The integration of periodic truss bridge design and impulse response method

Abstract

Global structural monitoring strategies for steel truss bridges have the challenges as the influence of boundary conditions on the comparison of predicted and measured properties, and the insensitivity of current methods to small flaws. It is important to consider the damage mechanisms and their influences to structural behavior in the design process. In this paper, the truss optimization is linked with periodic structure design such that each periodic unit (repetitive truss section) has distinct dispersion curve that can be monitored in time for the presence of damage. The numerical model of periodic unit is performed for pristine and cracked conditions. The changes in dispersion behavior with the increase of damage are noted. A section of the truss is built in the laboratory, and the dispersion of periodic unit is obtained using impulse response method in order to reduce the influence of boundary conditions. The changes of dispersion curve of periodic cell with the increase of damage are compared with the numerical results. The proposed design strategy integrates the damage detection philosophy to the design stage, and increases the reliability of nondestructive evaluation method.