needs and responded to the urban context . The strategy was structured in the following way :
• Remodelling of the existing office block on three of its edge conditions . The north finned façade to Smith Street was retained , existing windows removed and a new fenestration screen applied in performance glass curtain wall to address Smith Street with an appropriate scale . Removing all structural fins on the south façade to replace the support with four primary engaged columns and reglazed to interface the atrium : Demolition and extension of the east bookend wall , extending floor slabs and creation of the boardroom corner tower with window walls capturing panoramic views over the City Square ’ s historic buildings and elevated glimpses of the harbour south along Gardiner Street .
• Creation of a new 10 level garage capped with new office accommodation and suspended mezzanine canteen deck to connect with level 8 of the existing office block .
• Enveloping the space between the existing and new blocks with dramatic prism-like steel structure atrium and based on level 3 datum above new computer room and existing banking hall .
• Formation of a new west lift core set in the atrium space linking the parking garage , level 8 mezzanine and existing office block .
• Generation of a new public reception space on Gardiner Street tying in with the existing east lift core , integrating two access points from each street interface and announcing the entrance to the building .
• Integration of all elements at pavement level including the banking hall , ATM cluster , new entrance and parking garage access with a lightweight canopy . interface with the new atrium necessitated the insertion of a new columnar and beam structure over eleven floors .
• Retention of the level 0 banking hall prevented the positioning of new vertical structure from ground level to support a complex set of new floor plates above level 3 .
• The corner tower ’ s tubular sheath and halo generated unusual engineering and erection solutions in the deployment of a aluminium skeletal tubular structure and ‘ bicycle wheel ’ suspension concept to impact a floating ‘ lookma-no-hands ’ quality to the 22m diameter halo extending 6 m into the street space below .
Architectural Aspects ABSA Towers occupies a highly prominent site in Durban , diagonally opposite Francis Farewell Square and in the architecturally historic company of the City Hall and Post Office . These wonderful Edwardian and Victorian edifices act as the geometric counterpoint to the remodelled Bank Building and have driven its formal and contextual response . The tower of the Post Office and dome of the City Hall are set orthogonally and axially on the City Square and this arrangement generates the signature corner tower response of the ABSA Building . A spatial tension is created between these three architectural elements in the urban
Technical Aspects A myriad of technical challenges were faced in this development , apart from the obvious problems of construction in the city on a busy corner site with constrained access opportunities . The primary technical problems were overcome with innovative design solutions :
• The piling requirement for the new structure demanded considerable engineering ingenuity as the new foundation network had to fit between the demolished building ’ s retained pile grid .
• Anticipated settlement of the new structure over a two year period affecting the linkage to the original building at the east atrium glazed façade some 40m in height , required the design of a jacking system to overcome racking in the curtain wall .
• Removal of the original office block ’ s structural fins on the south façade to create a clean new
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