One fine Saturday, I was touring around the Willamette Valley and was passing through the city of Halsey. One structure stood tall compared to all the other buildings in the city. Curiosity caught me and I had to check it out. I stopped across the street from this tall structure, looking up in amazement. After studying it closely, I realized it was flat 2×8’s stacked on top of each with flat 2×8’s perpendicular to the outer wall every 48″. Guessing it was approximately 6-8 stories, I realized this is somewhat an example of an earlier version of cross laminated timber (CLT) construction.
I had to do a little research on this type of structure. My first stop was with my father who grew up as a farmer in his youth around in Tekoa, Washington. When I asked if these structures were indeed flat 2x’s, he confirmed my suspicion.
Further investigation led me to the internet. Architect Robert Hutchison posted a blog on “Timber Grain Elevators” and in the blog he stated,
“The timber grain elevator emerged as a predominant American rural building typology during the 19th and 20th centuries. Their singular purpose is to provide prolonged storage capacity for harvested grain. The elevators are typically located along railroad spurs, to permit the storage of grain until transfer could be made from the elevator into railroad cars. They typically are constructed utilizing what is commonly termed “cribbed” construction, consisting of 2×4 or 2×6 lumber stacked throughout the height of the structure. This construction technique provides a retaining wall structure that is capable of sustaining the substantial lateral loads imposed by the stored grain. Most elevators are comprised of numerous ‘bins’ arranged in 3×3, 3×4 or 4×4 or more modules. The bin dimensions are determined by the lateral structural capabilities of the 2x lumber. Often, the lower half of the structure is constructed of 2×6 lumber, while the upper portion transitions to 2×4 lumber, alluding to the decreasing lateral loads imposed at the upper portions of the elevator. The bottoms of bins are either sloped or flat. Flat bins, while easier to construct, require manual labor to completely empty. Sloped bins are more difficult to construct, but can use gravity to empty completely.”
Hutchison also quoted a section from a 1907 book entitled “The Design of Walls, Bins and Grain” by Milo Smith Ketchum, “For large bins, the “crib” construction is most used. In this construction, pieces of 2″x4″, 2″x6″, or 2″x8″ are laid flatwise, so as to break joints and bind the structure together, and spiked firmly. This makes a strong form of construction, and one very cheap with the former low price of lumber.”
Seems to me that this is an early form of the cross laminated timber (CLT) design and construction, before all the advancements we have currently made. Maybe it is time to start construction with this sustainable building material.
For other photos, see http://substreet.org/globe-elevator/#jp-carousel-49113