Field studies were carried out to investigate various parameters of bridges found in northern part of Pakistan. After the Kashmir earthquake of Mw7.6 in 2005, detailed field investigations of seismic performance of bridges was undertaken. A mathematical function to define the functionality of bridges was developed which is helpful for quantifying the seismic resilience of bridges. Criterion for minimum required functionality for different bridges and limit states were defined for large rare earthquake and for moderate occasional earthquakes. From the field data, a series of experimental...