|CLIENT:||Airport Authority of Hong Kong|
With a project capex of $US18 billion US dollars, Hong Kong International Airport (HKIA) is Hong Kong’s largest ever infrastructure spend and DBM Vircon’s largest ever project in Asia. To meet future air traffic growth and maintain Hong Kong’s competitiveness as an international aviation hub, Airport Authority Hong Kong has embarked upon a major expansion project that will see Hong HKIA become a Three-runway System (3RS).
The 3RS project is more than a new runway. Its scale is almost equivalent to building a new airport next to the existing one. A key element of the project is the Third Runway Passenger Building, which will encompass more than 280,000m2 of floor area, 57 new aircraft parking positions, and an apron. The aircraft concourse is comprised of 23,861 tonnes of steel sections, and approximately 79,374 sticks of steel, and 774,103 connections. To illustrate the sheer size and scale of this aviation mega project, if the concourse structure was to be stood vertical, it would be 785m in height—making it one of the ‘tallest’ buildings in the world.
DBM Vircon’s Scope of Work
DBM Vircon was engaged directly by the owner, the Airport Authority Hong Kong, to provide specialist modelling services for the new 57 aircraft concourse that will service the existing second runway, and new third runway.
DBM Vircon was engaged at an early stage to work collaboratively with the project engineer, moving away from the traditional staged silo mentality that is usually associated with delivering a major infrastructure project. The company delivered a fully connected design intent Tekla model for tender and LOC purposes, with the successful contractor then utilizing the model to produce erection methodologies and 2D fabrication deliverables. This way, all the steelwork details will be fully resolved, and the design complete at the time of contractor engagement. As such, the Airport Authority Hong Kong will be able to significantly de-risk the project by removing any assumptions or unknowns within the engineers’ traditional 2D design, which traditionally translate into fabricator claims and delays to the project.
This type of project delivery is a fairly new, unique process, particularly for a project of this size. As such, DBM Vircon in collaboration with the project Engineer AECOM turned to Trimble to help connect stakeholders across each phase of the project with digital construction solutions.
For example, instead of using traditional 2D drawing deliverables, the project engineer exported parametric analysis geometry directly from their engineering wireframe software – Rhino. This was passed directly through Grasshopper into a Tekla Structures model share arrangement, using Trimble Connect, where both AECOM and DBM Vircon could easily collaborate. Future updates to geometry could then be pushed into the shared model via scripting. The engineering team used these shared models for design verification and to produce their planning documentation for statutory approvals.
Change management controls were also critical once Rhino geometry updates were no longer possible due to thousands of connections being added to the models. Careful tracking of wireframe movements were required if steel was found to be misaligned or needed to move. Tekla and Trimble Connect were used to enable these functions to be carried out.
Another innovative solution made possible by Tekla Structures and Trimble Connect open source platforms was the use of Parametric Custom Components. A key challenge to this structure was the concourse roof featuring a subtle whaleback curve. While the geometry is similar bay-to-bay, it was different enough that each bay of steel was slightly dissimilar to the next. DBM Vircon was able to take these varying parameters of ever changing geometry, member sizes, plate thicknesses, welds and bolts quantities and develop parametric custom components, complete with engineered checking data, to control over 60,000 (82%) of these connections.
With 23,861 tonnes of steel in the roof and façade structure and 79,374 sticks within the seven Tekla models, the heavy use of parametric custom components enabled DBM Vircon to rapidly connect geometry that would otherwise have been extremely repetitive and time consuming. Likewise, connections that were required to change due to design updates could be updated on mass, far quicker than updating manually created ones.
A custom set of connection parameters were exported from Tekla to Excel allowing AECOM to rapidly check a set of parametric connections covering a wide range of variables. This ensured consistent output of modeled connections over having to individually check many manually applied components. DBM Vircon achieved ratios in some models of 100 parametric components controlling 10,000 connection locations.
“Whilst fabrication is only just commencing, a number of benefits have been identified, said Rick Sheldon, Project Manager at AAHK.
The collaborative process required DBM Vircon and AECOM to work to a coordinated program, resulting in AAHK having a much clearer understanding of the status of the structural steel design, in particular the connection designs, and the Architectural construction detailing. This provided greater certainty with the tender quantities. The transparency afforded by AAHK’s access to Trimble Connect provided greater certainty with tender quantities, resulting in reduced tender risk.
The process basically eliminated the usual requirement for significant RFI’s post award as AECOM addressed these prior to tender. It is believed this will also considerably reduce the potential for delays claims.
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