The structural analysis of six circular steel silos 12,75 m high with 9 m diameter, used for wheat storage in an industrial plant of southern Italy, was conducted due to an uncontrolled hoop strain, shown by the silos in correspondence with the walls of the lower regions after twenty years of service conditions. Analytical results were obtained in three steps, a simplified model based on the elastic theory of tanks was constructed using a cylindrical shell. However, the solutions resulted in insufficient accuracy due to the lack of accurate hypothesis. Subsequently, the theory of Janssen was applied in accordance to the Eurocode equations given for the design of steel silos. The presence of three CFRP (Carbon Fibre Reinforced Polymer) external rings were tensioned and modelled in order to apply an active external confining stress. A numerical finite element analysis (FEA) was also pursued and analytical results were found to be in good accordance with each other. The effectiveness of the design strategy (external confinement) was confirmed by the theoretical analysis. The application is then presented, three CFRP pultruded plates were placed as external “belts” and post-tensioned along the perimeter of the silos by using a simple dedicated device.
A STUDY FOR THE STRENGTHENING OF STEEL SILOS WITH ACTIVE CFRP HOOPS
MICELLI, Francesco
2012-01-01
Abstract
The structural analysis of six circular steel silos 12,75 m high with 9 m diameter, used for wheat storage in an industrial plant of southern Italy, was conducted due to an uncontrolled hoop strain, shown by the silos in correspondence with the walls of the lower regions after twenty years of service conditions. Analytical results were obtained in three steps, a simplified model based on the elastic theory of tanks was constructed using a cylindrical shell. However, the solutions resulted in insufficient accuracy due to the lack of accurate hypothesis. Subsequently, the theory of Janssen was applied in accordance to the Eurocode equations given for the design of steel silos. The presence of three CFRP (Carbon Fibre Reinforced Polymer) external rings were tensioned and modelled in order to apply an active external confining stress. A numerical finite element analysis (FEA) was also pursued and analytical results were found to be in good accordance with each other. The effectiveness of the design strategy (external confinement) was confirmed by the theoretical analysis. The application is then presented, three CFRP pultruded plates were placed as external “belts” and post-tensioned along the perimeter of the silos by using a simple dedicated device.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
