3 . TOWERS 3.1 Construction
Tower and foundation structural heights are of 215.717m for Central Tower and 216.367m for both North Tower and South Tower .
Each tower is of hollow reinforced concrete construction and tapers both longitudinally and transversely . At the base , the tower has outer dimensions of 14m longitudinally and 16m transversely . The tower tapers linearly in both directions :
- longitudinally to 10m at deck level and 7.5m at the tower top
- transversely to 8m at deck level and 5.0m at the tower top
Central Tower required thicker tower walls compared to the Flanking Towers ( North and South Towers ).
Longitudinal fixity is provided by a monolithic connection at the Central Tower with transverse support provided at all towers and piers .
As a result of this longitudinal fixity , the tower reinforcement quantities at the Central Tower ( CT ) are greater than those at the flanking towers ( ST and NT ), with typical examples of quantities below :
Table 1 : Typical tower material quantities
Due to the high reinforcement tonnages in the lower level of the tower walls ( 41t maximum per wall elevation ), the reinforcement was primarily constructed in-situ ( lifts 1 to 20 ). Prefabrication of entire wall elevation reinforcement cages was utilised from lift 21 upwards as the 18t maximum wall elevation reinforcement weight was within the operational crane lifting limits .
Segments 38 to 51 incorporate a steel anchorage assembly for the stay cables within the tower head . Stainless steel pipes were cast into the concrete wall and connected to the steel stay pipe . Within the stay pipe there are cable guide deviators , to assist with cable installation , and dampers that ensures the dehumidified zone within the upper zone of the tower remains effective .
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