Building by Numbers

Digital Process for Analysis and Documentation of Changi Jewel Grid Shell

Overview

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Abstract

This paper outlines the successful implementation of digital workflows between the design team composed of Architect, Structural Engineer and Project Manager for application to the real-world case study of the structural design and engineering of a free-form glass clad grid shell structure. The Jewel Changi airport grid shell in Singapore. The author was a key member of the design engineering team and acted as the specialty structural engineer for design, analysis, digital workflow concept, creation and implementation for the primary steel structure of the roof, ETFE mega cushion, and miscellaneous ETFE areas. The author was employed at a previous company, Buro Happold, for the duration of time that he was engaged on the project. The author wishes to acknowledge that he was part of a team at Buro Happold that included Crisotbal Correera, Gustav Fagerstrom and Liam Mcnamara. Key members without who this project would not have been realized.

The digital practice presented here is applied to provide multiple design and engineering alternatives for the architect/engineer where form and geometry is changed and optimized through multiple iterations before the pe construction phase to arrive at a “well-understood” end solution for bidding. A process of “optioneering”. This end design solution forms the construction documentation deliverable that is then put out to bid to appropriately qualified primary structural and facade fabrication and installation contractors. The author was only involved in the design/engineering and documentation of the Construction Document process, it does not refer to the fabrication or actual construction process. The paper is focused on the design and engineering process, not particulars of the project challenges globally with respect to coordination with other disciplines for instance.

The paper focuses on the analysis and design information storage and retrieval, visualization of graphical to textual data linking, interoperability, visual communication and data exchange. An overview of key bottle necks needing to be overcome and key design issues that need to be addressed using the collaborative workflow are presented. Suggested future best practice guidelines are given. This paper will illustrate the design, development and fabrication processes involved in the realization of this now built structure at Changi (Figure 1)

Singapore Changi Airport Grid Shell

Introduction

The authors (henceforth “The engineer”) were contracted as the consultant specialty structural engineer by a renowned international architectural practice for a project classed as a complex structure, composed of a

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Structural Narrative

Composition

The shell is primarily composed of custom built up tapered sections. These are defined as bias (diagonal) and hoop (horizontal) members. A typical unit is described as (Figure 2) below

Typical

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Process

Workflow and Environment

As in any architect-engineer collaboration, not the least where the structure and/or geometry is of a complex nature, there is a variety of factors influencing the evolution of

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Design Surface

Specialty complex structures cannot be defined graphically through the use of rigid rectilinear coordinate systems of grids and elevations. Instead we use the concept of a design surface. The design

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Data Visualization

Post-processing "Hot Spots" and "Onion Strata"

The optimization initially considered a preset database of a 1000 custom cross sections that were generated in the analysis program SAP 2000 – using the

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Conclusion

The engineering analysis, optimization and rationalization of complex structures require a carefully planned approach to the evaluation, exchange of information and documentation. This is in equal measure a task of

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Acknowledgements

The author wishes to acknowledge the work presented here was completed at the time of employment with Buro Happold, Los Angeles. The author is greatly indebted to the company for allowing me to work on this project. The author would like to also acknowledge the major contribution from Gustav Fagerstrom with the content presented here. Other key team members were Liam McNamara and Crisotbal Correa, principal in charge of the project. The project shown here is the Singapore Changi airport grid shell by Moshie Safdie architects.