Friday, June 24, 2011

Road design, and a happy birthday.

Today marked the end of a week as well as Dr. Julia’s 30th birthday. Naturally, there was cause for much celebration.

Stacy, one of the staff (and an urban planner), baked a cake for her. Apparently the two of them go all the way back to high school, so this act of love was not a total surprise. What was surprising is that she actually succeeded in making a fantastic baked confection. The cake, which was so delicious that I’d want to have it even in the comforts of the modern world, was a gluten-free concoction with chocolate mix, egg-white ganache (?), coconut, and a hint of ginger. (I’m probably missing a lot of other ingredients.) So freaking good. And she made it in an improvised Dutch oven. Kudos to Stacy for being a creative baker.

We intended to have a dance party tonight, but that fizzled when everyone crashed after the sugar high. Oh well. Probably another night, then. Between the cake, a beer, and an absolutely pitiful dinner, there was just not the right mix of nutrition for sustained energy tonight. Plus, we have to leave by 8am tomorrow for another site visit. I think these trips are great and all, but it sure would be great to sleep in now and then.

Over the last two nights, I’ve been able to call home. (Whoo!) A conversation with Lauren made me realize that I have not accurately described my work here. When you spend 8-10 hrs a day thinking about a task, it’s easy to focus on other subjects when journaling. They seem more interesting.

I’m essentially the engineer for much of the city’s infrastructure systems: transportation, stormwater management, and energy. They have a general vision for how the components work in Anam City, e.g. they want a walkable city, use neighborhood-scale utilities running on renewable energy, etc. What I do is come in with a critical eye, listen to what they want to accomplish, and explain how to make it a reality. I’m more than a designer – I’m an engineer. They give me a problem, I find a solution. And I get to information my solution with environmental, social, and economic inputs. Brilliant.

As a recent example, this week I’ve focused mostly on roadway design. Anam is subject to regular flooding, thanks to low terrain and two rainy seasons. The city will need a reliable road system to convey goods, materials, and passenger cars (ideally transit) that can somehow withstand the onslaught of 1.5m of rainfall each year. The question, then: how do we provide all-weather access without paving everything in concrete? In drier climates, it would be easy to just spec out an earthen road. In Anam, between the heavy rains and clayey soil, the roads must be carefully designed to improve service quality and lifespan. A simple gravel road would not withstand such flooding, quickly developing ruts, potholes, and washboards.

Here’s a quick technical lesson in roadway design. In its simplest form, a road is earth that is shaped (cambered) to drain away rainwater. The drains reduce erosion from rain. However, sometimes the soil is not strong enough – particularly when wet – to support the immense weight of trucks. So the next step is to provide a strong base of a certain rock and soil composition to support the weight. For areas with heavy rain, sometimes good drainage is not enough; the surface material (gravel, rocks, etc.) washes away or water seeps through the surface and erodes away the base. In these cases, the road surface is sealed – e.g. covered with asphalt chips or concrete – to make it impervious to water.

My goal, then, was to find a rural road surface that is impervious yet does not involve immense amounts of concrete or asphalt, both of which are energy-intensive roadway materials. After a thorough review of available literature, I compiled a list of options. Not all of them would be suitable, but I included them for the sake of comparison when evaluating the options. After presenting my findings to the staff, I will focus my investigation on the following types: earthen, gravel, stone, dressed stone, and fired clay brick.

The last option is particularly promising. Clay bricks are made of clay soil compressed into the shape of a brick and fired to improve strength. It is a promising solution for Anam because the area has an abundant supply of clay. Most paving solutions require coarse aggregate (rocks) or stone, which would need to be imported. Certainly within the realm of possibility, but it is far more exciting to create our infrastructure out of nearby materials – leveraging the available natural resources and stimulating local economy. They are building a brick factory, after all. (The bricks will be used for other purposes as well, including house construction material.)

When I put this all out in writing, it seems less exciting. Of course we should explore ultra-durable, low-tech, labor-intensive options like brick or stone road construction. But there’s no manual out there to say that. I had to learn about all the different road types, evaluate their strengths and weaknesses, consider the factors for a sensible design such as available materials and environmental conditions, and then make a recommendation. That’s… what an engineer does. Maybe I’m just making up the distinction in my head, but I’ve begun to see a separation between an engineer and a designer. While a designer provides the technical design for something, an engineer figures out what that something should be in the first place and then provides the technical specifications.

For the first time in my life, I’m working as an engineer. And it’s as a sustainable development engineer. Booyah.

Also, now I know the finer points of rural road construction. When the apocalypse happens, I can help construct new infrastructure for future ultra-sustainable societies.

1 comment:

Amber said...

Re: distinction btwn "designer" and "engineer"... I don't think you're making it up at all. Maybe it's because I work in theater, but I see the two as quite distinctly different jobs. The Designer comes up with an idea of what they want things to look like. The Engineer (or we might have a different title, depending) figures out how to implement it, within the budget allowed. There's often a lot of discussion/collaboration/negotiation between the two. But (at least on a large-scale theatrical production), the jobs are separate.