The Highways Department for the Government of Hong Kong Special Administrative Region (SAR) has successfully built a mega-size sea crossing to link Hong Kong, Zhuhai and Macau. Vehicles enter and leave Hong Kong through new boundary crossing facilities on a 150-hectare reclaimed island and the revolutionary project includes 50 kilometres of bridges and tunnels.

The Leighton-Chun Wo joint venture won the $4.6bn contract to construct the passenger clearance building and associated works. As the lead on BIM utilisation for contractor works, Leighton Asia used Bentley’s BIM technology as the common platform for anticipating and rectifying construction problems, as well as building the as-built digital model for delivery to the Highways Department. Leighton Asia’s innovative BIM strategy saved about 12 per cent of the construction budget.

A rendering of the pre-fabricated, pre-assembled roof structure, which was moved into place horizontally, eliminating the need for vertical movement above the airport height restrictions.

Construction of the project commenced in 2014 and the passenger clearance building’s wavy steel roof was a signature design feature and one of the major construction challenges of the project. Each steel roof segment was 60 metres long, 25m wide, and weighed more than 670 tonnes. Given the height restrictions imposed by the nearby airport, the constructors elected to use a horizontal installation method. The fabrication stages were performed at multiple locations, including Yinchuan, Hangzhou and Dongguan, and pre-assembly also took place offsite at ZhongShan. These steps progressed the roof’s construction at twice the usual rate. The sea crossing officially opened to public in October 2018.

Adopting a BIM-enabled approach offered the team several advantages. The platform facilitated communication and collaboration among all participants. Bentley’s civil software enabled Leighton Asia’s survey team to organise and analyse the 2D drawings submitted by contractors and convert their designs into up-to-date 3D models.

Visualisation

Using MicroStation, Bentley’s modelling, documentation and visualisation software, the BIM platform enabled models from the eight contracts to be combined into one geo-referenced 3D model.

Leighton Asia’s survey department performed 3D laser scanning of the construction progress using point cloud data to create as-built models. The survey team compared the 3D design models to the point cloud as-built models to assess the accuracy of the work.

Leighton Asia partnered with The Earth Solutions to construct and maintain a geo-referenced as-built 3D model and Leighton Asia’s survey department performed 3D laser scanning of the construction progress. The point cloud data was processed with applications called Pointools and Descartes to create as-built models. The survey team compared the 3D design models to the point cloud as-built models to assess the accuracy of the work and this process was integral to the project’s quality assurance programme.

By continuously updating the as-built models, the survey team created accurate as-built BIM models suitable for facility lifecycle management by the Highways Department. The cost-effective method pioneered by the Leighton Asia Survey Department streamlined the workflow, saving 15 per cent of the survey budget.

This article was originally published in MEED Mashreq Construction Report Vol 3: Delivering Innovation in Construction, in April 2018.

This article is extracted from a report produced by MEED and Mashreq titled Delivering Innovation in Construction. Click here to download the report