Execution Ways

Peeling back Layers from Geometrical and Structural Complexities in Facades

Overview

Authors

Photo of Viswanath Urala, P.E.

Viswanath Urala, P.E.

Senior Engineer

Enclos

vurala@enclos.com

Photo of Prakash R. Desai, P.E., S.E.

Prakash R. Desai, P.E., S.E.

Senior Structural Engineer

Enclos

ddesai@enclos.com


Keywords


Abstract

Business Insider has described San Francisco’s Chase Arena as setting “a new standard for a sports arena in the US”, and “the state-of-the-art arena includes the largest scoreboard in the NBA, an outdoor plaza, retail spaces, and luxurious suites that cost upward of $1.5 million.” Even the geometry of the exterior envelope is complex, requiring collaborative optioneering by the architects and design engineers over several years of coordination to establish an optimal geometry well suited for an accelerated construction timeline. Unlike most conventional facades, the design of the envelope of this arena utilizes few simple geometric rules. Instead, it is derived from intersections of compound curve ribbons of metal and glass intersected by non-orthogonal cutting planes forming the basis of the design intent, producing unique façade panels intentionally. This paper is a narrative of the design lifecycle about how communication and collaboration are the keys by setting reasonable expectations than reliance on technology when it comes to executing a project that has an aggressive construction schedule.

After competitive bidding, having delegated the task to the facade contractor for delivering a façade of this complexity with no flexibility in schedule meant that the design and engineering team at Enclos Corporation was tasked with looking beyond current construction practices to complete the arena envelope. In an extensive collaboration, Enclos introduced simplified construction means and methods into the project by engaging with the right stakeholders in a design-assist dialogue to understand the most important aspects of the original design intent to achieve the common goal with a positive spirit. Enclos' optimization of the panel geometries and subdivisions relied upon constant input from a vast collection of specialists with understanding the geometry, engineering, material procurement, site mobility, erection, and installation. Cladding for the Chase Arena also had to be coordinated with the cladding of adjoining Chase Towers also by Enclos. It involved experts from eight different departments within Enclos to execute this project before the opening in September of 2019 which is the new home for Golden State Warriors team of the National Basketball Association.

Introduction

With the advent of parametric tools, the Architecture Engineering Construction (AEC) community is seeing more complex designs that are data-driven and use complex mathematical formulations, most of which are digitally

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Form & Function

Optioneering is not an easy task as it requires a shorter feedback loop between the façade consultant and the design architect and often the architectural form has to blend with

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Functionless Form

During the bid phase, the proposed structural system included hanger rods, which may have been intended to stabilize the horizontal transoms while supporting the dead weight of the façade. However

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Design Assist

The design-assist phase is where all the critical and major challenges need to be identified including critical path items. For the Chase Arena, the transition between the design-assist to project

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Parametric Tools

The following coordination models were developed by Enclos’ designers using Rhinoceros 3D and Grasshopper:

The building envelope’s design surface was developed based on the rules given by the consultants.The different Grasshopper

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Projection Execution

About six months were spent for the design-assist, with emphasis on providing information for project execution. One can only work on such a critical path when rules of engagement are

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Field Fixes

Since the Level Of Detail on the primary steel structure was still under development, which did not include the exact location of primary structural connections, splice joints, stiffener plates, bolts

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Summary

The following summary is based on not just Chase Arena, but an experienced perspective derived after having worked on several different projects of similar size and complexity. The only takeaway

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Conclusion

Even with a fast-paced project schedule, combined with geometrically complex interfaces between structure and skin, and tight site constraints, the overall effort of the field crews was excellent. As with

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Acknowledgements

The authors thank Dennis Chow, Dr. Jeff Vaglio, Heather De Felicis, Matt Stopka for their time in reviewing this paper and providing relevant feedback. The authors also acknowledge and dedicate the success of this project during its construction lifecycle to Enclos design team, production engineers and operations crew, and extend the same gratitude to external stakeholders not limited to the architects, engineers, sub-contractors from Manica Architecture, Kendall-Heaton Associates, Magnusson Klemencic Associates, Walter P Moore, TrussWorks International, Aluminum Curtainwall Systems, MG Mcgrath Inc, and Botner Manufacturing. Special thanks to Dr. Douglas Noble, Karen Kansek, and the staff at Facade Tectonics and the anonymous reviewers who helped in several ways to bring this together.

Rights and Permissions

  1. Scott Davis, Business Insider, March 28th report - https://www.businessinsider.com/chase-center-tour-warriors-new-arena-san-francisco-2019-3.
  2. Gustav Fagerström et al., Façade Tectonics 2018 World Congress Proceedings, Vol 2.
  3. AISC 310-16, Section 10, Architecturally Exposed Structural Steel.
  4. Terri Meyer Boake, 2012, CISC Guide for Specifying Architecturally Exposed Structural Steel.
  5. Weisstein, Eric W. "Ruled Surface." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/RuledSurface.html.
  6. AIA E203-2013, Building Information Modeling and Digital Data Exhibit.