The Time-Dependent Effect of Corrosion of Steel Strands on Prestressed Concrete Beam Bridges

Based on the concrete carbonization theory, we analyze the time when prestressed steel strands begin to corrode, and put forward the degradation time-dependent model for cross-sectional area of a corroding steel strand; with the comparison of existing research results, we propose the degradation time-dependent model for mechanical properties of corroded steel strands, including the nominal ultimate strength and nominal elastic modulus. We deduce a time-dependent model for the prestressing loss due to steel strand corrosion. Taking a prestressed concrete hollow slab bridge as an example, we analyze the time-dependent effect of the corroded strands on the concrete stress at serviceability limit state and flexural bearing capacity at ultimate limit state. Research shows that the bottom edge stress and flexural bearing capacity at mid-span of the beams will reduce sharply if the prestressed strands corrode, even corrosion can damage the safety of bridge in just a few years. These results can be for information of further experiments and researches.