This study is intended to investigate the feasibility of health monitoring of short span bridges based on modal parameter identification using the vibration data of the bridge induced by a moving vehicle. The idea of this study using the traffic-induced vibration of short span bridges which is a kind of non-stationary process is that the modal parameters identified repeatedly under a given moving vehicle provide a pattern which may provide useful information to decide current health condition of bridges. The autoregressive (AR) model is adopted for identifying modal parameters such as frequency and damping characteristics of the bridges. Mode shapes of bridges are obtained using multivariate AR model. Feasibility of the modal parameter identification for health monitoring of short span bridges is observed through a moving vehicle laboratory experiment. Pattern changes of identified parameters are observable by comparing the identification results between intact and damaged girders, which encourages the use of the method for long term health monitoring even for short span bridges.

No abstract

This paper investigated dynamic responses of steel monorail bridges incorporating train-bridge interaction under strong earthquakes. Two types of steel monorail bridges were considered in the study: a conventional type with steel track-girder; an advanced type with composite track-girder and simplified lateral bracing system. During strong earthquakes, monorail train was assumed standing on the track-girder of monorail bridges. Observations through the analytical study showed that considering the monorail train as additional mass rather than a dynamic system in numerical modeling overestimated effect of the train load on seismic performance of monorail bridges. Earlier plastic deformations at the end bracing of the girder system absorbed seismic energy and reduced the stress at the pier base.