Author(s): Lukas Reinhardt, Emilia Vogt and Jonas Keller

Abstract: This study presents an integrated experimental and numerical investigation into the shear behavior of prestressed concrete girders, focusing on the effects of prestressing level, transverse reinforcement spacing, and shear span-to-depth ratio on ultimate shear capacity and failure mechanisms. Twelve full-scale prestressed concrete girders were fabricated and tested under four-point bending, with prestressing levels of 0.60 fpu and 0.70 fpu, and stirrup spacings of 100 mm, 150 mm, and 200 mm. The specimens exhibited distinct failure modes ranging from flexure-shear to web-shear, governed primarily by stirrup configuration and slenderness ratio. The experimental results revealed that higher prestressing levels and closer stirrup spacing significantly improved crack resistance, shear strength, and post-cracking ductility. A nonlinear finite element model, developed in ABAQUS using the Concrete Damaged Plasticity (CDP) approach, successfully simulated the entire shear response, capturing crack initiation, diagonal propagation, and ultimate failure with an average deviation of less than 5% from experimental data. Comparison with AASHTO-LRFD and Critical Shear Crack Theory (CSCT) predictions showed that both design models were conservative, underestimating shear strength by approximately 8% and 5%, respectively. Statistical analyses confirmed the strong influence of stirrup spacing and prestress level on shear capacity (p < 0.05), while the shear span-to-depth ratio exhibited an inverse correlation with ultimate shear strength (R² = 0.82). The study concludes that advanced nonlinear modeling, when calibrated through controlled testing, provides a reliable framework for predicting the shear performance of prestressed girders. Practical recommendations include optimizing prestress levels, maintaining moderate slenderness ratios, and incorporating calibrated finite element verification during design stages to enhance both safety and material efficiency. The research underscores the importance of integrating experimental evidence with computational tools to refine current design practices and improve the structural reliability of prestressed concrete bridge systems.

Pages: 37-41 | Views: 8 | Downloads: 3

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