A major agribusiness corporation had a project underway to upgrade a key grain receival terminal that it operates. The facility, which was largely designed in the 1960s, would see significant changes to the existing Cones of the grain silos as part of the project. One salient consequence of the changes would be redistribution of silo wall pressures, bringing a potential risk of structural failure. The issue created the need for a thorough structural engineering assessment of the upgrade.
SOTO was commissioned to measure the loads on the silo walls that result from the storage and discharge of bulk solids, and create As-Is and To-Be geometry of the grain storage facilities. Then using computer-aided engineering employing Finite Element Analysis (FEA). SOTO would assess the silo walls against the AS 3600 structural standards, and include its analyses, results, and conclusions in a comprehensive engineering calculations report.
SOTO engineers deployed their strong experience in FEA to model and analyse the complex wall pressure distribution that the storage and discharge of bulk solids cause in any structure. Through the Ansys Workbench software, the CAD geometries of the site were divided into small segments to better apply the loads as part of the FEA. SOTO considered multiple load cases to cover differing silo conditions. Both the Australian AS 3774 and European EN 1991-4 standards were considered in conducting the FEA, in order to ensure universal compliance.
The assessment located multiple regions in the silos which failed to withstand the loads predicted by the FEA. The analysis also found that load cases representing discharge of bulk solids from the storage structures caused greater load on the walls than the fill cases. Following the completion of its analysis, SOTO proposed modifications to the silo floor and recommended the construction of an additional discharge chute.
The analysis found that both the original and the proposed designs for the facility left wall regions failed to comply with the AS 3774 and EN 1991-4 standards with the proposed design predicted to have more of such non-compliant wall regions.
SOTO’s recommendations included a review of loading and discharge requirements to mitigate any adverse impact of bulk solid loads, further investigation into increasing the wall structural capacity, and a thorough risk assessment ahead of establishing more robust risk controls. Another key recommendation was to conduct a review of any past failures at the site. Finally, SOTO recommended the establishment of a structured condition monitoring program for the entire grain receival facility.