America has a throw-away culture. It’s so pervasive that it’s hard to recognize unless you spend some time in another country. During several stays in Europe, my wife and I observed much more re-use of clothing, furniture, jewelry and even plastic grocery bags (in many countries, you have to purchase your bags). As a structural engineer, I was most impressed with the re-use of centuries old buildings.

The trend of adaptive re-use has caught on with a passion in Chicago. Soldier Field, the Chicago Bears’ historic stadium, is the most prominent example of such a project. Critics allege that new space-aged grandstands rising from within the classically styled colonnade create a post-modern eyesore. Nevertheless, the ability to re-use the site and adapt it to the requirements of a modern pro football stadium is impressive.

Such adaptations, albeit on a less visible scale, are happening all around the city. My first assignment upon returning home was the renovation of an old 1920s warehouse building into a high-priced loft condo development. Loft-style condos with high ceilings and exposed heating and cooling ducts have a strong appeal to the young professionals moving into the city.

The scope of this project involved designing new balconies, reinforcing the old load-bearing masonry walls, and evaluating and strengthening the existing heavy timber beams and columns for a change in occupancy. In the 90 years since the building was first opened, construction materials and techniques have changed significantly.

The old brick walls are up to five wythes (brick rows) thick. The original designers were caught in a Catch-22 when designing the walls. Load demands required thicker walls, but each additional layer further increased the load to the point where the self weight of the wall dwarfs the applied loads from wind and occupancy. At some point in the building’s life, stores opened up on the first floor and large store-front openings were cut into the walls on the first floor. Our investigation revealed that the narrow piers between these openings were overstressed according to the current code requirements. Instead of prescribing an expensive process of drilling into the existing pier to attach steel reinforcement, we opted to provide new steel posts to share the load from above.

The columns, beams, and flooring in this old warehouse were timber. The architects on our project really appreciated the aesthetic of the large timber elements and decided not to cover up the structure. Unlike steel, a homogeneous material with reliable strength, wood strength varies by species, quality and direction of loading. We called specialists to the site to visually grade the timber columns and collect samples to determine the species. For those columns that were given a poor grade, based on splitting, the number knots and other criteria, we developed a steel reinforcement detail. Because the columns were to be exposed to the occupants, we avoided clunky bolts that might protrude from the surface and present a hazard. Our solution included a combination of long wood screws and metal strapping like the type used to fasten traffic signs to light poles.

I enjoy working on renovation projects, because they present interesting challenges. The structural materials and construction techniques are rarely discussed in school, so you sometimes have to dig for information in old manuals or discuss the problems with other experienced engineers. The work may not be as glamorous as a brand new skyscraper but it is rewarding in its own way, and you can feel good knowing that you’ve contributed to the socially responsible act of re-using a “perfectly good” old building.

The Great Chicago Fire of 1878 was a seminal moment in the history of the city.  Tragic at the time, it’s probably the single greatest reason for the thriving modern city.  It provided a chance to start over with a plan.  The rebuilding effort gave great architects like Louis Sullivan and Daniel Burnham a blank canvas from which to create a revolution in city planning and building design.  Even today, politicians and local activists decry the development of some public property as being opposed to Burnham’s master plan of the city.

Ironically, the city actually looks nothing like Burnham’s plan. A huge tapestry with a reproduction of the city plan hangs in the lobby of a prominent downtown skyscraper – open to visitors who take the Chicago Architecture Foundation’s Modern Skyscraper Tour.  The plan shows a radial street plan converging at a single city center and a grand boulevard similar to the Champs Elysées in Paris.  Chicago actually has a regular rectangular street grid.  Burnham’s major boulevard actually ran perpendicular to Michigan Avenue (the Magnificent Mile).  The most lasting legacy is the preservation of the waterfront for public use.  However, much of the current waterfront park system was really made possible by landfill (debris from the fire and, later, engineered soil fill) into Lake Michigan.

Ultimately, economics superseded the plan and the laws of supply and demand resulted in a construction boom in the central area of town nestled between the Chicago River and Lake Michigan.  Today, locals call this area The Loop.  It’s so named because the elevated light rail system (called the “El”, get it?) forms a closed circle around the business district.  Much of the El runs through the city, above the streets, providing an interesting view of the city from the second floor up.

Another irony of Chicago’s role as an architectural leader is that the soil is really lousy for supporting large structures.  So while cities like Paris and New York were busy digging subways through rigid limestone, engineers in Chicago were faced with soupy clay.  Two subway lines do run through the city, but old construction accounts indicate that the work almost collapsed several buildings.  Many of the major innovators in geotechnical engineering did their pioneering work in Chicago.

The El is now over 100 years old.  Decades of expansion and repair have done little to change the overall look and feel of the system.  To fit on the narrow elevated tracks, the cars are narrower than in most new transit systems.  To get close to someone in Chicago, you need only ride the El into the loop during rush hour.  The transit authority faces a serious challenge of accommodating the all-time high level of ridership, while the government becomes more reluctant to fund public transit.

Like the reopened speakeasies and blues bars, the El connects people with the city’s rich history.   Unlike some other historic ghosts, the El is a functioning reality that the city cannot live without.

This is your captain speaking.  We are on our final approach to O’Hare Airport in Chicago.  Winds are 20 miles per hour from the Northwest, and the current ground temperature is 14 degrees Fahrenheit.

Instinctively, I turned to my right to look out the porthole window.  Snow.  My heart sank.  Returning from a six month stay in Denmark, I had not prepared myself for the reality of returning to Chicago in late December.  Despite being several latitudes further north, it rarely snows in Denmark.  As I turned around to complain to my wife, I caught a glimpse of the famous skyline out the opposite window.  Immediately, my thoughts turned to the man-made wonders of Chicago.

By the time the plane lined up for landing, I had a perfect aerial view of the city – a skyline that no city in Europe can match.  The excitement of returning home insulated me from the cold as I walked up the long jet way into a new chapter of my life.

Before turning that page, however, I’d have to navigate my way out of the airport. Fortunately, the United Airlines terminal at O’Hare is actually one of my favorites. I really like how the designers used large windows and skylights to let a lot of natural light into the concourses. A system of regularly spaced steel frames is necessary to provide adequate stiffness for the glass. Custom bent steel beams are perforated with round holes to provide visual lightness and save material. However, I suspect that there was a lot of collaboration between the engineer and the architect on the appearance of these bents. The structural detailing is prominently featured as an aesthetic quality of the form; we like to call this expressed

Construction on the terminal started in 1985. My company first started working on airport buildings in the late 1960s in San Francisco. Today, that portfolio has grown to include projects as far away as the United Arab Emirates. Aviation is a huge market for almost all disciplines of civil engineering. In fact, many airplane designers, including those working with advanced composite materials, are recruited from the ranks of civil engineers.

Although it was freezing outside, I was able to enjoy the December sun inside the bustling terminal. I’m rarely so poetic about my time in an airport, but this occasion seemed special. I was fondly looking ahead to the projects and activities awaiting me in Chicago.

Likewise, I am excited about this opportunity to continue sharing my story with you. We have a lot of new feature planned, including YouTube videos and reader polls. I want to focus especially on making this blog compelling to ASCE’s student members, but everyone is welcome to participate in the experience. Finally, I look forward to your comments. For me, the most exciting part about writing this blog is reading your reactions to it.

Please look down. The moving walkway is about to end. It’s time to move on.