Development of seismic retrofit techniques for reinfored concrete structures

有形基础设施在最近几次地震中的表现清楚地表明，现有基础设施的很大一部分，包括关键设施，容易受到地震的影响。在1970年代颁布现代抗震设计准则之前设计的建筑物，以及那些最近建造的没有适当的抗震设计和详细做法的建筑物，构成特别高的地震风险。桥梁的抗震设计实践有着较近的历史，使得大多数桥梁基础设施和重要的交通网络容易受到地震破坏。用新的和经过改进的结构和设施取代有缺陷的基础设施在经济上是不可行和不实际的。因此，抗震改造（恢复和加固）仍然是一个有效和可行的减轻地震风险的战略。

The performance of physical infrastructure during recent earthquakes has clearly demonstrated that a large segment of existing infrastructure, including critical facilities, is vulnerable to seismic excitations. Buildings designed prior to the enactment of modern seismic design guidelines of 1970's, as well as those built more recently without appropriate seismic design and detailing practices, pose particularly high seismic risk. Seismic design practices for bridges have a more recent history, leaving the majority of bridge infrastructure and vital transportation networks vulnerable to seismic damage. It is economically not feasible and practical to replace the deficient infrastructure with new and improved structures and facilities. Therefore, seismic retrofitting (rehabilitation and strengthening) remains to be an effective and viable seismic risk mitigation strategy.