Effect of seismic retrofit of bridges on transportation networks

The objective of this research is to determine the effect earthquakes have on the performance of transportation network systems. To do this, bridge fragility curves, expressed as a function of peak ground acceleration (PGA) and peak ground velocity (PGV), were developed. Network damage was evaluated under the 1994 Northridge earthquake and scenario earthquakes. A probabilistic model was developed to determine the effect of repair of bridge damage on the improvement of the network performance as days passed after the event. As an example, the system performance degradation measured in terms of an index, “Drivers Delay,” is calculated for the Los Angeles area transportation system, and losses due to Drivers Delay with and without retrofit were estimated.