Background Soil mechanics is the study of soil and its properties. Because buildings and large infrastructure projects are almost always build on land and need foundations. In fact it is important to know the soil where they settle. The formal study of soils began with Karl Terzaghi who was the first person to use the term “Soil Mechanics”. He worked in several universities in USA, but he described Mexico as “the
paradise of Soil Mechanics” due to its poor soil and problems with foundations. Before Terzaghi, there was no real knowledge of soil properties and thus there was really bad design of foundations. Context Short time before Terzaghi started his studies about soil mechanics, there was a famous building failure in Canada. This failure is one of the most studied problems, second only to the settlement of Pisa Tower. The name of the building was the Transcona Grain Elevator. It was built to store a large quantity of grain for the Canadian Pacific Railway. The construction started on 1911 and finished on 1913. Problem Short after the Transcona Grain Elevator was finished it was ready to storage grain. On October 18th 1913, less than 24 hours after the bins were filled with grain, people could observe that the building started to move to the west. At the end the Grain Elevator rest at 27 degrees from the vertical. This problem was due the failure of the foundation and miscalculations on how much load the clay soil could bear.
Body of the report
The Transcona grain elevator is famous for the failure in its foundation due to poor clay soil and not accurate calculation of soil capacity. This incident happened short after the grain elevator was filled with grain. This incident happened before engineers had real knowledge of the behavior of the soils. This means that when the Transcona grain elevator was built there was not Soil Mechanics Studies to ensure that the soil could be able to support the weight of the structure without settling. The miscalculation of the values of the strength of the soil was the reason of the settlement of the bin-house of the Transcona grain elevator. Objectives
To straightening the building without damaging the store house and bins.
To make sure the soil resist the pressure of the structure and do not settle any more.
To make the grain elevator to storage the grain that comes from the train as was planned at the beginning.
To compute the real soil strength to avoid any more incidents.
Method The first step to make that the building recovers its vertical position was to empty all bins. To empty the bins, the engineers needed to make holes at the base of the bins using a line of pushers against the west side of the building. The grain that was storage in said bins needed to be storaged in other places. After the bins were emptied, there was an inspection of the building. This inspection showed that the structure of the grain elevator and storage house were not damaged.
The grain elevator was settled twenty-seven degrees to the west. To start straightening the building, the engineers decided to make excavations under the east side of the mat towards the west side. The next step for rightening the Transcona grain elevator was to underpinning the work-house. Poles were put under the work-house to avoid any settlement. Once the work-house was ensured, the engineers could start to work on the bin-house. To Straight the bin-house, the use of kicking braces and shoring screws were needed. Engineers used several methods to make the bin-house regain its vertical little by little. This step took most of the time because the engineers were extremely careful to rightening the structure and avoid any more damage in the foundations. The final step was the underpinning of the bin-house. The engineers needed to put many poles under the east side first and under the west side later. The purpose of the poles were to distribute the load of the building in uniform way into the soil and avoid more settlement and to keep the structure vertical. This step ensured to keep the foundations functional during the time of service of the Transcona grain elevator. Results As a result of the methods employed, the Transcona grain elevator was able to be vertical again. After the building was straightened, it made 27 degrees from the vertical. This inclination was huge in a structure like the grain elevator. Thanks to a careful management of the elements, the structure was not damaged and became operational short after the building was straightened. The bins not the store house were damaged, they were built well for their time.
Conclusión
One of the most studied failures in the world is the Transcona Grain Elevator. Its importance is because the cause of its failure was not due to structural reason. Transcona Grain Elevator failed due the lack of knowledge about Soil Mechanics. The grain elevator settled within the clay soil making the structure move to the west. At the time this structure was built, the engineers miscalculated the load capacity of the soil and the total weight of the bins full of grain. In conclusion the Transcona Grain Elevator failure was an engineering mistake that made engineers to really take into considerations the soil capacity and its properties. Thanks to this event many studies were made afterwards. This event occurred in 1913, so this failure marks the beginning of serious Study of Soil Mechanics. Soil Mechanics is very important because almost every structure on Earth is built on soil. Recommendations
If a building that will support great loads is going to be built, then a soil mechanic study must be done. This study have to be done in situ and in laboratory. The Transcona Grain Elevator was finished in 1913. If a better knowledge about soils have been available at that time, the Grain Elevator would not have failed. But the techniques used to straightening the building were well executed. Nowadays if a building settles, similar procedures are done. Civil engineers all over the world need to know the basics of soil mechanics as part of their formation to avoid settlement problems.
