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Five Questions for an Engineer – Avery Bang

Avery Bang is the Executive Director of Bridges to Prosperity, a nonprofit geared to helping isolated communities by connecting them with bridges!

Ms. Bang joined Bridges to Prosperity, first as the Director of Operations, after completing a graduate degree in Geotechnical Engineering at the University of Colorado Boulder.

Her graduate research was conducted with Engineers Without Borders (EWB) Founder Bernard Amadei, which considered appropriate geotechnical survey and design for rural low-tech applications.

As a Professional Research Assistant in the Mortenson-Center in Engineering for Developing Communities (MC-EDC), Avery led research teams in developing appropriate alternative energy solutions for developing communities, and mentored student-teams in various international projects. Prior to her time in Colorado, Avery worked as a structural engineer at Shoemaker & Haaland Engineers. As an undergraduate at The University of Iowa, she served as the President of Engineers for a Sustainable World (ESW) while founding Iowa’s chapter of Engineers Without Borders (EWB).

So go to B2P and help out! Thanks Avery!

1) What got you interested in a career in engineering?

My father is a structural engineer, and as a child, visiting bridges and Frank Lloyd Wright houses on vacations was the norm. I guess I fit the stereotype, in that regard.

2) Could you give an overview of your role with “Bridges to Prosperity”.

My first project with Bridges to Prosperity was in 2006, as a student at The University of Iowa. We designed and built a 30-meter cable-suspended bridge near Santo-Tomas, Peru as our senior design capstone project.

My passion was ignited, and I joined B2P’s Board of Directors as the Director of the newly-formed (our project being the first) University Program. Following graduate school in Geotechnical Engineering at The University of Colorado at Boulder, where I worked with Engineers Without Borders Founder Bernard Amadei, I joined B2P as the first States-based full-time employee, as Director of Operations.

Nearly four years later, I am now the Executive Director, working with a small team of engineers and staff here in Colorado, supporting Program Staff in seven countries on four continents. It’s all quite exciting.

3) How can engineers help non-profit organizations?

Each non-profit is certainly unique, but speaking on behalf of B2P, we rely on the technical expertise and support of engineers. From design detailing, to drafting, field-based construction support to Corporate Social Responsibility financial support, engineers and their companies are at the core of our success.

We strive to minimize overhead expenses, by focusing staff efforts on defining global footbridge needs, and supporting volunteer engineers who do the actual design and training program development.

4) Any advice for new engineers?

I had a professor who claimed that we were to be the 1% of the population that makes life possible for the other 99%, which has always stuck with me. Careers that truly help people are not limited to medical or teaching fields as many incorrectly assume. So think big–find your passion within the field and think outside the box, both in terms of what the impact of your existing work is going to be on society, but also how you can select your career path to be both interesting and rewarding.

5) What do you do for fun?

Well, traveling is certainly a favorite of mine, but when I’m in the States, I enjoy rock climbing, reading, biking and jogging with my pup Levi. I’ve been known to love a bit of good live music as well.

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The Devil’s Bridges

Happy Halloween! (Hat-tip David)

Devil’s Bridge is a term applied to dozens of ancient bridges, found primarily in Europe. Most of these bridges are stone or masonry arch bridges and represent a significant technological achievement. Each of the Devil’s Bridges has a corresponding Devil-related myth or folktale.

Local lore often wrongly attributes these bridges to the Roman era, but in fact many of them are medieval, having been built between 1000 and 1600 AD. In medieval times some Roman roads were themselves considered beyond human capabilities and needs, and therefore had to have been built by the devil.

D. L. Ashliman has a number of good Devil’s bridge folktales. The downside, it is always animals that pay the price for the bridge…

Regarding the building of this [Kilgrim] bridge is the following curious legend:

Many bridges having been built on this site by the inhabitants, none had been able to withstand the fury of the floods until his “Satanic Majesty” promised to build a bridge which would defy the fury of the elements, on condition that the first living creature who passed over should fall a sacrifice to his “Sable Majesty.”

Long did the inhabitants consider, when the bridge was complete, as to who should be the victim. A shepherd, more wise than his neighbors, owned a dog called Grim. This man having first swum the river, whistled for the dog to follow. Poor Grim unwittingly bounded across the bridge and thus fell a victim to his “Sable Majesty.”

Tradition says, from this circumstance the spot has ever since been known as Kill Grim Bridge.

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Manayunk Bridge trail “park in the Sky”

Hat tip David.

An old bridge is being re-purposed as a bike trail, near Philadelphia.


Oct. 21–In a wind-whipped setting high above the Schuylkill, officials shook hands Thursday over a plan to link the region’s trail system by running a pathway across the old Manayunk railroad bridge, creating a “park in the sky.”

“This is a fantastic opportunity we have to personally, economically, and physically unite the city with the suburbs,” Mayor Nutter said.

The ceremony at midspan launched a $1.5 million project that when complete — estimated at 18 months from now — will use the bridge as a greenway for hikers, bikers, and joggers.

The bridge will connect the Cynwyd Heritage Trail in Lower Merion Township with the Ivy Ridge Trail in Philadelphia. Someday, planners project, it will be possible to get on a bike in the city and ride by trail to the farthest reaches of the suburbs, or the reverse.

Photo Credit Michael Froio -

Built by the former Schuylkill Valley Division of the Pennsylvania Railroad, it is notable as a large concrete open spandrel arch bridge built on a reverse curve, earning both the current bridge and its 1883 wrought-iron-truss predecessor the nickname of “S-Bridge.”[1] SEPTA acquired the bridge in 1976 for its Cynwyd Line.

The bridge’s challenging geometry was executed by T. L. Eyre, a Philadelphia contractor. Another notable feature is the saw-toothed construction joints along a 65-degree skew.[2] Weather-related expansion and contraction of the bridge, coupled with corrosion of its internal steel reinforcement, led to its closure by SEPTA on October 25, 1986.

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Alberta Oil Pipeline

The magazine Engineering News Record has an editorial advocating for building an oil pipeline from Alberta (my old stomping grounds) to Texas. The oil sands in Alberta are huge but it is extremely difficult to extract the black gold, in an eco-friendly way.

I have some reservations about this quote,

Climate change is important, but not as urgent as the need for ample energy security and putting people to work.

Can’t we have both? Why is it one or the other. Is there no way to have a clean environment with clean energy and jobs? Has no one at ENR watched Blade Runner?

The U.S. and the rest of the world will be dependent on fossil fuels for the foreseeable future. The risks posed by the Keystone XL pipeline are not substantially more catastrophic than the risks we run every day with the hundreds of thousands of miles of pipeline that crisscross our country.

Acting as if the future of climate change hinges on this one big pipeline is just the kind of apocalyptic nonsense we don’t need.

From The Economist,

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Musical Bridges

David sent me some great links to musical bridges. I think the idea of pedestrians interacting with a bridge as they walk along intriguing……

Here is one with chimes, from

I love this bridge!


More great stuff from David!

bridge edge decorated with a musical / piano theme – visual rather than instrumental )
AND a semi-serious? high-tech proposal by some acoustic engineers, similar to the “Halfbakery” first option:
This is not to be confused with a bridge on which music can being played, such as here:
or here? (click on the images). The orchestra or band could play in the circular space above the pivot mechanism:
See also the old postcard of the Golden Gate site at this web page (second image):
(found at this page:
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Floating bridge concept

Not mine but I love these quotes,

After initial consultations with engineers dubbed the concept unfeasible, the route builders and organisers took up the challenge


Engineers considered statistics like the 100-year flood levels and took unseasonable rain and flooding into account. We are taking a calculated risk based on what we know of the seasonal factors

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County Bridge Concept – cast-in-place steel girder

Its no secret that counties across America are struggling with their bridges.

(Counties are typically responsible for their bridges, while the state is responsible for the primary system bridges. This leaves a huge number of bridges in county hands and in trouble.)

I am working on a concept for a single span 50’x30′ county bridge, with the goal of establishing a cheap bridge that county forces could install themselves. This is harder than you would think.  Most counties have limited funds, limited equipment,  and small busy workforces. (I still think a prefab bridge that is trucked to the site and quickly placed is the way to go.  See my past bridge here. But a prefab bridge can easily cost twice as much as a cast-in-place bridge because of prestressing, etc)

So, while I am sitting in the computer lab proctoring a Google Sketchup test, I came up with this idea. (forgive if someone else has already done this….I think the only thing new aspect is the prestressing.)

(And this bridge is using geo-reinforced earth abutments..)

Step one – Drive the sheetpile.

Sheetpile shortens the bridge by using a high abutment system, so it easier to develop a single span bridge.

Step 2 – construct the abutments and drag or use a crane to place steel beams.

Step 3 – prestress the steel beams on site. I may need cross bracing to minimize distortion of the beams.

Step 4 – add the metal arches. The arches provide voids in the deck reducing the deadload. (I know this has been done before.)

Step 5 – place some regular reinforcement (not shown, hey I’m giving a test here!) and pour the deck. (The purple portion and the white deck are the same concrete pour. I just showed it in stages.)

So what this does is prestress the concrete deck / steel beams into a typical T-beam system. A system I think any county could build.

Step 6 – after the deck and the abutment is poured, encasing the ends of the beams, bolt on the railing. And voila, a cheap, strong county bridge. Now, give me some feedback.

Would this work?

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Washing line bridge concept

Soooo, a local county would like to cast precast deck panels on site and then drag or lift them across the river without a crane. (The bridge abutments would probably use geosynthetic reinforced soil walls along with sheet piles.)

I’m not exactly sure how to get the panels across the stream but I suggest using the Roman Crane model. (Did you know Romans had cranes? Me neither.)

Roman crane

So you place a “crane” at either end and pull the concrete panels across like washing on a spring day….easy-peasy-lemon-squeezy.

Will it work, who knows but it would be fun to try!