Lynn S. Beedle and Arthur Casagrande

At the turn of the twentieth century, Lynn Beedle was one of the best-known U.S. structural engineers and educators in the world. The founder of the highly respected Council on Tall Buildings and Urban Habitat (CTBUH), he was a long-time distinguished professor at Lehigh University and a pioneer in the field of structural steel research and design.

As a member of the Structural Stability Research Council (SSRC), which he helped found and headed for nearly twenty-five years, he influenced industry-wide research developments and most of the major design and specification standards now followed in the area of stability for structures, especially those constructed of steel.

His groundbreaking research at Lehigh, over several decades, forwarded the understanding of the plastic behavior of structural steel and became the forerunner of many subsequent studies leading to new understanding in the design of complicated steel structures. “He was the force behind the 1963 American Institute of Steel Construction’s (AISC’s) LRFD Specification, which changed the whole design of steel structures,” said Ted Galambos, a former Beedle student and currently professor emeritus at the University of Minnesota.

Beedle’s creation of CTBUH in 1969 ushered in a monumental new concept for high-rise structures. For the first time, the study and integration of all the interdisciplinary fields relating to the planning and design of tall buildings—architecture, engineering, construction, environment, finance, sociology, and politics—were brought together in a comprehensive way. Once created, and under Beedle’s leadership, CTBUH effectively meshed together these disparate interdisciplinary elements and provided industry and society with the rationale that underlies the construction and operation of high-rise structures today.

According to John Fisher, another former student and now professor emeritus at Lehigh, “[Beedle] felt that tall buildings were a way to deal with populations in urban areas.” But for them to be truly effective, he believed you had to go beyond engineering into social issues. Through CTBUH, said Fisher, “[Beedle] brought in many groups besides structural engineers to look at the overall application of tall buildings.”

Beedle believed: “The whole point of tall buildings is function and even philosophy.” For instance, “How high can man go into the sky? How high can he support loads in the event of storms and earthquakes? How high can architecture go in creating a pleasing structure?”

CTBUH’s innumerable globally recognized publications and monographs, conferences, and international congresses advanced and enhanced the ongoing knowledge of the tall buildings and their effect on the urban environment worldwide. Members of the group reside in over ninety countries. (Both SSRC and CTBUH are headquartered at Lehigh University, Bethlehem, Pennsylvania, where Beedle resided for over fifty years.)

Born in Orland, California, on December 17, 1917, Lynn was the oldest of six children of Granville and Carol (Simpson) Beedle. His siblings were sisters Carol, Jane, and Virginia, and brothers Richard and John. Lynn was named after his maternal grandfather Lynn Simpson, part owner and editor of the Sacramento Union.

Lynn’s paternal grandparents were Charles and Mary (Holmes) Beedle of Gold Flat (near Nevada City), California. Lynn’s father Granville, the youngest of five children, was only four when his father Charles died, which greatly impacted his dropping out of high school and enrolling in a business trade school when he was in the eleventh grade. Using his trade-school-acquired skills, the hard-working Granville was employed at a variety of different office management-type jobs, and time and again moved his growing family while pursuing work opportunities.

When Lynn arrived on the scene, his father was office manager and wholesale agent for the Overland Automotive Agency, a position he held from 1917 to 1921. Once the Great Depression hit, automobile sales hit the skids and Granville moved his family briefly to Mill Valley and then to San Francisco where he worked for the Lithographers Association from 1921 to 1924.

In 1924, the Beedles moved to the Los Angeles area, where Lynn graduated from Glendale High School. By the time he entered college, the guns of World War II were banging in Europe, and once the United States was drawn into the war with the bombing of Pearl Harbor, his father secured a position with the War Production Board. Granville later moved back to San Francisco to be office manager for the Westinghouse Air Brake Company.

While Lynn was growing up, his mother contracted diphtheria and was frequently bedridden. Often the burden of running the household and helping his sickly mother care for his younger siblings fell on Lynn and his sister Carol, who was two years his junior. When they were seven and five, the two would occasionally be sent to the store to buy groceries by their mother. Said Granville, “The children are not certain to this day if the trip was really necessary, or just to keep them busy. She [Lynn’s mother] would make the children memorize the grocery list, not allowing them to rely on a written list. This was training to improve the memory skills.”

As youngsters, both Lynn and his sister took piano lessons and, according to Carol, he was by far the more dedicated of the two, often getting up early in the morning to practice. He would then hustle off to his paperboy job delivering the local daily morning newspaper, and then to school.

After a couple of years in the School of Architecture at the University of California in Berkley, Lynn transferred to the College of Engineering. When he graduated with his bachelor’s degree in 1941, he had a major in civil engineering and a minor in architecture.

With America now deep in the throes of World War II, Beedle and both his younger brothers became members of the U.S. Armed Forces—Lynn in the Navy. At first he was a design instructor in naval architecture in Annapolis. Later, he commanded underwater explosion research at the Norfolk Shipyard in Virginia and served as deputy officer-in-charge for the 1946 Bikini atomic bomb tests.

After the war, in 1946, Beedle and Ella Grimes were married and he took a position as an instructor in the college of engineering at Lehigh, where he would earn his masters (1949) and doctorate (1952) degrees, majoring in structural engineering with a minor in metallurgy. He would remain at Lehigh for fifty-plus years. During that time, he and Ella would have and raise five children—a daughter (Helen), and four sons (Lynn Jr., Jonathan, David, and Edward).

From the beginning until his final days at Lehigh, Beedle directed research on the plastic design of steel structures. He was the Fritz Engineering Laboratory director from 1960 until 1984. His research laid the groundwork for designing structures on the basis of their load-carrying capacity rather than their allowable stress.

Early in his stint at Lehigh, beginning in the late 1940s, Beedle became one of the world’s pioneers and leading researchers into the plastic behavior of yielding steel structures. This allowed the establishment of limits-state design concepts for industry and launched Beedle headlong into establishing and heading up the scholarly SSRC.

Over the years, Beedle was the author, co-author, or editor of roughly two hundred significant engineering papers, monographs, and books, several of which became industry classics internationally. Among them were Plastic Design of Steel Frames, ASCE’s Manual 41 (“Plastic Design in Steel”), and several editions of Structural Stability: A World View. He was also editor-in-chief of Planning and Design of Tall Buildings, a multivolume monograph series published by McGraw-Hill.

A dedicated and ardent protector of engineers and the engineering profession, Beedle took whatever opportunity he could to forward the merits of both. He regularly taught a course entitled “Research Procedure.” In it, he always gave his students a list of critical definitions, including these: (1) science is the correlation of observed facts; and (2) engineering is the use of the laws of science, mathematics, and economics in the production of things for the benefit of mankind.

When in 2001 the John Simon Guggenheim Memorial Foundation produced its list of U.S. and Canadian fellows for the year, it listed major categories for the creative arts, social studies, etc. Within its natural science category, the foundation named a handful of engineers, and listed engineering (and the engineers) not as a major division but as a subdivision of natural sciences. This caused Beedle to write a scathing letter to the foundation’s chairman, Joseph Rice. He stated, “I strongly encourage you to take steps so that future announcements indicate engineering for what it is: a major category deserving at least as prominent a heading as ‘creative arts’ and ‘humanities.”’

Often honored over his career, Beedle was the first recipient of the International Contributions Award from the Japan Society of Civil Engineers in 1994. ASCE awarded him the Ernest Howard Award in 1974, the John Fritz Medal in 1994, and the OPAL Award in 2002. Awards he received from AISC included the T. R. Higgins Lectureship, Distinguished Service, and Geerhard Haaijner Educator awards.

In 1999, Engineering News-Record (ENR) selected Beedle as one of its 125 “Top People” of the last 125 years and, in 2000, The Morning Star newspaper in Allentown, Pennsylvania, named him one of 120 “Persons of the Century” in the Lehigh Valley. In 2002, CTBUH honored him with its first annual Lynn S. Beedle Achievement Award. As a result of a national survey of U.S. structural engineers in 2003, he was listed in Structural Engineer magazine as one of the nation’s six most influential and respected structural engineering educators of his time.

Beedle was an honorary member of both ASCE and the International Association for Bridge and Structural Engineering, and a member of the National Academy of Engineers. He was also an elder in the First Presbyterian Church of Bethlehem.

Beedle passed away on October 30, 2003, at home, ten days after he and his wife celebrated their fifty-seventh wedding anniversary. He was eighty-five, and still a major force in his profession. “He taught us how people can respect each other and work together—and how people, through engineering, can achieve peace in this world,” said Galambos.

As a capstone to his contributions, during the year of his death, Lehigh’s Civil and Environmental Engineering Department bestowed on the great professor another significant annual honor, in his name—the Lynn S. Beedle Distinguished Civil and Environmental Engineer Award. Beedle was its first recipient.

Along with the great Karl Terzaghi (1883–1963), standing head and shoulders above all others in the field of soils and geotechnical engineering in the early-to-mid 1900s was Arthur Casagrande. Both pioneering legends were Austria born, educated in Europe, and moved to the United States early in their careers, where they engaged in their international and history-making work.

Especially notable among Casagrande’s achievements were the techniques he developed for classifying and testing soils, both in the laboratory and the field. Those advancements resulted from his far-reaching private consulting projects and his seminal work at Harvard University, which spanned four decades. His activities and numerous publications helped establish Harvard as the world’s leader in geotechnical and foundation engineering during his time. The list of the students he taught and engineers he mentored were like a “who’s who” of geotechnical and foundation engineering worldwide. Inspired by Casagrande, his pupils became the instigators and developers of the profession of geotechnical engineering as it is known today.

Arthur was born on August 28, 1902, in Haidenschaft, Old Austria, near Trieste, a cultural center in the German-speaking part of the old Austrian empire, an area that was torn apart by World War I. His siblings were one-year-younger Leo and several-years-younger sister Alix. Their father, Angelus Casagrande, who was a cavalry officer in the Austrian army during World War I, was taken prisoner in Russia and held captive for years after hostilities ended. He didn’t return from Russia until 1922.

By then, Haidenschaft was part of Italy and Angelus’s wife Anna and family were relocated, living in Vienna with his brother. And both of his two eldest children—Arthur and Leo—were in college studying to become engineers at the prestigious Institute of Technology in Vienna (ITV). Angelus only survived two years after being repatriated, passing away in 1924, the same year Arthur earned his first degree in engineering. Arthur, with Leo as backup, became the family patriarch responsible for the care of his mother and younger sister.

To be assured of a steady income and security, Arthur took a job as an assistant instructor in hydraulics at ITV, a position he held from 1924 to 1926. Once his younger brother Leo had his degree and a job, Casagrande was encouraged to make a bold move. He and his German-born wife Erna Maas decided to immigrate to the United States, landing on April 26, 1926.

At the time, Terzaghi was teaching and researching at the Massachusetts Institute of Technology (MIT), well on his way to becoming the world’s foremost authority on soil mechanics, which would one day earn him the title of “Father of Soils Engineering.” He was also in need of an able assistant and protégé. Casagrande would prove to be up to the task, and then some. After working full time for Terzaghi over the summer of 1926, Casagrande took his first steady job in his new country—research assistant with the U.S. Bureau of Public Roads, a group he remained with for six years, from 1926 until 1932.

One of Casagrande’s main assignments with Public Roads was to MIT, where he assisted Terzaghi in his numerous research projects directed toward improving the apparatus and techniques for soil testing. He essentially became Terzaghi’s “right-hand man” for several years, which allowed him to become a major force behind establishing soil mechanics as a major branch of civil engineering around the world. Among the many significant developments Casagrande is credited with are the triaxial test, now universally used as the basic technique for investigating strength and volume change characteristics of earth materials (his first triaxial apparatus was built in 1930).

The MIT arrangement also allowed Casagrande to initiate his lifelong study of the phenomenon of liquefaction and loss in strength of saturated cohesionless soils as a result of shock or earthquakes. It additionally presented him with the opportunity to research and delve into the shear strength and consolidation testing on undisturbed clay, which resulted in his fundamental discovery that excess pore water pressures develop during shearing. He established a procedure to identify the preconsolidation pressure of clays, evaluating time curves by means of semilogarithmic plots.

In 1932, Casagrande joined the graduate school of engineering at Harvard University, accepting a lectureship in its soil mechanics program where he taught courses in soil mechanics and foundation engineering. In his second year, he added a course in soil testing. His research and methods of instruction while at Harvard became the model for all other engineering college programs that came later. And who, after taking a soils laboratory class, ever forgets using Casagrande’s liquid-limit test apparatus consisting of a metal cup with a crank arrangement into which is placed a mixture of soil and water?

After cutting a properly calibrated groove in the center of the soil, turning the crank lifts the cup to the right height and allows it to free fall. The soil is at its liquid limit if twenty-five blows are required to cause the lower edges of the groove to come into contact with each other for a length of one-half inch. The water content at this number of blows is the liquid limit.

The Technical University of Vienna officially presented Casagrande with a doctor of science degree in 1933. Soon after, he was elevated to assistant professor at Harvard, where he started a course on seepage and groundwater movement. It resulted in his first project for the U.S. Army Corps of Engineers in 1935—to investigate the safety against liquefaction of the fine sand in the Franklin Falls Dam in New Hampshire and to advise on the control of seepage through dam foundations.

In 1936, Casagrande took advantage of his numerous world-class contacts within the newly emerging soils field and organized the first International Conference of Soil Mechanics and Foundation Engineering—the first-time ever event at Harvard.

During World War II, at the request of the Corps of Engineers, Casagrande trained four hundred of its engineering officers on the soil mechanics aspects of airfield construction. It was in connection with these training courses that he developed his soil classification system, which was later adopted by the Corps and the Bureau of Reclamation (with minor modification) as the Unified Classification System.

During the long association with the two federal agencies that ensued, especially with the Corps, Casagrande greatly influenced the practice of soil mechanics concerning the design and construction of earth dams. This association would include making studies of the failure of Fort Peck Dam, the stability of the banks of the Panama Canal and the possibilities for a sea-level canal, and serving as a consultant on many major dams constructed by the Corps on the upper Missouri River.

After World War II, Casagrande—by then the Gordon McKay Professor of Soil Mechanics and Foundation Engineering at Harvard—induced his brother Leo Casagrande (1903–1990), who was world-renowned for his contributions to research and application in the field of electro-osmotic soil stabilization, to permanently move to the United States and teach at Harvard.

Eventually, the two brothers—both internationally known giants in the geotechnical field—along with Leo’s son Dirk, formed the firm of Casagrande Consultants. Its projects took the three around the world. They were consultants to federal, state, municipal, and private organizations on a wide variety of projects involving soils problems and groundwater issues, including the design and construction of earth and rockfill dams and dikes, and foundation systems for difficult structures.

Among the firm’s more notable involvements were the foundation designs for the Liberty Mutual, Prudential, and John Hancock buildings in Boston, the Synchrotron at the Brookhaven National Laboratories, the construction of Logan Airport using soft clay dredged from Boston Harbor, and design of the railroad fill across Great Salt Lake. Casagrande, himself was a special consultant on the design and construction of a number of the world’s largest hydropower dams, including the Oahe Dam in South Dakota, the Manicouagan Three Dam in Canada, the Tarbela Dam in Pakistan, and the Itaipu Dam in Brazil.

In recognition of his numerous contributions to the profession, Casagrande was honored with many distinctions and recognitions. Among them was being named the first Rankine Lecturer of the British National Society of Soil Mechanics and Foundation Engineering (London), the first Nabor Carrillo Lecturer of the Mexican Society of Soil Mechanics (Mexico City), and the first Terzaghi Lecturer of ASCE.

He was the first recipient of ASCE’s Terzaghi Award in 1963. Additionally, he received ASCE’s Edmund Friedman Award in 1968. Other noteworthy awards included the Decoration for Distinguished Civilian Service from the Secretary of the Army, Award of Merit from the American Institute of Consulting Engineers, Order of the Rio Branco of Brazil, and the Moles Award from the construction industry. In 1978, the geotechnical research facility of the U.S. Army Engineer Waterways Experiment Station in Vicksburg, Mississippi, was dedicated to him and renamed in his honor.

He received honorary doctorates from the Technical University of Vienna, the University of Liege, and the University of Mexico. Upon his retirement from Harvard in 1973, he was named professor emeritus.

Cassagrande was an honorary member of the Boston Society of Civil Engineers (BSCE), ASCE, Soil Mechanics Society of Venezuela, National Academy of Exact Physical Sciences of Argentina, and the Mexican Soil Mechanics Society. He was also a member of the National Academy of Engineers.

He was author (or co-author) of over one hundred noteworthy research papers and reports on a wide range of geotechnical subjects. Representative papers include: (1) “Discussion on Frost Heave,” Proceedings of Highway Research Board, 1931: (2) “Seepage through Dams,” Journal of New England Water Works Association, 1937; (3) “Applications of Soil Mechanics in Designing Building Foundations,” Transactions of ASCE, 1944; (4) “Stress-Deformation and Strength Characteristics of Soils under Dynamic Loads,” Proceedings of 2nd International Conference on Soil Mechanics, 1948; (5) “Classification and Identification of Soils,” Transactions of ASCE, 1948; and (6) “Notes on the Design of Earth Dams,” Journal of Boston Society of Civil Engineers, 1950.

Active in a number of professional groups where he worked on countless committees, Casagrande also served as president of BSCE and the International Society for Soil Mechanics and Foundation Engineering for several years.

The seventy-nine-year old Casagrande died peacefully on September 6, 1961. He was survived by his wife Erna, and their two daughters Vivien and Sandra.

Healy, Carol Beedle. (2003). “Recollections of Lynn Beedle.” Online, ⟨www.bdhhfamily.com/recollections.htm⟩ (Sept. 30, 2005).

“In Memoriam—Lynn Beedle.” (2003). Modern Steel Construction, December.