Dynamic condition assessment of composite structures using different damage indices

In aging structures, the condition of shear connectors may not be acceptable due to corrosion and/or overloading. Damage or failure of shear connectors will deteriorate the composite action, and therefore reduce the bridge load-carrying capacity. Before retrofitting/strengthening these existing structures, one may be required to detect the integrity of the existing shear connectors. The inaccessibility of the connection system makes direct inspection difficult. In addition, the huge number of shear connectors prevents any local non-destructive testing methods to access the connectors one by one. It is of practical importance to develop a new non-destructive assessment technique to detect the integrity of shear connectors. In this study, two different damage indices are used to evaluate the condition of the shear connection system. A scale composite bridge model has been tested in the laboratory. Different damage scenarios have been created by loosening different shear connectors. Experimental results illustrated that the method is effective and reliable to detect the damage in the connection system of steel-concrete composite structures