Throwback Thursday: Statistics Program Transcends Decades

The following blog is from the book Forest Products Laboratory 1910-2010, Celebrating A Century of Accomplishments.

This major study, preformed in the 1980s, is referred to as the “in-grade testing of structural lumber program,” and is one of the largest cooperative research programs ever undertaken by the North American wood engineering community.

It included universities, the Southern Pine Inspection Bureau, the West Coast Lumber Inspection Bureau, the Western Wood Products Association, a number of companies, and the Forest Products Laboratory (FPL).

Failure of a piece of structural lumber that was subjected to bending forces to help determine allowable design properties for structural lumber.


Physical and mechanical properties information was obtained on 33 species or species groups of visually graded structural lumber. Over an eight-year period, nearly 70,000 pieces of lumber — approximately 1,000,000 board feet — were tested to destruction in bending, tension, or compression.

The information provided the basis for more accurately estimating mechanical properties of lumber and revising allowable design properties.

Thanks to FPLs statistical design for selecting the wood samples, testing them, and analyzing the outcomes, the results from the study were useful and applicable to structural lumber in general. The data garnered from this research is now part of the National Design Standard, and is still used today.

Science Olympiads Put Bridges to the Test

Students from the Science Olympiad team at Hamilton Middle School in Madison, Wis. had a unique opportunity to experience the Forest Products Laboratory’s (FPL) testing equipment first hand. FPL’s Engineering Mechanics and Remote Sensing Laboratory is equipped with machines that can perform load tests, including specimen compression, bending, and shear. Such tests can come in handy when one is attempting to design a strong, lightweight structure.


Bridge test in progress.

FPL engineers and technicians have been offering guidance to the team for the bridge building event, one of many events that the students compete in. The goal of the event is to build the lightest wooden bridge that can still hold a maximum weight of 15 kilograms.


Students examine their bridge design after testing.

FPL engineers met with the team before they designed their bridges, explaining stresses within bridges they might want to consider, and then tested one of several designs assembled by the team. Witnessing the testing in person allowed the students to see how their bridge deformed under the load of the testing machine and to make decisions about how they could improve their design.

The four-student team will be competing for the Wisconsin state title on March 14, 2015. Hamilton Middle School has won the state title for the past five years in a row and is hoping for a sixth consecutive victory, sending them to Nationals in May.