Dr. Richard Wright, NIST Building and Fire Research Laboratory (BFRL) Director, has represented NIST in the NEHRP Interagency Coordinating Committee (ICC), whose members are the senior line managers of the principal agencies. ICC provides policy-level directions in the preparation of the coordinated and consolidated budget for NEHRP and its presentation to the Office of Management and Budget, and the development of the Strategic Plan for NEHRP/NEP. ICC also coordinates the execution of the NEHRP/NEP program including: preparation of Congressionally-mandated studies, collaborations with private and public sector elements of the earthquake community, and development of the biennial NEHRP report to Congress. NIST participates in NEHRP/NEP planning and in the Subcommittee on Natural Disaster Reduction of the National Science and Technology Council. 6. DEVELOPMENT AND IMPLEMENTATION OF EARTHQUAKE HAZARD In accord with P.L. 101-614, NIST provides the chairman and technical secretariat for the Interagency Committee on Seismic Safety in Construction (ICSSC) through which 33 federal departments and agencies concerned with seismic safety collaborate to develop and incorporate earthquake hazard reduction measures in their programs. FEMA funds the work of the ICSSC secretariat. To link its activities to those of the private sector, the ICSSC chairman serves as a Board member of the Building Seismic Safety Council (BSSC), and ICSSC members serve on many technical committees of BSSC and Technical Council on Lifeline Earthquake Engineering, ASCE. Executive Order 12699, "Seismic Safety of Federal and Federally Assisted or Regulated New Building Construction," requires all federal departments and agencies to use the proper seismic design and construction requirements in the design and construction of new buildings. Following the President's issuance of this Order in 1990, NIST and ICSSC undertook a number of activities in support of he Executive Order's implementation. These included, Translating the "NEHRP Recommended Provisions for the Development of Seismic Regulations for New Buildings” into language suitable for incorporation into the national building codes, Issuing a Recommendation stating that codes and standards which are significantly equivalent to these Provisions are appropriate for implementing the Executive Order, and Developing RP2.1, "Guidelines and Procedures for Implementation oft Executive Order on Seismic Safety of New Building Construction," to assist the agencies in developing their programs in response to the Executive Order. The ICSSC continues in its efforts to promote the Executive Order and to assist agencies in developing their specific programs. In May 1995, a report was issued which compared the most recent editions of the ICBO Uniform Building Code, the BOCA National Building Code, the SBCCI Standard Building Code, the CABO One- and two-family Dwelling Code, and ASCE 793, "Minimum Design Loads for Buildings and Other Structures," to the 1991 edition of the NEHRP Recommended Provisions. Also in May 1995, the ICSSC issued a Recommendation, based on the results of this study, which stated that the seismic provisions of the current editions of the three model building codes, as well as ASCE 7-93 and Appendix, are appropriate for implementing the Executive Order. This recommendation is very important for cost-effective seismic safety. The designer of a federal-assisted or regulated building, can use the model building code familiar to the locality without incurring either the expense or the possibility of misunderstanding involved with use of an unfamiliar special federal seismic requirement. Damage from recent earthquakes has made it apparent that buildings constructed before the use of modern seismic codes are at much higher risk during an earthquake. However, there have been few requirements to upgrade any of these buildings and there have been no building codes or standards for the rehabilitation of these buildings. The federal government, through ICSSC, has taken a lead role in the recognition of this problem and the development of the tools to tackle it. Public Law 101-614 called for the ICSSC to work with appropriate private sector organizations in the development of standards for assessing and enhancing the seismic safety of existing buildings constructed for or leased by he federal government. These standards were published in February 1994 as RP4, "Standards of Seismic Safety for Existing Federally Owned or Leased Buildings." The Law also called for the President to adopt the standards by December 1, 1994. Executive Order 12941, “Seismic Safety of Existing Federally Leased or Owned Buildings" was drafted by ICSSC and signed by the President on December 1, 1994. This Executive Order is the implementing authority for the RP4 Standards and requires all federal agencies to use the RP4 Standards as a minimum when evaluating or rehabilitating existing buildings for seismic safety. The RP4 Standards describe certain trigger situations which require an agency to evaluate and develop a plan for the mitigation of any building found to be seismically deficient. These triggers include a change in the use of the building, other upgrades being performed on the building, and the determination of the building as representing an “exceptionally high seismic risk." This provides an initial effort to reduce the seismic risk in federal buildings. In order to determine the full extent of seismic risk in existing federal buildings a more extensive program must be put into place. For this reason, Executive Order 12941 tasks all affected federal agencies to develop a full inventory of their owned and leased buildings, and to develop estimates of the costs required to bring this inventory up to a level of acceptable seismic safety. The information collected through this effort will be used to develop recommendations for an economically feasible plan to mitigate earthquake risks in existing federal buildings. The Executive Order states that the details for the inventorying and cost estimating effort are to be published by the ICSSC within one year of the signing of the Order. In response, the ICSSC published two documents. RP5, “ICSSC Guidance on Implementing Executive Order 12941 on Seismic Safety of Existing Federally Owned or Leased Buildings," was published in October 1995 and provides the recommended methodology for collecting and reporting inventory and cost estimate information. An accompanying document, TR-17, “How-To Suggestions for Implementing Executive Order 12941 on Seismic Safety of Existing Federal Buildings, A Handbook," was published in November 1995 and suggests detailed techniques for developing this information. The information required from the agencies is due to FEMA by December 1, 1998. To assist the agencies in meeting this deadline, the ICSSC has hosted three workshops on "How to Comply with Executive Order 12941" since the publication of RP5. These workshops have provided agency representatives the chance to share information on the program of their programs and to benefit from the experience of other agencies. The next workshop will be held before the end of FY 1997. In addition to its support of the ICSSC, NIST also provides technical expertise to assist FEMA in the review of projects to develop both seismic design and seismic rehabilitation resource documents. Two major projects in these areas are scheduled for completion in 1997. The first is the "NEHRP Guidelines for the Seismic Rehabilitation of Buildings." This project, which is being developed by BSSC, Applied Technology Council (ATC), and the American Society of Civil Engineers (ASCE), is a multi-year effort to develop comprehensive guidelines for the seismic rehabilitation of existing buildings. Such guidelines currently do not exist, hence the document will provide an extremely useful tool to promote the cost-effective rehabilitation of seismically vulnerable buildings. The document is currently undergoing the BSSC consensus balloting process. The second project is the 1997 edition of the NEHRP Recommended Provisions. This edition continues to bring provisions for the seismic design of new buildings up to the present state of knowledge by incorporating new design values based on a new generation of seismic hazard maps developed by USGS. This is the first time these maps have been updated in over 20 years. This document is going through the BSSC consensus balloting process now. By providing technical assistance on these and similar projects, NIST is able to provide a link between the development of federal and private sector seismic design and rehabilitation guidelines. 7. EARTHQUAKE ENGINEERING RESEARCH ACTIVITIES NIST's earthquake engineering research activities focus on three major program areas: (1) structural control, (2) lifeline and geotechnical engineering, and (3) strengthening of existing structures and improvement of new structures. These program areas were selected through the collaborations with users described in Section 1 to make best use of the resources provided to NIST through NEHRP. Structural control is used to reduce the response of structures to vibratory motion from earthquake, wind and other loading condition. Structural control may be divided into three types: seismic isolation (base isolation), passive energy dissipation (devices or systems that do not depend on an external energy source to operate), and active and semi-active control (devices or systems that require an external energy source to operate). Structural control is planned and executed as a multi-year program in which NIST will develop test methods for structural control devices and systems in order to assist in bringing innovations into practice. NIST's current effort is focusing on the seismic isolation technology. Work has begun to address technical issues in the areas of passive control systems. 39-999 98-3 Performance Requirements for Seismic Isolation Systems Seismic isolation has been demonstrated in recent earthquakes as an effective means for reducing the level of response in structures during strong earthquake ground shaking. Testing of the isolation system prior to installation is required by each of the existing building codes that deal with the design of isolated structures; however, standards do not yet exist for conducting these much needed tests, and therefore, procedures and results are subject to considerable variability. NIST has completed the development of draft guidelines, a pre-standard, for testing of isolation systems. The guidelines address pre-qualification, prototype and quality control testing. The guidelines were developed ir collaboration with an oversight committee and with inputs from practicing engineers. ASCE has formed a standard committee to use the guidelines for developing an American National Standard Institute (ANSI) national consensus standard for testing of base isolation systems. NIST serves as the technical secretariat for the ASCE committee. Fluor-Daniel, an Irvine, California based engineering firm, has used the draft guidelines in the design of one of its base-isolated buildings in California--a typical example of measurement technology developed at NIST being transferred into engineering practice. Meanwhile, work is continuing to execute a detailed experimental plan which conducts tests according to the procedures established in the draft guidelines, and to report on the adequacy and feasibility of the guideline test procedures based on the observations and experiences gained from the test program. 7.2 Lifeline and Geotechnical Earthquake Engineering Failure of lifelines during an earthquake can result in loss of life, property, individual income, and revenue losses for business and governments. It can also result in adverse environment impact, fires, and hinder post-earthquake emergency and rescue operations. As demonstrated in the Northridge and Kobe earthquakes, disruption of lifelines can be devastating. Yet, unlike buildings, no nationally accepted guidelines or standards exist for design of new and rehabilitation of existing lifelines. The need for developing such guidelines is presented in Section 4.3. The objective of the NIST's lifeline and geotechnical earthquake engineering program is to develop the knowledge base, through appropriate research, that is needed to support the development of design guidelines, as proposed in the Lifeline Plan (FEMA 271-Section 4.3) NIST's in-house lifeline research effort has been focusing on technical topics common to all lifelines, such as determination of soil liquefaction potential, and assessment and development of methods to improve soil deposits to reduce or eliminate liquefaction potential. Estimating Liquefaction Potential and Assessment of Ground Improvement Technologies In geotechnical earthquake engineering, field methods are preferred since it is impossible to obtain "undisturbed" samples of loose soil deposits, which are most susceptible to liquefaction, for laboratory testing. For over 50 years, the state of practice has been the Standard Penetration Test (SPT) based method. Although in recent years, evaluation based on the Cone Penetration Test (CPT) has gained some attention; however, the method faces the lack of data from past earthquakes and also the fact that CPT may not be used to penetrate soils that contain particles larger than 75 mm. The Spectral Analysis of Surface Wave (SASW) technique has the potential for examining the large areal extent of lifeline routes. Its effectiveness as a tool for liquefaction potential determination as well as for determining the effectiveness of corrected measures to improve the ground against liquefaction has been the focus of NIST's research. NIST researchers, in collaboration with the University of Texas, Austin, and Subsurface Exploration Co., Pasadena, California, have conducted SASW tests at sites on Treasure Island and in Watsonsville, California. While we are completing the processing of the experimental data, preliminary results have shown that the method has great potential. Further, NIST researchers, working with the private sector, have examined the soil strength properties, as expressed by their shear modulus values, of over 120 sites that liquefied during 17 past earthquakes, to construct a set of design charts that can be used to complement, and eventually replace the SPT-based method as the state of the practice. We are now exploring means to promote the use of these charts by design professionals. 7.3 Strengthening of Existing Structures and Improvement of New Structure Design Post-earthquake investigation efforts following the Northridge and Kobe earthquakes again demonstrated the much higher vulnerability of older buildings designed and constructed using outdated methodologies and technologies. It is urgent to focus the engineering community's effort on developing methods for strengthening or retrofitting existing buildings and structures. Development of the best and most cost-effective strengthening techniques for different types of buildings and structures has been one of the NIST's major thrust. There is also need to improve methods for the design and construction of new buildings and structures. This includes the use of improved and new materials and systems for seismic resistant design and the ability to develop good detailing of structural components to improve their ductility when subject to seismic loading. NIST's current research in this area include (1) precast beam-column connections for high and moderate seismic zones, (2) strengthening methodologies for reinforced concrete buildings, (3) seismic resistance of masonry walls, (4) seismic performance of cladding systems, (5) lateral load resistance of manufactured housing, and (6) seismic design, retrofit, and repair of concrete bridge columns. Studies related to welded steel moment frame buildings have been presented in Section 3.1. This study has contributed to the NEHRP Recommended Provisions for Seismic Regulations for New Buildings and to the NEHRP Rehabilitation of Existing Buildings. An example of NIST's problem focused R&D in earthquake engineering is: Seismic Performance of Precast Concrete Connections The project has The system has been approved by the International Conference of Building Officials' Evaluation Service, and has been used in construction of parking structures in Eugene, Oregon and New York; and of a 25-story hotel in Seattle; and in the design of a 45-story apartment building in San |