Every day, often without thinking about it, we walk or drive or ride our bikes over roads and bridges and take trains and buses. We also send water we use to wash our clothes, bodies, and dishes into pipes that take it to the sewer and beyond. We don’t tend to notice the systems of roads, tracks, and water transportation and purification that make these activities possible … until slow traffic or stopped-up or leaky pipes remind us how great it is when these systems work well.
Standing behind these systems, making sure they work well, are civil engineers like Tysheina Robertson. She helps make “the things people use every day without thinking about it: highways, sewer systems, bridges, potable [drinkable] water systems: things we use every day to improve our quality of life.”
Denver Transit Partners, the company Robertson works for, is building a commuter rail system for the people of Denver, Colorado. This will “reduce pollution and make it easier for people to get to the airport without having to drive.” In the New York City area, where Robertson grew up, commuter trains bring hundreds of thousands of people to school and to work every day. But until recently, there were no commuter trains in Denver. “When you don’t have it, you realize what you had.”
Robertson’s father first inspired her to go into engineering. “He is a self-employed home improvement contractor and I wanted to be a construction worker.” She also found the books she read inspiring. “When I was younger, I used to read a lot of Nancy Drew. She had to put pieces of a puzzle together to solve a crime. The same goes for engineering: it all starts with a need. For example, whoever designed the Snuggie: we’ve all had that same idea. You’re reading, you put the blanket up, but your arms have to come out. What are you going to do with your arms? It all starts with a problem.” Though the mystery novels about the teen-detective Nancy Drew don’t say “that she used the scientific method, that’s pretty much what she used. I learned that in the third grade and I still use it today.”
In middle school, Tysheina’s dreams of construction work shifted towards engineering: “One day we were going around the class” at Adam Clayton Powell Junior High School “and my teacher was asking everyone what they wanted to be. I was 13 years old and I told him I wanted to be a construction worker.” Tysheina’s teacher told her “to think about being a civil engineer.”
Thanks to her father’s inspiration and her teacher’s encouragement, Tysheina took the exam for New York City’s specialized high schools and made it into one of the city’s most prestigious programs. At Brooklyn Technical High School, “they have different majors you select in your junior year. I selected civil engineering, liked it, and decided to pursue it in college.” After graduating from Brooklyn Tech, she headed to Morgan State University in Baltimore.
“Back then and even now, the part I liked best” about engineering “was that I wasn’t sitting in an office all day. I was a tom boy so not wearing dresses and all that stuff was appealing to me.” So was “the challenge, the thinking aspect of it (I’m a chess player): the problem-solving was something I liked.” Robertson also likes the variety involved in her work. “I like the fact that when the project is over, I start a new project. Each project is different.” “It’s a team environment.” “You get people that you work with from all over the world and all over the country: it’s a very diverse environment.”
At work, “we use geometry a lot: the angles and the curves that we use for our highways and our bridges.” Choosing the right one to “incorporate into your design increases the strength in your structure. There are a lot of triangles in bridges. A triangle is stronger than a square, because the forces that are applied to a triangle” cannot crush it as easily. “If you take your fingers and make a triangle, the triangle is stronger because they hold each other up.”
Robertson also uses geometry skills to make sure that the drainage systems in Denver’s railway stations work well. “When it rains, where does the rain go? The reason why there are puddles and things get backed up is because the sewer system wasn’t designed or constructed properly or was designed too small.” Robertson and her colleagues are building approximately 16 train stations. “In a train station, when it rains, the rain has to go somewhere. The water has to drain at a particular slope.” It’s important to take advantage of gravity. “When a sewer system is designed, the cheapest way to design it is to make sure that your flow always goes downward.”
As she works, Robertson converts metric measurements into customary units used in the United States. “Our actual physical trains are designed and built originally in South Korea; they are on a different system than we are: they use centimeters and meters.” Knowing how to work with these different units of measurement is an important requirement for people seeking an engineering license.
“There’s a lot of physics involved” in building a railroad as well. “Physics is the base level of engineering and it’s tied with the math. Differential equations, calculus, and higher levels of statistics: we use all of these things daily on this project.”
Working with the budgets required to fund these types of projects also requires using math. “You have to track how much money is spent where, so everyone gets a good return from their investment. My project is valued at about 2.5 billion dollars. The public came up with one billion from the federal government and my company invested another billlion. The transit system invested about half a billion dollars of their own money.”
Robertson audits the process for ordering equipment like girders for bridges. (Girders are horizontal main structural members that support vertical loads. They can be made of a single piece or of more than one piece bound together.) She has to keep track of the number of girders required for each project. “Every bridge is custom-designed. You need to know how many, which size, and which type of girder” to order. This information varies with the purpose of the bridge and the load it will have to carry: will people walk across it or will it have to hold cars, trucks, or trains?
Engineers must balance finances with architectural aesthetics. When a bridge is beautiful to look at, it often has a more complex design and costs more money to build. New York’s Tappan Zee Bridge “has a relatively simple design, which generally costs less money.” Robertson compares more complicated bridges to a “luxury car fully loaded: you pay more.”
Next time you drive, bike, walk, or take a train or bus across a bridge, think about the civil engineers whose work went into making sure its design would keep you safe, dry, and perhaps also inspired by its beauty.