The Suitability of Double-Layer Space Structures for Super-Tall Buildings:      A Study from Structural and Building Systems Integration Perspectives

Abstract

<p>As buildings rise higher, designers face two major issues. Firstly, how to design efficient structures to resist the lateral loads that impact so greatly on tall buildings. Secondly, how to effectively integrate building systems, which often consume large amounts of space in taller buildings and potentially detract from the building aesthetics. Double‐layer space structures have the potential to address these issues due to several beneficial design characteristics. As three‐dimensional structures, double‐layer space structures are rigid and structurally efficient. They can also integrate with other building systems by using the inherent structural cavities to accommodate services components and contribute a particular architectural aesthetic if their regular pattern is exposed. Double‐layer space structures have been used in long‐span structure buildings, but have yet to be applied as vertical structures for super‐tall buildings. Only two projects, proposed by Kahn and Tying, and Swenson, have applied double‐layer space structures as vertical structures in high‐rise buildings. However, they have not yet been executed and no literature has discussed the feasibility of the application of this structural system to supertall buildings. This situation leads to the research question; “Are double‐layer space structures suitable for super‐tall buildings?” To answer this question, a long‐term study with multidisciplinary knowledge, involving surveys of public opinion, and possibly real pilot projects would be required. This research focuses only on structural efficiency and systems integration as the initial step of the study of vertical double‐layer space structures in super‐tall buildings. The main objective of this research is to analyse the efficiency of this structural system, especially compared to other current tall structural systems. The second objective is to investigate to what extent these structures can integrate with other building systems as well as a discussion on advantages and disadvantages of the integration. The significance of this research is to provide initial scientific information for designers about the possibility of using double‐layer space structures as a structural system of super‐tall building. A research methodology including both quantitative and qualitative approaches is employed to measure the structural efficiency of vertical double‐layer space structures and to assess their potential to integrate with other building systems. This research covers structural aspects, building services systems including fire safety and approaches to energy efficiency, architectural integration, and construction. A quantitative approach by structural design and analysis, and comparison of double‐layer space structures with other structural systems is used to analyse structural efficiency. Case studies using the structural models of two 100‐storey double‐layer space structure buildings with different values of slenderness are designed and analysed using the computer software, ETABS. Other currently used structural systems, a bundled‐tube, a braced‐tube and a diagrid, are also designed using the same configuration and their structural analysis findings are compared to those of double‐layer space structures. Services systems, including HVAC, stairs and elevators, are also designed and integrated with the structure. The systems integration aspect of this research in double‐layer space structure buildings is analysed using a qualitative approach in three main steps. The first step is a review of relevant literature covering systems integration and current technologies in tall buildings. Based on this review, systems integration in double‐layer space structure buildings in general and the 100‐storey case study buildings in particular are explored using computer models. As the final step, the advantages and disadvantages of the systems integration in the designed case studies are discussed. These case studies are designed in order to represent current super‐tall buildings and recent technologies in high‐rise buildings. The structural models of 100‐storey buildings are relevant for buildings in the approximate range of 75 to 125 storeys or 300 to 500 metres high; the majority of current super‐tall buildings have been built in that range of heights. Recent technologies that are commonly used in super‐tall buildings, for example Centralised Air Handling and Localised Air Handling for HVAC system, double‐decking and sky lobbies for elevator system, and various façade systems, are adopted in these case studies. The aim is The Suitability of Double‐layer Space Structures for Super‐tall Buildings to investigate if double‐layer space structures can accommodate building components of current technologies. The results of this research show that double‐layer space structures are efficient where applied in super‐tall buildings when compared to other existing structural systems. Doublelayer space structures can also integrate with services components. The case study design shows how larger usable floor areas than those in typical tall buildings can be provided by positioning the majority of services and structural components within the space structure on the perimeter of the building. In terms of fire safety, positioning fire safety and egress systems in two different locations far apart, as proposed in this research, increases their reliability. Double‐layer space structures are highly redundant structures that enable loads to be transferred through other structural members if several structural members collapse. This advantage minimises the possibility of progressive collapse. The ability of double‐layer space structures to visually and physically integrate with architectural components and aspects like façade, interior space and building geometry in various ways is also explored. In terms of construction, simple connections and construction methods can be applied to double‐layer space structures leading to competitive construction costs. The research concludes by discussing the advantages and disadvantages of double‐layer space structures for super‐tall buildings and concludes that double‐layer space structures are indeed suitable for this application within the scope of this research. However, the study also recommends future research to address issues that are not covered in this research.</p>