Educator – Structural Engineer – Author – Consultant – Innovator – Builder of Engineers
Column Analogy – Arches – Continuous Frames – Haunched Beams
Eleventh National Honor Member Nominated by the University of Illinois Chapter
A native of the State of Virginia, Hardy Cross was born February 10, 1885. In 1902, at the age of seventeen he was graduated (valedictorian) from Hampden-Sydney (Virginia) College, with a bachelor of arts degree. The following year he was concurrently an instructor of English and earned a bachelor of science degree from the same institution. For the three years 1903-1906, he was instructor in English and mathematics at Norfolk (Virginia) Academy. He then (1906-1908) attended Massachusetts Institute of Technology, receiving a bachelor of science degree in civil engineering. From 1908 to 1910 he was an engineer in the bridge department of the Missouri Pacific Railway, after which he attended Harvard University; and there, in 1911, he was awarded his master’s degree in civil engineering.
“HX” headed into his professional career in earnest in 1911, as assistant professor of civil engineering at Brown University, where he remained until 1918. After three years in general engineering practice he returned to teaching and, in 1921, became professor of structural engineering at the University of Illinois. In 1937, he was offered, and accepted, the Strathcona Professorship at Yale University, where he served as professor of civil engineering and chairman of the Civil Engineering Department until 1951. In that year, he retired as Strathcona Professor Emeritus.
He was seventy-four years old when he passed away at Virginia Beach, Virginia, February 11, 1959. In an active span of some sixty years, he had earned recognition as an outstanding engineer and as a teacher. Highest honors were received from Hampden-Sydney College (Sc.D., 1934), Yale University (A.M., 1937) and Lehigh University (D.Engrg., 1937). He revolutionized the art of structural analysis and, throughout, maintained an active participation in the activities of the American Society of Civil Engineers (Hon. M., 1947), the American Concrete Institute, the American Railway Engineering Association, the Institute of Consulting Engineers, American Society for Engineering Education (Lamme Medal, 1944), and the American Academy of Arts and Science. He was an honorary member of the Connecticut Society of Civil Engineers.
Numerous articles by Professor Cross have been published in technical journals and in bulletin form. His “Column Analogy,” published in 1930 as a bulletin of the Engineering Experiment Station, University of Illinois, outlined the analysis of arches, haunched beams, and framed bents by an analogy to the computation for fiber stresses in short columns subject to bending. In the same year the Engineering Experiment Station released his bulletin, “Dependability of the Theory of Concrete Arches.”
One of Professor Cross’s best known works was his moment distribution method of solving continuous beams and frames. This method of analysis was first presented publicly to the 1930 convention of the American Society of Civil Engineers in a paper entitled “Analysis of Continuous Frames by Distributing Fixed-End Moments.” When published in the Proceedings, widely discussed by the membership, and finally published in the Transactions, ASCE, this paper earned for Professor Cross the Norman Medal. The method of moment distribution greatly simplifies the analysis of continuous frame structures. Most of the mathematical drudgery associated with former methods of solution was reduced to one of simple arithmetic. His other publications include the book (with N.D. Morgan) entitled “Concerning the Importance of Teaching School,” presented at a meeting of the American Society for Engineering Education in 1936, and widely known as an expression of his teaching theories. Hardy Cross’s work has not been confined entirely to the structural engineering field. His method of computing flow distribution and variation of head in various parts of a water-supply network has been a significant contribution to the field of water supply engineering.
His fraternity affiliations included Kappa Alpha, Sigma Xi, Tau Beta Pi, Sigma Tau, and Omicron Delta Kappa. The University of Illinois chapter of Chi Epsilon nominated him for the grade of National Honor Member. At the subsequent Conclave of the Fraternity at the University of Iowa in Iowa City, his name was selected from the national list and he was elected National Honor Member Number Eleven. He was elevated at appropriate ceremonies in the spring of 1941.
“HX” was one of an illustrious group of engineers selected to investigate and report on the Tacoma Narrows Bridge failure. It was during these very productive years on the teaching staff of the University of Illinois that he made his deepest and most lasting imprint on his chosen profession. As a crowning capstone of his career, he was called to London, England, in 1959 to read a paper before the Institute of Structural Engineers of Great Britain, and there he received the Institute’s gold medal for “outstanding contributions to the science and art of structural engineering.”
A devoted enthusiast of George Fillmore Swain of Harvard and MIT, “HX” reminded many older engineers of that earlier professional giant. Swain graduates, like Cross graduates, freely boasted “I studied under Swain.” As in the case of Swain, his intimates could always contribute some characteristic anecdote involving Professor Cross. A former student recalls a day when “HX” became so actively involved in a discussion of secondary stresses that he lost all sense of time. When the period bell rang, he pulled out his watch, impatiently looked at it, put it to his ear, shook it violently again, listened again, and casually threw it out of the open window.
In social gatherings, and outside of “business hours,” “HX” was a brilliant conversationalist, a jolly companion, and an unfailing friend. Possibly because of a severe hearing impairment and a very slight speech defect, he was inclined to be sensitive. He objected instantly and sharply if a person raised his voice to accommodate his hearing defects.
A stern demanding teacher of engineers, a proud, eager, and happy advocate of his successful students, Hardy Cross will be remembered longest as the builder of engineers. One of the proudest citations assumed by his graduates was “I studied under Hardy Cross.” Yet in the undergraduate years, when they were “stretched on the rack,” struggling desperately to satisfy his rigorous demands for independent thinking, students often hated him. Then year after year, following graduation, hate became respect and respect became affectionate memory. Because, like a blacksmith forming a bar of metal, “HX” heated his students’ thinking apparatus—by aggravating give-and-take questioning—into a red-hot flow. Only in later years did they realize that they had also been “tempered” as part of his teaching technique.