In 1990 HARTMAN ENGINEERING began a series of activities related to transverse stress in steel sheet piling. The original work was sponsored by Bethlehem Steel Company and the L. B. Foster Company. The research has been an ongoing process and is continuing today with the Chaparral Steel Company.

Transverse loads deform sheet piling perpendicular it its longitudinal axis. Historically it was believed that these stresses were so small relative to the longitudinal stress that they were not considered during the design of cofferdams and retaining walls.

In 1991 HARTMAN ENGINEERING designed a testing apparatus that allowed sheet pile to be loaded by water pressure. Strain gauges monitored the behavior of the test piles. The testing was performed in partnership with the late Dr. John A. Neal at the State University of New York at Buffalo. Eight sheet piles were assembled and clamped together (see figure at right).

It was observed that continued deformation of some sheet piles occurred even though the longitudinal stresses were below the level at which plastic deformation should have occurred.

In 1992 an excerpt from the full report was published. In this report Drs. Hartman and Neal reported their findings. They concluded that “The current design practice of using section modulus of the piling as the only structural criteria is inadequate and must be refined. It is appropriate that bidirectional loading and section slenderness ratios be recognized in design of sheet pile structures similar to the manner in which they are recognized in other types of structural design.”

In 1997 a second document, “Report of Investigation of the Effect of Transverse Loads on the Behaior of Z-Shape Steel Sheet Piling” was published. The purpose was to report on a technically reliable and easy to use design tool for practicing engineers. This tool could be used to determine the appropriate sheet pile to use based on the allowable moment and the pressure in a given set of design criteria.

Since the initial experimentation HARTMAN ENGINEERING, in cooperation with Chaparral Steel Company, has been instrumental in the design of sheet pile sections that incorporate the need for transverse stress resistance. Dr. Hartman holds patents for a new PZ27 section and for sections which have been designated PZ35, PZ40, PZC13, PZC18, PZC26, PZC36 and PZC48. Work is ongoing to develop additional sections.

Copies of the original reports are available by contacting us.