댓글 0건 조회 20회 작성일 21-04-06 11:50
|Better Buildings, Stronger Structures|
Structural design and analysis software adapted
By Jane M. Sanders
Ten thousand pounds of bells are safely swinging in the belfry of St. Luke's Episcopal Church in downtown Atlanta. Down the street, business people go about their work in the high-rise offices of One Peachtree Plaza. Across the globe, cars and trains travel from Denmark to Sweden across the world's longest cable-stayed bridge. And in China, citizens light their homes with power generated by the Three Gorges hydroelectric project.
These structures have all been made better, in large part, because the engineers who designed them used GT STRUDL™ software, a structural analysis and design computer program. GT STRUDL, which stands for Georgia Tech Structural Design Language, has been under continuous development for the past 25 years at the Georgia Institute of Technology.
The original STRUDL program was created in the late 1960s at the Massachusetts Institute of Technology (MIT) to operate on an IBM mainframe computer. Subsequently, GT STRUDL (based on MIT STRUDL) was written for Control Data Corporation's mainframe – and subsequently other platforms – by Georgia Tech civil engineers beginning in 1975. Today, GT STRUDL is used by thousands of engineers daily in about 900 firms and 39 countries. It takes engineers' initial ideas, performs mathematical calculations and rapidly predicts how a structure would behave under a variety of loads and stresses.
"We transfer cutting-edge technology in civil/structural engineering into the practicing engineering profession to the direct benefit of society," says Dr. Leroy Emkin, one of GT STRUDL's initial developers and a professor of civil engineering. "Our primary goal is improving the quality of life through structures designed with the assistance of GT STRUDL."
Though the general public doesn't always associate its quality of life with the safety and durability of its civil structures, Emkin sees a clear connection. "High quality engineering, aided by a powerful computer program, creates a winning combination," he says.
In its quarter-of-a-century history, GT STRUDL has had a successful career and a broad impact. It is the largest gross revenue-producing technology ever licensed by Georgia Tech, generating more than $25 million since 1978.
The program has been used throughout the world to analyze and design a variety of structures. "I am constantly amazed at the types of structures – both traditional and non-traditional – for which GT-STRUDL is used," says GT STRUDL co-developer Dr. Kenneth "Mac" Will. "They include everything from buildings to bridges to nuclear power plants." Other examples include towers, flood control dams, offshore platforms, highways and even an F-22 missile launcher.
One GT STRUDL user cites his rather simple, yet unusual, use for the program. Craig Bennett, a Georgia Tech graduate and engineer with Cummings & McGrady Inc. in Charleston, S.C., recently used GT STRUDL to determine the structural response of St. Luke's Episcopal Church's nearly 100-year-old bell tower to the swinging of 10,000 pounds of new bells. The program allowed Bennett to redesign the structure to meet the needs of good bell control, i.e. with movement at the belfry level limited to about one thirty-second of an inch.
"This project would have been very difficult to do only by hand," Bennett says. "I always do hand checks on everything to see if the numbers are realistic. In this case, I developed my analyses in rough form using hand checks, then put them in a simple GT STRUDL model that led to a series of finer and finer models until I had confidence in the final model."
Bennett has used GT STRUDL in numerous other historic renovation projects. GT STRUDL has always delivered superb results, he says.
Engineers can conduct a variety of analyses with GT STRUDL; these include static, dynamic, linear, non-linear, frame and finite element analyses. On the design side, GT STRUDL is used for creation of steel frame and reinforced concrete structures. The program contains a graphical user interface to create models and display results, including some in 3-D and others with animation. And GT STRUDL has a powerful menu system that enables the user to describe problem-solving requirements.
"GT STRUDL is recognized worldwide as the leading civil/structural engineering software," Emkin says, "measured in terms of functionality, depth of technology, breadth of technology, quality related to the accuracy of its computations, and performance. In fact, GT STRUDL is among a very few such programs in the world whose quality of software development and operation fully conform to the stringent requirements of the applicable provisions of the United States Nuclear Regulatory Commission's 10CFR21 and 10CFR50 quality standards. And we believe that we are also the leader in technical support services, such as education and training in the effective uses of computers for civil and structural engineering applications."
In fact, a 1998 article in Modern Steel Construction Magazine compared GT STRUDL to two other similar software programs. The magazine rated GT STRUDL highest in ease of learning, documentation, ease of data input, expectations, accuracy and productivity. The Tech program also received the magazine's highest overall rating.
Users also give high marks to GT STRUDL. John Bryson, a civil engineer at Parsons, Brinckerhoff, Quade and Douglas Inc., a large engineering firm headquartered in New York City, frequently uses GT STRUDL for static and dynamic analyses, most recently with a 1,550-foot suspension bridge project in Canada. The Lions Gate Bridge in northern Vancouver is being restored in 52 sections, with workers making the repairs at night and drivers continuing to use the bridge during the day.
"GT STRUDL is a good program," Bryson says. "It's one of the three better programs for this type of work. I am using it for analysis of very complicated structures."
Meanwhile, at John Portman & Associates Inc. in Atlanta, Housh Rahimzadeh uses GT STRUDL for 3-D frame analysis of complicated buildings. "We design many buildings with sophisticated geometry," Rahimzadeh says. "GT STRUDL is one of the best ways to cope with this geometry, and it gives us an accurate result.... The program can model the building like it is actually designed."
Rahimzadeh points out two other benefits of GT STRUDL. One, its analyses often result in savings on framing. And two, it was the first program, and the only one for many years, that could perform analyses based on a sequence of construction. This is an important factor in many of the high-rise building projects designed by Portman, he explains.
Another example of GT STRUDL's value to complicated projects is its use in designing and analyzing the recently completed Oresund Link Bridge, which crosses the main channel of a 10-mile span of water and small islands between Denmark and Sweden. Designed by a group of European firms, the Oresund is the world's longest cable-stayed bridge that carries both rail and vehicle traffic.
"This project involved an incredibly complex analytical process – both linear and non-linear and static and dynamic analyses, as well as a simulation of the sequence of construction," Emkin explains. "There are very few structural engineering and design programs in the world capable of this type of work."
Another GT STRUDL user likes the program's capabilities and technical support. "GT STRUDL is a better quality program than others that are available," says Henry Fix, a senior engineer for Frederic R. Harris Inc. in Philadelphia. "It is stable in performance.... I have very high praise for GT STRUDL's user support. If I have an analysis problem that I can't get my hands around, the tech support people usually have ideas on how I can get the model to do what I want to achieve. The program has broad capability from basic to advanced analysis."
Emkin and Will, who manage GT STRUDL development activities in the School of Civil and Environmental Engineering's Computer Aided Structural Engineering (CASE) Center, attribute GT STRUDL's success to one primary factor. Since its inception, it has been developed and technically supported in house, rather than relinquishing control to a commercial third party. It is the only academically based program of its kind.
Emkin and Will believe having this control maximizes the benefit to the educational process at Georgia Tech. "It maximizes our opportunity to do fundamental research into numerical methods," Emkin says. "Then we implement the results of that research into a technology that can be transferred into practice and provide a direct benefit to the profession and to society."
Will adds: "CASE control of GT STRUDL is the most effective and timely way of disseminating relevant research results to practicing civil engineers. Technology transer through GT STRUDL software eliminates the delays that occur with traditional technical publications."
"Software is one of the best ways to deliver knowledge," Emkin says. "There is a great benefit to society and the quality of life when that knowledge is delivered in a timely fashion and is properly used."
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