Shaken but overlooked: efficiency, economy and elegance in earthquake-prone areas

Are structures outside of the Euro-American canon being overlooked when we discuss structural art? In an essay that was selected as one of three finalist submissions for the 2018 SOM Structural Engineering Travel Fellowship, Tim Michiels argues through examples from Japan and Mexico, that extraordinary structures built in earthquake-prone areas do not always receive the attention they deserve. 1. Celebrated structural art is underrepresented in … Continue reading Shaken but overlooked: efficiency, economy and elegance in earthquake-prone areas

What is the value of critique in structural design?

Practicing chefs in the kitchen can revise and refine a recipe to their own satisfaction, yet their progress need not be limited by their own opinion. What might result from allowing a fellow chef or a mentor to taste their recipe? Each taster might give his/her own personal feedback – too salty, not crisp enough – and the aspiring chef, filtering through the responses, may … Continue reading What is the value of critique in structural design?

Assessing the Stability of Masonry Structures (part 2): Numerical and Physical Modeling

QUICK UPDATE:  Demi just had her paper published ‘Assessing the Stability of Unreinforced Masonry Arches and Vaults: A Comparison of Analytical and Numerical Strategies’, in the Journal of Architectural Heritage.  You can find it here

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This post is second in a series covering different assessment methods for stability of masonry structures. Part 1 covered classical and equilibrium methods; this post covers suitable numerical modeling techniques as well as different examples of physical modeling for masonry stability.

4. Numerical modeling

Several methods of numerical modeling for masonry structures exist, as demonstrated by the flowchart in Fig. 10.

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Figure 10: Overview of numerical modeling methods for masonry structures, adapted from [41] with [8]
As the first level of Fig. 10 suggests, numerical modeling of masonry structures can be divided into four main categories: macro-modeling, homogenized modeling, simplified micro-modeling, and detailed micro-modeling. Asteris et al. [41] provide discussions, summarized below with some additions where noted, on the differences between these modeling approaches. Fig. 11 also depicts the different numerical modeling approaches. In this section, macro-modeling and simplified micro-modeling are the focus.

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Figure 11: Illustration of different strategies for modeling true masonry sample (a): (b) one-phase macro-modeling, (c) two-phase micro-modeling, and (d) three-phase micro-modeling [41]

4.1 Macro-modeling: masonry as a one-phase material

The macro-modeling approach models both bricks and mortar (or all bricks, in the case of dry masonry) as a homogeneous continuum as in Fig. 11(b). As the subsets under macro-modeling in Fig. 10 suggest, these numerical models are typically finite element models.

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Our ultimate top 20 book list for 2016

As the holidays are approaching and as your loved ones – yet again – run out of inspiration for your holiday gift… the Form Finding Lab comes to the rescue. We present you a list of our favorite books on engineering, architecture and anything in between. Happy holidays, The Form Finding Lab. Compiled by Tim Michiels, with contributions of Sigrid Adriaenssens, Victor Charpentier, Demi Fang, … Continue reading Our ultimate top 20 book list for 2016

What I am thinking: Structural designer Jane Wernick

Jane Wernick is a British Engineer who has distinguished herself in the field of structural engineering. She has taught at Harvard University and has been the Chair of the Diversity Task Force of the Construction Industry Council, in addition to managing Ove Arup and Partner’s Los Angeles office from 1986 to 1988. In 1998 she founded Jane Werwick Associates Ltd., a superb engineering design consultancy which has worked on countless projects across the United States and Europe. I talked to Jane at the occasion of the Structured Lineages: Learning from Japanese Structural Design event, held earlier this year at MOMA. 

Sigrid Adriaenssens: You have worked with world-renowned architects, what is the value for you of working in a design team versus solo engineering?

Jane Wernick: I have only ever worked as part of a team. I very much enjoy the process of trying to work out and understand the aspirations of the client, architect and other consultants, and then trying to find structural solutions that support or even enhance those aspirations.

What objectives do you set for yourself when designing a structure? How would a trained audience recognize a structure designed by you?

I am keen to propose solutions that give delight, that are buildable and that give good value. As well as designing structures that are strong enough, stiff enough, durable etc. it is also important that, as engineers we appreciate what the structural elements will look like. For example, I think that a circular hollow section is likely to look much larger and heavier than a fabricated section with sharp corners. The triangular cross section is one of my favourites. This is what we used for the pylons of the Xstrata Treetop Walkway at Kew Gardens. Because we used weathering steel (because it didn’t need to be painted with an ‘un-natural’ colour) we couldn’t use rolled sections. And a tapered triangular cross-section was the most efficient we could use. It also looked more slender than the equivalent circular section would have appeared.

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South Elevation Xstrata Treetop Walkway showing the pylons
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Close-up Xstrata Treetop Walkway (Image credit LondonTown.com)

You once said “structural analysis is not a precise science, but difficult statistically; it is chaotic, and it is part craft” in the context of your work with the Fiat Team. This statement might seem upsetting to engineering students. Could you elaborate on this?

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Learning from Japanese Structural Design: Reflections on the Symposium

MoMA’s exhibit on Japanese architecture (through July 31, 2016) examines the “constellation” of influence in the country’s early-21st-century architecture and design community, but perhaps not so explicit in the exhibit are 1) the structural engineers’ parallel relationships of influence and 2) the structural engineer’s role in collaborating with architects to produce these works. In an effort to explore these characteristics of structural engineering influence in Japan, Prof. Guy Nordenson (of Princeton University and Guy Nordenson and Associates) and Prof. John Ochsendorf (of MIT) organized a symposium, titled “Structured Lineages: Learning from Japanese Structural Design,” which brought together some of the top structural designers from both Europe and the US for discussion.

Most of the lectures presented by the guests focused on the works and experiences of specific Japanese structural designers and educators such as Yoshikatsu Tsuboi, Mamoru Kawaguchi, Masao Saitoh, Gengo Matsui, Toshihiko Kimura, and Mutsuro Sasaki. Each half of the symposium brought the speakers together for a vibrant panel discussion moderated by our Prof. Sigrid Adriaenssens and MIT’s Prof. Caitlin Mueller. The final panel discussion welcomed Prof. Sasaki himself to the mix.

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First panel discussion moderated by Prof. Adriaenssens. Left to right: Seng Kuan, Marc Mimram, Sigrid Adriaenssens, Mike Schlaich, Laurent Ney.
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Second panel discussion moderated by Prof. Mueller. Left to right: Guy Nordenson, Chikara Inamura (acting as Prof. Sasaki’s interpreter), Mutsuro Sasaki, Caitlin Mueller, Jane Wernick, Bill Baker.

Several fruitful discussions and themes arose from the independently-constructed lectures. Reflecting the literal implications of “lineages,” Prof. Seng Kuan referenced the traditional lineage model in which Japanese arts and crafts get passed down for seven or more generations. As Prof. Ochsendorf demonstrated in his lecture with the help of Chikara Inamura, such a “lineage” is visible in 19th-20th century Japanese structural engineering:

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What I am Thinking: Thorsten Helbig on Curiosity and Collaboration in Engineering

Despite my arriving twenty minutes early to Knippers Helbig’s office in New York’s financial district on a brisk Friday afternoon, I am warmly welcomed at the door by an engineer whose work I probably just interrupted. As he goes to summon a man around the corner, I peek at the office space: not enormous, but still spacious and pleasant, giving no sign of being too small for the number of engineers at work. Thorsten Helbig, principal of the Germany-based engineering firm Knippers Helbig (KH), emerges immediately, equally warm and welcoming as he ushers me into the office’s conference room. The room opens up on two sides to the office space, and Helbig goes to shut both doors; despite the auditory privacy, the work carried out in this room is always transparent: one wall of the conference is a glass window, allowing any passersby to glimpse at our meeting through the satisfyingly enormous letters “KH” staining the glass orange.

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The Knippers Helbig office space at 75 Broad St, New York. © Knippers Helbig

It is perhaps no coincidence that the office space articulates such clear architectural considerations. Helbig’s approach towards meshing engineering expertise with architects immediately becomes our first and most fruitful point of discussion. “In a relationship between engineer and architect, I think what is most important is that there is mutual respect and a communication,” Helbig asserts. “Ideally, the communication starts very early in the design process.” In many projects, he explains, Knippers Helbig is involved from the very beginning—ideally, at the competition stage—to the final completion and execution of the project. From the start, every decision made by the architects in organizing the program leads to consequences that require the engineers’ input regarding limitations such as soil conditions, column spacing, and slab systems. Inevitably, the engineers put forth decisions and recommendations that influence the project’s appearance, but Helbig underlines that “we as engineers should not try to be architects, but rather maintain an engineering perspective.” Projects can benefit so much more from an engineer’s engineering contribution, Helbig points out. “At the same time,” Helbig qualifies, “I expect that everybody at the table has a qualified opinion. As an engineer, we can question some of the architect’s decisions, which can—in the best case—make the architecture even better.” Helbig says that while there exists the notion of signature architects, he doesn’t believe in “signature engineering.” We can look at some buildings and often guess at the architect, but Helbig doesn’t find it “right” to be able to do the same with the engineers of building structures, even if the engineers’ contribution can be clearly read in many building types. “As an engineer, I want to be able to support architecture. We start with the same open-minded approach in every collaboration, but it consequently leads to different results when we work with Massimiliano Fuksas, Renzo Piano or Liz Diller because their individual architectural approaches require individual engineering solutions. I see us as collaborators in exploring the inherent potential of the architectural intention – and sometimes innovatively engineered parts act as catalysts for specific architectural expressions.”

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