Study On Corroded Steel Bars Or Cables In Concrete Structure And Mechanical Behavior Of Them

Because of the influence of various factors, the reinforced bars in structure can be corroded and reduced their structural usefulness and durability greatly, even causes the structure to become invalid and cannot use. Therefore, the corrosion problem of the structure of reinforced concrete has become international serious problem especially the corrosion problem of prestressed concrete, the study to the mechanical behavior of it has very commonly and important project meaning, and has extensive application prospect.As the corrosion of reinforced bar, it causes the decline of load carrying capacity and durability of the structures, particularly in prestressed concrete structures. The work stress of prestressed high strength steel (wire or strand) is higher than the common one, and the prestressed high strength steel has a much smaller cross-section, so it is much more serious on the impact of corrosion than common reinforced bar. In order to understand the changes in mechanical functions of the prestressed steel after rust, 20 rusted cables removed from Zhongxiang Han River Highway Bridge with spans of 60+3×100+60m are tested to analyze the mechanical functions.Prestressed concrete beam bridges with bond between prestressing bundles (the tendons) and concrete reduce structure supporting capacity and damage ahead of the service life frequently because some defects, such as the prestressing ducts not fully grouted, make the prestressing bundles rust and slip between prestressing bundles and concrete. Based on the bridge analysis's characteristics of using beam element commonly, the Saenz formula is adopted to express stress—strain relation of the concrete, the Skogman formula is adopted to express stress—strain relation of the prestressing bundles, the non-linear springs is adopted to simulate bond slipping between rusted prestressing bundles and concrete, then rigid end element—nonlinear spring element—tendon element analysis method is proposed. In this way, a project example is analyzed to prove the validity of the proposed method used in the nonlinear analysis of the prestressed concrete bridges because of the rusted tendons.