SW News

A Neglected Bridge in Paris

We don't think of Paris as a place where one of the most beautiful bridges could be neglected. Providence maybe, not Paris, after all we are in the "where charm meets neglect" state and proud of it (see Milkcan Industries for terrific T shirt). It is a bridge I have been meaning to see, so I dragged my family from the charm of central Paris to the neglected east side - part of the Seine that doesn't get visited (tour boats turn around several miles prior to this bridge - so you need a couple subway rides and a long walk in the rain).

It is always raining at this bridge too.

This 8" x 36" Steel Bar splice (each side) with 386 weld passes is a thing of beauty - it is the catenary that carries the entire span… ignore the graffiti and mold.

Yes you have to walk up and down, nothing is flat, but when you find out is the shape of a moment diagram, who wouldn't want to! 

And you get to choose too!   Positive or negative!

At the moment diagram inflection point, remember, do not bother the homeless man in this tent! He is not nice!  And do not move the swivel chair, it is his!!!

Just get to other side as quick as you can, carry pepper spray, than sit back and then admire this

It is really a special bridge, an engineering marvel, a lightweight/efficient and stunning structural solution (a long-span lenticular - mirrored catenaries -  on rotational supports).  Still ranks in my top ten pedestrian bridges in the world.  When I think of the other 9 I will let you know.

 Passerelle Simone de Beauvoir – Mitterrand Library to Bercy https://feichtingerarchitects.com/les-projets/045_simone-de-beauvoir/

Shout Out to Our Steel Fabricators in New England

We are very proud to design steel connections (on too numerous of projects to name) and we sometimes forget to thank the best clients we can have! All those amazing steel fabricators and erectors out there.. Thank you!!!

We don’t just design standard stuff but love the complex connections, here are just a few connection we designed on a recent job… lots of love goes into these details and it is the fabricators/erectors that do the hard part of building them all.

And yes this is just a tiny sample of one single project (14 out of 18,143 connections we helped design on that one single project).

First Hemp Lime House in the US

The team (Estes Twombly + Titrington Architects) used a hemp lime system developed in France for thermal mass. Hempcrete or hemplime is biocomposite mixture of hemp hurds (shives, lime, sand) and according to the owner…

“this is the first cedar shingled hemplime house on the planet with some other notable innovations including a convertible closed-to-open deep foundation; a hybrid air-based / hydronic heating and cooling system; a geothermal system; a photovoltaic power generation system; and locally sourced materials with lower embodied carbon just to name a few.”

And there is no sheathing! No plywood so we developed wood braced frames. We also designed the foundation for wave loads (Cape Cod oceanfront) in the next 100 years with CMU walls that can be removed prior to a storm (or breakaway freely during the storm without damaging the house) which makes it capable of converting from a closed foundation into an open one, predicting a future FEMA code 50+ years from now.

This innovative project adds to our growing list including …

  • 2020 We designed this first hemp lime house in MA with the first convertible foundation on the planet

  • 2017 We designed the 4th Certified Living Building building in MA (the most rigorous building standard in the world, makes this the 23rd certified Living Building in the world)

  • 2015 We designed the first Passive House in RI

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Our FEM Models vs Reality

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David Krakauer of the Santa Fe Institute describes the m^cubed phenomenon or m^cubed mayham as confusions that arise in people minds between mathematics, mathematical models, and metaphors.  I would simplify this and call it m^squared and lump mathematics and mathematical models together as models.  In the past, I have described the FEM models we use in engineering practice differ from the real world and highlight how our models should never be assumed to mimic reality, but are simply tools for us to exercise our engineering (or moral) judgement (in my case, to design safe structures).  We should never mix up the model for what is actually happening in the real world.   This is analogous to Krakaur’s models and metaphors. 

Krakauer says in Harris’s book Making Sense

“you can talk about spring and levers and these are physical artifacts…and then there are mathematical models of spring and levers” and “there is this tendency to be epistemologically narcissistic.  We tend to take whatever current model we’re using and project that onto the natural world as the best-fitting template for how the natural world operates…for many reasons the model is imperfect, computers are not robust”.  

It is not that computers are not robust, they can be robust, it is that they don’t need to be – we humans need to be robust. We need to better understand computer models (and output) and not be subjects to its authority.   This is a actually a question of dominion – we need never forget that we rule over it. Also, to Krakaur’s point, we need recognize when we are being epistemologically narcissistic - it happens all the time and it is really lazy thinking.  This will make us better engineers.  We need to constantly question our models. Again models serve us, not the other way around.

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New Providence Library Ready to Open!

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Projo Article on our new library posted today! We designed new hung floors within, ultra thin, and long span stairs through very large new floor openings (we removed) in the existing art deco 1950s addition downtown (pan joists with concrete encased steel). Arch: DesignLab, Builder: Bond, Steel Fab/Erector: Capco. Picture from Projo links to article.

Stainless Steel Pipes and Fabric on “Pressure Springs”

We designed the cantilevered steel support structure for a future tensile fabric membrane at the Garrahy Parking Garage in Providence. Capco Erection is currently installing the stainless steel pipes for a future tensile fabric covering.

Glass Elevator Wins Silver Prism Award

We were structural engineers for the glass elevator and worked for Oasis to design this award winning elevator. Our team won the Silver Prism Award last week. Project located in Boston at Union Wharf and check out Oasis for more info…https://oasisspecialtyglass.com/oasis-glass-elevator_wins_2019_prism-award/

Here is our Revit model with some images…

We designed the glass, glass connections, steel and steel connections as well as wood and wood connections. Fun and challenging project!

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Erik to Present at “Steel School”

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Steel School: Practical Wisdom from 3 Industry Experts

3.0 SEAMASS-Certified PDHs

On October 9, SEAMass is hosting Steel School, an informative three-part seminar that will cover several aspects of designing with and working with steel.

Braced Frames, Moment Frames and Cantilevers
Presenter: Erik Nelson | Structures Workshop

• Lateral systems, axial thru forces, collector forces with amplification, and R factors
• Simple design advice on when axial forces are too high for beam web connections and when moment designation should be used
• Load paths on axial thru forces and moments on stiffener welds within the column web.
• Stiffeners and doubler plates within moment frames, a discussion
• Larges difference in connection review and design of cantilevers vs lateral moment connections– what to look out for

Walking Tour of Providence Hosted by Erik / SEARI

Tuesday May 21st, 2019 4:30-6:00

Come take a walking tour with us and learn about the development of the street and buildings on Westminster to learn about historic and modern building systems in this city. Erik of Structures Workshop will introduce the evolution of Providence’s streetscape, from late 19th century 5+/- story buildings (ie first building with elevator) to early “skyscrapers” (the first steel building in Providence) to later 20th century modern and post-modern buildings. We will determine which buildings are cast iron, which are concrete encased steel, and which are terra cotta facades We will see Art Deco next to Art Nuevo and discuss ides for the future of the city (Superman Building / Arcade / Etc) and walk by current transformations happening at the Old Projo and Kresge Buildings, as well as changes to Laptham / 270-290 Westminster and the Providence Library and many others. We start just east of the river and work west, first we will witness the early 20th century Federalist style makeover of Victorian Providence prior to touring downtown along Westminster. We will also see the height of the water elevation of historic flood events to remind us of the importance of the hurricane barrier.

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"Ethical Decisions in Engineering Practice" ASCE Conference in Orlando

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I will be presenting a session at this year’s ASCE conference in Orlando within “Ethical Decisions in Engineering Practice: How Will You Choose?”

My contribution is called “Humans, Trees, Ethics” Come join us! This talk will argue that all the main ethical traditions (Utilitarianism, Deontology, Virtue Ethics, etc) should be strengthened by thinking beyond human interests but at the intersections of animals, plants, and the land.

Track: Business and Professional Practices  (11:00 AM – 12:30 PM) Thursday, April 25, 2019

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