Dublin Airport, one of Europe’s fastest-growing connectivity hubs, continues to prepare for the future with the construction of a new visual control tower that, together with a new runway, will help with airspace management and traffic flow.
At 87.7m high, the visual control tower is the country’s tallest occupied structure and is a commanding new addition to the city’s skyline.
The tower, a key element in complex high-traffic airports, was designed as a slim, elegant structure offering clear sight lines of both the current and future runways. Arup carried out the civil, structural, mechanical and electrical engineering; and also provided environmental, lighting and façade consultancy services, bringing the project from concept to construction stage.
Salam Al-Sabah, Associate and Chartered Structural Engineer at Arup, said, “The design solution of this dynamically wind-sensitive structure was achieved through close collaboration of the structural, mechanical and electrical, façade, geotechnical, environmental and lighting teams working together to attain an elegant solution.”
The new visual control tower will be ready to provide single runway operation during the first half of 2020, transitioning to provide parallel runway operations by 2021, when the new runway becomes operational.
87.7m high tower
35tonnetuned mass dampers reduce wind-induced vibrations
Designing for the needs of air traffic controllers
Visual air traffic control towers are an airport’s central processing hub, a piece of critical safety infrastructure to ensure that aircrafts move seamlessly through airports. The height of the new tower ensures appropriate visibility of runways, thresholds, manoeuvring areas and stands. The needs of the air traffic controllers were a key consideration during the design, with a view to aiding concentration by ensuring maximum comfort and reducing potential distractions.
Given the height of the tower, minimising wind-induced vibrations was a crucial aspect of the design. Arup engineers, in conjunction with RWDI, carried out a series of wind tunnel tests to determine the specifications for the two tuned mass dampers (TMD). A TMD is a large mass of steel inside the tower designed to absorb vibration energy. It is tuned to vibrate at the same frequency as the structure, reducing the sway of the tower and creating a positive work environment for air traffic controllers.
We have enjoyed the opportunity to cater for the unique challenges of designing such a tall, slender building. Reducing the wind-induced vibrations for this important piece of national infrastructure was a vital part of our involvement. ” Sean Barrett Associate, Structures
Bespoke façade design enables 360-degree views of the airfield
The façade was designed to ensure that air traffic controllers have optimum views to enable efficient take-offs and landings. The size of the glass panels was maximised. A bespoke conical shaped unitised curtain wall façade was designed, delivering the architectural intent for the control room.
Insulating glass was used for the visual control room and conical façade below, with solar radiation minimised through the use of a high performance solar control coating. Appropriate interlayers in the glass minimise internal reflection while also improving acoustic performance. The lighting design for the curved façade ensures a consistent appearance for the tower at night.
The tower lighting gives the control tower a distinct visual identity, with nine bands of multi-coloured LED strip lights allowing a range of colours and visuals to be programmed to show on the façade by night.
Future maintenance was a key consideration, with the luminaires housed within the interior of the façade and special care applied to develop the access strategy, incorporating a building maintenance unit (BMU) for future glass replacement and façade maintenance.
Resilient design safeguards air navigation services
Resilience, safety and operational comfort for air traffic controllers were key when designing the tower. Due to the vital nature of air traffic controllers’ work, it was important to ensure that all building services and safety systems are resilient. Critical equipment has uninterruptible power supplies (UPS), with duplicate supplies and routes incorporated on many primary and secondary mechanical and electrical systems, ensuring that they will continue to operate when the plant is under maintenance or should power failures occur.
The design of the landscaping adds further resilience, protecting the plant areas at the base of the tower in the event of heavy rain. Floodwater is diverted away from the tower and the adjoining pavilion building, protecting the critical infrastructure in basement areas.
Solving unique design challenges
In order to manage the risks posed by local ground conditions, Arup provided full-time supervision, giving visual confirmation of the rock socket and carrying out verticality and integrity tests. There is a fluvio-glacial channel within the tower’s footprint, with the site also sitting within a zone of variable underlying rock.
We also undertook the Environmental Impact Statement (EIS) for the tower, ensuring that the environmental impact was considered from an early stage. Planning was successfully granted by An Bord Pleanála in 2010.
We designed the tower to take into consideration the necessary techniques when constructing high-rise buildings. Slipform concrete core construction was used for the tower, whereby the concrete is poured in a continuously moving form 24/7. Slip forming is not a common method of construction in Ireland but is incredibly beneficial for tall buildings.