Commentary for New LRFD Seismic Criteria

1986年，新的AISC负荷和阻力系数设计 （LRFD）规范的引入， 钢结构建筑作为传统建筑的替代设计 许用应力设计 LRFD代表了一个重大进步 基于安全可靠性的钢结构设计技术 概念和明确考虑系数荷载， 极限状态 然而，该规范主要旨在 适用于受重力或风荷载控制的设计。 因此在 中强地震活动区，补充特别 详细的要求是必要的，以提供足够的 结构延展性和能量吸收， 地震危险程度。 现有的地震 详细规定为容许应力条款， 因此，它们与LRFD不直接兼容。 制定了一套抗震设计规定， 第一次在LRFD格式，最近完成了一个 AISC专家小组委员会。 只有准备一个 在这份必要的文件之前仍有适当的评注 可以发布并广泛分发用于LRFD设计 应用. 该项目将在未来3-6年内支持协调一致的努力 完成本文件并满足 工程师和建筑法规官员的迫切需要。 这 将有助于保持适当的设计实践和安全水平， LRFD用于地震条件。 任务将包括 相关研究参考文献的回顾和列表， 解释背景材料和 标准和讨论/其他一般 条款中未直接涉及的建议。

In 1986, the new AISC Load and Resistance Factor Design (LRFD) Specification was introduced which makes the limit state design of steel buildings as an alternate to the traditional Allowable Stress Design. LRFD represents a major advancement in steel design technology that is based on safety reliability concepts and an explicit consideration of factored loads and limit states. However, the Specification is primarily intended for designs governed by gravity or wind loads. Thus, in regions of high and moderate seismicity, supplemental special detailing requirements are necessary to provide adequate structural ductility and energy absorption commensurate with the degree of earthquake risk. The currently available seismic detailing provisions are in allowable stress terms and, therefore, are not directly compatible with LRFD. The development of a set of seismic design provisions, for the first time in LRFD format, has recently been completed by an expert AISC Subcommittee. Only the preparation of an appropriate Commentary remains before this needed document can be published and broadly distributed for LRFD design applications. This project will support a concerted effort over the next 3-6 months on the Commentary to finish this document and satisfy the urgent needs of engineers and building code officials. This will help maintain proper design practice and safety levels as LRFD is used for seismic conditions. The tasks will include review and listing of related research references, thorough explanation of background material and practical implications of criteria, and discussion/artwork of additional general suggestions not covered directly by the provisions.