Six New Reports Reviewed
NCEER technical reports are published to communicate specific research data and project results. Reports are written by NCEER-funded researchers, and provide information on a variety of fields of interest in earthquake engineering. The proceedings from conferences and workshops sponsored by NCEER are also published in this series. To order a report reviewed in this issue, fill out the order form and return to NCEER. To request a complete list of titles and prices, contact NCEER Publications, University at Buffalo, Red Jacket Quadrangle, Box 610025, Buffalo, New York 14261-0025, phone: (716) 645-3391; fax: (716) 645-3399; or email: firstname.lastname@example.org .
In addition, NCEER's World Wide Web site offers a complete list of technical reports and their abstracts.
Note that customers can now use credit cards to purchase technical reports. For more information, contact NCEER Publications.
Dynamic Response of Unreinforced Masonry Buildings with
A.C. Costley and D.P. Abrams, 10/10/96, NCEER-96-0001, 324 pp., $20.00
The overall objective of the research was to provide recommendations for the evaluation and rehabilitation of unreinforced masonry buildings. An experimental study was performed to investigate nonlinear dynamic response of two-story building systems with flexible floor diaphragms. Two reduced-scale test structures were subjected to a series of simulated earthquake motions on the University of Illinois shaking table. The experimental parameters were the relative lateral strengths of the two parallel shear walls and the aspect ratios of piers between window and door openings. The accuracy of several computational methods were examined by contrasting estimates with measured response. These methods included procedures that are prescribed in building code requirements for new construction and guidelines for rehabilitation of existing buildings, as well as more complex finite element and dynamic analysis methods. A nonlinear dynamic analysis model was developed to estimate large-amplitude displacements. This report includes descriptions of the experimental and analytical investigations, and provides a number of recommendations for evaluation and rehabilitation of unreinforced masonry buildings.
Ductility of Rectangular Reinforced Concrete Bridge
Columns with Moderate Confinement
N. Wehbe, M. Saiidi, D. Sanders and B. Douglas, 11/7/96, NCEER-96-0003, 116 pp., $15.00
This study examines the ductility and behavior of rectangular reinforced concrete bridge columns with moderate confinement. The research comprised experimental and analytical investigations of the response of such columns when subjected to lateral loading. Four half-scaled rectangular bridge columns were built and tested. The specimens were divided into two groups, based on the amount of lateral steel. The transverse reinforcement ratios in the long direction for the two groups corresponded to 42 percent and 54 percent of the minimum lateral reinforcement required by AASHTO for seismic detailing. The specimens exhibited moderate displacement ductility ratios ranging between 4 and 7. In the analytical study, several existing models pertaining to the concrete stress-strain relationship and the plastic hinge length were utilized and compared. For unconfined concrete, the Kent and Park model was used; the modified Kent and Park model and the Mander et al. model (as modified by Paulay and Priestley) were utilized to represent the constitutive relationship of confined concrete. The equivalent plastic hinge length was calculated using two different models, the Baker model and the model by Paulay and Priestley. The analytical study revealed that for rectangular bridge columns with relatively low axial loads and moderate confinement, it is possible to predict with reasonable accuracy the response of the columns to lateral cyclic loading.
Proceedings of the Sixth Japan-U.S. Workshop on Earthquake
Resistant Design of Lifeline Facilities and Countermeasures
Against Soil Liquefaction
Edited by M. Hamada and T. O'Rourke, 9/11/96, NCEER-96-0012, 782 pp., $40.00
This sixth Japan-U.S. workshop provided a forum for new approaches to the earthquake resistant design and damage mitigation of lifelines, and advanced techniques for characterizing liquefaction, stabilizing hazardous sites and improving post-earthquake response and recovery. The proceedings volume contains 52 technical papers. Ten papers review lifeline performance during the Northridge and Hyogo-Ken Nanbu earthquakes, in particular that of buried pipelines pertaining to water supply systems. Another twelve papers deal with observed seismic performance of underground structures, quaywalls and foundations. Six papers concern observations of ground motion, displacement and strain during a number of recent Japanese earthquakes. Analytical and experimental studies of liquefaction mechanisms and prediction are the focus of a group of eleven papers. Ten papers concern a variety of techniques and approaches for the remediation and mitigation of liquefaction, as well as the earthquake resistant design and construction of lifelines. It is intended that research findings herein may be applied in engineering decision-making and that the workshop will help to promote the transfer of technology from research to practice.
Chemical Hazards, Mitigation and Preparedness in Areas of
High Seismic Risk: A Methodology for Estimating the Risk of
Post-Earthquake Hazardous Materials Release
H.A. Seligson, R.T. Eguchi, K.J. Tierney and K. Richmond, 11/7/96, NCEER-96-0013,146 pp., $15.00
The first significant step towards developing a constructive area-wide response and mitigation program for chemical facilities is to be able to quantify the seismic risk potential of hazardous materials release and its effect on surrounding communities. Thus, the objective of this project was to develop a methodology that would enable local jurisdictions to determine the magnitude of the problem and identify areas most susceptible to earthquake-induced hazardous materials release. The generalized methodology includes five major steps: inventory development, seismic hazard analysis, component vulnerability assessment, regional vulnerability assessment, and population risk assessment. The results enable local emergency managers to prepare for and mitigate potential earthquake-induced releases. This report illustrates the application of the methodology for assessing the risk of earthquake-induced hazardous materials release and its impact on surrounding population. The methodology is demonstrated on the Los Angeles area using data from a survey conducted by the South Coast Air Quality Management District, limited to 22 facilities using ammonia and/or chlorine within Los Angeles County.
Response of Steel Bridge Bearings to Reversed Cyclic
J.B. Mander, D-K. Kim, S.S. Chen and G.J. Premus, 11/13/96, NCEER-96-0014, 232 pp., $20.00
The seismic performance of low and high type steel bridge bearing specimens is investigated in this study. Experimental apparatus was developed to allow large cyclic horizontal loads and displacements to be applied to bearing specimens while keeping gravity loads constant. Simple seismic retrofit strategies are proposed and investigated experimentally to increase seismic performance. To increase the resistance in the longitudinal direction of the high type rocker bearings, retrofitting consisted of welding steel wedges to the masonry plate. It is shown that retrofitting the existing high type steel bridge bearings provides sufficient strength and displacement capability to withstand substantial ground shaking. The weak link thus becomes the anchor bolts and/or the reinforced concrete pedestal. To understand the influence of the reinforced concrete pedestal and mild steel anchorage on the overall behavior of a high type fixed bearing assembly, a full scale reinforced concrete cap beam with pedestals was constructed. The test results demonstrate the importance of considering the flexibility of the concrete pedestal-anchor bolt system. As a retrofit method for the damaged reinforced concrete pedestal, a steel jacket was wrapped around the damaged reinforced concrete pedestal.
Highway Culvert Performance During Past Earthquakes
T.L. Youd and C.J. Beckman, 11/25/96, NCEER-96-0015, 96 pp., $10.00
To assess performance of culverts during earthquakes, the authors reviewed reports from six earthquakes, interviewed highway officials in areas shaken by four earthquakes and conducted field investigations in epicentral regions of three earthquakes. Seventeen corrugated metal pipe (CMP), one thermoplastic pipe, five reinforced concrete pipe (RCP), and thirty reinforced concrete box (RCB) structures were specifically evaluated through field inspection of literature review. Five of these culverts (all CMP) were deformed into a dysfunctional condition; nine (three CMP, five RCP and one RCB) required major repairs or replacement; six RCB structures required minor repairs (epoxy of cracks). Thirty-five surveyed culverts suffered inconsequential or no damage. Lack of observed or reported damage to hundreds of additional unsurveyed culverts in strongly shaken areas indicated inconsequential effects to these structures. Primary causes of culvert damage were liquefaction-induced embankment penetration or spreading, slope instability, and fault rupture. Other causes of damage were increased lateral earth pressures and inertial forces generated from thick overlying fills. These findings indicate that culverts generally perform well during earthquakes except in areas affected by foundation failure or subject to large lateral or inertial forces.
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