Palm Jumeirah Service Tunnels, Dubai

Technical recovery and rehabilitation of structurally damaged undersea service tunnels
Delivered by Tasos Stavrinides in a senior project leadership capacity with Al Naboodah Engineering Services LLC, 2004–2006.

Project context
The project involved the construction of two major service tunnels approximately 30 metres below seabed level using micro-tunnelling and tunnel-boring methods.
The Works incorporated large-diameter precast concrete pipes, deep launching and reception shafts, secant-piled structures, waterproofing systems and reinforced-concrete liners within a technically demanding marine environment.

The challenge
During the tunnel drive, sections of the precast concrete pipeline suffered serious structural damage. Excessive jacking forces, combined with difficult external subsoil conditions and obstructions around the installed pipes, placed the continuation and successful completion of the works at risk.
The project required more than a routine repair. It needed a technically credible rehabilitation strategy that could stabilise the damaged sections, address the causes of the increased jacking resistance, allow tunnelling operations to resume and secure the confidence of the client and
engineer. 

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The technical response
Drawing on this project experience, Tasos International Projects demonstrates the ability to assess technically distressed construction works against their actual site conditions, construction methods and delivery constraints.

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On Palm Jumeirah, the aforementioned:

• Coordinated with the specialist German pipe designer to develop a rehabilitation solution for the damaged tunnel pipes.

• Developed remedial measures incorporating internal steel-plate liners, vertical supports and grouting between the liner and the existing pipe.

• Directed pressure-relief and obstruction-removal measures to reduce jacking resistance and allow the tunnel drive to continue.

• Prepared a detailed 600-page rehabilitation methodology covering the proposed temporary and permanent repairs in accordance with applicable American and British standards.

• Translated the proposed engineering solution into a fully documented and executable site methodology for review by the client and engineer.

• Coordinated the technical recovery process through approval, implementation and completion.

The outcome
The rehabilitation methodology was accepted by the client and engineer. The damaged pipes were repaired, tunnelling operations resumed and the service tunnels were successfully completed and handed over.
The successful technical recovery and delivery of the project also contributed to the contractor receiving a further award from the client for an undersea vehicular access tunnel.

Capability demonstrated
This project demonstrates practical technical advisory capability in:

• Micro-tunnelling and specialist underground construction

• Diagnosis of construction failure and site constraints

• Rehabilitation and remedial strategy development

• Coordination with specialist designers and engineers

• Technical methodology and method-statement preparation

• Construction sequencing and recovery planning

• Client and engineer technical approval processes

• Converting a complex engineering solution into an executable site response

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Dubai Airport Cut-and-Cover Tunnel, Dubai 

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Construction sequencing and technical delivery beneath operational airport taxiways
Delivered by Tasos Stavrinides in a senior project leadership capacity with Al Naboodah
Engineering Services LLC, 2003–2004.

Project context
The project involved the construction of a cut-and-cover vehicular access tunnel beneath existing operational airport taxiways at Dubai International Airport.

The Works included deep open-cut excavation supported by steel sheet piling, a reinforced-concrete tunnel structure, approach ramps, pumping and drainage systems, substations, fuel pipelines, passenger-boarding-bridge relocation, aircraft parking aprons and extensive civil and electromechanical service diversions.

The challenge
The Works had to be delivered within a live airport environment where operational continuity, safety, access restrictions and critical programme milestones could not be compromised.

Construction activities were affected by multiple interfaces involving taxiways, aprons, aviation fuel systems, drainage, tunnel ventilation, lighting, electrical services, telecommunications and air-traffic-control infrastructure.
The existing construction sequence also required review to determine whether the planned wall, base and roof-slab activities could achieve the required milestones within the available operational windows.

The technical response
Drawing on this project experience, Tasos International Projects demonstrates the ability to review construction methods and programmes where technical complexity and operational restrictions are closely connected.

On the Dubai Airport project, the aforementioned:

• Reviewed the critical-path construction sequence for the tunnel walls, base slab and roof structure.

• Reorganized the sequence of wall and base construction to improve production cycles and reduce delays between dependent activities.

• Modified wall-pour dimensions and sequencing to enable larger, full-height concrete pours and improve the rate of progress.

• Introduced continuous working arrangements across critical construction phases to accelerate delivery.

• Coordinated civil, structural, drainage, fuel, electrical, mechanical and telecommunications interfaces within the active airport environment.

• Managed reconstruction of taxiways and aircraft parking aprons while maintaining close coordination with the client, engineer and airport stakeholders.

• Aligned construction methodology, resource deployment and programme requirements around fixed operational milestones.

The outcome
The revised construction sequence improved planned-versus-actual production durations, accelerated the Works, increased monthly progress and reduced project costs.
Critical milestones were achieved to the satisfaction of the client and engineer, and the tunnel and associated airport infrastructure were successfully handed over. The project team received formal appreciation from the client and engineer for the successful delivery of the Works.

Capability demonstrated
This project demonstrates practical technical advisory capability in:

• Construction beneath live operational infrastructure

• Cut-and-cover tunnel construction

• Critical-path sequencing and methodology review

• Deep excavation and temporary works coordination

• Multidisciplinary civil, structural and MEP interfaces

• Utility and aviation-service diversions

• Programme acceleration under fixed operational constraints

• Translating programme requirements into practical construction sequences

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Qurum Heights EPC Road Project, Muscat

Constructability, phased design and live-traffic delivery on a complex urban
infrastructure corridor
Delivered by Tasos Stavrinides in a project-director capacity with Larsen & Toubro LLC, 2011–
2015.

Project context

The project involved the EPC design and construction of major road, bridge and infrastructure Works along the Darsait–Al Wadi Al Kabir corridor to Qurum Heights in Muscat.
The Works included highway widening, flyovers, underpasses, at-grade intersections, retaining structures, box culverts, utility infrastructure and modifications to existing bridges within a heavily trafficked urban environment.
Design information was released in phases, while construction progressed alongside existing roads, services and surrounding developments.

The challenge
The project required major infrastructure to be constructed while maintaining movement on an existing urban highway.
Frequent traffic diversions had to be planned and approved in coordination with government authorities, stakeholders and the Royal Oman Police. At the same time, phased design development and additional client requirements introduced changes to scope, sequencing and programme priorities.
The interaction between evolving design, live traffic, utilities, authority approvals, construction access and resource deployment created significant constructability and interface risks.

The technical response
Drawing on this project experience, Tasos International Projects demonstrates the ability to examine how design, construction methodology, access, traffic management and programme requirements operate together on complex EPC infrastructure.
On the Qurum Heights project, Tasos:

• Reviewed evolving design information against actual site conditions, construction access and programme requirements.

• Coordinated the sequencing of roads, flyovers, underpasses, retaining structures, culverts and utility works.

• Developed practical technical solutions as design and scope requirements changed during construction.

• Managed live-traffic constraints and coordinated frequent diversions with government authorities, stakeholders and the Royal Oman Police.

• Aligned designers, construction teams, planners, quantity surveyors and project managers around changing technical priorities.

• Adjusted resources and construction activities to maintain progress as new scope and design information emerged.

• Introduced value-engineering and constructability input to improve delivery and align the Works with the client’s requirements.

• Connected technical and sequencing decisions with their programme and commercial consequences.

The outcome
The project progressed through significant live-traffic, authority, design and interface constraints while maintaining coordination between the client, consultant, designer and construction teams.
Technical solutions, resource adaptability and revised activity coordination supported successful project delivery and the management of changing scope.
The project also secured agreed payment variations and acceleration-cost recovery of approximately $24 million arising from additional requirements and programme impacts.

Capability demonstrated
This project demonstrates practical technical advisory capability in:

• EPC and design-and-build infrastructure

• Constructability review during phased design development

• Roads, flyovers, underpasses and retaining structures

• Live-traffic management and construction access planning

• Utility and multidisciplinary interface coordination

• Authority and stakeholder approvals

• Value engineering and technical problem-solving

• Resource and sequence adjustment during scope change

• Connecting technical decisions with programme and commercial impact