Dr. Man-Chung Tang is as likable as his bridges are construction friendly. Meeting him for the first time on the podium at the awards luncheon during the International Bridge Conference in Pittsburgh in June, he greeted me with a warm smile and friendly handshake. Dressed in a bluish-gray suite, the diminutive man with gray hair and glasses seemed genuinely happy and humbled by his selection as the recipient of the Engineers' Society of Western Pennsylvania's 1998 John A. Roebling Medal for lifetime achievement in bridge engineering.
Although his hair is gray, his youthful attitude toward his work and his fellow engineers in the room belies any hint of age. He doesn't seem old enough to be eligible for a "lifetime" award. However, his resume shows that he is more than deserving of the medal. The chairman of the board and technical director of T.Y. Lin International has experience throughout the world in the design and construction of more than 100 bridges, including more than 30 cable- stayed bridges and four suspension bridges. It is estimated that he has been involved in 30%of all the segmental bridges in North America. In 1995, he was elected to the National Academy of Engineering for his contribution to the advancement of cable-stayed bridges, an accomplishment he lists as his highest honor.
Dr. Tang is one of the world's authorities on cable-stayed bridges," said Ron Crockett, vice president of American Bridge, Pittsburgh, a specialty general contractor on large bridge projects. "But he doesn't have a huge ego. He listens to others' opinions." Dr. Tang has worked with Crockett as a construction design consultant on several bridge projects throughout the world, most recently on a bridge expansion project spanning the Tagus River in Lisbon, Portugal.
He became a bridge engineer for a simple reason. "I like to work on something that I can see," he told ROADS & BRIDGES. "When a civil engineer designs something he can see the results and bridges are one of the most visible objects. Bridges also are more advanced in structural theory because they are more advanced structures. They require an engineer to keep up on the latest knowledge."
Although he finds all bridges interesting, Dr. Tang made his mark, designing and building cable-stayed and segmental bridges.
"Engineers should always keep an open mind. Nowadays materials and products change so fast," he said. "Also one place may have different conditions than another. If you are building the same bridge in Florida and New York the price will be different and the way of doing things may be different. You have to research the local conditions, the market, the equipment available. These things can change the whole design."
Born in China just prior to World War II, Dr. Tang's work as an engineer is driven by his quest not only to build bridges for transpiration but to build bridges for the good of mankind. At the close of a presentation on his work during the awards luncheon, he said to his fellow engineers, "Build bridges that you can see and touch, but I encourage you also to build bridges between people for the purpose of peace."
Toward this goal, Dr. Tang has traveled the world providing design and construction engineering services. When I contacted him in early July to continue our conversation on his work and his philosophy, he was in his office in San Francisco preparing to leave for Hong Kong to work on another project.
As he said in Pittsburgh, "The sun never sets on my bridges." The phrase that has become his trademark, is more a statement of his own surprise and joy at this achievement than it is a sign of ego. "I was talking to some friends on one occasion when one of them asked where I had built bridges. I took out a globe and pinpointed areas, in South America, Africa, Europe, the Middle East, the U.S. and China. I had never noticed it until that happened, then I said, 'you know, the sun never sets on my bridges.'"
Dr. Tang took a circuitous route on his road to becoming a bridge engineer. In 1959, he received a scholarship to attend school in Darmstadt, Germany, where he majored in soil mechanics. "At that time, the most famous professor, Dr. Kurt Kloeppel, was very well known for his work on bridges and steel structures. I said to myself that since I came all this way I wanted to do research work with the best professor."
According to Dr. Tang, at the time, the Technical University
Darmstadt was the smallest university in Germany with about 4,700
students. Though small in size, Dr. Tang was surprised by the
richness of the school's curriculum. "Besides the regular civil
engineering curriculum, the school offered many special courses,
which were taught by specialists and practitioners. Because tuition
was free, a student was free to take as many courses as they wished.
Consequently, I was able to take many very special courses."
Building a career
Following school, Dr. Tang worked in Germany from 1965 through 1968. As a bridge engineer for the steel company, Gutehoffnungshutte (GHH), in Germany, he worked on the tender design of the Little Belt Bridge, a steel suspension bridge in Denmark. "GHH was similar to what U.S. Steel used to be," said Dr. Tang. "They produced, fabricated and designed. They did everything from iron ore to finished structures."
As co-designer of the 320-m span cable-stayed Knie Bridge, he was in charge of cable and anchorage design, nonlinear analysis and aerodynamic investigations. The structure was constructed of steel and featured an open girder design and an orthotropic deck.
Dr. Tang credits the training he received in school for his initial success at GHH. "All these special courses and the knowledge in computer programming gave me a big advantage in the practical design when I started working," he said. "For example, it allowed me to study the aerodynamics for the Knie Bridge in the short period of time afforded by a design/build schedule. The bridge, a world record at that time, was extremely slender and sensitive to wind, especially during construction with a 1,050-ft free cantilever, which was another world record at that time."
Subsequently, he served as project engineer in charge of the design of the 350-m span cable-stayed Neuenkamp Bridge in Germany. At the time of its completion, the steel box girder orthotropic deck bridge surpassed the Knie as the world's longest span cable-stayed bridge.
"I've worked on a lot of cable-stayed bridges and concrete segmental bridges," Dr. Tang said. "I've probably worked on more long-span cable-stayed bridges than anyone else in the world.
"I must make it clear, however, that I didn't design all the bridges on which I've worked. On a bridge project there are two parties: the designer for the owner and the designer for the contractor. Someone has got to show the contractor how to build the bridge. In the old days, companies like American Bridge would design and build the bridges. They're all out of that business now."
In 1970, Dr. Tang joined the firm of Dyckerhoff & Widmann Inc. in the U.S. as vice president and chief engineer, where he was responsible for the design, redesign, and construction engineering of many long-span segmental concrete box girder bridges in the U.S. and Canada.
In 1978, he founded DRC Consultants Inc. in New York. In 1995, DRC and T.Y. Lin International merged. Dr. Tang assumed the offices of chairman of the board and technical director of the combined company.
"In the '70s and '80s, I saw an opportunity to bridge the gap between the engineer and the contractor by providing design services to the contractor, as well as to the owner," Dr. Tang said. "Cable-stayed and segmental bridges were just getting started in the U.S. at that time and no one knew how to build them. I had had experience working with them in Europe."
The timing couldn't have been better for Dr. Tang; his services were in high demand. He recalled one particular long-span segmental bridge in Canada. "The owner specified that the contractor needed someone to do construction design for them. Out of the eight contractors bidding on the project, all of them listed me as the construction designer. They couldn't find anybody else."
Dr. Tang's first major segmental bridge in the U.S., the 450-ft-span Pine Valley Bridge near San Diego, was designed for Caltrans.
"There's been a lot of projects go under the bridge, so to speak, since
we first worked together," said Walter Podolny, senior structural
engineer for the Federal Highway Administration (FHWA). Podolny
and Dr. Tang first met in 1971 and have worked on bridges around
the world, including the Pine Valley Bridge. "I've always found him
to be professional. He always does his best, which is more than
enough." He later added, "He's also a barrel of fun."
Bridges of choice
Does Dr. Tang have a favorite bridge? "I have over 100 bridges. When one is finished it's like a child. You can't say you love one more than another. Structurally and aesthetically I would have to say the Talmadge Memorial Bridge in Savannah, Ga., is my favorite. It's very elegant." The bridge is an 1,100-ft-span cable- stayed design.
Another bridge on his list of favorites is the Acosta Bridge, a girder bridge in Jacksonville, Fla. "We had to resolve some problems with the bridge. We had to make the bridge unsymmetrical to accommodate local conditions having to do with the channel the bridge spanned. We made one side bigger to attract more bending moment to allow the other side to be shallower."
Dr. Tang is held in high regard with those with which he has worked on both the government and contractor sides. "I consider Man-Chung Tang to be one of the top structural engineers in the U.S.," said Kevin Davy, a vice president in the Monroeville, Pa., office of general contractor Balfour Beatty. Davy has had the opportunity to work with Dr. Tang in two capacities, first Dyckerhoff & Widmann in the early and mid-'80s and then with Miami-based contractor Recchi America on the Acosta Bridge. "He understands the engineering side of things, but he also has the construction viewpoint to make a bridge more constructable."
Telephoning from Lisbon, Ron Crockett added, "He is extremely knowledgeable, astute and construction oriented. He's a practical engineer. In his designs, he's always thinking about how the contractor will build the bridge."
Among Dr. Tang's current bridge projects is the T.Y. Lin design of the eastern segment of the San Francisco-Oakland Bay Bridge (see Suspension Design Approved for East Span of San Francisco-Oakland Bay Bridge, July 1998, p 18). As T.Y. Lin's technical director, he oversees the concept development and design of the bridge.
This four-kilometer structure includes a skyway, for which both a concrete segmental and steel box girder design were being considered, and a signature bridge, for which both a cable-stayed and suspension design were being considered.
"We proposed two designs-a cable-stayed design and a self-anchored single-towered suspension bridge," Dr. Tang said.
The self-anchored single-towered suspension bridge was the chosen design. "Most self-anchored bridges have two towers," he said. "But one side of the bridge was rock while the rest was mud. It's difficult to have two towers in that type of situation. Because of the mud we decided to anchor the cable force back to the girder. It's usually anchored in rock, but the area was too muddy."
What are his thoughts on the future of bridge design and construction? Equipment and construction materials such as hydraulics are much more inexpensive today versus years ago, which is an advantage to today's engineers, he said. "The construction method and bridge design will change accordingly. New materials are a bit slower to be used in the field because bridges are public works structures and people tend to be more conservative when dealing with them.
"On the horizon, things like high-strength concrete, which has been around for a long time, are coming into use. Composites are very expensive. Unless the price comes down and some details are worked out as far as their use for prestressing tendens and reinforcing, it will be difficult to use them in mass."