The building utilizes an external structural system that greatly reduces the number of structure columns of the typical floor, creating large and open office space, allowing for the ongoing flexible division of functional layout in the future. The Exo Towers therefore derives its architectural language from the manner in which the space and structure are completely integrated. 2.0 Integrated Design A 1.5m x 1.5m modular grid system is utilized to regulate the architectural form, position and define the spatial layout, structural form, building envelop and MEP services, facilitating mutually dependent and defined systems through collaborative interfaces.
3.0 Space and Structure The building adopts a hybrid system of steel structure and concrete structure. The central concrete core and the external steel frame jointly constitute a supporting system. From the 4th floor of the building, the south tower and the north tower are composed of 2 and 3 repeated structural and spatial clusters, respectively. Each cluster includes 6 floors. The cluster on the south and north facades adopts a 4+2 mode and includes a pair of 4-storey high external columns to support 4 typical floors.
The load at the bottom of columns is transferred to the masts on both sides through a pair of 2-storey high diagonal braces. The double-height communal space and outdoor terrace are arranged in the position corresponding to the brace. The cluster on the east and west facades adopts a 2+2+2 mode and are composed from top to bottom of 3 groups of symmetrical hangers dropped from diagonal suspension trusses, creating column-free corners within the office spaces and offering a sweeping panorama of the city.
The 70m full-height glazed atrium between the two towers is the spatial core of the whole building. Along the west facade, six sky bridges span between the two towers and in breaking down the scale of the atrium both visually and socially enhance the building's horizontal connections. 4.0 Building Envelop and MEP Services The details and quality of a building largely depend on the presence of the envelop and service terminals, in other words, how the two systems are harmoniously integrated into one seamless order.
The cladding of the external structure, perhaps the most characteristic part of this project, adopts a linen pattern stainless steel plate, reflecting the surroundings and interacting with the light that changes throughout the day. Between the two towers, a 27-metre-wide glazed canopy with a 15-metre cantilever creates a dramatic entrance experience, leading to the 70m-high atrium. The same design language is applied to the south and north entrances of the building, with a guiding entrance space being formed by a double-height glass curtain wall that retreats inwards.
A cable-net glass curtain wall is used for the east facade of the atrium, creating an extraordinary transparency and clarity by hiding the anchors and spring assemblies in an ingenious way. Six sky bridges span between the two towers on the west side of the atrium, structurally bearing the load of the glass curtain wall. Suspended from the atrium, the ceiling system filters sunlight gently, whereas at night, it acts as atrium lighting. The maintenance catwalks of the ceiling system provide an access to clean the glass roof and ceiling panels or replace the luminaire.