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Major addition to office tower in Singapore adds new depth to existing structure
This project involved adding a new office tower extension to an existing high rise office tower at 78 Shenton Way. The existing building comprises a 34-storey tower sitting on a large 3-storey podium linked to a 11-decks multi storey carpark. The existing complex has site coverage of 65 %, leaving little space for the new tower without tearing down part of the existing building to make space.
One key constraint and challenge of the development is the existing tower and sprawling car park has to be operational during the construction of the new tower. To overcome this, the new tower comprising 8,000m sq. of gross floor area is built over and suspended above the existing multi-storey carpark deck. The new office floors are supported by five steel columns and one reinforced concrete core in strategic locations in order to allow the car park below to remain in operation during construction. The six supports will carry a mega steel truss base (4.2m in height), which in turn carries the floor slabs. At the same time, suspending the floors in the sky starting at 6th storey allows the new areas to be located above the coastal expressway viaduct to capitalise on the unimpeded views.
Instead of the traditional central core, the typical floor plate is designed with the service core on the west façade, which also helps to cut down the western sun and heat gain. The arrangement opens up a large unobstructed column free space with spans up to 21m and net areas of about 1250m sq. per floor, which also allows out 270 degree unimpeded view out. There is clarity in segregation of master space (office area) and servant space (service core)
The existing solidly granite cladded tower has a strong volumetric expression with regular square granite cladding, punctuated with deeply recessed square windows. The overall façade expression of the new extension is strictly superimposed with 1100 x 1100mm square modular grid and articulated as pure cubic volumes, which echoes subtly the existing tower. In deliberate contrast with the existing solid granite tower, the new extension is fully cladded in glass curtain wall, with the strong modular lines diffused by ‘dissolving’ frit or perforation pattern on the glass or aluminium cladding.
To accentuate the height and the lightness, the top of the new tower is crowned with a ‘halo’ roof, which floats above the tower. It is finished with a custom designed and fabricated dichroic glass lighting modules. Each module is constructed of 16 pieces of 1.1mm thick dichroic glass in 4 tiers. The glasses are placed in a zig-zag fashion to create mutiple reflections. Overall, the effect is a soft crystalline colour with changing iridescent appearances when back lit with LED lights.
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