Solving constructability issues of 2.2 km-long boardwalk under Hong Kong highway
The project and redesign
A pedestrian boardwalk beneath the Island Eastern Corridor elevated highway is a 2.2 km long landmark improving connectivity and accessibility along Victoria Harbour.
The original design hit a wall due to construction limitations. Two main elements were re-designed to solve construction issues: a part of the boardwalk designated as Span 38, and a fishing platform.
That's why Tony Gee and Partners created a new design. They are specialist consultants, mostly working with contractor clients and their strength is in focus on constructability of designs: they help the contractors through construction engineering and methods, along with adopting technologies to ensure sustainability and efficiency in costs and time.
Project and visualizations
Redesign of Span 38
The original design included four pre-bored socketed steel H-profile piles beneath IEC bridge deck. But it faced installation challenges due to limited clearance under the road bridge – the pile rigging machine could not be operated safely and efficiently.
That’s why Tony Gee and Partners replaced socketed H-piles with RC monopiles, and redesigned spans for constructability. They introduced new steel framing system to transfer boardwalk load to existing IEC pile caps.
Redesign of the fishing platform
Originally, the project assumed new piles supporting full RC superstructure. The design included 10 additional piles under the fishing platform area.
To create a lighter superstructure, the redesign introduced a steel superstructure with RC slabs, and the replacement of the RC frame by steel-concrete I-beams. This created a span with approximately 25.4 meters between column stubs, and an 11-meter overhang forming the fishing platform.
In the new design, steel I-beams are connected to short steel column stubs, which are supported by IEC bridge pilecaps. These crucial changes in geometrical shape and structural materials used offered a new solution in those cramped spaces, but also created new challanges for steel connections. The designs had to reflect the complexity of the whole structure geometry and spatial possibilities for erection on site.
Examples of designs used in the project
Ensuring quick delivery and handover
High-quality 3D images, stress maps, and deformation visuals were used for design meetings, approvals, and even workshop discussions, which reduced miscommunication between the structural engineers, and the reviewers and fabricators.
As Mohammad Elayyan describes: “Connection modifications due to contractor or site constraints could be updated quickly. The design-check loop became significantly faster without compromising code compliance.”
Thanks to IDEA Statica’s ability to modify designs without the need to start from scratch to implement proposed changes, the review process was shortened significantly.
Incorporating IDEA StatiCa to company workflow
As used to be a standard, engineers at Tony Gee and Partners were using spreadsheets and hand calculations for connection design – apart from very complex cases, where they used FEA tools that were not practical for this use-case.
To solve these issues, they have tried IDEA Statica. “To make sure they can rely on IDEA StatiCa for their calculations, Tony Gee and Partners have have double-checked and verified the outcomes of IDEA StatiCa, and the results were fantastic,” says Mohammad Elayyan.
And how will the future of using CBFEM method and IDEA StatiCa look like at Tony Gee and Partners? “I see that there are some quite nice improvements coming especially in the detailing and the concrete part, and I'm looking forward to adopt that in the future,” says Mohammad, who has come from bridge design background and is thus interested in what capabilities IDEA StatiCa has to offer there.
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