Transcona+Grain+Elevator

toc =** Transcona Grain Elevator, 1913 **= //Tim Annin, Katherine English, Theresa Judge, Emily Stein//

**Introduction** The Canadian Pacific Railway began storing grain in the Transcona elevator starting in September 1913. On October 18th movement of one footing on the elevator was noted, a movement that by the next morning would make it one of the most famous bearing capacity failures in history (Day, 2005). At the time of this shift the elevator was filled with 875,000 bushels of grain. 24 hours later the bins were leaning at 27 degrees (see image 1) and the clay below the foundation was 29 feet below its starting level and the opposite side had raised 5 feet above. The failure of the structure was due to the instability of the stiff clay the elevator stood on.

Key words
clay soil, dead load, grain elevator, settlement, soil strength

Grain Elevator Construction


The first grain elevator was invented in Buffalo, New York by Joseph Dart. It was used as a storage space for grain and got the name "elevator" because it was designed to take the grain off of ships and move the grain into elevated storage bins until it was was ready to be further transported or milled. The grain could be kept cool and dry if it was elevated and this construction also prevented pests from getting into the storage bins. ("Grain Elevators...", 2006) Like many towns during the early twentieth century, Transcona existed because of the railroad that ran through it. This brought many people to the area. (See image 2) The name Transcona got its name from a combination of "transcontinental" and "Strathcona". Strathcona was to commemorate Lord Strathcona who was very involved in the construction of the Canadian Pacific Railway that passed through Transcona. ("History of Transcona", 2010) Because Transcona was a transportation hub, it would make sense to locate a grain elevator there. 1911 marked the beginning of construction of a grain elevator in Transcona. (See image 3) The structure was made of a work house and a bin storage house for the grain. The bin house was constructed on a reinforced concrete raft foundation and the soil beneath it consisted of stiff blue clay which is very plentiful in the Red River Valley Region. (Anderson, 2005) The concrete foundation was 2 feet thick, with the footings reaching a depth of 12 feet below grade. (Baracos, 1957) Various tests were conducted before construction of the grain elevator began to make sure the soil could withstand the load of the grain elevator filled to maximum capactiy. The tests showed that the soil should be able to handle a pressure four to five tons per square foot. The designed grain elevator filled completely would only bear pressure of 3.3 tons per square foot, so the soil would have no problem holding the pressure of the filled grain elevator. (Delatte, 2009) However, the actual built load of the bin house was 20,000 tons, which when computed is well over 3.3 tons per square foot. (Baracos, 1957) Construction of the Transcona Grain Elevator ended in September of 1913.

Causes of the Failure
On October 18th, grain was being transferred into the Transcona Grain Elevator. As it was loaded, the bin house began to settle, going down 1 foot in the first hour. Over the next day, the structure settled further and came to rest at a 27 degree angle from the vertical to the west. The foundation of the building which otherwise sat on weak clay soil was supported by a line of bolders on its east side which then permitted the grain elevator to sink more so on the west side. (Remington, 1923) The pressure exerted on the soil beneath the elevator caused the failure. Clay, silt, and glacial deposits sit beneath the structure. The clays were of the stratified type, meaning that pockets of silt sat between thin sheets of actual clay. (Baracos, 1957) The present clay types lack the unconfined compressive strength of other soil types. The foundation pressed downward with a force of 3.06 tsf (tons per square foot) while the clay beneath it could only support approximately 1.13 tsf based on samples. Soil strength calculations done at the time of construction approximated that it should be able to withstand loads of 4 to 5 tsf. Based on these calculations, the grain elevator’s weight was well within the acceptable range. Basic errors in soil strength computations were the cause for this failure. (Delatte, 2009) Soon after it came to rest, the elevator was righted using jacks and an elaborate system of piers. It had tilted over without incurring any damage, and as a result, it was structurally sound after being pushed back up though it sat 14 feet below grade. (Skatfeld, 1998) The stiff blue clay of the Red River Valley has been responsible for various other structural failures one of which was the Fargo Grain Elevator in 1955. The weakness in these failures is due to an overbearing amount of pressure on soil which cannot hold the structure. The soil then gives way and essentially swallows the structures into the ground. (Anderson, 2005) (See image 4)

**Lessons Learned from this Failure**
Incidents like the bearing capacity failure of the Transcona Grain Elevator are mysterious in nature, but do allow for geotechnical theories to be tested. Decades after the actual failure a theory arose among geotechnical theorists that the internal friction of saturated clay is equal to zero. This theory had been circulating since the 1920s and many advances towards its proof were made, but there were no actual failures used in testing this theory until Robert Peck in the 1943. He used the data collected from the soil before and after this failure and through a series of Terzaghi’s equations about ultimate bearing capacity developed in the 1930s to prove that this theory was actually true. The proof of this theory allows for a variety of new assumptions and theories to be made about the tricky ways in which soil moves. (Morley, 1996)

More accurate soil tests and calculations could have prevented the failure of the Transcona Elevator. Advances in technology since 1913 have enabled more precise studies. However, the true maximum mass that soil can hold is difficult to predict exactly. The true number is often not known until the building actually collapses. Reports documenting the failure of the elevator have aided engineers in buildings since its collapse. (Delatte, 2009) Also located in the Red River Valley, the Fargo Grain Elevator collapsed in 1955 due to a similar building failure. Apparently the geological engineers had not learned their lesson, as the Fargo elevator also failed due to unstable foundation soils. (Anderson, 2005)

**... and Lessons Not Learned** More recently, the Ocean Tower on South Padre Island, Texas also began to collapse due to soil conditions. Ocean Tower was also made of reinforced concrete. They had not compensated for the fact that the tower was much heavier than the garage, and therefore would sink farther into the ground. ("Leaning Tower of ...", 2009)  Another example of a bearing capacity failure occurred on June 26, 2009 in Shanghai, China. A 13-story tower toppled over due to excavation work done for a parking garage on one side of the building. The soil from the excavation was piled about 30 meters from the base of the building. The fill's load and not the actual excavation caused the building to rotate and overturn. For this reason the tower rotated away from the excavation, not toward it as one might assume. (Post, 2009)

Conclusion
When the Transcona Grain Elevator began to tilt on October 18th, 1913 it had written itself a place in history. The drastic shift in soil level leading to its 27 degree tilt has made this failure is one of the most studied soil failures in history. Well, aside from maybe the leaning Tower of Pisa (Morley, 1996). It allowed the engineering community to gain slightly more understanding of soil, even though the true ways of the substance are still a challenge to pin down.

This article examines the reasons for the failure of the Ocean Tower.
 * "Leaning Tower of Padre Island." Construction and Advisory Group. Blogspot, 8 Oct. 2009. Web. 28 Apr. 2010. .**

This source examines the calculations and assumptions made with regard to soil strength. It proves the validity of the computational methods used at the time of the failure.
 * Morley, Jane. "'Acts of God': the symbolic and technical significance of foundation failures."//Journal of Performance of Constructed Facilities// 10.1 (1996): 23-31. //ASCE Library// . ASCE. Web. 10 Feb. 2010. < http://ascelibrary.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JPCFEV000010000001000023000001&idtype=cvips >.**

**Post, Randy. "13-Story Tower Topples Over in Shanghai." //Geoprac.net.//** **2 July 2009. Web. 4 May 2010. ** This website describes a failure case of an apartment complex in Shanghai which occurred this past year.

After the elevator collapsed on October 19th, 1913, efforts were made to repair the structure and restore it to its upright position. This process begun in March of 1914 and completed it in October of that same year.
 * Remington, Franklin. "Righting a Million Bushel Elevator." //The Ohio State Engineer// May & June 1923: 9-12. Print. **

This journal article discusses the soil strength issues that resulted in the failure of the grain elevator. It also brings to light the erroneous calculations that lead to its collapse.
 * Skaftfeld, Ken. "Failure and Righting of the Transcona Grain Elevator." //Geotechnical News//** **16.2 (1998): 61. Print.**