Overview of the 2019 Blue Book

摘要

Since 1959, the Recommended Lateral Force Requirements "'Blue Book," published by the SEAOC Seismology Committee, has influenced the seismic design of structures worldwide. The intent of the Blue Book up until the seventh edition (1999) was to provide recommended minimum code requirements and commentary regarding best practice. The Blue Book no longer contains building code recommendations, which now fall under the purview of FEMA's NEHRP Provisions. Recently, there has been momentum for building more earthquake-resilient structures, and growing public awareness regarding the expected performance of minimum code designed buildings and their potential economic impact on a community in a major earthquake. A significant barrier to implementing such change is that code provisions are characteristically minimum requirements, and affecting major improvements within the code amendment framework is difficult and time consuming. There is clearly a need for the industry to have a reputable set of consensus guidelines the practicing engineer can use to meet the challenge of "better than code" seismic design for improved performance, which has historically been the role of the SEAOC Blue Book commentary. The 2019 edition of the Blue Book responds to the ongoing needs of engineers practicing in seismically active regions. Similar to the previous edition, it focuses less on the drafting of code provisions and more on their interpretation and implementation. This Blue Book presents the Seismology Committee's recommendations for the practice of earthquake design. It supplements building codes and standards and, in places, suggests alternative code approaches. It is not intended, however, to replace the building code or to represent a legal standard of care. This article is based on the preface to the 2019 Blue Book.