Numerical and Experimental Evaluation of Bursting Force in Post-Tensioned Anchorage Zones with Practical Plate Geometries

Abstract The anchorage zone plays a critical role in the structural performance of post-tensioned concrete elements, as it governs the distribution of stresses induced by prestressing forces. The behavior of anchorage systems varies significantly depending on the magnitude and configuration of the post-tensioning force. Finite-element analysis (FEA) using actual anchorage geometries enables a realistic simulation of stress distribution and accurate prediction of bursting tensile forces. This study conducts a detailed parametric investigation using ANSYS on four widely used anchorage systems, and experimental validation was carried out to verify the numerical results. Key outputs, including transverse tensile stresses and bursting tensile forces, were analyzed to assess the influence of anchorage shape and size on the structural behavior of concrete beams. Based on the finite-element results, a new empirical equation is proposed for estimating the bursting tensile force, incorporating key parameters often neglected in design standards. The proposed equation estimates significantly higher bursting forces, considering the actual anchorage plate geometry, beam dimensions, and duct configuration. All four anchorage systems evaluated in this study exhibited greater bursting forces than those predicted by current code provisions for anchorage ratios less than 0.5.