Hardy Cross - Career

Career

Cross next became an assistant professor of civil engineering at Brown University, where he taught for seven years. After a brief return to general engineering practice, he accepted a position as professor of structural engineering at the University of Illinois at Urbana-Champaign, in 1921. At the University of Illinois Hardy Cross developed his moment distribution method and influenced many young civil engineers. His students at Illinois had a hard time arguing with him because he was hard of hearing. He left Illinois in 1937 to become the chair of the civil engineering department at Yale University, a position from which he retired in 1953.

Accurate structural analysis of large reinforced concrete building frames in the 1950s was a formidable task. It is a tribute to the engineering profession, and to Hardy Cross, that there were so few failures. When engineers had to compute the stresses and deflections in a statically indeterminate frame, they inevitably turned to what was generally known as the "moment distribution" or "Hardy Cross" method. In the moment distribution method, the fixed-end moments in the framing members are gradually distributed to adjacent members in a number of steps such that the system eventually reaches its natural equilibrium configuration. However the method was still an approximation but it could be solved to be very close to the actual solution.

The Hardy Cross method is essentially the Jacobi iterative scheme applied to the displacement formulation of structural analysis.

Today the "moment distribution" method is no longer commonly used because computers have changed the way engineers evaluate structures, and moment distribution programs are seldom created nowadays. Today's structural analysis software is based on the flexibility method, direct stiffness method or finite element methods (FEM).

Another Hardy Cross method is also famous for modeling flows in complex water supply networks. Until recent decades, it was the most common method for solving such problems.

He received numerous honors. Among these were an honorary Master of Arts degree from Yale University, the Lamme Medal of the American Society for Engineering Education (1944), the Wason Medal for Most Meritorious Paper of the American Concrete Institute (1935), and the Gold Medal of the Institution of Structural Engineers of Great Britain (1959).