Development of practical health monitoring system for short-and medium-span bridges based on vibration responses of city bus

This paper proposes a new method of assessing the condition of existing short-and medium-span bridges based on monitoring data obtained from public bus vibration. This paper not only describes details of a prototype monitoring system that uses information technology and sensors capable of providing more accurate knowledge of bridge performance than conventional ways but also shows a few specific examples of bridge condition assessment based on public bus vibration measured by using an inservice public bus instrumented for vibration measurement. This paper also describes a sensitivity analysis of deteriorating bridges based on city bus acceleration response conducted by the ''substructure method'' based on a finite element model to verify the above mentioned results regarding bridge performance. The main conclusions obtained in this study can be summarized as follows: (1) because the vibration responses of a passenger vehicle such as a city bus has a good linear relationship with the vibration responses of the target bridges, the proposed system can be used as a practical monitoring system for bridge condition assessment; (2) the results of sensitivity analysis performed by the substructure method show that public bus vibration responses are useful for the evaluation of target bridge performance; (3) the proposed method was applied to a network of real bridges in a local area to evaluate its effectiveness. The results indicate that the proposed method can be used to prioritize the repair/ strengthening works of existing bridges based on various vibration information in order to help bridge administrators establish rational maintenance strategies.