20141009

Portland Civil Links 10/10/14

Transportation funding, Portland’s parks and using active transportation to promote health in our school system. Here are the Portland Civil links for the past week.

  • First, I would like to encourage Portland voters to check out the Fix Our Park campaign, which is working to pass the upcoming Parks Replacement Bond. This bond will fund much needed repairs to Portland’s park system and will not result in a tax increase. As a parent and President of our local Little League, I can testify first hand to how critical these parks are to our community and how much they contribute to livability in our city.
  • Here at Civil PDX, I explored how the OTIA funding surge has affected competition between engineering firms for public infrastructure projects. In short, I believe that the OTIA work has created a large supply of qualified engineering firms, while transportation funding problems have resulted in less demand for their services.
  • Portland Parks and Recreation opened the agency’s first entirely nature based playground at Westmoreland Park, a KPFF project that I had the opportunity to work on. The park uses logs, boulders, plants and other natural elements to create a fun, exploration based environment for kids to play in.
  • Metro debuted an innovative stormwater wall at the Portland Expo Center last week. Designed by landscape architecture firm GreenWorks PC, the wall uses vegetation to treat runoff from the building’s roof before it is directed into the sewer system.
  • A new effort is underway to define the future of Veterans Memorial Coliseum.  The study will explore options ranging from addressing deferred maintenance to gutting the building and creating an entirely different venue.
  • Finally, Wednesday was International Bike and Walk to School Day! In a country that struggles with obesity, teaching our kids about the benefits of active transportation is a critical piece of maintaining the health of our communities. Growing up in a rural area, I didn’t get to enjoy the benefits of biking and walking places until I was an adult, but my own kids testify that their walk to and from school is one of the most enjoyable parts of their day.

That’s all for this week. It looks like the rain might hold off to give us a last weekend of beautiful fall weather before the pineapple express blows Oregon’s real fall into action.

Mount OTIA

Mount OTIA: Back at Base Camp

The Oregon Transportation Investment Act (OTIA) and the Jobs and Transportation Act (JTA) brought much needed improvements to our state’s highway system. Now with the programs largely in the past, engineering firms face a much more competitive market for their services.

Mount OTIA
Mount OTIA, as captured by the Oregon Department of Transportation.

In 1953, Sir Edmund Hillary and Nepalese Sherpa mountaineer Tenzig Norgay became the first people to set foot on the summit of Mt. Everest. Upon their descent the two were met by fellow expedition member George Lowe, who brought them a hot bowl of soup and to whom Hillary proudly proclaimed, “Well, George, we knocked the bastard off.”

Here in 2014, the State of Oregon finds itself having reached the base of a much different mountain, this one the result of reaching the end of a nearly 15 year series of funding measures that brought the state’s highway system a period of unprecedented improvements. Unlike Hillary, the joy of victory is behind us, though our infrastructure will serve for decades to come. Like Hillary, we might all find some comfort in a warm bowl of soup.

Much has been written about this decline and the lack of transportation funding in Oregon and the nation. The Oregon Department of Transportation (ODOT) has pointed to six trends that spell trouble for transportation funding here. No matter the exact combination of problems, the crux of the issue is that ODOT finds itself in a position where it must limit its scope to three areas: 1) Servicing debt incurred over the past 15 years; 2) Continuing to run the agency; and 3) Performing regular highway maintenance. As a result, ODOT’s ability to perform necessary capital improvements is now almost entirely dependent on federal funding, which is in short supply as it has its own very serious issues. Should the situation continue unchanged, ODOT anticipates that projects currently planned for the coming years could be delayed or cut entirely.

While debate continues on how to solve our nation’s transportation funding issues, I would like to focus on an often overlooked result of this surge. Because of the massive volume of state highway projects created under the OTIA program, there is now an unprecedented level of competition among engineering firms for highway transportation work. Competition is driven by supply and demand, and with OTIA in the past there is now an extensive supply of qualified engineers with directly applicable experience and dwindling demand for their services.

First, supply. Engineering firms typically compete for large public agency contracts under a qualifications based selection (QBS) process. The central idea of QBS is that construction work is expensive and construction claims and changes orders can ruin an otherwise successful project. Therefore, it is in the public’s best interest for agencies to select design firms by determining who is most qualified and will develop the best deisgn and not who offers the lowest price. Spending an extra $10,000 during design could result in a solution that saves more than ten times that during construction. In using QBS, agencies openly acknowledge this fact.

In a typical QBS process, the agency issues a request for proposals (RFP), establishing their priorities for the project and how proposers’ qualifications will be measured and scored. Each RFP is unique and requires a unique response, but most typically ask some version of three basic questions.

  • How has your firm’s previous work prepared you for this project?
  • Who on your staff will perform the work and how has their experience prepared them for the assignment?
  • Based on your experience, how will you approach this specific project?

Now take a minute to scroll back to Mount OTIA at the top of this post. Notice that from 2001 to 2007, Oregon’s transportation funding more than doubled. As a result, and without exact numbers, it would be safe to assume from this that there were something like twice as many projects under development in 2007 than there were in 2001. Put another way: There were significantly fewer opportunities for an engineering firm to build its resume in 2001 than there were in 2007, and there were likely significantly more firms with strong resumes with ODOT in 2007 than there were in 2001.

Adding a final piece to this supply puzzle, for a variety of reasons agencies typically place a time window on relevant project experience. Most ODOT RFP’s request information on something like three similar projects completed within the last 5 years. Completed in this case means that construction was completed. Since the design and construction processes can each take a few years on even a mid sized project, this means that a sample project for a proposal in 2014 may have begun as early as 2004 or 2005.

Look again at Mount OTIA. The span from 2004 to 2014 captures the very summit of the funding mountain. Oregon has seen a lot of infrastructure development since 2004 and 2005. It is not hard to believe that this work served to bolster the resumes of many engineering firms. Ten years ago, there was so much work being performed that if a firm could prove that they were capable of taking on these projects, they were often simply awarded a bundle of bridge replacements. Such was the supply and such was the demand.

Demand today is much different. Having studied the OTIA funding graph, you may have noted that this particular version projects 2015 funding to be similar to pre OTIA levels. The difference, as we just explored, it that there is now a much longer list of firms with relevant experience. As compared to 10 years ago, there is a much larger supply of qualified engineers and a much smaller demand for their services. Everyone has “arrived”, but the party ended awhile ago.

So demand is down and supply is up. Economics aside, we can absolutely see the affects of this situation in the current state of public agency contracting. Consider ODOT’s own on call list. In the mid 2000’s, a place on the list might provide a firm with the opportunity to be handed a project or even an entire bundle of projects. This could be enough work to bolster the firm’s resume and occupy their staff for years. Today, earning a place on this list offers the same – but now more qualified – firm the opportunity to compete for the same project by responding to another RFP, making it more expensive and more difficult to pursue new work.

The current state of competition makes it much more difficult for firms of all sizes and abilities to bring in new work, but that is the reality of where we are and where we have been. Just as these companies thrived under the opportunity of the OTIA programs, they now struggle under the pressure of more qualified competitors and a lower project count.

Just as QBS protects agencies from having to select an unqualified firm because they offer a low price, it also more or less eliminates the price reduction that should accompany a high supply, low demand scenario. Still, in a backwards, off hand way, this particular piece of the situation is to ODOT’s advantage, as they now have a deeper, hungrier pool of consultants ready to respond to their needs.

To stay up to date with future Civil PDX content, subscribe to the blog by entering your email address at the top of this page. New posts will automatically be delivered to your inbox.

If you found this post interesting, you might also like these past posts from Civil PDX.

The First Rule of Design
Passive vs Proactive Design
And then there was a sinkhole…

20141002

Portland Civil Links 10/2/14

Development, trees, playoff baseball and a dose of engineering philosophy. These are your Portland Civil weeks for the first full week of fall.

  • Here at Civil PDX, I wrote about the first rule of design, that design is iterative. This is in contrast to math and science education, which teach us to seek direct solutions. The resulting conflict centers around professionals being expected to solve problems in a way that their education has not prepared them to. Cue internal conflict.
  • Portland designer Carl Alviani wrote an incredible article about the major changes that are on the horizon for Portland over the next 5 years. Everyone in the city senses that development is booming, but this article argues that we are only getting a taste of what will very soon be here. Seriously, even if you don’t want to read anything else right now, just click the link and scroll down the page to see some of the buildings that you may see on our horizons before long.
  • Portland Parks and Recreation highlighted the history of the 120 year old copper beach tree that stands in front of the Portland State University Library. This is one of 317 trees throughout the city that have been granted special protections as “heritage trees”. Because the Northwest is so green, we can be tempted to think that sometimes trees need to be cut down to make room for our work, and that replacing them is almost as good as saving them. True, trees sometimes need to be removed, but it is important to balance this with the understanding that the replacing could take 120 years.
  • Finally, after 161-1/2 games, the Seattle Mariners were eliminated from the Major League Baseball playoffs in the middle of their last game of the regular season, when the Oakland Athletics finished a clinching win against the Texas Rangers. As sad as this is, 2014 was the most entertaining season to be a Mariners fan since 2001. At the beginning of the year, the consensus was that a winning record would be a success. The M’s blew past that to finish 87-75, giving us a taste of how fun a pennant drive can be.

That’s all for this week. Have a great weekend!

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First Rule of Design

The First Rule of Design

Science and math education focus on finding direct solutions to direct problems. In practice, though, design is iterative and questions and answers are rarely direct, absolute or obvious, leading to the first rule of design: Design is iterative. Despite your best efforts, your first solution will almost never be right.

Right now you are thinking that I have an overly negative view on this topic. You might be right! Before deciding, though, let me tell you why I think this statement isn’t negative at all, why I think this is actually a hopeful idea, and why I think this idea frees us from having to be “right” every time. Further, this idea protects creativity from being overcome by practicality at the first sign of weakness. As we get into the topic, let’s first explore a bit of back story.

Good engineering is the foundation of the built environment, and is itself founded on the realities that we call math and science. Math and science education, then, are essential building blocks of creative design in the engineering and architecture fields. Think back to your own math and science education. If it was at all like mine, it began with math and the understanding that math can be reduced to a series of rules. Science then followed as a related field, with its own set of rules.

Under this system, presented with a problem, a student applies these rules within a structure defined by more rules. After applying all of the rules, the student arrives at an answer. When the rules were all applied correctly, in the right order, we call this the “right” answer. Everything else is “wrong”. Plug and chug. Close only counts in horseshoes and hand grenades – an actual quote that I learned from an actual math teacher. Except, close counts in almost everything else, too, and plugging and chugging relies on having something to plug into and chug along with.

Bringing us back to engineering, consider the process for sizing pipes in a sewer system. The set of equations that governs modeling fluid flow in a pipe network was developed over centuries and is very complex. Thus, directly calculating the exact pipe sizes needed to carry water through a sewer can be almost impossibly difficult. Fortunately for us, pipes only come in certain sizes! Instead of spending hours determining that we need a 13.625 inch diameter pipe, we can just guess that we need a 12 inch, then use a much simpler calculation to check that assumption. That won’t carry the flow? Then try an 18 inch pipe. That seems too big? How about 15 inches? Perfect!

In this example, we knew that there was a very good chance that our first solution – the 12 inch pipe – wouldn’t be right, but the process saved us time. What could have taken hours of careful modeling, took us 15 minutes in a simple spreadsheet.

Engineering education stands in stark contrast to the key concepts that guide an engineer’s daily work. Simply put, design is iterative and your answer – or at least your first answer – is less a solution and more a starting point for a process that could well lead the design in an entirely different direction. This is the power of creativity, something that we should work our hardest to protect. This is also a direct challenge to our way of thinking.

What then is the intent of the first solution if it is not an attempt to solve the problem? I would say that the first solution less needs to solve the problem and more needs to define the box that the eventual solution must exist in. In protecting the creativity of the design, it is to our interest to define this box in the biggest, most flexible terms possible.

Let me be clear that I am not advocating for sloppy math or ignoring the importance of understanding the mechanics of problem solving. Quite the opposite, these things are very important and too many engineers rely on computer programs as substitutes for understanding them. This appears in my own work as a path of least resistance temptation to view myself as a well trained CAD technician and permit form filler instead of striving to become a thoughtful, experienced engineer. This is a topic for another time, but for now my point is this: Understanding how an internal combustion engineer works is only one part of understanding what a car is and does and can be used for. So to are math and science rules to their fields.

As stated at the beginning of this post, knowing that your first answer can’t be right isn’t actually discouraging at all. True, the engineering mind has been taught to love correctness, exactness and direct problem solving and in this case it won’t find any of these for awhile. This is disappointing, but by acknowledging that your first answer can’t be right, you also accept that your first answer doesn’t need to be right. You aren’t the gatekeeper though, responsible for keeping out far fetched, impractical ideas. You are a member of a creative team responsible for continually defining and refining a concept that will one day grow up to become “the solution”.

Letting go of the outcome frees us to focus on the process, and focusing on the process puts us in a position to serve the design team in a way that only we can. We became engineers because we are interested in the puzzles created by the realities of math and science. By looking for direct, exact solutions to these puzzles, we turn our realities into limitations. When we accept that there aren’t any direct, “right” solutions and make the choice to instead engage in the creative process, these realities become challenges and opportunities and we free ourselves to truly do our best work.

To stay up to date with future Civil PDX content, subscribe to the blog by entering your email address at the top of this page. New posts will automatically be delivered to your inbox.

If you found this post interesting, you might also like these past posts from Civil PDX.

Engineering Concepts in LID
The Engineer and the Fisherman
Achieving Zero and the Value of Experience

The repaired sinkhole, as seen last Thursday.

Sinkhole Update: The hole has been fixed!

A few weeks ago, I wrote about a sinkhole that appeared along my daily commuting route, exploring what may have caused it and the condition of the pavement above it before it collapsed. Last Wednesday, about two months after the hole appeared, it was suddenly fixed!

The post I wrote explored a host of possibilities for what may have caused the sinkhole and what would be required for repairing it. Since the hole was next to a drywell, it seemed that ground water had likely been entering the sides of the well, and had washed some of the surrounding soil in over time. Seeing the finished work, I think for a few reasons that this guess was probably accurate.

The sinkhole after the area had been excavated and refilled last Wednesday.
The sinkhole after the area had been excavated and refilled last Wednesday.

First, the repair seemed to consist of digging out around the manhole and refilling the area. Drywells are typically surrounded by a “filter layer” that is designed to gradually transition from bigger, coarser gravel near the manhole structure to the native soil at the edge of the excavation. This is supposed to keep dirt from moving along with the water, preventing the kind of failure that happened here. Had the problem been a leak in a connecting pipe – another common cause of sinkholes – a much larger area would have been affected by the repair work.

The repair was also completed fairly quickly. On Tuesday the sinkhole was still there; on Wednesday the pavement had been cut and the hole excavated and backfilled; and on Thursday the area had been repaved. I have seen issues like this where the City has also needed to replace the manhole. These repairs require equipment to remove the old manhole and set the new and there is usually some sign – a staged backhoe or a manhole waiting to be installed the day before – that a more involved repair took place. This work included none of these. One day there was a hole, the next there wasn’t.

The hole before repair.
The hole before repair.

So the sinkhole is fixed! Now drivers (and cyclists) can use the full street width and we don’t have to worry about this particular instance of the problem growing. This has been a learning experience for me. Based on what I saw over time, I suspect that there is a way to use the condition of the overlying pavement to identify some holes before collapse. I have even found a few spots that I think are undergoing this same process. You can look forward to these being the subject of a future post!

To stay up to date with future Civil PDX sinkhole content, subscribe to this blog by entering your email address at the top of this page. New blog posts will automatically be delivered to your inbox.

If you found this post interesting, you might also like the following past posts from Civil PDX.
And then there was a sinkhole…
Passive vs. Proactive Design
Three Raindrops

20140911

Portland Civil Links 09/12/14

It was another week of great weather in Portland, as summer continues to hang on. Here are some civil engineering stories for the week that I found interesting.

  • Here at Civil PDX, I investigated a sinkhole that appeared along my daily bike route. Holes like this are not uncommon – a product of the City’s aging infrastructure. This one looks to be the result of an improperly functioning drywell. The process of discovering and writing about this problem has been an eye opening one for me and has made me rethink the possibilities of what could be happening beneath our failing streets.
  • With the school year underway, the Architecture Foundation of Oregon is gearing up for another round of the successful Architects in Schools program. This program teams AEC professionals with elementary school teachers to help kids learn about the design process. This is a great opportunity for working folks to contribute to educating the youth in our communities. I will be volunteering for my first time this year and I encourage you to consider doing the same.
  • Private development is going strong in Portland. The latest example being Gerding Edlen’s bid to buy 3/4 of a block in Old Town from the Portland Development Commission, where the developer plans to build a $37 million mixed use building. The story offers a slight twist in that Mark Edlen, the company’s CEO, is expected to joint the commission in October.
  • Speaking of a changing Portland, the Bureau of Planning and Sustainability launched a web site this week that allows you to tour the City’s Comprehensive Plan Open House from the comfort of your own couch. This seems like a great way to get more people involved in the process. The downside is that you will have to supply your own coffee and donuts.
  • Finally, the Hillsboro Hops – the Portland area’s minor league baseball team – beat the Vancouver Canadians 4-3 on Monday to claim the Northwest League Championship. This is a big accomplishment, coming off the second season after the team’s move from Yakima. Having been to games during both seasons, I have to admit that this year’s team was much improved and their record showed it. If you are thinking that this has nothing to do with civil engineering, you are right, but it is great anyway.

That’s a full lid for this week. Have a great weekend!

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Sinkhole-Warning

And then there was a sinkhole…

At times our city streets look like a patchwork of potholes, trench cuts and repairs – all signs of a long life of hard work. Some of these also point to the unseen problems and hazards that lie beneath the pavement.

Concord & Killingsworth Sinkhole

Cycling to work is one of my favorite parts of living in Portland. Engineering work is interesting and engaging, but like many modern professions it involves a good amount of sitting at a computer, and it is nice to be able to start and end each day with some exercise. I also feel like regular riding helps me as an engineer to better understand the needs of drivers, cyclists and pedestrians, and the effects of pavement conditions and different levels of pavement maintenance.

Each evening, my commute home takes me along Concord Street, a quiet bicycle boulevard through North Portland’s Overlook neighborhood. It’s often getting dark at this point in my trip, making it more difficult to see potholes and other potential ground level hazards. Hitting one of these isn’t serious, but a cyclist has to stay aware and be prepared to recover from a random jarring bump.

For months one particular pothole seemed to surprise me every time I passed. Each day I tried to remember the cross streets and location of the pothole, and each day I seemed to hit it head on. The situation was even more frustrating because this bump wasn’t really that big and should have been easy to avoid. It was less a pothole and more a dimple really. Instead of being broken or missing, the pavement here was depressed about 2 or 3 inches within a 6 or 8 inch diameter circle.

A dimple is a strange shape to see pressed into the pavement, even in a place that sees a pretty wide range of pavement distresses. Being an engineer, I would inevitably spend the next mile or so after hitting the dimple wondering what could have left such a weird shape in the ground. Construction equipment? A meteor? A bowling ball falling off a passing moving van?

And then, one day, there was a sinkhole. This video was from about a month after it first appeared.

The hole shown here is about 8 inches in diameter through the pavement – about the size of the preceding dimple – and widens to roughly twice that below ground. The cut extends down and around the adjacent manhole for about 5 or 6 feet. The axis of the hole is on a slight angle, but there is a fair amount of loose dirt on the low side, which could mean that the walls of the collapse are below the surface that we see here.

So where did this hole come from? It is a strange thing for something as strong and reliable as pavement to suddenly be swallowed up by the earth, and the question is (understandably) asked whenever a sinkhole appears. Believe it or not, even the biggest sinkholes are usually caused by very small, almost unnoticeable problems occurring over long periods of time. The overwhelming majority of these problems involve two things: rats and leaky sewers.

Our urban sewer systems are essentially massive underground tunnel networks and they make perfect highways for rodents to move around the city. Once in the sewer, a rat would exit through a break in the pipes – of which there are many more than we would like to believe. Digging upward, he would eventually reach a point where the roadway subgrade is too hard for him to continue, would flatten his trajectory and would head for softer ground, usually ending up in a landscaped area.

Inside the sinkhole: bad picture, bad problem.
Inside the sinkhole: bad picture, bad problem.

This rat burrow is now an open conduit for surface and ground water to enter the sewer system, much like our catch basins and pipes except that this conduit isn’t planned or lined. Over time, flowing water will wash soil into the sewer, which will in turn carry it away. The pavement above the hole will grow weaker and weaker as it loses support until it is entirely relying on its own material strength to stay in place. The hole will of course continue to grow and then, one day when either the hole has grown too big or a heavy load is placed above it, there will be a sinkhole.

While ratholes are a major cause of this type of problem, I don’t think they are the cause of this specific instance of the problem. First off, the hole is bigger and more wandering than might be expected from a rat. Second, as you can see on the map below, the manhole next to our sinkhole isn’t part of some long continuous pipe network. In fact, it isn’t a manhole at all. It’s actually a drywell, disposing of stormwater runoff collected from nearby local streets.

Concord & Killingsworth Sewer Map
The nearby sewer system as recorded on portlandmaps.com.

This map comes from the engineer’s best friend portlandmaps.com – a database of a wide range of GIS information for Portland and its outlying areas. The red dot on the map is the approximate location of the sinkhole. You can see that in this location water flows from the intersection into one of four catch basins, then into a manhole and through a series of two drywells.

I don’t know much more about the system than what you see here, but I think this is enough information to suspect that if a rat wanted to move from one end of the system to the other it might just cross the street. However, even if rats aren’t to blame for this sinkhole, the description of how it may have formed is basically the same. Somehow water starts to enter a leaky sewer, bringing dirt with it. Slowly over time the leak creates a hole until, one day, there is a sinkhole.

In this case the sinkhole borders a drywell. Drywells basically act as local disposal points for stormwater, which is directed into a well and then infiltrates into the ground. Systems like this one work well and are used throughout Portland to keep stormwater from overloading our ancient combined sewer system, in turn keeping sewage from flowing into the Willamette River. These drywells and the streets that surround then, however, are quite old themselves.

The City of Portland requires that all new conveyance pipes be designed for a 100 year service life. That span is shortened to 50 years for manhole structures. It is unlikely then that this drywell has “failed.” More likely is the possibility that groundwater, in addition to the intended surface water, is entering the drywell. The walls of a drywell are perforated and water is intended to move from inside the well to outside. Reversing the flow direction usually results in a small amount of dirt washing into the well each time there was a storm, creating a void under the pavement and eventually a sinkhole.

Sinkhole-Top
Unfixed, how much will this hole grow over the coming months?

So, we have a suspected cause for the sinkhole! What does that mean, though? The hole has still been sitting in the street for nearly two months with a single traffic barricade and a paint circle the only signs that the City knows it exists. My suspicion is that this repair may be complicated and that the City is having difficulty working it into their already overburdened maintenance budgets and schedules. Still, there is now a hole in the road and it will probably keep growing, especially as we start to see more rain.

Also, thinking back to the original dimple, I am pretty sure that I have seen similar marks on the pavement. Could these be hidden sinkholes waiting to surface? Could there be a way to use pavement distress to easily and proactively identify possible sinkholes like this one before they result in a potentially dangerous collapse? Does this process already in exist?

I plan to explore all of these questions in future posts. I am keeping a close eye on this particular sinkhole since I ride past it every day, and will track any developments here on the blog. In the meantime, I wish you safe travels. Watch out for those odd dips in the pavement. They might not be anything, but sometimes who knows.

To stay up to date with future Civil PDX sinkhole content, subscribe to this blog by entering your email address at the top of this page. New blog posts will automatically be delivered to your inbox.

If you found this post interesting, you might also like the following past posts from Civil PDX.
Passive vs. Proactive Design
A Framework for Understanding Details
Three Raindrops

Engineering commentary from Portland, OR

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