Design criterion and methodologies have been developed and implemented that require bridges to be without significant damage following severe ground shaking. The design philosophy used to obtain these results is often referred to as “Performance Based Design.” These criteria differ from traditional codes in that they correlate levels of damage noted in laboratory testing and real earthquake damage to quantifiable material properties and design parameters. This design approach provides reliability of a structure’s performance by addressing the requirements of a defined load path and using rational analytical methods to envelope the expected demands on the structure. The result is a reasonable level of confidence in achieving the desired structural behavior and predefined performance.