Here’s a thought that’ll freak me out the next time I cross the Verrazano-Narrows Bridge linking Brooklyn and Staten Island: The span sits as much as 12 feet lower in summer than in winter because of the seasonal expansion and contraction of its steel suspension cables.
Not 12 inches, a variation I could comfortably assimilate into my simpleton’s comprehension of bridges. Twelve feet.
Here’s another arresting fact that also comes courtesy of the bridge’s owner, New York City’s Metropolitan Transit Authority (MTA). When placing the towers eight-tenths of a mile apart and dealing with the mind-numbing variables relating to structural weight, cable strength, anticipated vehicular loads and the geology of the Narrows’ floor — to name but a few considerations — the engineers who designed and built the bridge had to account for the curvature of the earth.
It was the longest suspension bridge in the world for 17 years and is still long by any standard. Yet this massive structure, visible from the distant boroughs of Queens and the Bronx, can shimmy uncomfortably when runners pound across it during the New York City Marathon. It’s a function of the flexibility designed into long-span bridges to accommodate motion and stress.
Now consider this tale of two bridges. New York’s monumental oceanic gateway opened to traffic in 1964, the same year as the steel truss arch bridge that faithfully carried Interstate 35 West’s traffic across the Mississippi River at Minneapolis until it collapsed under the evening rush on August 1, 2007. Thirteen people died, more than 100 others were injured.
MTA is preparing to spend $300 million to replace the New York double-decker’s concrete upper level with an orthotropic steel deck, an expensive retrofit that will make it thousands of tons lighter and extend the bridge’s expected life 100 years.
Inspectors had twice declared the Minnesota bridge — like thousands of others across the country — “structurally deficient,” a federal designation that doesn’t foretell imminent doom so much as it urges serious repairs. The day after the collapse, Governor Tim Pawlenty said the bridge had been tentatively scheduled for replacement in 2020. Instead, Minnesotans spent nearly $300 million to replace it in one year, pay out an early completion bonus and compensate families for their incalculable loss. The result, the award-winning I-35W St. Anthony Falls Bridge, is also expected to last a century.
The Minnesota disaster happened a few weeks before some 40 young men and women thinking about a future as civil engineers arrived for their freshman year at Notre Dame. Now these students are juniors immersed in what one professor calls the “real, hardcore concepts” of civil engineering. The ominous boom above their heads one sunny Sunday morning this past autumn wasn’t the nation’s infrastructure problems crashing down upon them. It was an experiment-in-progress at Lehigh University, the last stop on their class field trip to New York City, testing the next upper deck of the Verrazano-Narrows Bridge to make sure it really will serve 100 years without cracking.
‘One big pothole’
We all might want to think seriously about civil engineering and infrastructure because our report card is ugly. At a time when the nation is fighting two wars, has flunked capitalism for the first time in 70 years and is aggressively negotiating its grades in healthcare and education, the American Society of Civil Engineers (ASCE) says we’re pulling a D in infrastructure. Their 2009 report card awarded one of the best marks in any category, a C, to our bridges.
The secretary of transportation has called the United States “one big pothole.” A study released last May by the American Association of State Highway and Transportation Officials declared a third of our interstates, highways and major roads “mediocre” or worse.
Oliver Wendell Holmes Jr. famously said that taxes are the price we pay for civilization. Today we can add that sensational auto repair bills are the price we pay when civilization crumbles. Bad roads cost car owners $400 yearly. Double that if you live in a metro area of more than a quarter million people, the transportation officials say.
What about the rest of our infrastructure? The civil engineers say we daily lose about 7 billion gallons of water to bad pipes and face an $11 billion backlog to replace obsolete water works and meet federal safe drinking water standards. ’Tis but a drop compared to what comes out the other end, an estimated $390 billion to overhaul our wastewater treatment systems and meet new demand over the next 20 years.
Suburban development has crept up on our dams and levees, which are getting old and dangerous much quicker than we’re fixing them. Mass transit, the fastest growing transportation sector for 15 years, isn’t keeping pace with demand. The bottom line, according to ASCE, is $2.2 trillion to catch up with ourselves over the next five years.
That doesn’t count the persistent threat of terrorism and everything else we know is coming: rapid population growth; natural disasters like the massive earthquake the Pacific Northwest anticipates within the next 200 years; the high-stakes coastal clash already pitting the oceans against those of us who insist on living next to them.
Cue every cliché you’ve heard about opportunity in adversity, but today’s civil engineering students are going to spend much of their careers fixing or replacing this stuff. Demand for their services far exceeds supply. “This is a fantastic time to be an engineer,” says Michael Sweeney, the vice president of engineering superfirm AECOM’s Transit Rail East division and the emcee for the Notre Dame field-trip stop at the company’s offices in downtown Manhattan.
A show of hands reveals this is a first visit to America’s largest and most complex, confounding and fascinating city for more than half the students. Sweeney welcomes them with internship applications, enticing them to come back next summer.
Building to last
You don’t go into civil engineering if your goal in life is to make a lot of money, student Kimberly Duffy says.
That’s not to say it never happens. Notre Dame sends just a few dozen graduates into the field each year, and for a small program it’s well represented in the senior leadership of firms with national and global reach like AECOM, Skanska, Granite and Kiewit. But civil engineers draw the lowest starting salaries among their peers. Money comes easier in petroleum and nuclear.
Instead, civil engineering is about service to society, says Professor Tracy Kijewski-Correa, a tall-buildings expert who teaches structural engineering. Students learn to provide basic public services. “There’s no consumer for what we do,” she says.
“That’s one thing that sometimes attracts students into civil engineering,” agrees Professor Yahya Kurama. “The fact that you’re going to make something that will last for a long time.”
Some years ago it wasn’t clear the attraction was holding. So in 2003, the department tapped a travel fund created by Dennis Murphy ’71 and worked with his firm, Kiewit, to create a field trip that would introduce ND civil engineering students to the challenges of large-scale projects. Kijewski-Correa led a group up the Pacific Coast to examine bridges. They wound up at the Tacoma Narrows Bridge in Washington, where Kiewit had begun construction on a second span the year before.
“It isn’t always possible to force yourself in the middle of the night to remember why you’re studying differential equations or thermal dynamics,” notes Murphy, who got hooked on construction as an undergrad and valued the trips he’d taken with classmates to Chicago and Lake Michigan’s dunes.
“Get them dreaming,” is how the current trip leader, Professor Joannes Westerink, distills the purpose. In 2006, Westerink and his colleagues took students to the Mississippi Delta and New Orleans to study the hell wrought by Hurricane Katrina. They couldn’t have bought a better guide. Westerink, affable and courteous, builds weather models for the ocean that predict with incredible precision how fast water flows, how it carries sediments and pollutants, how it forces itself inland when propelled by severe storms.
The Advanced Circulation Model he has developed with his colleagues, many of them former students, is the vehicle for collective work on storm surge shared by the Army Corps of Engineers, the Federal Emergency Management Agency, the Navy and a host of other agencies, consultants and universities. It’s the kind of knowledge engineers need to build better levees, create all-important digital flood insurance rate maps for threatened states and think critically about the future of coastal cities like New Orleans.
Now teams of ND faculty will apply their wide expertise to a pair of hurricane preparedness projects. One will model flood risk for Pacific islands. The other will create a comprehensive model for Hawaii, detailing the impact that rushing, piling water and high winds would have on roads, buildings, bridges and people. “It combines everything related to infrastructure,” Westerink says.
On the New York field trip, the students learn that storm surge and rising seas are no less a concern for Manhattan than New Orleans. Subway entrances in some places are only a few feet above sea level; a devastating 1893 hurricane took out elevated tracks in Brooklyn and obliterated an island near what became JFK Airport. Even under normal conditions, “New York is in need of retrofitting for a significant part of its infrastructure,” Professor Alexandros Taflanidis says. The catalog of challenges in a metropolis of 19 million people is exhaustive.
This year, after 12 hours on a bus barreling east from South Bend on I-80, Westerink, Taflanidis and their students begin with an after-dinner walk across an old challenge gloriously met: one of the city’s first world-class engineering achievements, the Brooklyn Bridge.
Faster, safer, greener, smarter
The following morning, after Michael Sweeney’s introduction at AECOM, the students learn about the company’s work on the Second Avenue Subway (SAS) line and the World Trade Center Transportation Hub.
The long overdue 8.5 mile SAS and its 16 new stations will relieve the Lexington Avenue Line, the sole north-south subway option up Manhattan’s East Side that carries 1.3 million riders daily. The project has been kicking around since 1929, only to hit the vagaries of finance and local politics. It stalled out in the 1940s and again in the ’70s.
The project’s final design is expected later this year, but the brutal-yet-delicate job of excavating station sites and tunneling through the undulating bedrock and sediments beneath Second Avenue’s six lanes and 20-foot sidewalks has begun. Public relations are sensitive. Whole blocks have become worksites. “The big challenge in New York is finding space while minimizing impact on the public,” explains senior tunnel engineer Jaidev Sankar. Things don’t get easier underground. “We found utilities even the utility companies didn’t know were there.”
The WTC’s Transportation Hub will glamorously reconnect the surface city with the PATH commuter rail station that served lower Manhattan before 9/11 — and has again since its 2003 reactivation. Riders will arrive and depart through an underground structure similar in size to Grand Central Station, designed by Spanish engineer and architect Santiago Calatrava. It will emerge above grade in a white monument of steel ribs and glass that Calatrava envisions as a child’s hands releasing a dove.
Project managers say one goal is a more versatile facility linking riders with Manhattan’s throng of transit options. Another is to restore what was once the highest grossing retail space in North America — engaging a “small city” of commuters and shoppers each day — under the natural light filtering down through Calatrava’s design.
The design challenges are both practical and spectacular. Sixty escalators, 40 elevators. Steel platforms cantilevered out 75 feet. “One of the joys of Mr. Calatrava’s architecture is holding stuff up with no visible means of support,” project architect Joe Hand notes with an exasperated mixture of professional appreciation and irony. “What he does is challenge your mind to say, that thing shouldn’t be hanging out there, but it is.”
Some 200 designers worked five years to ensure redundancies in structural, mechanical and electrical systems, Hand says, “so that this building doesn’t suffer the same fate as its predecessor.” Terrorism, a leading concern, will be a fact of professional life for engineers working on prominent projects. Meanwhile, transit through the hub must function continuously.
Later that afternoon, the focus shifts to sustainability when the students visit the headquarters of Skanska USA on the 32nd floor of the Empire State Building, the first office in its class to receive “platinum” certification under the Leadership in Energy and Environmental Design criteria set by the U.S. Green Building Council. About 80 percent of New York’s carbon footprint today comes from the energy used to construct and maintain buildings, city data shows. It’s a compelling statistic, given projections that the square footage of our built environment will more than double globally over the next 20 years.
Skanska officials lead students through an on-site review of the company’s work in progress on the United Nations’ Capital Master Plan, a sweeping modernization that will yank the epicenter of global diplomacy out of 1954 in everything from its electrical wiring to its audio translation systems while preserving the five-building complex’s historically spacey look and feel.
By evening it’s back to bridges at Columbia University’s Carleton Laboratory, a major locus for bridge monitoring and research. One eye-catching experiment lives in a transparent chamber the length of a charter fishing boat. It contains a segment of 20-inch bridge cable undergoing a corrosion simulation while sensors measure humidity, pH levels, temperature shifts and other enemies of structural integrity.
Designing long-span bridges is part of the curriculum for Patrick Brewick ’09, who is getting acquainted with it all as a Columbia grad student. Nearly three in 10 ND civil engineers pursue graduate study. Brewick traveled to New Orleans as a junior and caughtWesterink’s passion. “I saw that same enthusiasm in all the engineers there. They really had a love for what they were doing,” he says. “It actually led me to start getting interested in graduate school.”
Fluid development
Professor Stephen Silliman, who has spent a lot of time working on water quality in such countries as Benin and Haiti, says we have civil engineers as much as doctors to thank for the sharp decline in U.S. infant mortality rates since the mid-19th century.
Today, “We have no fear — or maybe just a tiny bit of fear — but we have no real fear of turning on a water faucet and drinking out of it,” Silliman says. Should we get complacent or stingy about maintaining our high standards though, we’re fools.
New Yorkers boast that they have the best drinking water in the world. Ten percent of their supply comes from the Hudson Valley’s Croton watershed. Since the city started drawing there in 1842, the water has flowed unfiltered some 125 miles to customers’ taps. Now development in the watershed threatens quality and the water no longer meets federal standards.
The $1.3 billion Croton Water Filtration Plant is the largest single construction contract in city history, and the largest project Skanska has ever undertaken. Today it’s a nine-acre square cut 95 feet into the earth and run through with pipes large enough for people to stand in. Think of it as a giant packing box that could store about 1,500 single family homes underground.
When it’s done, the filtration plant will lurk quietly beneath a golf course in the Bronx’s Van Cortlandt Park. Gravity will pull the water in and pumps will force it through mixers, filters, chemical processes and UV treatments, nine minutes in and out, up to 13 million gallons per hour.
“On a construction site, you don’t want to multitask,” project safety director Michael Caterina warns. Walking through the plant’s unfinished maze of pipes, rebar and concrete wall, student Megan Smith strains to talk above the staccato drumming of air compressors and jackhammers and the unnerving air horn blasts that remind workers of the murderous, crane-borne loads passing over their heads.
Smith says her generation’s biggest challenge will be matching its ideals and desire to tackle big problems like global poverty to the long-term commitments required to really help poor communities. One hurdle is the absence in developing nations of the kind of regulatory environment that keeps workers at the Croton plant safe and healthy. So Smith has added classes in political science and economics to her heavy engineering courseload to prepare for the human and cultural dimensions she expects will shape her career. She may work a few years and pursue graduate study in international development.
“You need to have some expertise and know how to do this,” she says, motioning at the activity around her, “before you can think about how to change it, make it cheaper, make it efficient and then take it somewhere else.”
Pardon our progress
“Without water and the subways, New York City wouldn’t exist,” Granite Construction project manager Jim Steers posits later that afternoon. The students are standing on a temporary footbridge at the Avenue J subway station on Brooklyn’s Brighton Line. Miles away, the Empire State Building looms above the trees and a bend in the tracks, a scenic view that draws attention from the gaps in the corroded steel posts big enough to put your arm through, or the concrete missing from the station’s beams and platforms.
Steers’ team is rehabilitating five stations. Thirty years ago, he tells the students, New Yorkers endured several minor derailments a day. It’s down to two or three per year now, thanks to the city’s persistent reinvestment.
For the most part, life and business go on around the work, slowing it down. Granite can’t shut down three stations in a row and must keep Avenue J open to allow “backriding” — riders travel past their stop, switch trains and return from the other direction. Complex scheduling, Steers says, accounts for much of the relatively high cost of these projects.
So it’s ironic when the lead stories on local news broadcasts that night report some of the worst rider headaches in memory. MTA said 18 of the city’s 20 lines were affected and 400 buses were employed in order to expedite maintenance work around the city before winter.
Not to fear. The sun rises on New York the next day. The students forge once more into the quiet city for Mass at Saint Patrick’s Cathedral before the long trip home.
Take nothing for granted
If you have a child obsessed with Lincoln Logs, Legos or K’nex, you may be raising part of tomorrow’s infrastructure solutions. That child playing on your living room floor may one day, as Professor Westerink says, make the world stronger, greener, safer and more efficient.
Olga Beltsar was one such child about 12 years ago, she explains before a presentation about graduate programs at Pennsylvania’s Lehigh University, the trip’s final stop. Girls liked to build things, she confides with mock superiority. The boys she knew liked to break them. Fortunately, for work that marshals both creative and destructive impulses, ND’s juniors are split about 50-50 down the gender line. But her classmate Brian O’Connor says engineering began for him with the suspension bridge he fashioned out of drinking straws in the 5th grade. That structure didn’t survive the trip home, but the foundations of his future were poured.
Brian Wysocki rode the train every day from Long Island to high school on Manhattan’s 84th Street. “He tried to take a different route each time,” his mother had said over pizza at Brooklyn’s L&B Spumoni Gardens, explaining her son’s fascination with transit. Beltsar’s path was even more circuitous. In high school, the father of a young girl she tutored helped her find an office job in an engineering firm. She’s since interned in both construction and design, and expects to pursue the latter in her career.
Engineering often matches youth with responsibility. Ken Burns’ 1981 documentary about the Brooklyn Bridge notes that the average age of the engineers was 34. Most of the engineers leading the Croton plant tour were a few years out of school. At lunch that afternoon, Eric Harvan, one of the ND students, had mentioned an internship documenting progress on the construction of a factory and helping with bids and contracts. One day two superintendents handed him drawings for a shipping office the client wanted inside the warehouse and said, “Get it built.”
Not to be grim, but all those young engineers will be dead by the time the Verrazano-Narrows needs another deck in the 22nd century, which brings us back to that apocalyptic thrum above our heads in Lehigh’s Advanced Technology for Large Structural Systems lab. The sound, explains senior research scientist Sougata Roy, is actuators simulating the passage of highway truck traffic, one tandem axle lumbering by every two seconds. “The idea,” Roy says, “is to ensure that even the heaviest truck will not cause any cracking to the structure.” Keep things going for eight months without stopping, and you’ve simulated 100 years of constant, reliable service.
Lehigh professors brief the students on several current experiments. Across the room, actuators apply earthquake forces to a four-story “self-centering” steel frame, testing a system that will essentially allow buildings to rock their way through overpowering winds or a seismic event and restore themselves, undamaged, to their original shape. The computers driving the actuators also simulate the behavior of the rest of the building — a hybrid test that extends the research beyond the physical space of the laboratory. Understanding how large structures fail is a lesson as valuable now to the funding entities as it will be to students throughout their careers.
Therein lies our hope, says Westerink — given adequate finances, planning, determination and the right people, of course. As our grasp of the physics of the world around us has shot forward over centuries, our computational capacity has grown exponentially in just a few years. It’s possible now to imagine hurricanes in Hawaii and earthquakes in Southern California in all their random ferocity, or forces and stresses of any kind, really, across the thousands of sprawling, fragmented jurisdictions and markets that together support our national infrastructure.
As all knowledge does, this holds the power to make us stronger. Or at least a little less freaked out.
John Nagy is an associate editor of Notre Dame Magazine.
Photos by Brian Bloom.