Advanced Steel Construction

Vol. 12, No. 2, pp.83-93(2016)



Goman W.M. Ho
Arup, Level 5, 80 Tat CheeAvenue, Kowloon Tong, Hong Kong
              (E-mail: goman.ho@arup. com)
Received: 23 February 2012; Revised: 10 September 2015; Accepted: 30 September 2015





The structural efficiency of tall buildings heavily depends on their stiffness and lateral resistancecapacity. Among those structural systems for tall buildings, outriggers system is the most common one forbuildings with a relatively regular floor plan. Research in outriggers system is relatively limited and usually focuseson the optimal locations/levels of outrigger only. However, the locations of the outriggers are usually dictated by thefunctional use of the tall buildings and outriggers are usually located in the less commercial valuable floors such asmechanical or refuge floors. Because of this limitation, the topology of outriggers becomes an important element inproviding an optimum design. Furthermore, most engineers considered that the performance of buildings is a linearrelationship with the stiffness and the critical load of the outriggers. Nevertheless, this is not always true if theultimate design load condition is being considered. This paper starts with various topologies of outrigger which arecommonly used in practice; studies their stability behaviour, compares their stiffness and finally their ultimate loadcapacity. Examples demonstrate that for some outriggers geometry arrangement or topologies which deliveredmaximum stiffness and critical loads do not always yield the highest ultimate load capacity even for same outriggermember sizes.


Keywords:Tall buildings, outrigger systems


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