Ronald O. Hamburger

Translating Research to Practice: FEMA/SAC Performance-Based Design Procedures

The extensive research on steel moment-frame performance developed by the FEMA/SAC program was implemented in a probabilistic reliability framework to develop performance-based design and evaluation procedures. These procedures, presented in a familiar demand and resistance factor engineering format provide engineers with the ability to define a level of confidence associated with the prediction that a building design will be able to meet a desired performance objective. This approach builds upon and extends the performance-based design procedures developed under the SEAOC Vision 2000 and FEMA 273 projects in two important ways. First, it provides a direct method for structural performance to be evaluated on the basis of global, as opposed to local behaviors. Second, it permits quantification of the likelihood that desired performance will actually be achieved, potentially alleviating liability concerns related to implementation of performance-based design approaches. Perhaps more important, the procedures implemented by the FEMA/SAC project provide a direct method for the incorporation of analytical and laboratory research into design procedures with defined reliability.

The Performance of Steel-Frame Buildings with Infill Masonry Walls in the 1906 San Francisco Earthquake

Following the great 1906 San Francisco earthquake and fire, engineers recognized the superior performance of buildings with complete vertical load–carrying steel frames and infill masonry walls. These buildings were noteworthy in their ability to survive both the ground shaking and fire, many remaining in service today. Observation of this superior performance led many California structural engineers to believe that steel frames were the best structural system for resisting earthquake damage, in turn, leading to a proliferation of steel-frame construction in California cities. Not until the 1994 Northridge earthquake did many California engineers recognize that steel-frame structures can and do experience severe earthquake damage. The performance capability of early steel-frame buildings with infill masonry walls, however, remains unclear, despite improved understanding of their structural response characteristics.

Response History Analysis for the Design of New Buildings in the NEHRP Provisions and ASCE/SEI 7 Standard: Part I - Overview and Specification of Ground Motions

This manuscript, the first in a four-part series, describes the response history analysis approach developed for Chapter 16 of the ASCE/SEI 7 Standard and critical issues related to the specification of ground motions. Our approach provides new procedures for demonstrating adherence to collapse safety goals for new buildings (≤10% collapse probability at the MCER shaking level), creating nonlinear structural models, selecting and applying ground motions to the structural model, interpreting computed structural responses, and enforcing acceptance criteria to achieve the collapse safety goal. The ground motion provisions provide the option of using target spectra having more realistic spectral shapes than traditional uniform hazard spectra. Ground motions are developed using a two-stage procedure emphasizing spectral shape in their selection, followed by scaling or matching them to the target, with a modest penalty for matching. Horizontal component motions are applied to the structural model with random components to avoid bias associated with the maximum-component definition of the target spectrum.

Response History Analysis for the Design of New Buildings in the NEHRP Provisions and ASCE/SEI 7 Standard: Part II - Structural Analysis Procedures and Acceptance Criteria

This paper represents the second part of a series of four publications on response history analysis for new buildings. It specifically focuses on modeling assumptions, consideration of important effects in the analysis, and interpretation of analysis results via global and local acceptance criteria. A statistical basis for development of both force- and deformation-controlled acceptance criteria consistent with the collapse probability goals of ASCE/SEI 7 is illustrated. More explicit sub-classifications of force- and deformation-controlled actions are proposed within the statistical framework. Additional philosophical discussion and simple probabilistic arguments are presented on the topic of consideration of unacceptable response, and guidance on addressing unacceptable response is given. Similarities and differences between the new requirements and those in other performance-based design guidelines are also enumerated.

Overview of the U.S. program for reduction of earthquake hazards in steel moment-frame structures

Considerable research has been conducted worldwide to assess the unexpected damage to welded steel moment-frame buildings during the 1989 Loma Prieta, 1994 Northridge, and 1995 Hyogo-ken Nanbu earthquakes, as well as to find effective and economical remedies that can be incorporated into analysis, design, and construction practices. A major six-year program has been undertaken with the sponsorship of the U.S. Federal Emergency Management Agency (FEMA) to synthesize and interpret the results of this research, and to conduct additional investigations to develop reliable, practical, and cost-effective guidelines for the design and construction of new steel moment-frame structures, as well as for the inspection, evaluation and repair or upgrading of existing ones. Topics investigated as part of this program include (1) performance of steel buildings in past earthquakes; (2) material properties and fracture issues; (3) joining and inspection; (4) connection performance; (5) system performance; (6) performance prediction and evaluation; and (7) social, economic, and political impacts. The project utilizes a performance-based engineering framework and addresses issues pertaining to various types of steel moment-resisting frames including those utilizing welded, bolted, and partially restrained connections. The guidelines are applicable to regions of low, medium, and high seismicity throughout the United States. This paper reviews the overall organization and management of this program of research, guideline development, training and peer evaluation, the scope of the investigations undertaken, and the general organization and contents of the guidelines developed.

Response-history analysis for the design of new buildings: A fully revised chapter 16 methodology proposed for the 2015 NEHRP provisions and the ASCE/SEI 7-16 standard

This paper is the result of a multi-year effort to rewrite Chapter 16 of the ASCE/SEI 7-10 Standard, which is entitled Seismic Response-History Procedure. This paper documents the newly-proposed Chapter 16 requirements, as well as the rationale and logic behind the requirements. The goals of this paper are to: (a) explain the rationale for the newly proposed requirements, for those interested in why changes are being proposed; and (b) provide detailed explanation of the new requirements, to help future users properly apply the requirements in the design of new buildings. This effort was initiated by the Building Seismic Safety Council (BSSC) Provisions Update Committee (PUC) who formed an Issue Team with the specific mandate of proposing a fully rewritten version of Chapter 16. This newly proposed Chapter 16 will become a part of the 2014 National Earthquake Hazard Reduction Program (NEHRP) Provisions and then will be considered for inclusion in the ASCE/SEI 7-16 Standard. 1 Chair and Assoc. Prof., Dept. Civil Eng., Calif. State Univ. Chico, 207 Langdon Hall, Chico, CA 95929-0930 2 Chief Operating Officer, Magnusson Klemencic Assoc., Seattle, WA 98101-2699 3 Assoc. Prof., Dept. Civil and Environ. Eng., Stanford Univ,, Stanford, CA 94305 4 Senior Principal, Simpson Gumpertz & Heger Inc., CA 94111 5 Prof., Dept. Civil, Struct., & Environ. Eng., State Univ. of New York at Buffalo, Buffalo, NY 14260 6 Prof. and Chair, Dept. Civil & Environ. Eng., Univ. California Los Angeles, Los Angeles, CA 90095-1593 7 Assoc. Prof., Dept. Civil Eng., Univ. British Columbia, Vancouver, B.C. V6T 1Z4 8 Research Struct. Engineer, U.S. Geological Survey, Denver CO 80225 9 Principal/Director of Earthquake Eng., Magnusson Klemencic Assoc., Seattle, WA 98101-2699 10 Prof. and Director Ctr for Extreme Load Effects on Structures, Virginia Tech, Blacksburg, VA 24061 11 Applied Research Consultant, Rutherford + Chekene, San Francisco, CA 94105 12 Assoc. Principal, Degenkolb Engineers, San Francisco, CA 94109 Haselton, Curt B., et al. Response-History Analysis for the Design of New Buildings: A Fully Revised Chapter 16 Methodology Proposed for the 2015 NEHRP Provisions and the ASCE/SEI 7-16 Standard. Proceedings of the 10th National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014. _________________________________________ 1 Chair and Assoc. Prof., Dept. Civil Eng., Calif. State Univ. Chico, 207 Langdon Hall, Chico, CA 95929-0930 2 Chief Operating Officer, Magnusson Klemencic Assoc., Seattle, WA 98101-2699 3 Assoc. Prof., Dept. Civil and Environ. Eng., Stanford Univ,, Stanford, CA 94305 4 Senior Principal, Simpson Gumpertz & Heger Inc., CA 94111 5 Prof., Dept. Civil, Struct., & Environ. Eng., State Univ. of New York at Buffalo, Buffalo, NY 14260 6 Prof. and Chair, Dept. Civil & Environ. Eng., Univ. California Los Angeles, Los Angeles, CA 90095-1593 7 Assoc. Prof., Dept. Civil Eng., Univ. British Columbia, Vancouver, B.C. V6T 1Z4 8 Research Struct. Engineer, U.S. Geological Survey, Denver CO 80225 9 Principal/Director of Earthquake Eng., Magnusson Klemencic Assoc., Seattle, WA 98101-2699 10 Prof. and Director Ctr for Extreme Load Effects on Structures, Virginia Tech, Blacksburg, VA 24061 11 Applied Research Consultant, Rutherford + Chekene, San Francisco, CA 94105 12 Assoc. Principal, Degenkolb Engineers, San Francisco, CA 94109 Haselton, Curt B., et al. Response-History Analysis for the Design of New Buildings: A Fully Revised Chapter 16 Methodology Proposed for the 2015 NEHRP Provisions and the ASCE/SEI 7-16 Standard. Proceedings of the 10th National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014. Response-History Analysis for the Design of New Buildings: A Fully Revised Chapter 16 Methodology Proposed for the 2015 NEHRP Provisions and the ASCE/SEI 7-16 Standard Curt B. Haselton, Andy Fry, Jack W. Baker, Ronald O. Hamburger, Andrew S. Whittaker, Jonathan P. Stewart, Kenneth J. Elwood, Nicolas Luco, John D. Hooper, Finley A. Charney, Reid B. Zimmerman, and Robert G. Pekelnicky

Performance Based Analysis of a Historic High Rise Building

The authors employed high-fidelity computer modeling to analyze the probable seismic performance of an ex- isting high-rise, steel frame building with unreinforced masonry infill walls in downtown San Francisco. The Pacific Telephone and Telegraph Co. building at 138 New Montgomery is a 26-story, historic office building. Constructed in 1926 this building was the tallest building in the western United States for a long period of time. The buildings structural system comprises perimeter unreinforced brick masonry walls infilled within and supported by a steel frame. We con- ducted our analysis in support of the buildings conversion to residential occupancy. As a result of the occupancy conver- sion, along with associated architectural modifications throughout the building, Section 3403 of the San Francisco Build- ing Code (SFBC) requires a seismic upgrade such that the building has a code-compliant lateral-force resisting system with no less than 75% of the strength specified by the code for new buildings of similar occupancy and structural system. Since the existing building does not have a lateral force-resisting system recognized by current U.S. codes, compliance with the prescriptive requirements would have required expensive retrofits. Instead, the authors employed a performance- based approach using the existing masonry infilled steel frame for a substantive portion of the buildings seismic resis- tance, together with a new supplemental interior reinforced concrete shear wall. Rather than design to achieve code- specified strength limits, we used nonlinear response history analysis to demonstrate acceptable behavior under Maximum Considered Earthquake (MCE) shaking. Detailed modeling of the interaction between the masonry infill and steel frame is a key component of this approach.