Experimental Investigation Of Material Prpperties Of 1860mpa Prestressing Seven-wire Strand At Stress And High-temperature

With the constantly improve and enhance of prestressed concrete theory and technology, Prestressed concrete structure has been widely applied. The fire resistance performance of prestressed concrete structures and the method how to evaluate damage and repair structures after fire gradually get the attention. As one of the most important factor on fire resistance of Prestressed concrete structur, the prestressing seven-wire strand fire resistance performance test research has very vital significance.The strength and deformation behaviours of 1860Mpa diameter 15.2mm prestressing seven-wire strand which commonly used in prestressed structural engineering under high-temperature are studied in this thesis. The electrical furnace and deformation measuring are specially designed and produced. The main testing results are as follows:Yielding strength, ultimate strength, stress-strain relationship, the Yang's modulus and strain caused by temperature of 1860Mpa prestressing seven-wire strand of every grade ranging of 20℃to 600℃. Two different paths of stress-temperature are adopted in the tests: elevated before loading and loading before elevated. And then, the test results from both testing paths are compared and some conclusions are drawn .The coupling action between stress and temperatures is also studied. The influences of temperature to the strength and deflection of the prestressing seven-wire strand are discussed as well.According to the test results, the equations describing the mechanic performance of the prestressing seven-wire strand under high-temperature are given in this thesis, which can be applied to the structural computation for prestressed concrete structures under high-temperature cases.