Structural Characterization of a Stone Arch Bridge by Experimental Tests and Numerical Model Updating

Abstract

The Rakanji stone arch bridge has three spans of approximately 26 m, and the total length of the bridge is approximately 89.3 m. The rise:span ratio is approximately 0.19; hence, the arches are very shallow. To clarify the structural characterization of the Rakanji stone arch bridge, a series of dynamic, non-destructive and destructive tests are conducted. From material tests, the Young's modulus and compressive strength of the stone are estimated to be 17.2 kN/mm2 and 28.5 N/mm2, respectively, whereas those of the mortar are estimated as 5.5–7.8 kN/mm2 and 3.9–9.1 N/mm2, respectively. From the results of dynamic tests, the fundamental frequencies, modes, and damping factors of the Rakanji stone arch bridge are identified by eigensystem realization algorithm (ERA) model. From the results of numerical model updating based on inverse eigensensitivity method (IEM), the damaged areas including the effect of boundary condition and bridge-soil interaction are identified and these areas correspond well to those through the in situ tests and visual inspection.