Living Building Challenge and Passive House Projects

Structures Workshop just completed the structural design of the Hitchcock Center in Amherst, MA meeting the Living Building Challenge.   The project (DesignLab Architects) is aiming to be net zero energy, water independent, using all non-toxic materials (all locally sourced wood construction - black spruce gluelam beams, spruce decking, exterior northern cedar frames, eastern white pine, etc).  This is one of just a few LBC projects on the East Coast.  Below is our Revit model  which helped us complete the CDs... hitch

In addition, Structures Workshop (Swansan Builders) was the structural engineer for the first Passive House in Rhode Island.   This will lead to energy consumption reduction of 60-80 percent (we designed double wood walls and roof frames for continuous unbroken insulation).

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We've moved!

Structures Workshop has moved! We purchased a boiler room building in a former knife factory in the Jewelry District of Providence for our new home. This will allow us to grow from 4 to 5 (or 6) as well as provides enough space for a small workshop in the back for testing materials/joints, building stuff, creating steel/wood/glass connections, not sure what. Also, we will finally have our own sink! Come visit us... 18 Imperial Place, Courtyard Building - Providence.

Long Span Stair without Stringers

We designed a long span stair with the appearance of a folded plate.   No stringers!  (picture below courtesy of Diamond Iron, the fabricator and erector) IMG_1698

 

The stairs were actually designed with thin saw tooth vertical plates hidden within the thickness, here is an FEM screen shot...

websiteThe stair was not governed by strength (only about 11ksi) but by live load deflection (1/4") and vibration.  We wanted to keep the vertical frequency above about 8Hz without adding to the steel weight.  This was set to limit affect of exciting the second harmonic when descending stairs quickly.   We did this by trimming down the thickness of the tread and risers, and increasing the fin plates thickness.  Also, we reduced the landing hangers from 6 to 4 and cantilevered the corners of the 3" platform over 4 ft.

Concrete in Torsion

Please join SEARI for an educational presentation on torsion in concrete by Erik Nelson, PE, SE of Structures Workshop, Inc. Erik will introduce the basics of designing for torsion using ACI 318-11.  He will describe best practices for evaluating various components of concrete structures for torsion, including stiffness assumptions in modeling spandrel beams.  Please note that the event will take place at the Department of Administration, One Capitol Hill, Providence in Conference Room B on Tuesday, May 20, 2014.

Infinite Load Path Created in Steel House

I while ago, my friend and I wrote about the analytical challenge of a peculiar type of framing orientation that we called the Infinite Load Path, which can occur in projects - but we didn't have a built example at the time.  Now we do.  It looks something like this in plan, and can occur around openings (not a great example, but illustrative)... 1 ilp

There are two associated problems with this framing layout, one of analysis and the other of construction.  To erect this framing layout would require temporary shoring of at least one of the inside corner connections.  In practice, therefore, we should make every attempt in avoiding this condition, although the completed system is perfectly stable (and is easily solved by most structural analysis programs).   Recently, we designed one on a project.   It required the edge of two finished openings to be lined up (so we could not do a continuous beam).

2 ilpYou can see the built steel framing below, the two arrows indicate two separate but parallel beams...

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We know this system is stable from statics, but it seems to have a dynamic or iterative quality (point loads seems to move in circles).  If we think about a uniform load applied to all four beams, how do we solve for equilibrium?  And second, how and when does the system actually reach equilibrium?  See that article for suggestions.

“Infinite Load Path” beam systems can be shown to work for larger scale structures too.   We built a small dome at RISD a few years back that could be scaled much larger...

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They can become domes only because if stacked they form curvature based on the tangent of the thickness of the material to the length.  But they can be flat as well.   Lamellas (and tensegrities, for that matter) are special cases of these types of framed structures (where member sizes is repeated, or Platonic/Archimedes solids used as starting points for geometry).

For this steel project, it was economical and efficient (even though erector had to shore the first member to build the next three).   But again, these types of structures should only be used when simpler framing is not possible.  Here is the house during final days of construction...

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Truth (and Beauty) are Useless, Seek "Good" instead

Beauty, Truth, or Goodness?  In a previous article I wrote called 'Twilight of the Idols', we learned (from Nietzsche) that truth is not a useful concept to designers and structural engineers.   Let science (or religion, for that matter), have ownership of truth.  We can do 'truth' in our spare time.  We also have learned (from manifesto on goals being useless), that beauty is a by-product of our work, not something we need to consciously drive towards.   What is left?  Goodness.  Quality.  We should focus in this arena of Plato's Trinity, not the other two. 2 quality

We design buildings, bridges and other structures, but how do we do this well or how do we improve over time?   Does our conception of the structure to be built change with experience and improve?   Yes, we learn what is feasible and what is practical with experience but what about Quality?  When we develop options for consideration or make a decision based on a certain amount of information, how do we choose the best option and make the best decision?

The entries in the Manifesto blog herein, are some attempts at improving design, and many others have written on the subject for structural engineers.  For example, David Billington in The Tower and the Bridge, described how the best designers of the past made engineering decisions based on a balance of efficiency, economy and elegance.  We can add to those considerations such as durability, constructability along with  resilience and sustainability.  Also, when thinking about quality, we can do this in two ways, the end (the structure itself), and the process (the design process).  We can say to ourselves “I want quality in the form of the structure and the assemblage of materials” or “I want to design well, I want to be good at engineering decision making”.    These may overlap.  For example, how does the description or idea of the final artifact as “quality”, create a path for working towards it?   After all, we are typically designing new and novel things (i.e.. not pancakes that we can taste, recook and/or adjust ingredients easily).

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In may be worth investigating what the Philosophers of antiquity thought on the subject of quality, beauty, and art.   I found that a terrific anthology to get a good background on this subject is Hofstadter’s Philosophies of Art and Beauty: Selected Readings in Aesthetics from Plato to Heidegger.  In it we find the beginnings of our conception of quality.  For example, we find that Aristotle, in his Parts of Animals Book I believes that one has to have a clear picture of the structure first (the end), and simply work towards that.

He starts by forming for himself a definite picture, in the one case perceptible to the mind, in the other sense of his end – the builder of a house – and this he holds forward as the reason and explanation of each subsequent step he takes.  Art indeed consists in the conception of the result to be produced before its realization in material... The plan of the house has this or that form; and because it has this or that form, the construction is carried out in this or that manner.  For the process of evolution is for the sake of the thing finally evolved, and not this for the sake of the process. (Aristotle, Parts of Animals Book I, 640).

But how does one conceive of an end first?    How does one know ahead of time that something will be good, correct and well proportioned or efficient and economical?   Here we learn from Aristotle, that good design is done by those who can take a complex task and split it up into smaller and simpler problems.  One step at a time.   Engineers are pretty skilled at this.   It may also be that when a good engineer has a vision, or an end to be aimed at, he/she has a command of measure (what we now may think of as proportion).  The engineer, according to Plato, must know the nature of measure for the proper portioning of structures (artistic as well as scientific).  Measure for Plato, is essential to quality and is the fundamental principle that defines quality.  A column should be this size, not that, for many reasons.

Basic to any art, is the art of measure without which there can be no art at all.  For to know the proper size of a column, proportion of a window, the proper organization of language in a poem, is to command the art of measurement.... There are accomplished men, Socrates, who say…the art of measurement is universal, and has to do with all things.” (Plato, Statesman 285b)

So if we think we succeeded in the proper form by creating something well proportioned, how do we know we are right?  How do we judge quality?

Every art does its work well – by looking to the intermediate and judging its work by this standard. (Aristotle, Nicomachean Ethics Book II 1106)

He agrees that the science may have a hand in the judgment of art.

The chief forms of beauty are order and symmetry and definiteness, which the mathematical sciences demonstrate in a special degree. (Aristotle, Metaphysics Book XIII 1078)

So we can learn a bit about what Aristotle and Plato thought about how to conceive and judge quality structures, but we have learned less about the individual engineering designer.   It is the engineer's personal ability that contributes to great work. The engineer that seeks personal excellence will see that transcend themselves and into the built world.  It may be obvious that all designers aim for quality structures as Aristotle suggests in his opening to Nicomachean Ethics.

Every art and every inquiry, and similarly every action and pursuit, is thought to aim at some good; and for this reason the good has rightly been declared to be that which all things aim. (Aristotle, Nicomachean Ethics Book I 1094).

And to which all engineers should aim - but not aim towards goodness, it is not a goal, it is a way.  Here we are back to the process of design, how the individual designer takes action and aims at some good, or quality (and being good is integral to this, but not going there).  It a process that requires constant reflection and the way to create safe, economical and efficient structures and do it better and better over time.

We know that the design of structures combines the objective science (material mechanics) with more complex subjective decision making requiring sound judgment (heuristics). Problems encountered by the structural engineer are complex and nuanced and require experience and judgment to better sift through the multiple design ideas.  If you have been reading this blog, one recurring theme is that idea that engineering is more of an art than a science.   Not art as beauty or aesthetic vision, not at all.  Again, that is useless.  In the forward to Nervi’s book Structures, Mario Salvadori says it best when describing one of the greatest structural engineers of the 20th century:

Nervi’s results are not achieved by consciously trying to meet aesthetic demands, but by tackling the fundamental structural problems from the outset, and giving them an obvious and clearly articulated solution.  Beauty, says Nervi, is an unavoidable by-product of this search for satisfactory structural solutions.  [Salvadori 1956:  vi]

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So no answers or short cuts to quality, just more questions.  The original of my poem on Nervi called  "The Structure That Sings" (later published in STRUCTURE) has a similar conclusion (beauty as an end and not sought after)...

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There is something called "design science" (bio-mimicry, form finding, geodesic geometry, etc) which has mathematical, scientific, and objective procedures to create form.  So "truth in form" is okay -  but again, it is very rare that good design is driven by scientific methods.   It can be, but more often not.   So, if I could re-write this, I would replace "truth in form as a means", with "quality as the means".   Quality, is by definition, process.   As Pirsig would say, quality is "the knife edge of experience", and living in it and with it, beauty just becomes.

2013 - Another Record Year for SW

2013 was a terrific year with a new record 149 projects along with 20 new and great clients!   This allowed us to reinvest in new technology including 3 new and powerful computers, 6 large monitors, new/updated licenses of Revit, SAP, ETABs, SAFE, Tedds, and BlueBeam.  We continue to have amongst the best computer/software infrastructure in the industry, as much as the largest firms, to tackle all types of projects.    In addition, we have hired our 4th engineer at the beginning of 2014 (see previous blog entry).    Check back with blog/website for completed 2013 projects which have not been included yet.   More to come!

1: Understand Structural Engineering Itself

In order to grow, we need to understand who we are. A popular but limited definition of structural engineering is "the art of molding materials we do not wholly understand into shapes we cannot precisely analyze, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance." This is clever and fun but only addresses uncertainty of forces and materials. What a limited understanding of what we do! Yes, we are experts in the ability to make decisions under great amounts of uncertainty, but that is only one aspect of our work. Stress and strain are necessary calculations but represent only a small fraction of all that we do; otherwise, we could be completely replaced by computers. Those of us who do genuine engineering are never concerned about this.

Another flawed definition comes from the British Institution of Structural Engineers: "Structural engineering is the science and art of designing and making, with economy and elegance, buildings, bridges, frameworks and other similar structures so that they can safely resist the forces to which they may be subjected." This sounds pretty good, right? Unfortunately, it fails completely in describing how one goes about designing. Like most other definitions, it puts too great an emphasis on force resistance. Yes, we proportion members based largely on forces, but that is only one of many design considerations - we also have to take construction practices, architectural constraints, client needs, and many other factors into account. As Hardy Cross famously put it, "Strength is essential, but otherwise unimportant."

The American Society of Civil Engineers unfortunately defines civil engineering thus: "The profession in which a knowledge of the mathematical and physical sciences gained by study, experience, and practice is applied with judgment to develop ways to utilize economically, the materials and forces of nature for the progressive well-being of humanity in creating, improving and protecting the environment, in providing facilities for community living, industry and transportation, and in providing structures for the use of humankind." How could a definition of engineering omit the most important word - design! This one is lengthy and dull, and fails to describe what we do, instead focusing on the end product, what we make. Saying that a cook makes cake does not describe cooking very well.

Here is more of the same from the National Society of Professional Engineers (NSPE): "Engineering is the creative application of scientific principles used to plan, build, direct, guide, manage, or work on systems to maintain and improve our daily lives." This suggests that our creativity is not employed for artistry, self-expression, costs, or constructability, but solely for science. That is just plain weird - and wrong. The applied science portion of what we do is actually the easiest and most straightforward. It is objective and has its own linear, step-wise methodology. That is why young engineers are doing the calculations and the modeling, while more experienced engineers are doing less. Yes, it needs to be right, so there is a lot of responsibility in this phase; but that does not necessarily make it difficult. The experienced ones are doing the other 90% of what we do, the more difficult tasks that require much more than calculations. Design is the other 90% of engineering that is only achieved after one graduates from being a mere applied scientist (or technician) to being a genuine engineer!

It is a widespread misconception that engineers are applied scientists. Scientists are applied scientists. Most of our engineering educators are applied scientists. Scientists make sense of what exists in nature. They test and examine nature. Scientists discover. Engineers take nature and make what exists outside of it. Engineers invent and create. Engineers are makers. Engineers are designers. Alan Harris put it succinctly: "Engineering is no more applied science, than painting is applied chemistry."

Here is my own definition: 

Structural Engineering is the design of BIG things.

The know-how required to do this is immense and is only obtained via lifelong learning. Engineers are 1% to 10% of each of the following:

  • Scientists

  • Mathematicians

  • Computer Scientists

  • Information Seekers (State of the Art)

  • Specialists in Systems

  • Experts in Construction

  • Citizens of a Locality of Construction Practices and Material Availability

  • Cost Estimators or Experts on Best Practices to Reduce Cost

  • Experts on Local Fabrication and Construction Technologies

  • Experts on Building Codes, Specifications, Standards, Guides, and Regulations

  • Risk Evaluators and Code Interpreters

  • Experts in Calculations

  • Experts in Three-Dimensional Representation in the Mind

  • Experts in Synthesizing Complex/Unsolvable Things into Simple/Solvable things.

  • Experts in Analysis Modeling Using Software

  • Skeptics of Engineering Software

  • Debaters of Efficiency, Economy, and Elegance

  • Artists, Philosophers, Poets, and Dreamers with Unconstrained Self-Expression

  • Drafters and/or BIM Specialists

  • Collaborators Working Within Design Teams

  • Listeners of the Vision and Needs of the Project/Client/Architect

  • Users of Rules of Thumb (Heuristics)

  • Experts in the Ability to Make Decisions Under Great Amounts of Uncertainty

Civil (Structural) Engineering is the design of big things.  You might ask, well Architects design big things too don’t they?  This is correct, but they are not hired precisely because the thing is big.  We are.  "Big" does not mean good - I use it here to clarify what we do (we do not design spoons).

This definition may contribute to a positive re branding of the profession and I believe it will  improve “career appeal” if we simply and succinctly told the truth.   Why is the retention rate in engineering schools around 50%?  That is a real problem but I think it is a marketing problem.   Our educators are not good engineering mentors and they likely mislead our students into believing we engineers merely complete calculation procedures.   Engineering is so much greater than that!

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See 03/2012 ASCE-SEI Structures Congress Procedings “What makes an Engineer, an Engineer”

2: Embrace the Process

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Let the design process push and pull you constantly.  It is healthy.    Design is nonlinear.  It goes backwards as much as forward and it curves around back on itself.  That is okay.   If you have issues with that, this may not be the best profession (although there are engineers that successfully do only computer modeling or code research, so there is still hope). Yes the Architect will keep changing things until the very last minute, get over it.

Above is a bridge truss, the top one may be familiar with, but the bottom one is new and novel.   How does one do this improvement?   You start with what you know and proceed.   You ask questions “how can I improve this boring Pratt truss (the top truss A)?”   Well maybe I can study the shear and moment diagrams and adjust the spacing of the verticals such that the axial force in the diagonals is always the same.    The cost saving will be significant if the rods, gusset plates, welds, bolts etc are all the same.  Then you can proceed from B to C and remove the middle diagonal – (zero shear).   This is a new truss, a novel and beautiful truss  - an economic, efficient, and elegant truss.   One that is created.

3: Listen

Be a better listener and collaborator.  Architects (and other clients) will make you a better engineer, but you have to listen.

Seth Horowitz, an auditory neuroscientist at Brown University and the author of “The Universal Sense: How Hearing Shapes the Mind”, wrote a terrific article in the New York Times called The Science and Art of Listening which starts...

"Here's a trick question. What do you hear right now?  If your home is like mine, you hear the humming sound of a printer, the low throbbing of traffic from the nearby highway and the clatter of plastic followed by the muffled impact of paws landing on linoleum — the slight trick in the question is that, by asking you what you were hearing, I prompted your brain to take control of the sensory experience — and made you listen rather than just hear. That, in effect, is what happens when an event jumps out of the background enough to be perceived consciously rather than just being part of your auditory surroundings. The difference between the sense of hearing and the skill of listening is attention.   [Horowitz, NY Times 11/9/2012]

This trick of asking yourself what are you hearing right now, reminds us of the difference between listening and hearing.   Many of us have no trouble hearing sounds, but listening to meanings with our full attention is another matter.  Can we shut of our internal thoughts and really listen to our design team around us?   Can we listen to the Architect or Contractor or co-worker without assuming what they will say or without interruptions by our own thoughts?   This is hugely important.  I for one am an extremely poor listener, so this #3 of my manifesto is the most difficult for me.

4: Ask and Pursue

Ask stupid questions often and pursue answers.  These stupid questions are really smart...Who am I?   What is engineering?   What is a weld, really?   How can something turn from a liquid to a solid within a liquid (concrete underwater)? How come I don't add that tension force I calculated to the pretension already within the bolt shank from tightening?   If you are constantly thinking about these types of questions, you are in great shape.  In order to maximize your well being now, you need to pursue answers to all your questions, and think up new questions to pursue.   Engineering, like the good life, requires this and your efforts will result in lifelong learning (ie happiness according to Aristotle).

5: Take Risks

Take Risks.   Design of big things requires risk taking.    Design of new and unique solutions to problems takes even more risk.  Because engineering requires ingenuity, it requires risk.  Be daring.  We need to continue to be leaders in design and construction and we need to take more active roles in pushing our projects forward, not getting pushed. In Uncertainty in Structural Engineering by William M. Bulleit, there is a great little quote taken from Lord Kelvin:

Lord Kelvin, the physicist William Thomson, said, “It’s no trick to get the answers when you have all the data. The trick is to get the answers when you only have half the data and half that is wrong and you don’t know which half.” Although he was talking about science, Lord Kelvin’s statement fairly well summarizes the problems associated with uncertainty in structural engineering.  [Bulleit, 2008]

In popular terminology, scientific applications or procedural calculations are about the "known knowns."   Design is much more about the "known unknowns."  Embracing this means embracing risk.

Also, maybe taking risks isn't really that risky.

People who don't take risks generally make about two big mistakes a year. People who do take risks generally make about two big mistakes a year. [Peter Drucker, Austrian-American writer]

So... don't not do it.   Do not let things prevent you from doing the thing you want to do.   (i.e. take risks)

6: Accept Imperfection

If there is not a perfect solution,  it follows that, all solutions are imperfect.   In other words, there is always a better solution than the one that you just submitted for construction.   Every design has many compromises such as code requirements, construction skill, material limitations, conservativeness on new construction techniques, possibly errors of design, bad decisions early, etc, etc.  Get accustomed to that, own it, it is a good thing.   All designs are fallible.  All designs can be improved. Guess what, your design you submitted last week has numerous problems or design compromises, that is okay.   Learn and do better next time.   Hopefully, you didn't just lose a client.   That will happen too.   Take your imperfect project to a lower state of imperfection on the next project.  That is the design process, taking something to a lower state of imperfection.

Above you can see a joint that affected the clear glass.   The joint was required when the bridge extended to the cantilevers and it compromised the aesthetics.  Compromises in design are the imperfections, but they are necessary.   The cantilever is fixed on the building, whereas the bridges floats freely on large friction pendulum isolators.  Isolating the bridges from the towers not only reduces the forces on the towers, but it also protects the light bridges from the movement of the towers.   Thus, we took our design to a lower state of imperfection, but still kept a healthy dose of imperfection.

7: Forget about Goals

Structural Engineering is a process without a goal.  Design constraints are not goals, they are ways to make decisions and move the project forward in the present.  Engineering is an evolution from a concept to a built project.   Let the final product be unknown during the design process. Understanding that design is inherently goalless is good for you.  Design is means driven, not ends driven (not the outcome).  It is the present, not the future.

Ask "What am I doing right now?"  Ask yourself that question often. How are you improving the project now?   Today, not tomorrow.   How are you increasing your well being, your team around you, and your project?   If you have an end product first, that is less effective than if you live and work honestly in the present.   When you take meaningful steps in the present, the next day the project will evolve to a higher level.  This repeats itself day after day.  The end product (building / structure) simply becomes.   Let it become.  Nurture the process.   Be patient.

We don't know the end product, the final construction is unknown.  So it is pretty reasonable to suggest that the goal of achieving this or that building is useless.   How could something unknown obligate us?   But the tricky types of goals, are the known goals.   I would submit that even known goals are useless whether it is to be successful or to win a super bowl.   These are not only obvious, they are superfluous.   Goals themselves are always good things for the person, so I am not debating whether this or that goal is a worthy pursuit.   Worthing pursuits like yearning for the vast and endless sea, as a goal is fine - but the more immediate task is building the boat.  Focus on the boat not the sea.   The sea is a useless goal, it is obvious.  Freedom to float on the water is inherently good.   Freedom in the sea or the goal of greatness is obvious.   The goal of the sea is superfluous - how can something superfluous, obligate us?   Just like the goal of being great.  That is just as useless.  Be great instead.  Let the design process produce the next evolution of the concept.  Try to design the boat by asking what materials are available first, and keep proceeding.   The built project, the boat itself in its final state should not be known.   Let the boat become, and then hop on board.   The sea will be reached.   Greatness will be achieved.

This is the problem with goal-laden appeals to our industry like ASCE's Vision 2025.   There is nothing wrong with the goal that we should be better planners, designers, stewards of the natural environment, innovators, and leaders.  Yes we should be all this, but we don't need a goal, we don't even need some dense roadmap toward that goal.    The real problem is that with Vision 2025, ASCE is submitting to the fallacy that "goals" themselves are useful in some way.  Goals are completely useless.   As a father of three, I never, ever, push my kids to get straight A's.  I could care less about their grades.  I encourage clarity of thought.  I encourage love of learning by reading, playing, climbing, etc.  I encourage being a good person, a good citizen.  I encourage them to be selfless.   Giving makes you feel good.  I teach them the golden rule (or better yet Kant's Categorical Imperative,  John Rawl's Theory of Justice).   I encourage them to be active learners through play or challenging questioning.   With this encouragement, they will get As, and hopefully they too won't even care.   That is good.  This is why goals for money and success are problematic.   Another problem with goals is the confusion one has after achieving them, I guess my new goal is going to have to win another super bowl?  I guess my new goal is that second million dollars?   So my point here is that known goals are useless too.   So if that is the case, that the unknown ones (a finished building) are definitely useless.   Again, you don't need goals.   Purge them if you have them, it is liberating!

8: Kick Ass

Design is an incredible process (again, from step 7 we learned it is not an end).   It is good for you to make the process of design your own. Drive the process and in so doing you will grow and become a better engineer.   Cooperate, listen, be humble, but don't let that prevent you from kicking ass.

You need love of learning, pursuit of excellence (not the goal of excellence - pursue excellence by being excellent in the present), you need process, you need means.   Ends are useless to process.  If you focus on the present and work to maximize your well being, others' well being, the building's well being -  now - what results is the achievement of any goal.  Take action now.  Act as though everything you do will become universal law.  Your pursuit of well being will help others, which will in turn come back to yourself and everyone benefits.  Do not picture yourself as a great engineer, a rich engineer, or a famous engineer.   Do great engineering now and you will be great (not in the famous type of great, the un-famous type of great which is more worthy of the word).

9: Improve the Codes

Codes are good and extremely important, but they are getting completely out of control and unsustainable.   There is an old Faraday adage:

Make every effort to ensure that the results of your experiment are proportional to the evidence and assumptions that produced them.

I remember listening to a great lecture by Ronald Hamburger regarding this same topic at an AISC conference.   He used the example of a provision in the ASCE 7-10 code regarding how QCQ methods should be employed when combining model results where translational and torsional modes are intermixed.   While admitting not knowing what this meant himself (and for Mr. Hamburger, that is saying something) and how to go about determining if in fact QCQ-4 should be used, he discussed whether the provision was actually important.   He questioned the code provision, something we all need to do.  This also helps us understand them better.  The questions we may ask in this case are:

  • “Why do I care about exact modal superposition methods when I am doing Response Spectrum Analysis, which is exceedingly approximate?”
  • “Do I really need to be exact when I just took my elastic response spectrum and divided by 500% (R=5 for example)?”

Of course not (should be the answer to question 2).  

The code committees should keep in mind the approximate nature of this enterprise called structural engineering.  Not only are there large uncertainties in our loads and material strengths used in design, there are huge uncertainties in construction.  Before meeting in a conference room, the code committee members should visit a construction site to remember how reinforcing is placed within a slab on grade.  While they are there, they can see what a true pinned base support looks like (a thick base plate with four heavy anchors).  They can see the soil and the assumptions used for designing the footings.  They can see what shear connections look like that are not supposed to transfer moment.  They will notice the large non-structural interior and exterior walls that were completely neglected when modeling the stiffness of the structure.

In summary, the code committee should ask themselves the following two questions:

  • Is this provision important to the design of safe structures?
  • Is the provision too exact?

In other words (from Faraday)  "is the proposed provision proportional to the assumptions and uncertainty inherent in structural design (loads, strengths, construction, etc)?”   If they asked these questions, the codes would not balloon to the size they are now.

Codes are getting so large they are becoming impossible to meet.  This is also going to hurt the profession.  We need to reduce code provisions and in their place, increase design guides to continue producing the state of the art.  Should we stop updating codes?  No.  Should we slow down?  Yes, absolutely.  The updates to the codes are out of control and unsustainable.  My ASCE 7 is a half inch thicker and depressing.  I am now a voting member of ASCE-7 and will fight every provision that does not meet these simple requirements.

Codes already contribute to the need for fully automated applied science because no one would be able to apply the amount of code information to a particular problem.   What does automation foster?  Non-thinkers.  I understand the codes are becoming more and more sophisticated and provisions are being improved to better mimic reality - but there was a time when people understood that code requirements needed to exist to ensure public safety, and that was the standard that they needed to meet.  That should be the only standard.  I like to compare my ACI 318-63 (no, I am not that old, I am an asshole who bought an old code to compare) with my ACI 318-11 just to remember which provisions are actually very important and how to prioritize my reading.  We need to join code committees and take our profession back - join me on the ASCE-7 committee or other important committees!

We will never be able to mimic the complexities of nature (the real world) in our computer models.  Our professor's are trying and great work is being done.  This great work may lead to larger codes and more accurate requirements at modeling and designing structures.  Some of this is good and some of this is harmful.  Larger codes means less understanding and more reliance on software to be code compliant, which leads to less understanding, less interest, more errors, and, possibly, more lawsuits and more collapses.  I don't believe the common wisdom that computers reduce error.   Computers just hide more error.

10: Become an Educator

I never thought being a teacher would make me a better engineer.   It is undoubtedly the best decision I have ever made as an engineer.  If not interested in teaching in a formal university setting, teach your fellow colleagues at work, set up lunch seminars ,etc. It allows you to reflect on important concepts and theories that you thought you understood but never really did.   In order to teach, you need to be able to translate complex ideas into clear language which requires that you master the material.  It also allows you to explore how best to communicate to people with different learning styles.  As we know, teaching is not about sharing facts, it is about assisting the student in discovery - but how?  I learned a couple tricks in my young career as an educator (now only 8 years).

One is to simply understand how knowledge itself is transferred and then retained. Socrates can even help us understand how structural engineering can be taught.  We know from his actions and through Plato's writings that he is clearly able to help us understand the importance of a liberal education (helping students in the process of discovery, so their knowledge is their own).  How does this translate to engineering education?  For Socrates, education within any classroom needs to foster freedom and inquiry.   He lost his life in defense of the spirit of inquiry (read the Apology or Crito). The most telling dialog of Socrates on the importance of inquiry is Plato's Meno. It is where we find Socrates asking fundamental questions about learning/teaching itself and the method of attaining knowledge.  I wrote about Meno, see “Socrates, How is Engineering Knowledge Attained?”  in STRUCTURE magazine April 2013, and edited the entire dialog (replaced words) because I think this is exactly the type of conversation that should take place in all of our classrooms.  I also borrowed heavily most of these ideas from my Dad's writing on liberal education... that every class needs to foster enquiry (especially about how ignorance is important to recognize, to be able to learn).  It took me a while to understand that a liberal education should be the same as an engineering education.  We need to resist cramming students' heads with more and more knowledge, whether it is more mathematics, new theory based on a particular research agenda, or trends in the marketplace.  This may numb the minds of our future engineers, let them seek information when they are ready.  Again, teaching should be about assisting the student in discovery (a liberal education), not supplying knowledge or listing the latest facts.  So we need to ask questions, open the classroom up and share our thoughts on solutions, criticize and praise worthy ideas, etc.  We do not want engineers who merely regurgitate what they have been taught and what they have memorized. We want them to struggle and to engage the world and people in meaningful ways. We want engineers with a spirit of inquiry and love of learning that will last a lifetime. So we had better make sure that Socrates joins us in every class.

A second idea is to teach forwards, not backwards.   This means, like our engineering history, our knowledge sharing should start from actively playing in the world and with materials - and then later asking how science and math contribute - not the other way around!   For example, I can lecture about the moment of inertia and provide the mathematical derivation or formula for stiffness.  Or, I can hand the students strips of wood to play with and ask them "why is one stiffer and by how much?" The math should never be the start, it is the end (see "science is applied engineering" blog to understand how art and engineering are the beginnings, and science and math, the ends of design).  Never teach backwards - unfortunately, that is how most do it (I am certainly guilty of this too, since it is actually much easier to teach backwards).

You can make four strips of wood (or Masonite), say 1″ wide by 1/8″ thick.   Take a pair and tape the middle together, take another pair and only tape the ends.   Feel the difference in stiffness…

100_1226

100_1226

The one you one tape in the middle will act as two separate beams.  The one you taped at the ends will act as one beam with double the thickness.  How much stiffer will the beam that is taped at the ends be?   Since deflection is proportional to moment of inertia, and I is proportional to thickness cubed, it will be 4 times more stiff!  Two cubed is eight, and 1 cubed times 2 members is 2, and 8/2 = 4.  It will be double the strength and 4 times the stiffness – just by taping the ends so it resists horizontal shear and acts as a composite beam.  Go ahead and try this simple experiment in your classroom and design other ones. Let the numbers follow the art/design/engineering and try to teach that way, teach forwards, just like our history (and the same way as how we design).

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