ITC Colombo One, Hotel and Luxury Apartments ‘Estimated year of launch – 2020’

Thornton Tomasetti is providing structural design, through design development, for a 48-story luxury residential tower and a 29-story hotel tower connected by a two-story sky bridge. Located off the coast of Sri Lanka, the development includes a four-story shared podium that will offer a lobby and visitor drop-off area, a conference center, high-end retail space, amenities and four below-grade levels to accommodate parking for 1,210 vehicles, MEP and back-of-house functions.

During concept design, Thornton Tomasetti conducted a cost-benefit study comparing framing options for the hotel and residential floor plates. Parameters included concrete volume, rebar cost, formwork cost and construction speed. Facilitating a column-free space to enhance the overall architecture of the project was also a primary consideration. The selected scheme is a 350-millimetre-flat (conventionally reinforced) structural slab spanning between perimeter columns that are spaced at 10 meters. This unique structural system maximizes the floor-to-floor height, accommodates floor-to-ceiling windows and simplifies the routing of MEP services.

The structural system consists primarily of reinforced concrete. The towers’ lateral stability is provided by reinforced concrete shear walls organized around the core of each tower. Concrete
link beams connect individual wall segments, within each core, enabling them to work together to resist lateral loads.

The project presents a number of structural challenges including a 54-meter-long sky bridge connecting the hotel and residential towers at the 19th and 21st floors. The upper level of the sky
bridge will serve as an exterior pool deck while restaurants and lounge areas will occupy the lower level. Thornton Tomasetti studied several structural schemes to achieve a sky bridge design that would best support the architect’s vision and planned program. A load-carrying central spine scheme formed by a box truss between levels 20 and 21 was selected to allow for maximum transparency at the lounge/bar while concealing pool mechanical systems.