Critique of Milstein Hall: Nonstructural failure

Jonathan Ochshorn

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Nonstructural failure contents: 1. introduction | 2. water and thermal control | 3. sloppy or dysfunctional details | 4. dangerous details | 5. maintenance issues | 6. cracks

1. Introduction

Figure 1. Building It Twice: Video (5 minutes long) by J. Ochshorn shows numerous examples of Milstein Hall building elements that were built twice — that is, built, demolished, and rebuilt — an outcome that is more likely with a peculiar or complex building (video clips shot between 2009 - 2013; can also be viewed directly on YouTube).

I have written previously about nonstructural building failure. Designing Building Failures, written in 2006, examines the "relationship between building envelope failure and attitudes towards design," with a concluding section that "examines the implications for pedagogy and practice." A Probabilistic Approach to Nonstructural Failure, written in 2013, takes a closer look at one of the conclusions suggested in the first paper: that only a risk-based approach to the design of nonstructural building elements — analogous to limit-state design methods in structural engineering — can create conditions in which building design becomes rational and nonstructural failure is thereby reduced. Both of these papers should be reviewed to better understand the context within which Milstein Hall's nonstructural failures are discussed.1

Preliminary conclusions about nonstructural risk. In the second of the two papers cited above, I outline two characteristics of buildings that can increase or reduce the risk of nonstructural failure: a greater degree of peculiarity or complexity can increase the risk (Figure 1), while certain types of redundancy reduce the risk.

Whereas the probability of structural failure (i.e., the actual collapse of buildings or structural components like beams or columns) is made explicit within the design methods enforced by building codes and, in fact, forms the very basis of structural design, the design of nonstructural parts of buildings has no underlying probabilistic basis. That is, when architects create drawings and specifications for buildings, they have no basis for determining the probability of nonstructural failure. Where a clear pattern of architectural failure emerges, building codes may or may not be modified, depending on the severity of the problem. Even in those cases, however, the recommended "fixes" do not approach the problem from an explicitly probabilistic standpoint, so that it is still not possible to assess the reliability of one system in comparison with another, or to assume that an equivalent level of risk resides in all systems sanctioned by the codes.

A probabilistic basis for architectural failure is acknowledged neither in theory nor in practice; systematic research in this area does not exist. Nevertheless, it is still possible to draw some important conclusions about the nature of such failure, and point towards future areas of research.

Peculiarity. The most important conclusion derives from the fact that, for unusual architectural designs, the interaction of materials, systems, geometries, environmental conditions, installation methods, and so on, is rarely systematically tested or theoretically grasped. Conventional construction details and methods, on the other hand, have at least a track record of generally successful (or unsuccessful) application. While the lack of a consistent measure of reliability applies to such conventional systems as well, there is at least an informal understanding of how such systems perform over time. For this reason alone, one can state that architectural failure will generally increase as the peculiarity of the architecture (i.e., the deviation of the design from well-established norms) increases.

This conclusion requires a disclaimer: it presupposes an ordinary level of attention given to all aspects of building design and construction. In other words, it is assumed that little or no original research (i.e., research following protocols such as those sanctioned by ASTM) is undertaken to establish the behavior of unusual design elements or their interactions; and that little or no additional time is spent in order to properly identify and document all special building conditions resulting from unusual geometries or materials. Of course, if one has the budget, the time, and the expertise, it is certainly possible to reduce the probability of failure when designing unusual or complex buildings. However, doing so requires not only a commitment to research, but also sufficient time and money to conduct the research, produce the necessarily complex and complete construction documents consistent with the research results, and hire contractors willing and able to carry out such a project. An example of such an attempt can be seen in the glass enclosure system developed for La Cité des Sciences et de l'Industrie in Paris by Peter Rice and others (Figure 2).2

Rice and Dutton: Structural Glass book cover and La Cité des Sciences et de l'Industrie

Figure 2. La Cité des Sciences et de l'Industrie (left) and the book by Rice and Dutton describing the thorough and intense research process underlying the "peculiar" technology of the "structural glass."

Clearly, the parameter "peculiarity" has not been rigorously defined, but it is worth noting the following characteristics of peculiarity in architectural construction:

  1. Within a given length, area, or volume, the number of building elements is unusually large, or unusually small; what constitutes an unusual density of such elements is simply a comparison to what is usual. In general, increasing the number of building elements increases the probability of failure since it is typically at the intersection or interface of such elements that failure occurs (and increasing the number of elements increases the quantity of such intersections).

    However, there are instances where reducing the number of elements actually increases the probability of failure. For example, a smaller number of uninsulated facade panels means that thermal movement of the panels, relative to an insulated structural frame, is concentrated over fewer joints, so that joint movement is greater. Greater joint movement can increase the likelihood of certain types of sealant failure, for example.

  2. The number of different types of building elements is unusually large.

  3. Well-understood details are distorted/twisted/altered — or else simply invented without reference to any precedent — to accommodate unusual geometries, or to subvert conventional formal expectations. In particular, the right angle is eschewed in favor of bent, curved, or otherwise non-orthogonal geometries, and conventional expectations about "walls" and "roofs" are discarded in favor of more abstract characterizations.

  4. Materials are used in combinations, or in applications, that have not been well tested.

As a result of this peculiarity, the following outcomes become more likely:

  1. Structural movement in buildings with "peculiar" geometries is less well understood and less well modeled and predicted. Complex structural geometries make it more difficult to i) coordinate the interaction of structural movement and cladding, etc. ii) model the structure accurately — even if a geometrically "simple" building is modeled inaccurately, the simplicity and uniformity of the model suggests that errors will at least correspond to behavioral tendencies of the actual structure, even if numerically out of scale.

  2. Junctions (intersections) of materials or systems deviate from well-established norms.

  3. Architectural drawings and specifications are less likely to address the full range of conditions present within the building, especially in their three-dimensional manifestations.

  4. Contractors are more likely to apply conventional knowledge to unconventional situations. Ironically, in the case of so-called green buildings where more environmentally-benign, but less well-understood, materials are employed, the opposite situation may occur with the same result: contractors are more likely to apply unconventional knowledge to conventional situations (see item "e").

  5. Untested material combinations are more likely to interact in unpredictable ways.

  6. Basic strategies for enclosure (continuity) are more likely to be violated: membranes become penetrated rather than continuous, or penetrated in ad hoc ways; surface complexities promote discontinuities in thermal/vapor/water/air membranes or materials.

Redundancy. The benefit of redundancy, examined from a probabilistic standpoint, is a relatively unexplored and potentially fruitful area of research. For example, providing two roof membranes instead of one doesn't merely cut the risk of failure in half, but — assuming that the failure of each membrane is independent of failure in the other — rather decreases the risk of failure by an order of magnitude. Of course, it is crucial that any strategy employing redundancy take into account the specific mode of failure: adding an extra (redundant) layer of paint over an improperly prepared substrate confers no particular advantage since the utility of the redundant layer depends on the integrity of the layer below. In other words, the conditional probability of failure of the redundant layer, given failure of the layer below (and therefore failure of the system as a whole), is 1.0, conferring no advantage. At the other extreme, the conditional probability of system failure for the two membranes discussed earlier, each membrane assumed, hypothetically, to have a failure probability of 0.1, is 0.1 × 0.1 = 0.01, a significant improvement.

Conventional practices, such as the provision of roof overhangs (Figure 3), can be reevaluated in this light. For a given exterior wall surface area, if the probability of failure due to water intrusion through an unintended hole in the wall is, say, 0.05, and if the probability that wind-driven rain will reach that wall surface is 0.07 when an overhang is in place (both values entirely hypothetical), then the conditional probability of failure with an overhang is 0.05 × 0.07 = 0.0035, a dramatic reduction in risk compared with the hypothetical failure probability of 0.05 without the overhang.

Wright's Robie House

Figure 3. Frank Lloyd Wright's Robie House: while leaking roofs are not unknown within Wright's oeuvre, the likelihood of leaks through the windows or walls below the roof overhangs is dramatically reduced. (image source)

The failure mode interaction described above — involving a combination of two or more failure modes where the redundant combination actually decreases the probability of failure — can explain the benefits of redundancy from a probabilistic standpoint. Having two barriers instead of one doesn't just double the safety (cut the probability of failure in half), but rather can be shown to be much more significant.

Heroic complacency. Aside from causes originating in the complexity or peculiarity of buildings (or their lack of redundant details), buildings also experience nonstructural failure because of designers' "complacency." I use this term to includes things like sloppy detailing and inattention to functional considerations. Some of this is related to the peculiarity or complexity of their buildings, since such buildings require a great deal more attention to detailing. This means that a great deal more time, money, and expertise needs to be devoted to such detailing, rather than assuming that the complexity will be somehow dealt with "in the field."

However, the reasons for this type of complacency do not all originate in the desire to save money (see Designing Building Failures). In particular, a heroic attitude pervades much high-end architectural production, where heroic is used not only in the metaphorical sense of "surpassing the ordinary (especially in size or scale),"3 but more importantly in the literal, Joseph Campbellesque sense of confronting danger:

"Artists are magical helpers. Evoking symbols and motifs that connect us to our deeper selves, they can help us along the heroic journey of our own lives... The artist is meant to put the objects of this world together in such a way that through them you will experience that light, that radiance which is the light of our consciousness and which all things both hide and, when properly looked upon, reveal. The hero journey is one of the universal patterns through which that radiance shows brightly. What I think is that a good life is one hero journey after another. Over and over again, you are called to the realm of adventure, you are called to new horizons. Each time, there is the same problem: do I dare? And then if you do dare, the dangers are there, and the help also, and the fulfillment or the fiasco. There's always the possibility of a fiasco. But there's also the possibility of bliss."4

While it may seem counterintuitive to equate this type of "heroic journey" with complacency, an inattention to function and detail is — precisely — what this version of heroism entails. The architect (qua artist) is not so much "help[ing] us along the heroic journey of our own lives" but rather creating, out of thin air, a heroic journey for herself: leaving the world of safe, predictable constructions; proposing buildings that have both the appearance and the reality of danger (where danger comes from challenging the conventional; challenging conventional notions of aesthetic, and sometimes literal, comfort; challenging class-based conventions regarding economy of means; and especially, challenging forces of nature such as gravity, or rain, or snow); and returning in glory from this confrontation with the agents of conformity (whether owners, users, public officials) with the building constructed (or not: sometimes the act of not building is even more heroic — see Leon Krier's Drawings 1967-1980, or Harris Stone's Workbook of an Unsuccessful Architect).5 For such a hero, having built such a brave thing with all the attendant risks of failure is a badge of honor:

"'There's not an architect I know that doesn't have problems with important buildings,' Mr. Eisenman said in a recent interview in his New York office. He cited a comment that Frank Lloyd Wright is said to have made when a client called to complain that a house was leaking: You mean you left my building out in the rain? 'Do you know any architect that's been free of that? I don't know any,' Mr. Eisenman said. 'Frank, Rem — they all do,' he said, referring to Frank Gehry and Rem Koolhaas. 'Wright, Corbu, Mies. Look at Mies and the Farnsworth House — enormous problems'"6 (Figure 4).

Frank O. Gehry, referring to suit brought by M.I.T. over leaks, cracks and drainage problems at the Stata Center, said: "These things are complicated and they involved a lot of people, and you never quite know where they went wrong. A building goes together with seven billion pieces of connective tissue. The chances of it getting done ever without something colliding or some misstep are small."7

The heroic attitude was articulated brilliantly by Piet Mondrian in 1925: "If one takes technique, utilitarian requirements, etc., as the point of departure, there is a risk of losing every chance of success, for intuition is then troubled by intelligence."8

4 musketeers parady image-Wright,Gehry,Eisenman,Koolhaas

Figure 4. Four of the many heroic architectural "musketeers" (from left to right): Frank Lloyd Wright, Frank O. Gehry, Peter Eisenman, and Rem Koolhaas (collage by J. Ochshorn).

A performance-based strategy provides more opportunity to indulge in the heroic freedom of design, since most nonconventional design moves can be made to work with sufficient investment of time and resources. In the end, however, one loses more than a bit of the heroic sheen that emanates from the more reckless designer. For in this case, rather than confronting both the appearance and the reality of danger, one only confronts the appearance of danger, as the actual risks of failure have been reduced to acceptable (conventional) levels through a thorough and engineering-based methodology. It's like using an artificial cigarette so that one can appear to be smoking.

This discussion of heroic complacency is not meant to imply that architecture must sacrifice its expressive qualities in order to reduce the risk of nonstructural failure. However, it does suggest that an architectural design strategy that starts off with heroic intentions and then attempts to "make it work" by superimposing some rational elements will be more likely to experience nonstructural failure than a design strategy that starts off on a rational basis and then "adds" expressive elements that leave the rational basis intact.9

Nonstructural failure in Milstein Hall. Milstein Hall at Cornell University in Ithaca, NY, USA (designed by OMA and Rem Koolhaas, Figure 4) is a classic example of a peculiar and complex building for which only routine attention was given to nonstructural detailing and performance. Contract documents were produced, and contracts for construction were signed, without having established a clear and comprehensive understanding of critical construction details. Even from casual observation, without having official access to records or correspondence, several instances of this phenomenon can be seen.

Milstein Hall at Cornell, OMA, Koolhaas

Figure 4. View of Milstein Hall connected to Sibley Hall (to the left) and Rand Hall (to the right), Photo by J. Ochshorn, July 2012.

While only recently occupied (beginning in Fall 2011), Milstein Hall has already (by this writing in 2013) experienced numerous forms of nonstructural failure, including rain water infiltration through building enclosure elements, extensive cracking of concrete slabs, blotching of concrete wall finishes due apparently to VOC-compliant form-release agents, staining of concrete floor finishes apparently due to premature contact with plywood protection boards, and cracked exterior lighting fixtures. Given the secrecy surrounding the actual construction process — the ongoing crises, panicky phone calls, hastily-called meetings, negotiated remedies, and change orders that invariably accompany such complex projects are not made public — it is undoubtedly accurate to suggest that those defects and failures immediately visible in Milstein Hall represent only a small fraction of actual nonstructural failure incidents.

Yet is it fair to classify Milstein Hall as a "peculiar" building? Unlike building designs that obviously deviate from traditional constructional geometric norms (e.g., those manifesting things like "splines, nurbs, and subdivs"),10 Milstein Hall is, at least in part, designed with a regular orthogonal grid of columns, rigid frames, girders, and beams, and is clad with an expensive, but otherwise conventional, glass and stone veneer curtain wall. It is true that the lower level geometry is far more complex, consisting of a reinforced concrete doubly-curved "dome." However, even the "conventional" orthogonal steel framework is itself highly unusual (peculiar) in terms of its large cantilevers, rigid-frame "trusses," and moment-connections for lateral-force resistance. As a result of both the peculiarity of the design and the lack of adequate attention given to its detailing, numerous sites of actual or potential nonstructural (or even structural) failure can be identified. These are described in the sections that follow.

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Nonstructural failure contents: 1. introduction | 2. water and thermal control | 3. sloppy or dysfunctional details | 4. dangerous details | 5. maintenance issues | 6. cracks

Notes

1 See Jonathan Ochshorn, "Designing Building Failures," Proceedings of the 2006 Building Technology Educators' Symposium, University of Maryland, College Park, August, 2006. Some of the background material used here on nonstructural failure is taken directly from the second paper: J. Ochshorn, "A Probabilistic Approach to Nonstructural Failure, Proceedings of the 2013 Architectural Engineering Conference, State College, Pennsylvania, April 3-5, 2013 (Edited by Chimay J. Anumba and Ail M. Memari, American Society of Civil Engineers — ASCE).

2 Peter Rice and Hugh Dutton (1995) Structural Glass, E & FN Spon, London, New York.

3 dictionary.net, accessed 6/9/10.

4 Joseph Campbell, Pathways to Bliss: Mythology and Personal Transformation, Edited by David Kudler. Novato, California: New World Library, 2004, pp. 132, 133 (accessed 6/9/10 at Wikipedia)

5 Krier writes: "I can only make Architecture, because/ I do not build./ I do not build, / because I am an Architect." Léon Krier, Drawings, 1967-1980, Bruxelles: Archives d'Architecture Moderne, 1980, p. vii. Harris Stone never reaches the ideologically extreme position of Krier, but still complains about the state of the profession in heroic terms: "...the creative energy of the architect is squandered and misdirected; in fact, the very concept of creative work has nothing to do with the requirements of being a successful architect." Harris Stone, Workbook on an Unsuccessful Architect, New York: Monthly Review Press, 1973, p. 174.

6 Peter Eisenman quoted in Robin Pogrebin, "ARCHITECTURE; Extreme Makeover: Museum Edition," New York Times, September 18, 2005, accessed 6/9/10.

7 Robin Pogrebin and Katie Zezima, "M.I.T. Sues Frank Gehry, Citing Flaws in Center He Designed," New York Times, November 7, 2007, accessed 6/9/10.

8 L'Architecture Vivante (Autumn, 1925), p.11; referenced in Collins, Peter. Concrete: The Vision of a New Architecture, 2nd edition. Montreal: McGill-Queen's University Press, 2004, p.281.

9 I discuss the false symmetry between expression and rationality in Designing Building Failures, op. cit. A discussion of nonstructural failure in buildings designed by Santiago Calatrava can be found in: Suzanne Daley, "A Star Architect Leaves Some Clients Fuming," NY Times, September 24, 2013 (accessed at NY Times Dec. 12, 2013); and at Raphael Minder, "Spanish Opera House to Lose Crumbling Facade by Star Architect," January 12, 2014 (accessed at NY Times Jan. 14, 2014.

10 Patrik Schumacher, "The Parametricist Epoch: Let the Style Wars Begin," The Architects' Journal, Number 16, Volume 231, 06. May 2010: "Instead of the classical and modern reliance on ideal (hermetic, rigid) geometrical figures — straight lines, rectangles, as well as cubes, cylinders, pyramids, and (semi-)spheres — the new primitives of parametricism are animate (dynamic, adaptive, interactive) geometrical entities — splines, nurbs, and subdivs — as fundamental geometrical building blocks for dynamical systems like 'hair', 'cloth', "blobs', and 'metaballs' etc. that react to 'attractors' and that can be made to resonate with each other via scripts." Online here (accessed 14 Dec. 2011).