Analysis Of Strength And Stability Of Flat-bottom Squat Steel Silos Strengthened With CFRP

Steel silos have been widely used to store cement, fly ash, coal, chemical fertilizer, grain and many other loose materials. The advantages of steel silos include, but are not limit to, large storage capacity, simple and convenient construction, simple structure. With the rapid development of industry and agriculture in recent years, demand for steel silos has been increasing in China.Accurate evaluating the load capacity of a cylindrical thin-walled shell silos is always challenging because of both the mechanical behavior of silo wall and the nature of material properties. Silos are sensitive to small disturbances, and prone to buckling. For example, it can lead to damage of the silo when the storage falls down along the wall because of the asymmetric distribution of longitudinal and circumferential pressure as well as the local stress concentration on the silo wall caused by the storage material.Therefore, there is a need to reinforce the damaged silos effectively to ensure the safety during their service life.The traditional reinforcement methods use steel components to connect the damaged parts by welding, riveting, screwing and pasting. They are causing new problems, such as stress concentration. During the past decades, Carbon Fiber Reinforced Polymer (CFRP) has been widely applied to the reinforcement of engineering structure systems because CFRP is advantageous over traditional methods in high strength-to-density ratio and superior durability. Compared with traditional reinforcement methods, the application of bonding CFRP to silo wall might reduce stress concentration, residual stress, and facilitate construction and maintenance.The work reported in this study is focused on investigating the strength and stability of collapsed steel silos strengthened with CFRP. The finite element method is used to analyze the load capacity. Linear stress analyses, linear eigenvalue buckling and geometric-material nonlinear buckling are carried out. Some findings include:1) height and thickness of CFRP are key CFRP factors that impact the buckling strength of the strengthened silos;2) the buckling strength of silo increases as the height and thickness of CFRP increase;3) the strength and the stability of the silo can be more effectively improved by reinforcing the lower section of the silo;4) the stability of silo is more sensitive to the thickness but less to the height of CFRP.