SGER: Critical Appraisal of Research Needs for SMF Connections in Steel Buildings

SGER：钢结构中SMF连接研究需求的批判性评估；PI: Linda Hanagan，宾夕法尼亚州立大学在1994年北岭地震之后，在钢弯矩连接中发现了意想不到的破坏。为了解决这一重大安全问题，联邦紧急事务管理局（FEMA）资助了SAC合资企业，该合资企业编写了FEMA 350系列指导文件、最新报告和其他出版物。随后，这些发现已被纳入新建筑的建筑规范要求。自这些指导文件发布以来，美国钢结构协会（AISC）通过正在进行的共识标准《钢结构建筑抗震规定》（AISC, 2002）的发展，将钢结构建筑设计和施工的许多建议正规化为要求。通过这种方式，将从北岭地震中吸取的教训纳入新建筑的建筑规范要求的工作正在进行中。由于联邦应急管理局350系列文件不是协商一致的标准，因此其中所载的建议必须经过一个通过过程。目前，《钢结构建筑抗震规定》（AISC, 2002）将梁柱连接要求定义为特殊弯矩框架。这些要求的本质是不仅要提供足够的强度，而且要提供足够的延展性。符合这一要求可以通过以下两种方式之一来满足：通过测试或使用符合《抗震规定》附录P的“预审”连接。为了减轻对基于项目的测试的需求，AISC通过其连接资格预审小组（CPRP）正在制定共识标准。该标准预计将以FEMA 350为模型，因为它将概述几种连接的设计，细节和制造过程，这些连接被认为是预先合格的，无需进一步测试。前提是对一系列典型连接进行了充分的测试和评估，以便将其纳入共识标准。事实上，我们的希望是FEMA 350的建议可以在稍加修改的情况下全部被采纳。自FEMA 350发布以来，其中包含的许多建议受到了加州结构工程师协会（SEAOC）和其他机构的质疑。除了RBS连接，其他所有连接（WUF-W， FF， WFP， BFP）在SEAOC评论中都获得了不利评级。CPRP将认真考虑SEAOC和其他机构提出的关切。目前，CPRP内的任务小组正在审查FEMA 350的建议和支持数据，以符合地震规定（AISC 2002）中规定的资格预审要求。如果不立即对一些关键问题进行调查，很有可能第一版的连接预审标准将只包含RBS连接，而该标准将有效地管理地震地区的所有钢弯矩框架结构。在如此多的资源致力于这个主题之后，这对建筑行业来说将是一个非常不幸和不必要的结果。由于SAC合资企业的大多数研究都是并行进行的，因此对个体关系的研究没有回顾性分析的好处。有了一些探索性的资金，PI作为CPRP成员的角色可以扩展到完成三个额外的目标：1)审查现有的文献和测试数据，以推断连接特定结果到其他连接的可能性。实现这一目标可能会导致更多的连接被纳入AISC连接资格预审标准。2)制定一套通过CPRP和PI的工作确定的当前研究需求。作为CPRP的成员之一，PI在确定扩展AISC标准以包括更多FEMA 350推荐连接所需的研究方面处于某种独特的地位。3)制定一份研究计划，根据NEES联盟计划提交，以解决目标#2中确定的一些关键研究需求。SGER的理由这项研究可以被描述为具有“严重紧迫性”，因为实现目标取决于已经开始的CPRP的审议。预计在拟议的研究计划下进行的工作将对AISC资格预审标准的制定产生几乎直接的影响。如果没有拟议的研究提供的侧重点，除了RBS之外，CPRP可能会使许多关于连接的工作变得无用，直到进行进一步的调查。

SGER: Critical Appraisal of Research Needs for SMF Connections in Steel Buildings; CMS proposal 0335718 PI: Linda Hanagan, Penn State UniversityFollowing the 1994 Northridge earthquake, unexpected damage was discovered in steel moment connections. To address this substantial safety issue, the Federal Emergency Management Agency (FEMA) funded the SAC Joint Venture, which produced the FEMA 350-series guideline documents, state of the art reports and other publications. Subsequently, theses findings have been incorporated into the building code requirements for new buildings. Since the publication of these guideline documents, the American Institute of Steel Construction (AISC) has formalized as requirements many of the recommendations made for steel building design and construction through the ongoing development of the consensus standard Seismic Provisions for Structural Steel Buildings (AISC, 2002). In this way, work is ongoing to incorporate the lessons learned from the Northridge earthquake into the building code requirements for new buildings.Because the FEMA 350-series documents are not consensus standards, the recommendations contained therein must undergo an adoption process. Presently, the Seismic Provisions for Structural Steel Buildings (AISC, 2002) define the beam-to-column connection requirements for classification as a special moment frame. The essence of these requirements is to provide not only adequate strength, but also adequate ductility. Conformance with this requirement can be satisfied in one of two ways: by testing or by using a connection "prequalified" in accordance with Appendix P of the Seismic Provisions. To alleviate the need for project based testing, AISC, through its Connections Prequalification Review Panel (CPRP), is in the process of developing a consensus standard. This standard is expected to be modeled after FEMA 350 in that it will outline design, detailing, and fabrication procedures for several connections that are considered prequalified without further testing. The premise is that adequate testing and evaluation has been conducted for a range of typical connections such that they can be included in the consensus standard. In fact, the hope was that the recommendations of FEMA 350 could be adopted in their entirety with some minor modification. Since the publication of FEMA 350, many of the recommendations contained therein have been brought into question by the Structural Engineers Association of California (SEAOC) and others. With the exception of RBS connection, every other connection (WUF-W, FF, WFP, BFP) have received an unfavorable rating in the SEAOC Commentary. The CPRP will seriously consider the concerns raised by SEAOC and others. Currently, task groups within the CPRP are reviewing the FEMA 350 recommendations and the supporting data for conformance with prequalification requirements set forth in the Seismic Provisions (AISC 2002). Without immediate investigation into some of the critical concerns, it is very possible that the first edition of the prequalified connections standard, which will effectively govern all steel moment frame construction in seismic areas, will contain only the RBS connection. After so many resources were dedicated to this topic, this would be a very unfortunate and unnecessary result for the building industry.PROPOSED RESEARCHBecause most of the SAC Joint Venture research was done in parallel, the research on individual connections did not have the benefit of retrospective analysis. With some exploratory funding the PI's role as a CPRP member can be extended to accomplish three additional objectives: 1) Review existing literature and test data for the possibility of extrapolating connection specific results to other connections. Accomplishing this objective may have the result of more connections being included in the AISC connection prequalification standard. 2) Develop a set of current research needs as identified through the work of the CPRP and the PI. As one of the members of the CPRP, the PI is in a somewhat unique position to identify research required to expand the AISC standard to include more of the FEMA 350 recommended connections. 3) Formulate a research proposal, to be submitted under the NEES Consortium program, to address some of the critical research needs identified under goal #2. SGER JUSTIFICATIONThis research can be characterized as having "severe urgency" in that accomplishing the objectives is dependant on the deliberations of the CPRP, which have already begun. It is expected that the work conducted under the proposed research initiative will have a nearly immediate impact on the development of the AISC prequalification standard. Without the tangential focus afforded by the proposed research, it is possible that much of the work on conections other than the RBS will be rendered useless by the CPRP until further investigation is conducted.