Abstract: A method for non-destructive evaluation of a conduit, gallery or similar structure as shown which involves mechanical tests using an apparatus for applying forces to the walls of the structure in one or two opposite directions and measuring the displacement and or deformation resulting from the application of the forces. The applied forces and the displacements are measured, received, processed and stored in memory for further processing analysis and diagnosis to determine the condition of the structure over the length evaluated. A suitable expert computer system is utilized to establish the overall condition of the structure and classify the structure into zones of risk for maintenance and or repair.