Resilient Infrastructure is the fourth Strategic Theme defined by PIARC in the 2020-2023 Strategic Plan. During this cycle, Technical Committee 4.2 Road Bridges was assigned 5 issues. The fifth issue, titled “Damage-Resilient Bridges in Seismic Areas”, was consistent with the fourth Strategic Theme, and was addressed by preparing two deliverables :

1. a collection of case studies and
2. a full report.

The collection of case studies provided information given by stakeholders worldwide regarding:

• Retrofit strategies and techniques,
• Prioritization of the bridges to be retrofitted,
• Examples of retrofit techniques and best pratices

This information was analyzed by the authors resulting in the present report, with the following content. First, typical damage to bridges from historical events are presented, which help the reader understand the evolution of the seismic codes and their main provisions that enhance bridge performance during seismic events and thus manage seismic risk. Further, it is shown how countries prioritize bridge assets to be retrofitted for seismic actions. For this purpose, some countries apply a decision tree process whereas others examine each case individually. Regarding standards and level of risk, each country uses different strategies to improve seismic resistance and provide resilience. These seismic retrofit strategies are presented in detail. The strategies depend on the seismic hazard, available retrofit techniques, cost-benefit analysis, resilience of the road network, and overall asset management policy. Special attention is given to retrofit techniques which are more commonly used in the countries that responded to the questionnaire.
This state-of-the-practice report should be a valuable reference for bridge owners and operators worldwide in making decisions on how to optimize their seismic retrofit strategy and make best use of the presented retrofit practices for existing road bridges.