Eccentric discharge of a round silo designed for concentric discharge upsets the balance of pressures in the bin, causes bending of the concrete walls and compromises the structural integrity of the bin.
Concrete structures that are properly designed and operated can last well over 50 years, and newer construction methods and materials may extend that figure even farther. But in other cases design, construction or operator errors can lead to structural issues as early as the first time that the bin is unloaded.
Preventing structural failure
Today building codes are in place to help keep facility workers safe. Concrete bins are designed to meet the Building Code Requirements for Structural Concrete (ACI 318), and Standard Practice for Design and Construction of Concrete Silos and Stacking Tubes for Storing Granular Material (ACI313) as established by the American Concrete Institute. Generally, the drawings for the facility must be submitted for a building permit and must be sealed by a Registered Professional Engineer.
Although there are building codes and regulations in place, if your structure is older and has signs of prior distress and deterioration that are not accelerating, or if the facility is 25 to 30 years old and you are concerned about its age and integrity, you may want to contact a professional engineer.
The engineer can work with a testing company to determine the most cost-effective method for identifying the volume and placement of reinforcing steel in your structures. Based on the testing data and knowledge of your operations, the engineer can perform the structural analyses to determine the soundness of the structure.
Kobetz points out that even in older structures, not every crack or spalling is a catastrophe or cause for concern. “If you regularly monitor your concrete structures and have not observed any signs of distress or deterioration, there is no technical justification for professional inspection or testing; you should continue to monitor the structures and contact an engineer when you observe changes.”
Maintaining concrete structures is an easy task that can get brushed aside with all of the other aspects of operations to manage. Taking the time each year to inspect your structures and update your baseline will provide peace-of-mind as well as serve as an important document for your engineer should a problem ever arise.