tunnels northward and access to the cut-andcover tunnel section southward. The TBM’s rotation was facilitated by an innovative “nitrogen skates” system using a complex hydraulic jacking system.
Finally, Ayesa played a part in the design of the “Retrieval Chamber,” where the TBM is currently being disassembled. The successful completion of the “launch,” “rotation,” and “retrieval” chambers marks a significant milestone in the project. With the main tunnelling works at Silvertown now finished, attention turns to the ‘cut and cover’ sections, including portal entrances. A temporary bridge installed on Millennium Way is enabling the continuation of excavation work beneath it.
The project remains on target to be completed in 2025.
Benefits and Positive outcomes
Groundbreaking Design: Ayesa has played a pivotal role in the Silvertown Tunnel project, as it played a signficant part in its innovative design solutions, notably the “Peanut Shaft.” This groundbreaking temporary shaft facilitated the launch of the UK’s largest Tunnel Boring Machine (TBM), named “Jill.” The Peanut Shaft’s inventive concentric circle structure, which earned the Innovation in Shaft Design & Construction award, superseded the initial client concept and eliminated the need for external ground treatment or anchors. Other innovative structures, like the Rotation Chamber and the Retrieval Chamber, were instrumental in managing the TBM’s complex journey.
Enhancing Efficiency: The Rotation Chamber
The project hit a major milestone with the successful launch of Jill in September 2022. Ayesa’s design of the oval-shaped Rotation Chamber showcases their ability to innovate for better programme and cost outcomes. This chamber, 18 meters deep, 40 meters long, and 39 meters wide, enabled the TBM to rotate 180 degrees in sections. This feature significantly reduced construction time and costs, demonstrating Ayesa’s commitment to efficiency and practicality in engineering solutions. The chamber will eventually provide dual access: facilitating TBM tunneling northward and entry to the southern cut and cover tunnel section.
Employing Advanced Techniques
Ayesa’s use of sophisticated modeling techniques and specialized software like Plaxis enabled precise simulations of shaft construction. Their comprehensive design work encompassed various project components, including the Cut and Cover sections and control shafts. These efforts have been instrumental in successfully navigating one of the largest TBMs in British history, showcasing Ayesa’s ability to blend innovative design with practical application.
Awards:
WON: 2023 Tunnelling Project of the Year (over $200m), Riverlinx CJV: BAM UK & Ireland, Ferrovial Construction & SK ecoplant | Silvertown Tunnel.
WON: 2022, Innovation in Shaft Design & Construction Secant Bored Pile Peanut Shaft design and construction
SHORTLISTED: 2022 Geotechnical Team of the Year: Ayesa, Cowi & Riverlinx CJV
“Silvertown Tunnel - transforming East London’s Infrastructure”
Engineering Geology
Exploring The Link Between Buildings and The Ground
Engineering Geologists provide the bridge between the built and natural environment and our diverse team of geologists and civil engineers, allow us to take a holistic approach to design. Our engineers are constantly exploring innovative ways to optimise designs based on the conditions at the site, which means every design we provide is unique.
Ayesa engineers are experienced in assessing earthworks for signs of distress and designing remediation solutions to stabilise structures that could be at risk of failure from stresses such as climate change, subsidence, capacity limit and ageing or non-resilient materials. During site visits, we investigate infrastructural risks associated with earthworks and recommend long-term and short-term mitigation strategies. Our engineers undertake kinematic, limit equilibrium, and finite element analyses to accurately model earthworks and deliver optimal design solutions. Our engineers work across various sectors, including rail, highway, infrastructure, and private construction.
Our rope-access trained geologists can get up close to investigate tricky and remote areas that would otherwise be inaccessible. While there, they assess hazards, tactilely inspecting, taking structural rock measurements, and logging slopes to gain a complete understanding of risks presented by earthworks. Our studies and investigations can be conducted in numerous phases of public and project projects: planning (including assessing environmental impacts), civil/structural engineering design, value engineering, construction, forensic phases and post-construction. We can provide comprehensive assessments, including geological hazard assessments, for geotechnical, material properties, stability of landslides and slopes, erosion, flooding, dewatering, and seismic investigations.
Guildford Sands, Guildford, UK
London Gateway - Cooling Marshes, UK
PROJECT FOCUS: Reviving the most dramatic coastal walk in Europe
THE GOBBINS CLIFF PATH WALKWAY
OVERVIEW
The original Gobbins coastal path was opened in 1901 but fell into disrepair and was closed in 1951. This reconstruction project consisted of a series of 23 footbridges and cantilevered walkways forming a 1km-long pathway at the base of 60m-high cliffs spanning between rock outcrops and sea stacks along the Antrim Coast. The pathway follows the original route and the iconic bridges have been reconstructed to closely match the original Victorian structures with original steps and walkways retained.
PRIMARY ROLE
Ayesa acted the geotechnical designer for the bridges, cantilever anchorage systems and cable stayed anchors for the main contractor, McLaughlin & Harvey Ltd. We also carried out rockfall assessments and site investigations and developed value engineered solutions along the coastal pathway route to mitigate against unstable sections of the cliff face. We developed a rockfall management plan to assist in managing operational rockfall risks, through a systematic process of geological inspections, continual monitoring and intermittent tactile assessments.
Location: Larne, UK
Capital Value: £4.5m
Project Name: The Gobbins Cliff Path Walkway
Country: UK
Client: McLaughlin & Harvey Ltd.
One of the most ambitious engineering projects Northern Ireland
PROJECT FOCUS: Maintenance of the infrastructure slopes to ensure rail safety
BRANDON CUTTING
OVERVIEW
Following a period of very wet weather, in February 2020, a section of cutting slope along the RBS1 line between Rugby & Coventry failed, resulting in slumping of the shallow slope material and formation of a significant back scarp. In response a temporary speed restriction was put in place and emergency works undertaken to remove the slumped material and install additional temporary support along the toe. Ayesa were engaged by J Murphy & Sons (working on behalf of Network Rail) to assess the cutting and undertake the design of both temporary and permanent solutions. The permanent solution comprised a concrete Redi-Rock wall and slope regrade. This arrangement was eventually extended over a length of approximately 200m of cutting slope to address other areas of concern.
PRIMARY ROLE
Following an emergency callout and weekend inspection of the slope failure, Ayesa’s initial role was to design a temporary works arrangement to make safe the failed sections. Once the cutting slope was made safe, Ayesa then undertook the detailed design of the permanent solution. During the construction stage Ayesa provided regular site attendance and additional design activities as required to ensure successful delivery of the project.
INNOVATION / VALUE ADD
After a review of the retaining wall options to support the cutting toe, the use of pre-cast concrete “Redi-Rock” blocks was selected due to its quick construction time and engineering performance. The construction of the slope regrade above the new toe wall was completed using a combination of “Menzi” slope climbing excavator and a long reach machine. This removed the need for plant to be in the cess and hence lengthy track possessions.
Location: Coventry, UK
Capital Value: £2m
Project Name: Brandon Cutting
Country: UK
Client: J Murphy & Sons Ltd
Location: Wadhurt, London UK
Capital Value: £3m
Project Name: Wadhurst Cutting Country: UK
Client: BAM Ritchies/Network Rail
EDITORS AWARD WINNER: “The power of collaboration including supply chain partners, created one team focused on the project’s success.”
WADHURST CUTTING
Ayesa in collaboration with BAM Ritchies/Nuttall, has played a pivotal role in enhancing Network Rail’s service reliability on vital routes. A standout project is the Wadhurst Cutting, a testament to our joint efforts in delivering exceptional outcomes. Through innovative value engineering, Ayesa significantly lowered costs and accelerated project timelines, while our tight-knit team promptly resolved any construction challenges. The cutting, carved over 170 years ago, has experienced numerous landslips, disrupting travel between the coast and central London. Our stabilisation efforts now promise a more dependable train service between London and Hastings, ensuring a minimum 60-year lifespan for this critical infrastructure.
Summary: The Ayesa and BAM Ritchies team brought renewed strength and resilience to the historic Wadhurst Cutting. Employing both active and passive rock bolting, netting, and soil nails, we navigated logistical hurdles, protected local wildlife, and maintained a flawless safety record.
Project: The Wadhurst Cutting, a vital section on the Tonbridge to Hastings rail line, spans approximately 300 meters between the north and south tunnel portals. Characterized by varying heights of 8 to 18 meters, the cutting’s geology comprises predominantly weathered
Wadhurst Clay, underpinned by the Wadhurst Clay Formation and Ashdown Formation. Due to a series of collapses in recent years (2014, 2016, and 2019), Network Rail commissioned BAM to implement an approved design for the cutting’s restoration.
The restoration was divided into two segments: initial emergency works at the country end and subsequent works at the London end. This multifaceted project incorporated a variety of geotechnical stabilization techniques typically employed in failing earthwork structures. It involved three main systems: an active soil nail system on the upper slopes with varying nail lengths (5 to 14 meters), overlaid with Greenaxe integrated mesh and erosion matting; a passive rock bolt drape net system from the tunnel portal to ground level; and an active rock bolt system around the portal’s entrance. The project installed approximately 13,000 linear meters of soil nails and over 1,000 linear meters of rock bolts, covering an area of about 15,000m2. A subsequent LiDAR survey post-vegetation clearance led to further design refinements, shortening soil nails in certain areas.
Upon reviewing the initial emergency work, BAM Ritchies identified an opportunity for significant value engineering. Partnering with Ayesa, a feasibility study was conducted to determine the scope for such enhancements. Our analysis revealed potential cost
savings by strengthening the reinforcement mesh, allowing for increased spacing of soil nails (from 1 x 1.5 meters to 1.5 x 2 meters) and rock bolts (from 2.2 meters to 3 meters). These modifications proposed a 46% reduction in the linear meters of soil nails and rock bolts, cutting the project duration by 20 weeks and saving approximately £1.5 million. Network Rail approved these changes for their cost-effectiveness and adherence to safety standards and specifications, though they were only implemented at the London End due to time constraints.
During the blockade at the country end in October 2021, BAM Ritchies executed emergency works including the installation of lower rock bolts and soil nails, a task previously unachievable. The team delivered an incident-free, efficient, and sustainable 7-day operation, reinforcing the earthwork’s infrastructure on the Kent and Sussex Railway. Over 450 soil nails and rock bolts were installed, totaling more than 2,200 meters. The use of HVO fuel in the three drilling rigs, as opposed to traditional diesel, resulted in a 90% reduction in carbon footprint.
Our collaborative approach, leveraging the collective expertise of the project team, consistently aimed to challenge and improve outcomes, even amidst complex strata comprising Wadhurst clay over Ashdown rock formation. Initial tests with self-drilling nails indicated that the Wadhurst clay’s hardness would complicate drilling and installation. This obstacle was surmounted by integrating hydraulic drill heads with traditional air masts in a hybrid system that maintained air flush efficiency with the added speed of a hydraulic terrapin face rig, leading to production exceeding expectations and demonstrating our commitment to innovative solutions for Network Rail.
Sustainability and Ecological Considerations:
The project emphasized sustainability, notably by simplifying design elements to prevent unnecessary complexity. Special attention was given to erosion protection, initially planning to incorporate plasticbased erosion mats in the mesh reinforcement. However, discussions with the supplier uncovered a risk of microplastic pollution due to product degradation. Consequently, BAM Ritchies and Ayesa engineers, in collaboration with our team, advocated for an environmentally friendly alternative, persuading Network Rail to approve the use of woven coir matting instead.
The site also posed ecological challenges, such as accommodating a resident badger sett and Dormice habitat. Measures included obtaining a license to temporarily close the sett and creating a “dead hedge mouse highway” to reroute the Dormice from the construction area. Additionally, plans were made to plant Dormice-friendly vegetation post-project. The project team also partnered with EAVE, utilizing GEN3 ear defenders for a productive and safe work environment. The two-week trial provided valuable noise exposure data for site operations, further underscoring our commitment to ecological and workplace safety.
Benefits and Achievements
Enhanced Line Stability: Over the past decade, the Wadhurst tunnel has necessitated numerous engineering interventions to address weather-related issues. The stabilization of Wadhurst cutting, achieved with 5,400 soil nails and mesh and the removal of 15,000m2 of vegetation, significantly mitigates the risk of landslips and weather-related disruptions to the railway.
Swift and Efficient Emergency Work: The seven-day emergency blockade during the October half-term enabled engineers to rapidly reinforce the cutting, thereby ensuring its stability and safety in a very short time frame.
Minimised Passenger Disruption: By consolidating critical work into the blockade period, the project substantially decreased the overall disruption to passengers and delivered benefits more swiftly.
Improved Journey Reliability: The comprehensive stabilisation work is expected to reduce long-term delays, enhancing the reliability and overall experience of passenger journeys.
Significant Cost and Time Savings: The innovative design changes led to a 46% reduction in the amount of soil nails and rock bolts used, shortening the project duration by 20 weeks and saving approximately £1.5 million, while also reducing material usage.
Environmental Risk Reduction: Our team’s recommendation to use woven coir matting instead of plastic-based erosion mats significantly lessens the environmental impact, offering a more sustainable solution.
Ecological Considerations: Post-project, the planting of dormice-friendly vegetation highlights our commitment to ecological sensitivity and habitat preservation.
Value-Driven Engineering: The project’s value engineering approach resulted in notable cost and timeline efficiencies. The collaboration among BAM Nuttall, BAM Ritchies, and Ayesa was instrumental in overcoming construction challenges swiftly. BAM Ritchies’ contributions were key in helping Network Rail provide a more reliable and enhanced travel experience on the crucial London to Hastings route for at least the next 60 years.
EDITORS AWARD
Underground Spaces
Taking Development Underground - Solving Urban Problems With Innovation
Population growth, urban development and the requirement for environmental preservation have led to underground space becoming increasingly important in solving urban problems. Ayesa has been involved in a wide range of projects in the underground space sector, providing design services to clients throughout the project cycle from initial concept design through to detailed design and construction supervision to solve critical infrastructure needs. Our team of geotechnical engineers, structural engineers, engineering geologists and civil engineers deliver project and client requirements in areas such as tunnelling, deep shafts, temporary works, retaining walls in a variety of ground conditions throughout Ireland, the UK and the middle east.
Our team of engineers are regularly involved in challenging and complex projects working directly for developers, as well as supporting contractors with design and build services. In Qatar, our role included the selection of the tunnel alignment and shaft locations and the design of permanent and temporary shafts for the Lusail Expressway. While, as part of the Elan Valley Aqueduct, we designed several TBM (tunnel boring machine) launch and work shafts including a 30m deep, 13.5m diameter permanent secant pile wall-drop shaft.
As part of the New Children’s Hospital project, in Dublin, our appointment included the detailed design of close to 1km of permanent secant pile wall for the triple-level basement. Through close collaboration with our clients and technical expertise and experience in this area, we provide efficient and effective design solutions.
Deepham’s Shaft, London, UK
Crossrail Eastern Running Tunnels
PROJECT FOCUS: Construction of Stepney Green shaft using deep diaphram walling techniques
STEPNEY GREEN CROSSRAIL
OVERVIEW
The new Crossrail line in London divides at Stepney Green, with one line continuing north and one line crossing the Thames to the south. A deep shaft and large mined cavern was required at this location as TBM reception and launch and to accommodate the converging tunnels. The shaft was constructed using deep diaphragm walling techniques. The tunnel cross-passages are some of the largest ever constructed using sprayed concrete lining, being 50m long, 17m wide and 15m high.
PRIMARY ROLE
Ayesa was initially appointed by the specialist contractor SPIE UK to design and detail the diaphragm wall. This wall facilitated the enormous 35m deep excavation, with the wall panels being 1.2m thick and 50m deep. A particular challenge was the detailing of the reinforcement for the wall panels, ensuring these large cages could be safely lifted from horizontal to vertical for placement into the excavation. Each cage weighed 25 tonnes necessitating a robust temporary works design.
EXPERTISE
Subsequently, the main contractor DragadosSisk JV appointed Ayesa to design the temporary propping to facilitate excavation of the shaft. We worked collaboratively with Dragados-Sisk to devise the value engineered construction methodology and sequencing and internal support system in order to accelerate the construction program and improve buildability. Ayesa also provided guidance on the cross-passage excavation stability and the sprayed concrete lining solution.
Location: London, UK
Capital Value: Undisclosed
Project Name: Stepney Green, Crossrail
Country: UK
Client: SPIE UK
PROJECT FOCUS: 23M DEEP PUMPING STATION ON
DIYAR AL MUHARRAQ
DIYAR AL MUHARRAQPUMP STATION
OVERVIEW
As part of the sewer network upgrade in the Kingdom of Bahrain, a 23m deep pumping station was constructed on the man-made reclaimed island of Diyar Al Muharraq. To enable the construction of this pump station a 23m diameter shaft was constructed using 900mm interlocking male and female secant piles.
PRIMARY ROLE
Ayesa undertook a detailed design review and value engineering exercise for the deep shaft. This included an independent check on the process design and the structural design, a geotechnical assessment of the proposed solution along with the overall final configuration and suitability. Advice on the dewatering strategy in this aggressive marine environment was also provided, including consideration of pile overlap, drilling methodology and the degree of water cut-off that could be achieved.
Location: Diyar Al Muharraq
Capital Value: Undisclosed
Project Name: Diyar Al Muharraq - Pump Station
Country: Bahrain
Client: Undisclosed
Analysing below ground for a diverse group of projects
Site Investigation
Navigating the unpredictable nature of subsurface conditions is often the most significant challenge in construction projects. A comprehensive site investigation is vital in identifying these potential risks and substantially mitigating them. In contrast, insufficient investigation can lead to project delays and the need for additional measures to address issues like contaminated soil and groundwater or reconstructing building systems. At Ayesa, our team of geologists, engineers, environmental scientists, and technicians specializes in providing valueadded, risk-focused, and site-specific solutions. Our extensive field service offerings are designed to ascertain the nature, extent, and risks associated with substances in soil, sediment, surface water, groundwater, and building systems. Our services cover the entire project lifespan, from site investigation and feasibility studies to risk assessment, monitoring, remedy selection, remedial design, site reuse, the preparation of competitive bids adhering to third-party specifications, and construction management.
Our clientele is diverse, encompassing individual customers, major contractors, and developers, and extends to constructing energy-from-waste (EfW) facilities and peaking plant power stations. We are adept at working in demanding conditions such as soft ground, peat bogs, sloped terrains requiring specialist rigs or scaffold platforms, overwater surveys in harbors, rivers, and lakes, landfills, crane lifts, and the exploration of basements and other subterranean structures.
To conduct thorough site investigations, we utilize a blend of internal and external resources, employing a variety of techniques to ensure the highest data quality. These methods include cable percussion boring, rotary open-hole and cored drilling, Geobor, and resonance equipment with optimal flushing mediums for maximum recovery, dynamic sampling and probing, static cone penetration testing (including piezocone, magcone, seismic cone, gamma cone), and both mechanical and hand-excavated trial pits.
Our deliverables include the Ground Investigation Report (GIR), the Geotechnical Design Report (GDR), and specialized geo-environmental interpretations and recommendations. We adhere to the latest local quality standards (British, EU, or Middle East) and comply with Eurocode 7. Our ground investigation data can be electronically formatted in the latest AGS format for integration into BIM systems.
Askar Landfill Solar Farm, Bahrain
Wrentham Site Investigation, Suffolk, UK
Tropical Fruit Warehouse, Dublin, Ireland
PROJECT FOCUS: A new Global Leisure Capital
and tourist destination
QIDDIYA GEOTECHNICAL INVESTIGATION
OVERVIEW
Qiddiya is set to become the Kingdom’s capital of Entertainment, Sports and the Arts to meet and satisfy the recreational, social and cultural needs of current and future generations. Located 45km west of Riyadh, Qiddiya will comprise of a Resort Core, Motion Zone, City Centre, Eco Zone Golf Community, Aerodrome and Airfield Future Development and Green Buffer development zones.
Overlooking the Resort Core from its perch 200m above on the edge of the Tuwaiq escarpment, will be a City Centre mixeduse village dedicated to sports & the arts. Qiddiya’s City Centre development area covers approximately 530,000m2, allotted across 33 plots.
PRIMARY ROLE
Ayesa was appointed by the Qiddiya Investment Company, to provide geotechnical support for the proposed development in Qiddiya. Our role included identification and detailed requirements for test and investigations by plot, preparation of the required tender documents, review of technical & commercial submissions and provide any additional support. As the lead geotechnical Consultant, our scope included the provision of specifications, drawings, BOQs for pricing and monitoring works during construction, as well as GIS drawings and data.
INNOVATION / VALUE ADD
Ayesa utilised BIM modelling by integrating Holebase SI and Civil 3D along with Autodesk Infraworks. This aided with faster revisions of the site investigation layout to reflect the masterplan layout changes.
Location: Qiddiya, Riyadh
Capital Value: SAR 30bn
Project Name: Qiddiya Geotechnical Investigation
Country: KSA
Client: Qiddiya Investment Company (QIC)
PROJECT FOCUS: Where the wind blows - helping the energy transition
BROCKAGHBOY WIND FARM
OVERVIEW
Situated in County L/Derry, Brockaghboy Wind Farm features 19 Vesta 3MW V90 turbines and spans 8.6 kilometers with its access tracks. Ayesa’s Belfast office served as the civil, structural, and geotechnical consultant for this project. Our role included delivering designs for crane hardstands and access tracks, enhancing and value-engineering the client’s initial tender package, as well as designing sustainable urban drainage systems (SuDS) and drainage solutions tailored for the challenging, undulating terrain of the site.
PRIMARY ROLE
In addition to our earlier contributions, we developed solutions for culvert crossings, bridge structures, and upgrades to public roads to facilitate the transport of turbines to the site. Our structural engineering team was responsible for designing the 19 wind turbine gravity bases. Ayesa conducted thorough site inspections and provided sign-offs and approvals for the turbine base formation levels, as well as the completed crane hardstands and access track surfaces. This project was initiated by ERG, a prominent Italian energy company.
Location: County Derry, Northern Ireland, UK
Capital Value: £65m
Project Name: Brockaghboy Wind Farm
Country: UK
Client: Adman Civil Projects Ltd.
PROJECT FOCUS: A ‘first class’ approach to expanding one of the busiest airports in the world
HEATHROW AIRPORT EXPANSION
OUR ROLE
Our team was appointed to provide enviromental assessment, permitting support for the project as well as landfill remediation and design. The Heathrow Expansion Programme is a £14bn project to construct a third runway and new taxiways linking it to the rest of the airport complex, a new terminal building and satellite, additional stand areas, new airport gateways, carparks and other associated infrastructure. It will involve re-routing the M25, diversion of rivers and substantial earthworks to achieve.
SOLUTION
Our primary role was to provide advice on the remediation of three existing permitted landfill sites located along the line of the proposed new runway and to design and support the permit applications for four new landfills. The new runway is to be constructed on top of three preexisting landfills posing complex remediation and foundational design issues. The existing leachate and landfill gas control systems needed to be replaced and a new capping system installed.
The four new landflls are being designed to EU/UK standards and need to take account of their close proximity to a working airfield with associated access restrictions. Our Waste team were subcontracted to Jacobs who were appointed as lead earthworks consultant for the project. Our role in this project was multi-disciplinary with our consultants providing a full range of services; earthworks design, site investigation support, hydrogeological risk assessments, stability risk assessments, air quality assessment, design of landfill gas, leachate and odour control systems, environmental monitoring, regulatory compliance and advice on landfill tax.
Location: Heathrow
Capital Value: £15bn
Project Name: Heathrow Airport Expansion
Country: UK
Client: Jacobs Engineering
PROJECT FOCUS: Lidl Distribution Centre, Naas, Ireland - at 58,000m2, is one of the largest single buildings in Ireland.
LIDL NAAS DC
OVERVIEW
Lidl Newbridge Distribution Centre (DC) is a new 58,000m2 distribution centre constructed on the outskirts of Newbridge, Co. Kildare. The new Distribution Centre will serve Lidl’s network of stores in the Leinster area and create 100 fulltime jobs for the area.
Variable soft cohesive and loose granular materials were encountered within the initial 3m to 4m below ground level during the ground investigation. A ground improvement scheme was proposed at the site to reduce foundation costs over traditional piled/ bulk dig and replace solutions.
PRIMARY ROLE
Ayesa’s role (2016-2019) on the project was to appraise the initial ground improvement solution, prepare the earthworks and ground improvement specification, review the contractor design and build proposals and tender returns, review the ground improvement works and review the compliance reports.
Following the tender process, a soil stabilisation solution of lime and cement stabilisation was selected as the most suitable solution.
Ayesa ensured that the construction works were carried out in accordance with the overall project and designer’s specifications to ensure the settlement criteria would be met. This involved numerous site visits and reviewing them in situ as well as laboratory testing.
Following the completion of the works, a detailed review of the compliance reports was conducted to ensure the works had been completed to the required specifications.
INNOVATION
The innovation in this project lies in the ground improvement scheme proposed by Ayesa for the construction of Lidl’s Newbridge Distribution Centre. Instead of using traditional piled or bulk dig and replace methods, a soil stabilisation solution of lime and cement stabilisation was
implemented. This innovative approach offered several benefits:
Cost Reduction: The ground improvement scheme aimed to reduce foundation costs compared to conventional methods. By using lime and cement stabilisation, the need for extensive piling or bulk excavation and replacement was eliminated, resulting in cost savings for the project.
Time Efficiency: The alternative ground improvement solution helped expedite the construction process. Compared to traditional methods that require more time for piling or extensive excavation, the use of lime and cement stabilisation allowed for quicker preparation of the ground, enabling faster progress on the project.
Enhanced Stability: The stabilisation of variable soft cohesive and loose granular materials beneath the ground provided improved stability for the distribution centre. By treating the ground with lime and cement, the soil’s strength and load-bearing capacity were enhanced, ensuring a solid foundation for the facility.
Compliance Assurance: Ayesa played a crucial role to ensure construction works were carried out in compliance with the project’s specifications.
Through site visits, in-situ review, and laboratory testing, they ensured that the ground improvement works were carried out in accordance with the design requirements, meeting the settlement criteria.
Location: Newbridge, Kildare
Capital Value: €100m
Project Name: Lidl DC
Country: Ireland
Client: Lidl GMBH
PROJECT FOCUS: Lidl Regional Centre, Mullingar - an impressive energy efficient facility.
LIDL MULLINGAR RDC
OVERVIEW
The Lidl Regional Distribution Centre project in Mullingar is a 15,000m2 extension to Lidl’s existing centre in Lough Sheever Park, Mullingar. Opened in April 2023, Lidl’s new distribution centre is not only the largest on the island, totalling 62,000 sq.m, but it is also one of the most energy-efficient buildings in the country. Following an €80 million investment, the centre incorporates an impressive 1.2MWp solar array, making Lidl the country’s largest owner of rooftop solar arrays.
PRIMARY ROLE
Ayesa managed the ground investigation including part-time supervision. The scheme involved ground improvement works and upfilling of up to 3m to connect the extension with the existing structure. The Ground conditions were varied across the site with an area of Peat located in the east of the site. Following the ground investigation, Ayesa prepared the Interpretative Report detailing encountered ground conditions, geotechnical risks and geotechnical recommendations. Ayesa then assisted the Engineers for the scheme in preparing the Performance Specification, reviewed the tenderers’ technical submittals and reviewed the appointed contractor’s detailed design. The final solution involved excavating to a suitable subgrade and backfilling and compacting using ground stabilisation techniques. Ayesa subsequently carried out construction supervision. During construction, we supervised and designed temporary haul roads to facilitate the ESB plant relocating overhead pylons.
INNOVATION
Our work leveraged advanced techniques, datadriven insights, and tailored design solutions to enhance decision-making, mitigate risks, and optimize project outcomes: Our geotechnical team specified an extensive round of Peat Probes that confirmed peat depths to allow the clients to make more informed commercial decisions regarding the proposed development. Ayesa designed temporary haul roads and platforms to facilitate the relocation of overhead pylons for the ESB plant. As part of the ground investigation, Ayesa prepared a detailed schedule of laboratory testing to enable a detailed classification of the soils and inform the appointed contractor of likely mix designs for ground stabilisation proposals.
Location: Mullingar Ireland
Capital Value: €80m
Project Name: Lidl DC Mullingar
Country: Ireland
Client: Lidl GMBH
Land Quality & Regeneration
Sustainable Development and Brownfield Site Regeneration
We offer a fully integrated geotechnical and environmental consultancy, providing a wide range of services from initial feasibility studies and investigations to the design, management, supervision and validation of remediation projects. With expertise in a range of disciplines, our geoenvironmental staff work together to assess the natural and anthropogenic issues relating to site conditions within the context of a proposed or existing development.
Contaminated Land Consultants
With over 20 years in the contained land sector, Ayesa has extensive experience in providing practical solutions to our client’s brownfield site issues. Developers of brownfield sites across the UK face the challenges of an industrial legacy and our aim is to adopt a collaborative approach with clients to understand the feasibility, opportunities and constraints in relation to the regeneration of a brownfield site. Contaminated Land is a field with strict legislative standards and we assist with initial site appraisals to master planning to optimise land value and discharging planning conditions.
Advice Across all Stages of Brownfield site projects
Our technical advice, risk assessment and appropriate mitigation can help you find a costeffective and safe solution that meets statutory requirements. We assist developers to resolve the contamination issues that increase risks and add uncertainty to programme, costs and schedules. Our teams have delivered services at every stage of contaminated land management from initial due diligence and desk study through to investigation, risk assessment, remediation and post-completion monitoring. Our team understands the regulatory frameworks surrounding contaminated land and land quality issues in different jurisdictions. We take a pro-active approach working with regulators to achieve solutions that satisfy legal requirements while minimising delays to development projects.
Our consultants are adept in the preparation and completion of Conceptual Site Models (CSMs), undertaking environmental risk assessments following the source, pathway, receptor model and developing remedial options. With an excellent working knowledge of the planning regime and contaminated land legislation, our team are able to provide guidance and support to clients through all aspects of development.
Large and Small Brownfield Projects
Our consultants have a wide range of experiences from small scale residential developments through to large-scale commercial and industrial projects. In partnership with experienced contractors, we deliver a fully coordinated ground investigation, remediation or earthworks programme to comply with regulatory requirements in both the planning and legislative frameworks. When you work with Ayesa, we combine our geo-environmental, geotechnical, environmental and structural engineering services to deliver an integrated cost-effective approach with a lens on sustainability.
Jebel Ali Landfill, Dubai, UAE
PROJECT FOCUS:
Value engineering on contaminated land at Dublin’s docklands
THE SORTING OFFICE, CARDIFF LANE
OVERVIEW
The Sorting Office is located in Dublin’s North Lotts and Grand Canal Dock Strategic Development Zone, a regenerated city quarter which is home to a number of international technology companies such as Facebook and Google.
The development - being undertaken by Marlet Property Group - includes the construction of 56 residential units, 12,000 sq. ft. of retail space and 202,000 sq. ft. of office space across 7 storeys plus a basement.
OUR ROLE
The Sorting Office development site was considerably contaminated due to former uses of the dock area. The design solution, detailed by the engineer, involved the installation of a 1m wide diaphragm cut off wall to attenuate the contamination on site in order to prevent migration off site, potentially negatively impacting the nearby River Liffey.
Ayesa value engineered a bespoke design solution to reduce the construction programme and costs of constructing the cut off wall, detailing a cement-bentonite cut off wall which could be constructed using standard CFA piling techniques in a secant arrangement. Detailed testing and compliance inspections ensured the scheme was completed to the highest standards, with the required permeability and depths achieved to ensure the contamination is attenuated on site over the design life of the scheme.
Location: Dublin
Capital Value: €158m
Project Name: The Sorting Office, Cardiff Lane
Country: Ireland
Client: PJ Edwards and Co. Ltd.
PROJECT
FOCUS: From contaminated land to a fresh-water surf lagoon in
Snowdonia, Wales
ADVENTURE PARC SNOWDONIA
OVERVIEW
The centrepiece of the Adventure Parc is the Surf Snowdonia fresh water lagoon, in which artificial surf is generated. It is roughly the size of six football pitches, set in the Conwy Valley, North Wales and features a two-metre high barrelling wave that peels perfectly for more than 150 meters. The Adventure Parc also features a range of other facilities including glamping pods, a restaurant and various other indoor and outdoor leisure activities.
OUR ROLE
Conwy Adventure Leisure Ltd. (CAL) and their contractors, (D Morgan) built the Surf Snowdonia facility on a former Industrial site –an aluminium rolling and casting works which closed in 2007.
Before they set to work, it was a derelict, contaminated, brownfield wasteland with little prospect for development. Ayesa undertook extensive site investigations, undertook the contaminated land assessment and made recommendations for the clean-up and redevelopment of the site.
Location: Snowdonia
Capital Value: £12m
Project Name: Adventure Parc Snowdonia
Country: UK
Client: D Morgan plc / Conwy Adventure Leisure Ltd
Surface Water & Groundwater Risk Assessments
Understanding the Complex Cycle of Water
Surface water in streams and rivers is an essential resource, as is the groundwater stored below ground in geological strata called aquifers. Ayesa conducts complex groundwater and surface water risk assessments to guide the design and management of many public and private projects and fulfil compliance and regulatory obligations.
Water Flow and its Ecosystem
When undertaking water-based risk assessments, we combine inputs from multiple experts (hydrogeologists, hydrologists, water and geotechnical engineers) analysing the flow and quality of water and its implications across the entire ecosystem. Our expertise within this area is evidenced by our consulting services across significant wide-ranging schemes: our hydrological and surface water risk assessments guide the design of the flood relief schemes at Arklow and Bandon Ireland; the team’s groundwater monitoring (including baseline and postremediation) of our land remediation solution at the Ineos Grangemouth Chemical Facility provided the regulatory approval and validation to help deliver the £50 million energy from waste facility.
Groundwater Flow Modelling
We utilise groundwater flow models to inform water resource management, schemes and planning by simulating current conditions and predicting the effects of land-based activities. Our groundwater modelling specialists develop site-specific conceptual and detailed models such as the SWAT model for surface water catchments and the WAVE Modflow and MT3D for groundwater. We model the contaminant and its impacts on receptors. The resulting applications allow us to evaluate and predict contaminant migration, dewatering, potential human health impacts, and design mitigation solutions.
Assisting the Waste Management Industry
We complete detailed hydrogeological risk assessments for the planning and environmental permitting of new landfill sites. Our hydrogeological risk assessments ascertain the necessary pumping activities and permits needed to dewater quarry sites before commencing a new development. We complete geological and hydrogeological risk assessments to support planning applications for Energy from Waste facilities and for extractive mineral activities.
Meeting Monitoring Requirements
We help our clients meet the monitoring requirements set out in their environmental permits and discharge consents through monitoring programmes. Our specific water quality sampling services of groundwater and surface water combines chemical, biological and toxicological assessments to support compliance. Landfills are required by legislation to periodically review hydrogeological risks to ensure that original site risks and groundwater risk assessments are valid, and we report to the relevant authority on behalf of the client (required by UK regulators, the Environment Agency, the Scottish Environmental Protection Agency, National Resources Wales and the Northern Ireland Environment Agency.)
Landfill Leachate and Surface Drainage
We also provide risk assessments for discharges to surface water from landfill leachate and surface drainage. Our knowledge of leachate composition also allows us to consider, outline, and design treatment options to minimise the impact of discharges on surface water and provide longterm sustainable management solutions.
Design and Mitigation Schemes
We design passive treatment systems that provide long term solutions to low concentration but environmentally significant pollutants including the design of reed beds for the treatment of weak landfill leachate to complex wetland constructions that remove nitrogen from sensitive waters in chalk streams in Hampshire.
PROJECT FOCUS:
engineering one
of
the largest hazardous waste facilities on the planet
SOHAR INDUSTRIAL WASTE HANDLING AND TREATMENT FACILITY (IWHTF)
OVERVIEW
Ayesa was appointed the lead design engineer for the Sohar Industrial Waste Handling and Treatment Facility (IWHTF), one of the world’s largest hazardous waste management facilities being developed by Oman Environmental Service Holding Company (Be’ah).
The facility includes three landfill sites, which will provide 18 million m3 of void space on the complex together with a 30-hectare development platform, which will accommodate a range of waste storage and treatment facilities.
The first cells of a Class I Hazardous Waste Landfill, Class II Non-Hazardous Waste Landfill and Inert Waste Landfill were was constructed as part of the Design and Build Contract. The Hazardous Landfill incorporated a double composite engineered containment lining system, a basal leachate collection system and an adjacent leachate evaporation pond. The Class II landfill was constructed with a single composite lining system and a separate evaporation pond.
OUR ROLE
Our primary role was to prepare the 30 year masterplan, provide detailed designs and construction support for three new landfill cells and to design the 400,000 m3 earthworks for a 30-hectare development platform.
Our brief on this Design & Build contract included tender support, site investigations, environmental monitoring, hydrogeological studies, earthworks design, geosynthetics design, surface water management design, sitebased construction support (including CQA) and preparation of the operations, environmental monitoring and closure plans.
Location: Sohar
Capital Value: £20m
Project Name: Sohar IWHTF
Country: Oman
Client: Al Ahlia Environmental Services
