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Steel and Composite Structures   Volume 10, Number 4, August 2010, pages 361-371
DOI: http://dx.doi.org/10.12989/scs.2010.10.4.361
 
Effect of FRP composites on buckling capacity of anchored steel tanks
M.A. Al-Kashif, H. Ramadan, A. Rashed and M.A. Haroun

 
Abstract     [Full Text]
    Enhancement in the seismic buckling capacity of steel tanks caused by the addition of fiber reinforced polymers (FRP) retrofit layers attached to the outer walls of the steel tank is investigated. Threedimensional non-linear finite element modeling is utilized to perform such analysis considering non linear material properties and non-linear large deformation large strain analysis. FRP composites which possess high stiffness and high failure strength are used to reduce the steel hoop stress and consequently improve the tank capacity. A number of tanks with varying dimensions and shell thicknesses are examined using FRP composites added in symmetric layers attached to the outer surface of the steel shell. The FRP shows its effectiveness in carrying part of the hoop stresses along with the steel before steel yielding. Following steel yielding, the FRP restrains the outward bulging of the tank and continues to resist higher hoop stresses. The percentage improvement in the ultimate base moment capacity of the tank due to the addition of more FRP layers is shown to be as high as 60% for some tanks. The percentage of increase in the tank moment capacity is shown to be dependent on the ratio of the shell thickness to the tank radius (t/R). Finally a new methodology has been explained to calculate the location of Elephant foot buckling and consequently the best location of FRP application.
 
Key Words
    steel tanks; seismic design; finite element analysis; elephant
 
Address
Department of Engineering, Cairo University, Egypt
Steel Structures and Bridges, Structural Engineering Department, Cairo University, Egypt
Dean of Engineering American University, Cairo, Egypt.
 

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