Robert Bird Group (RBG) were appointed at the end of July 2019 to deliver a construction methodology for the new Terminal 2 superstructure at Schiphol Airport in Amsterdam, based on the Preliminary Design Stage 2 release of information.
The appointment comes from the complexity of the structure and the understanding that it would require complex temporary works and sequencing, which had not been estimated in the engineering design, pre-construction budget or construction programme at that stage.
The uncertainty in these elements of work was deemed to be a risk against successful project delivery and RBG prepared an engineering peer review and construction engineering/construction plan to mitigate it.
Key technical challenges
The structure is a 3D space frame composed of long span triangular trusses spanning N-S, linked by 2D planar trusses in the E-W direction. They are supported on long span 2D planar trusses supported on columns. There is a reduced number of columns creating big open spaces within the terminal, with spans going from 25 to 60m in the N-S direction.
The structure will serve as a building services (MEPF) plenum hence, the installation of MEPF services within it, is as important as the erection of the steelwork. Ideally, as much as possible should be pre-installed in the structure to speed up construction, to include the cladding to enclose these services. The RBG proposals provided solutions to these issues, integrating them to provide a coordinated off-site/on-site construction strategy.
- The proposed construction methodology delivers the following benefits:
- Minimises temporary works by simplifying, preassembling and prefabricating large elements of roof structure and envelope;
- Flexible temporary works systems that can be re-used at various locations, using off-shelf re-usable systems;
- Reduces the number of bespoke permanent and temporary works elements;
- Reduces the impact on follow-on trades by minimising the installation timescales for temporary works to a minimum duration;
- Avoiding some of the temporary works back-propping and compensating it with strengthening of permanent works, if needed.
RBG Value Add
The detailed peer review and construction sequence and methodology analysis carried out by RBG challenged the permanent works design, the result being that the the client was keen to implement several RBG recommendations. These were aimed at improving the buildability of the structure, minimizing risks and ensuring cost control by increasing the certainty in the structural design.
Eventually they prompted a revised design and a repetition of Stage 2 which was postponed due to force majeure Covid-a9 circumstances.
Key technical innovation
Our recommended construction methodology for the terminal superstructure is based on an innovative approach that is similar to a production line that will achieve the following:
- Maintain the Airport’s operational requirements for the baggage hall and boundary limitations;
- Compliance with construction constraints, most notably viewing constraints from the adjacent ATC;
- Consider the local construction logistics constraints including transportation lengths, crane lift limitations, carriageway limitations for transportation of large elements to site and site construction transport strategy on a shared access highway.
- Reduce working at height and provide safe access for operative within the design of temporary works where necessary;
- Reduce onsite labour;
- Maximise the use of both offsite and onsite pre-fabrication and pre-assembly to reduce construction programme;
- Maintain a simple engineering approach that avoids unnecessary jacking and load transfers in achieving the desired structure;
- Utilise a rolling production method of towers and supports to minimise temporary works. Two sets of platforms will be used to install the main roof trusses and all the cladding and services within the roof as seen below:
- Re-use of the temporary works by repetition of the systems required to provide temporary stability across different areas of the building;
- Design re-usable temporary works to be moved without the use of tower cranes to avoid using crane time for moving temporary works;
- Minimise the duration that temporary works are in place to avoid impacting follow on construction activities;
- Develop a common tower crane strategy that can be used for the basement, cores and superstructure works;
- Reduced permanent works steelwork tonnages, simplified connection and welding requirements by replacing tubular steelwork with angle sections, creating consequential savings in fire protection and carbon intensity.
This project, at stage 2, already included some sustainable design trends which were to be developed further in the following stages. Remarkable is the use of wood materials, greenery and abundant natural light to ensure a smooth transition for the passengers between the exterior and the terminal space.
The goal is to minimize the energy consumption as the direct sunlight will provide heating and will reduce the need of artificial lightning.
The structural strategy was aimed to achieve a low carbon footprint building by using preassembled steelwork modules in the roof, that incorporated the MEPF services increasing efficiency.
RBG involvement and peer review comments led to increased construction efficiency, increased used of re-usable temporary works structures, lowered overall permanent works steelwork tonnages and reduced the amount of fire protection required.
14M passengers per annum;
Schiphol Nederland (SNVB)
KAAN Architecten and Estudio Lamela
Robert Bird Group Services: