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MCEER Bulletin, Volume 21, Number 2, Summer 2007

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Volume 21, Number 2, Summer 2007

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New Technical Reports

A Study of the Coupled Horizontal-Vertical Behavior of Elastomeric and
Lead-Rubber Seismic Isolation Bearings

By G.P. Warn and A.S. Whittaker, MCEER-06-0011, September 22, 2006, 272 pages, $35.00

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This report presents an analytical and experimental investigation of the coupled horizontal-vertical response of elastomeric and lead-rubber bearings focusing on the influence of lateral displacement on vertical stiffness. Component testing was performed with reduced scale low-damping rubber (LDR) and lead-rubber (LR) bearings to determine vertical stiffness at various lateral offsets. The numerical studies included finite element (FE) analysis of the reduced scale LDR bearing. The results of the experimental and FE investigations were used to evaluate three analytical formulations to predict vertical stiffness at a given lateral displacement. One of the three analytical formulations, based on the Koh-Kelly two-spring model, was shown to predict the measured reduction in vertical stiffness of the LDR and LR bearings at each lateral offset with reasonable accuracy. Earthquake simulation testing was performed to investigate the coupled horizontal-vertical response of a bridge model isolated with LDR or LR bearings. The results of simulations performed with three components of excitation were used to evaluate an equivalent linear static procedure to estimate vertical load due to vertical ground shaking. The procedure was shown to conservatively estimate measured maximum vertical loads due to the vertical component of excitation for most simulations.

Proceedings of the Fourth PRC-US Workshop on Seismic Analysis and Design of Special Bridges: Advancing Bridge Technologies in Research, Design, Construction and Preservation

Edited by L.C. Fan, G.C. Lee and L. Ziang, MCEER-06-0012, October 12, 2006, 404 pages, $35.00

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The fourth workshop in the PRC-US Workshop on Seismic Analysis and Design of Special Bridges, was held June 19-21, 2006 in Chongqing, China. The workshop was designed to exchange state-of-the-art information on highway bridge technologies and to plan and develop future cooperative research projects between the United States and the People’s Republic of China. A total of 39 participants, 16 from the U.S. and 23 from China, attended this workshop. These proceedings contain 32 papers covering a wide range of research fields.

Cyclic Response and Low Cycle Fatigue Characteristics of Plate Steels

By P. Dusicka, A.M. Itani and I.G. Buckle, MCEER-06-0013, November 6, 2006, 84 pages, $25.00

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Due to the lack of experimental data on the stress-strain behavior of specialty steels and conventional grade steels, a comprehensive study on the stress-strain and low cycle fatigue properties was conducted. The purpose of the study was to evaluate the stress-strain characteristics of plate steels subjected to repeated cyclic plastic deformations. The steel grades ranged from high performance steel HPS 485MPa to low yield point steel LYP Grade 100 MPa. Of specific interest was the cyclic stress as measured relative to the yield strength and the variability of the achieved stresses across the different steel grades. In addition, low cycle fatigue characteristics were desired to compare the fatigue life. The experimental results showed that all of the steels would be suitable for earthquake engineering applications, although the effects of welding or multi-axial stresses were not considered.

User Manual and Technical Documentation for the REDARS™ Import Wizard

By S. Cho, S. Ghosh, C.K. Huyck and S.D. Werner, MCEER-06-0015, November 30, 2006, 136 pages, $25.00

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As REDARS™ moved from a methodology to a fully functional software program for seismic risk analysis of highway systems, a key element in encouraging widespread use was developing an import module that could process standard data formats into a format suitable for REDARS™. This report documents the development of an Import Wizard, including the base data, research, modeling assumptions, and user requirements, necessary for importing source data into the REDARS software. Data from several national and regional databases are able to be accommodated by the Import Wizard, such as the National Highway Planning Network (NHPN), Highway Performance Monitoring System (HPMS), National Bridge Inventory (NBI), National Earthquake Hazard Reduction Program (NEHRP) Soil, and Origin-Destination zones and trip tables (OD data) (available through local Metropolitan Planning Organizations). A complete user manual and technical documentation is included in the report. The REDARS methodology and software is presented in a companion MCEER special report, “REDARS 2 Methodology and Software for Seismic Risk Analysis of Highway Systems,” by Werner et al., MCEER-06-SP08.

Hazard Mitigation Strategy and Monitoring Technologies for Urban and Infrastructure Public Buildings: Proceedings of the China-US Workshops

Edited by X.Y. Zhou, A.L. Zhang, G.C. Lee and M. Tong, MCEER-06-0016, December 12, 2006, on CD-ROM, $25.00

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This CD-ROM contains papers, photos and movies from two US-China workshops on multi-hazard mitigation strategies for large public buildings and other infrastructure. Co-sponsored by NSF and the China National Natural Science Foundation and co-organized by G.C. Lee and X.Y. Zhou, both workshops were held at the Beijing University of Technology in Beijing, China. “Protection of Urban Infrastructure and Public Buildings against Earthquakes and Manmade Disasters” was held February 21-22, 2003 and featured sixty papers. Discussion focused on the use of advanced technologies in critical public buildings and transportation networks to protect them from damage due to earthquakes and other hazards. A follow-up workshop was held November 14-15, 2005. Fifteen papers on research related to multiple hazards resilient critical facilities were presented. Topics included structural health monitoring, design structural strength under multiple hazard loadings, indoor air quality and safety monitoring, structural damage detection and response control, multiple hazard risk analysis and evacuation systems.

Static and Kinetic Coefficients of Friction for Rigid Blocks

By C. Kafali, S. Fathali, M. Grigoriu and A.S. Whittaker, MCEER-07-0001,
March 20, 2007, 104 pages, $25.00

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The study described in this report is the first phase of research on the seismic performance evaluation of block-type nonstructural components. The analytical work was performed at Cornell University, while the experimental study was conducted at the University at Buffalo. The objective was to characterize the coefficients of friction of three interfaces for rigid blocks with low, medium, and high coefficients of friction. The interfaces selected were PTFE on steel, wood on steel, and carpet on steel, which represented interfaces with low, moderate, and high coefficients of friction, respectively. Two sets of blocks with different geometry were designed and constructed to model block-type nonstructural components. The static coefficients of friction for the three interfaces were characterized by a series of standard pull and tilt tests. Estimates of the kinetic coefficient of friction were calculated using the maximum responses of the blocks obtained through laboratory experiments and analytical relationships between the maximum responses and the kinetic coefficient of friction. The method explicitly accounted for the uncertainty in experimental errors, imperfections in block-floor interfaces, and the relationship between the kinetic friction coefficient and the loading and block size.

Hazard Mitigation Investment Decision Making: Organizational Response to Legislative Mandate

By L.A. Arendt, D.J. Alesch and W.J. Petak, MCEER-07-0002, April 9, 2007, 4/9/07, 94 pages, $25.00

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This is the third in a series of reports on overcoming obstacles to implementing hazard mitigation policies against extreme events. It focuses on developing an organizational decision-making model that may be used to predict the conditions under which organizations will spend money to reduce the likelihood of damage to their buildings from natural hazards. The report describes a theoretical framework of organizational decision making around hazard mitigation investments, primarily developed from theoretical literature and structured interviews with hospital executives and other stakeholders over a three-year period. Public, not-for-profit, and investor-owned acute care hospital facilities in California and their response to State legislation known colloquially as SB 1953 are examined.

Earlier reports are “Seismic Safety in California Hospitals: Assessing an Attempt to Accelerate the Replacement or Seismic Retrofit of Older Hospital Facilities,” by Alesch et al., MCEER-05-0006 and “Overcoming Obstacles to Implementing Earthquake Hazard Mitigation Policies: Stage 1 Report,” by Alesch et al., MCEER-01-0004.