Deflection Control in Composite Building by Using Belt Truss and Outriggers Systems

The design of high-rise building is more often dictated by its serviceability rather than strength. Structural Engineers are always striving to overcome challenge of controlling lateral deflection and storey drifts as well as self weight of structure imposed on foundation. One of the most effective techniques is the use of outrigger and belt truss system in Composite structures that can astutely solve the above two issues in High-rise constructions. This paper investigates deflection control by effective utilisation of belt truss and outrigger system on a 60-storey composite building subjected to wind loads. A three dimensional Finite Element Analysis is performed with one, two and three outrigger levels. The reductions in lateral deflection are 34%, 42% and 51% respectively as compared to a model without any outrigger system. There is an appreciable decline in the storey drifts with the introduction of these stiffer arrangements.

Authors:

• S. Fawzia
• T. Fatima

Keywords:

• Composite building
• belt truss
• deflection
• FE model
• outrigger truss
• 3D analysis.

References:

[1] B.S. Taranath, Structural Analysis & Design of Tall Buildings. New
York, Mc Graw Hill, 1998.
[2] M. H. Gunel, and H.E. Ilgin, A proposal for the classification of
structural systems of tall buildings. Faculty of Architecture, Middle East
Technical University, Ankara 06531, Turkey, 4 July 2006.
[3] I. Hal, Composite and Steel High Rise Systems. Habitat and The High-
Rise, Tradition & Innovation. In Proceedings of the Fifth World
Congress. 14-19 May 1995.Amsterdam, The Netherlands, Bethlehem,
Pa : Council on Tall Building and Urban Habitat, Lehigh University
[4] P.S. Kian and F.T.Siahaan, The use of outrigger and belt truss system
for high-rise concrete buildings. Dimensi Teknit Sipil, Volume 3, No1,
Maret 2001, Page 36-41,ISSN1410-9530.
[5] R. S. Nair, Belt Trusses and Basements as "Virtual" Outriggers for Tall
Buildings. Engineering Journal / Fourth Quarter/ 1998.
[6] Standards Australia/Standards New Zealand, Structural design actions,
Part 0: General principles, Appendix C, Guidelines for Serviceability
Limit State (Informative), AS/NZS 1170.0:2002.
[7] Strand7 Pty Ltd. Strand7, Finite Element Analysis System, User-s
Manual 2005, Sydney, Australia.
[8] Standards Australia, Steel Structure, , AS 4100:1998.
[9] Australian Steel Institute (ASI), Design Capacity Tables, Volume 1,
Fourth edition 2009.
[10] BlueScope Lysaght Manual, Using Bondek- design and construction
guide 2003 edition, BlueScope Steel limited, Australia.
[11] Standard Australia/Standard New Zealand ,Structural design actions
Part 2: Wind actions, ASNZS 1170.2:2002