The Twins makes its debut in phases, and Tower I now officially opens its doors welcoming shoppers, with the new SOGO Kai Tak store as the main highlight and dedicated dining areas on the 12th, 14th, and 15th floors.
With a total GFA of more than 100,000m2, The Twins comprises two 22-storey structures and four-levels basement located in two adjoining individual sites in Kai Tak area. To realise this retail landmark, WSP has provided structural, geotechnical, civil, MEP, traffic and façade engineering consultancy services. In particular, our innovative structural design of The Twins has earned Commendation Merit at HKIE Structural Division – Structural Excellence Award 2024 and has been selected as one of the finalists for the ACEHK Annual Awards 2024. It was also an award winner of Autodesk BIM Awards 2022.
Our expert engineers faced challenges in designing over 25m deep excavation for basements construction at both individual sites simultaneously, while the MTRC tunnels, which are float tunnels for the Tuen Ma Line located in-between the sites, are in normal operation with the nearest distance being around 6m. Moreover, Drainage Services Department’s drainage box culvert cut across the sites, with the nearest distance to the proposed basement structure being 1m.
Therefore, BIM was utilised in the early stage of master planning to demonstrate the underground constraints such as MTR tunnels and geotechnical features, providing a holistic picture for deriving a master plan for the project. Furthermore, our engineers adopted a stepping-basement design and controlled the excavation sequence to minimise the risk to adjacent tunnels, resulting in the most cost-efficient design for the entire project development.
The Twins are supported by 120 large diameter bored piles reaching 100m into bedrock. A diaphragm wall with jet-grouting for ground treatment was design, as an excavation and lateral support system, to ensure safety and efficiency during construction.
As the scheme will have to provide 500 parking spaces and over 100 loading/unloading spaces to accommodate a large number of shoppers and goods, this presents significant challenges in terms of traffic analysis in the vicinity, access arrangement, traffic layout and safety, all within a confined footprint. To avoid peak period queuing and traffic congestion, we focused on designing the entire carpark areas with maximum efficiency, ensuring all users can park and pick-up in the most convenient ways to provide the best car parking experience.
We also proposed a two-storey high mega steel truss for the MEP floor to address unsymmetric underground constraints and lease conditions of the two sites involved. This design allows for maximum floor area while minimising impact on space usage, transferring loads efficiently from bottom to top and back to the foundation. It also allows high headroom retail area at the low floors.
Our MEP design is also well integrated with the Kai Tak District Cooling System, which can achieve better energy efficiency while saving space for installing chillers and the associated electrical equipment. Together with other sustainability features, The Twins has obtained Provisional Platinum rating under local BEAM Plus green building certification scheme.
