South elevation: naturally ventilated double skinned Naturally ventilated double skinned façade. The inner skin is a “bomb blast resistant” structural silicone bonded fully framed curtain walling system (SSG), with a deep edge rebate to accommodate the high stresses caused by the blast resistant requirement. A naturally ventilated cavity separates the two skins. The ventilation is achieved by air entering the open grilles in the sloping soffit above the shopfronts and exiting through the opening vents on the glazed roof. Bespoke ironmongery and twin electrical activators operate the opening vents. The automatic blinds are placed inside the cavity. A central control panel has been specifically designed to operate the blinds and the opening vents in order to control the exchange of energy flows between the interior and the exterior of the building throughout the seasons. North elevation: steel and aluminium The Northern façade faces Exchange Square The façade encloses an open space of 43m. x 3.5m. x 19m. An aluminium frame supports SSG glazed panels 1.9m x 3.2m. In this situation a low iron glass has been used to enhance natural lighting. The façade is supported by elegant structural steel trusses (Virendeel type) 18m high, connected horizontally by means of stainless steel rods (AISI 316). Also this façade is designed to be bomb blast resistant. East/west entrance and corners : suspended curved façades The façades are contained between two concrete bearing walls, which create a 14m high clear area internally. In order to obtain the required mechanical performances, it was decided to use a curtain walling system, which is suspended from the structural steelwork at roof level. The horizontal forces (wind load and bomb blast pressure) are supported by the transoms which span 9m in a horizontal direction. The mullions in turn span vertically between the transoms. In order to obtain the required mechanical strength, a deep finned transoms, featuring holes in the fins have been used. The vertical forces are supported by vertical stainless steel rods suspended from the top beam of the roof. In this particular case, a special bending machine had to be designed because of the unusual shape and dimension of the finned transoms. All the problems associated with a project of this complexity were successfully resolved within program and budget, thanks to the excellent co-operation of all parties and the trust established between the Main Contractor (BOVIS Lend Lease), the Architectural designer (BDP) and Focchi Group who provided the design, production, installation and management techniques.