The magnificent One Za’abeel is a prestigious mixed-used development located between the old and new business districts in bustling Dubai. The scale of this development is as complex as it is enormous, with two beautifully designed towers standing at 304 metres and 241 metres, sitting over the top of an operational six-lane carriageway. The development also features seven basements of 28 metres below ground level.
Above ground, the One Za’abeel towers sit on podiums A and B which are connected by a 125-metre tall (in the air) and 225-metre horizontal steel and glass structure – and is the world’s longest cantilever.
BG&E was appointed as the contractor’s third party engineer responsible for checking the link bridge structural calculations and drawings submitted by the steelworks’ contractor. Our experienced structural engineers also designed the related temporary works, including those for the link bridge construction and erection.
Checking the tower stresses and deformations across the entire construction programme, including the erection of the link, was essential to ensuring the bridge was installed safely and met the rigid serviceability criteria set in the architectural requirements.
The link bridge was fabricated on top of a temporary steel structure assembled over podium A and podium B, which had to be partially strengthened. The link was constructed over podium A and launched incrementally across the live highway, until seating down on the podium B temporary structure. To facilitate this solution, significant propping through the podiums supporting up to 20Mn (steel grade), were coordinated by BG&E.
Our team also provided technical assistance for construction of the link which considerably reduced the construction programme time and cost. The original design required the tower construction to be suspended above the link bridge, until the link bridge was fully welded to the structure. BG&E provided a sensitivity analysis to confirm that tower construction could proceed prior to lifting the link bridge and determined the maximum floor levels which could be completed prior to, and during the link bridge lifting and fixing with the link bridge to be lifted into place from lifting gantries connected and integrated into the towers. This approach enabled the tower construction to be taken off the critical path.
During the lifting of the link bridge, extremely high loads were transferred to the towers. BG&E assisted the steelworks’ and lifting contractors by providing several design options for the lifting gantries, as well as solutions for strengthening the tower’s structure, after the final scheme was chosen. The additional strengthening of the towers was enabled by using existing permanent steelwork, therefore reducing the embedded steelwork which was constructed on site.