The roof structural model of liquid manure storage tank was designed to improve a structural safety and an ability of resistance to corrosion by the bad environmental condition with high humidity and high gas concentration.
Due to corrosion of a general steel, the 5 years used materials were reduced to one-third of a new material in the result of a bending strength test. Some structural materials were tested to evaluate a strength and an anti-corrosion, and stainless steel pipe(STS439), steel angle with zinc hot dipping, rectangular steel pipe covered with FRP(Fiberglass Reinforced Plastics) resin were selected finally. A stainless steel is more expansive about 3~5 times than general structural steel. But its durability under heavy corrosive environment is expected twice as long as general steel. The roof models were designed as closed cone type for each of the three structural materials.
In the result of a FEM(Finite Element Method) structural analysis for the developed models, the safe snow depth was higher 2.3 times than a general roof structure, when elements of equal section modulus were used.