Bending tests to estimate the axial force in tie-rods

This paper presents a static method for the axial load identification of prismatic structural elements, with known geometric and elastic properties, which can be idealized as simply supported beams constrained by two end rotational springs. To this aim, the beam is subjected to an additional, transversal static force and the flexural displacements are measured at three given cross sections. Numerical and experimental tests are developed to validate the analytical procedure. In principle, use can be made of the proposed algorithm to evaluate both the axial force and the flexural stiffness coefficients of the end constraints. In fact, very good agreement is obtained between estimated and measured values of the axial force. Vice versa, the end stiffness identification gives reliable results for low values of the axial force only whereas, for all other cases, scattered and unreliable results are obtained.