The Hardy Cross Method

Hardy Cross first published this method, in 1930, during his years at the University of Illinois. The Hardy Cross Method is actually an adaptation of his Moment Distribution Method, which was originally used to test the moments of indeterminate structures. The adaptation, by contrast, set forth an entirely new method for analyzing building frames.

Hardy Cross Paper Reprint, 1939

Amusingly, Cross published such a landmark piece of work largely due to the pressure put on him by his dean, Milo Ketchum. Supposedly, Ketchum was resentful of Cross for his reputation as a great teacher. One of the allegations Ketchum launched toward Cross was that he did not publish enough papers. In response to this, Cross put forth a ten page paper in the May,1930 Proceedings of the American Society of Civil Engineers.

The paper, entitled "Analysis of Continuous Frames by Distributing Fixed-End Moments”, instantly garnered a lot of notice. Discussion of the paper was closed in 1930, but the paper itself was not published until two years later. At that time, space was afforded for 38 commentators who took up 146 pages, which may or may not be a record for commentators on a single paper. Cross was immediately hailed for not only solving one of the “knottiest” problems in Engineering, but doing so in such a way that could be adopted by any engineer working in the field. The Hardy Cross Method has made many architectural feats possible, ranging from skyscrapers to bridges to dams. 

Hardy Cross

Hardy Cross was born February 10th, 1885 on the family plantation in Nansemond County, near the Great Dismal Swamp, Virginia. Both Cross and his brother Tom Peete were both educated at the Norfolk Academy in Norfolk, VA. The brothers then both went on to Hampden-Sydney College where Cross received both B.A. and a B.S degrees in 1902 and 1903. Both of these degrees were awarded before his eighteenth birthday.

Hardy Cross

After graduation, Cross taught English and Mathematics for three years before going to MIT to receive a B.S in Civil Engineering after only two years of study. By 1911, Cross had moved on to Harvard University, where he received his Master of Science degree in Civil Engineering.

Cross soon moved on to teaching. His first appointment was at Brown University, where he served for seven years, between 1911-1918. Outside of the classroom he  served as a bridge engineer for the Missouri Pacific Railroad, worked with prominent consulting civil engineers that specialized in structural and hydraulic engineering. He also spent the year of 1920 as an assistant engineer for Charles T. Main.

Cross then came to the University of Illinois at Urbana-Champaign in 1921. He was replacing Charles Alton Ellis, who had resigned to design the Golden Gate Bridge. While at the University of Illinois, Cross advanced some of his most important work, including developing simplified methods of analysis by means of converging approximations. The most significant of these, the fixed-end moment distribution for analysis of continuous structures, greatly simplified the way stresses could be calculated. This method was published in 1930 and went on to be commonly called the Hardy Cross Method.

One of Cross's Many Papers on Structural Design, 1936.

As a teacher, Cross was a staunch supporter of oral examinations for candidate of advanced degrees, often leading discussions on the topic. Furthermore, he was very against educational inflation, once saying:

“A common characteristic of the campus inflationist is that he benefits from the inflation but pays for it not at all; he has bigger department, more courses, more contacts, without cost to himself: usually he hopes for more money for himself and certainly hopes for more influence. I here indict him as responsible for the penalties that others pay for inflation”.

Cross was on faculty at University of Illinois until 1937, when he went to Yale University to head and chair the Department of Civil Engineering. He remained at Yale until he retired in 1951. He and his wife Edythe moved to Virginia beach until their deaths, his in 1959 and hers in 1956.