Another Structural Engineering Genius!

The McArthur Fellowship program has named another structural engineer recipient. This is great news because engineers will have a large role in solving the problems of modern society, just as they have helped improve human conditions for the past several hundred years.


This is the second year in a row a structural engineer has been named. See earlier post (Structural Engineer awarded McArthur Fellowship) as well. Will there be an SE three-peat? We will have to wait until next year to find out, but all you SE's out there need to keep working hard!

Re-Burbia and the Perpetual Motion Machine

On August 10, 2009, the finalists for Dwell/Inhabitat's Re-Burbia contest were revealed. All of the finalists had invested a substantial amount of time in preparing their submissions. All looked impressive, most were interesting, and some were eminently practical.

However, I can't even begin to explain how upset I was when I came to the Vehiforce entry. This is nothing more than a perpetual motion machine. All of the energy needs of a suburban home can now be met by installing a machine in each garage that not only keeps a vehicle's weight bouncing up and down perpetually but actually extracts useful energy from the process.


Are you kidding me? A finalist?

Honestly, I don't fault the "inventor". Many people believe they can invent such machines, even famously brilliant people like Leonardo da Vinci. Unfortunately, the second law of thermodynamics prevents such a device. From the smallest atomic particles to the slow rotation of the Milky Way galaxy, no existing matter is capable of circumventing this law. Stephen Hawking even proved that Black Holes (singular gravity entities) follow similar rules. There truly is no such thing as a free lunch.

What made me upset and caused me such anguish is that the contest jury obviously had no scientific oversight, and probably lacked any technical experts. The contest hosts should be absolutely ashamed to allow this project to have progressed this far. The fact it was not killed immediately upon arrival proves that the contest was not judged according to its stated criteria of:

1. innovation and creativity
2. clarity of design
3. usability and practicality of implementation
4. originality
5. aesthetics
6. quality of solution

I can instantly see that the proposal should have been given a score of zero for criteria 3, 4, & 6. If I were on the panel and it was selected as a finalist I would have withdrawn my name from the jury, I would never allow myself to be associated with such a embarrassment. However, in the parlance of our times this can also be a good opportunity for a "teachable moment". Allow me to explain what made me so upset, and how everyone can avoid these issues in the future.

Make no mistake that the energy crisis is serious. It will define our future as a species on this planet. We have exhausted much of the easily retrieved energy that our planet had been storing in the form of petroleum. The energy in petroleum came from the same source that all usable energy on earth does - sunlight. Photovoltaic cells, wind turbines, wave power, hydroelectric dams, and photosynthesis all come directly from solar energy. Only nuclear power, geothermal, and certain chemical decompositions at the bottom of the ocean do not involve energy input from the Sun. Any future energy source must come from sunlight (or nuclear fission if you lean that way).

To summarize the relevant laws of thermodynamics:

• Energy can not be created nor destroyed, only shifted from one form to another
• Transferred energy must pay a tax to entropy

Basically, the usefulness of energy degrades as it is used. New, useful energy must come from an outside source (e.g. the sun). Useful energy can not be found in a garage unless someone is storing plutonium.

Once an energy source is found it must be converted to useful work. The most efficient process ever created would almost achieve 100% conversion from one form of work to another. Cars with internal combustion engines achieve about 20%-30% efficiency. They are not now, nor will they ever be a viable solution for our energy needs.

This is important because the source of the energy from a device such as a Vehiforce, if built, would be the car's engine. The design as drawn would never work. But, as suggested in the comments, it could be reconfigured as a linear system slowly lowering the car from a higher garage level to a lower one. This would be a ridiculously bad idea, however, as you would be wasting a lot of energy.


The car would drive itself up a ramp, stop on the Vehiforce platform, slowly travel downwards recapturing at most 1/3 of the energy used to get it up the ramp to begin with. The rest of the energy would be lost as useless heat out of the tailpipe and the engine. Thus, the Vehiforce would represent one of the most expensive, polluting, and inefficient ways to produce electricity.

As I stated above, our energy crisis is the most serious issue confronting our society right now. To award an important prize to such an idea as this is irresponsible.

What is needed is to break down the barriers of the design world. The innovators must combine forces with the technical experts. Design juries must involve some form of technical oversight to ensure feasibility criteria are met. This will encourage submissions from design teams that are broad based and experienced in design talent as well as technical talent.

Rising Tides Design Competition

With our current debate over climate change policy likely to be derailed by climate change skepticism, maybe it's time we start looking at ways to accommodate climate change rather than preventing it. Civil engineers will be called upon to perform some of the largest public works projects since the Panama Canal all along the US Coastal areas, just to keep the status quo (i.e. not "waterworld").


So, if you think "Cap & Trade" policy is expensive, just imagine how much money it will cost to do this in every port city of the US. Honorable Mention awards also listed here. An ounce of prevention is worth a pound of cure, as they say.

Castles in the sky

My friend and I collaborated on conceptual design last year for a critiqued design project. It was a lot of fun, I ended up contributing very little to the finished product but it was fun to be involved.

The basic concept was simple, design a skyscraper. Here was our response:



Architectural contests are great because they really push your thinking to new areas. You know from the beginning that many entries will be received so you have to go big or go home. Some of the best modern buildings had their start as inspirations during a design contest. For those willing to have a go at it, there are always plenty of competitions published on Bustler.net

We didn't win, but honestly I don't think that was the important part. I learned a lot more about what architects go through, and it reinforced the fact that what architects and engineers do are entirely different things. And in the end, I preferred my job.

Bracing is Beautiful!

Heads up for all the building designers out there... Bracing is Beautiful!


There are very few building systems as cheap and efficient as braced frames. Allowing your engineers to put just a few braces in the building will make them a very happy person. You'll see a lower cost per sq. ft of building, use less material, and make a green statement. Moment frames open up the floor areas, but you sacrifice a lot of room for the deeper beams, bigger columns, and tricky connections.

The most important reason to consider bracing is that people love seeing structure expressed in their buildings. It worked for the Hancock Center in Chicago, and it can work for you! There are buildings and architectural styles that it won't work for, but you can hide the braces pretty easily.

There are many flavors of bracing. Concentric, eccentric, chevron, knee, buckling restrained braces, multi-story bracing, etc. Just put those terms into an image search and you'll see a world of options waiting for you.


If you are concerned about exposed steel members (fire resistance, corrosion, vandalism) then you may want to coordinate with a specialist during your initial design. If appearance is a concern, then I strongly recommend you consider some of the newer imported components available. For smaller loads, a pin-connected rod from StaLok will work, whereas for a Cast Connex bracing component can handle even large bracing forces seen in high seismic areas.


We all want to do our part to help the owners get the building they want - at a reasonable cost with great performance. I think recommending a bracing system is a great way for engineers to add value to the project, without the high initial cost of shearwalls or moment frames.

Bamboo Reinforced Concrete

Bamboo is a grass. That's a hard concept for me because some bamboo stalks are 40 feet tall. Bamboo is also composed of many different species in different countries. Some are short, some are tall. Some green, some black, some other colors as well. Pandas eat it. Bamboo is great stuff, apparently.

So imagine you are building a flagpole 40 feet tall. You will have a lot of bending forces at your base. You would want to use a material that had high compressive and tensile strength to meet the moment requirement. You would want to make sure that you could resist the wind from any direction. Nature already took a look at the problem and came up with bamboo.

We can use bamboo in all kinds of applications that mother nature didn't intend, like tension reinforcing in concrete beams. It even has ridges on the outside that prevent bond slip. It's extremely high tensile strength can rival conventional steel reinforcing. For anyone looking to lower the cost of their steel reinforcing budget, bamboo might be a good alternative.

Now for the issues...
1) you still need to tie it up, so labor costs remain high
2) it's not code approved for reinforced concrete, so you'll have to design as unreinforced
3) it's quite expensive if supplies are short in your region
4) you'll need to keep it dry and insect free

But hey, if you are looking for an alternative and green building material, I think combining bamboo reinforcing with other proven options like ICF construction, high fly ash content concrete, and other bamboo/sustainable products throughout would gain a lot of respect in the design world. Bamboo reinforcing is completely accepted in certain parts of Asia, so there is a lot of information about it already. See this for a very well done thesis by Leena Khare at UTA regarding bamboo reinforcing, with test data. See this for other examples of natural fiber reinforcement.

Now, bamboo is getting a lot of good press right now because of it's environmentally friendly properties. It grows superfast and can generally replace any conventional building material, as long as it stays dry and insect free. But be careful if you are considering using bamboo that you only select sustainably farmed products, because we don't want to lose more panda habitat.