Influence of bond deterioration on shear-flexure failure of prestressed girders with post-tensioned tendons

Internal prestressing with bonded tendons suffers corrosion of wires and bond deterioration due to the bad infill of grouted sheaths. Many bridge girders show this state through cracking, deflections and in the worst cases, sudden failures. In Italy these are common situations, and the internal tendon corrosion is among the major causes of bridge degradation and damage, especially for grouted post-tensioned tendons. This paper presents the analysis of failure of prestressed cross-sections considering shear and flexure in the case of bond deterioration due to corrosion of internal post-tensioned tendons. The structural behaviour is analysed for different typologies of bridge deck composed of prestressed beams with bonded tendons. The rate of corrosion is correlated to the bond deterioration and the consequences on the ultimate shear-flexure domains are discussed, giving indications to the engineer on the assessment of existing damaged bridges for safety evaluations