Research Activities

NCEER Technical Reports

Seven 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: .

In addition, NCEER's World Wide Web site offers a complete list of technical reports and their abstracts.

Click here to view the Listing of NCEER Technical Reports

Note that customers can now use credit cards to purchase technical reports. For more information, contact NCEER Publications.

Modeling of Masonry Infill Panels for Structural Analysis
A.M. Reinhorn, A. Madan, R.E. Valles, Y. Reichmann and J.B. Mander, 12/8/95, NCEER-95-0018, 96 pp., $10.00

A smooth hysteretic model based on an equivalent strut approach is proposed for masonry infill panels to be used in nonlinear analysis of building structures. The hysteretic model furnishes a versatile and robust simulation tool for representing masonry infill panels. The model, which is applicable for degrading "pinching" elements in general, can be implemented to replicate a wide range of hysteretic force-displacement behavior resulting from different design and geometry by varying the control parameters of the model. An available theoretical model for masonry infilled frames is recommended for estimating the control parameters of the proposed hysteretic rule. The hysteretic model is incorporated in the structural analysis program, IDARC2D Version 4.0. Quasi-static cyclic and dynamic analysis of prototype infill frame subassemblages are performed to validate the proposed model and presented herein. A lightly reinforced concrete frame structure is analyzed for strong ground motions to evaluate the influence of masonry infill panels on the response.

Retrofit of Non-Ductile Reinforced Concrete Frames
Using Friction Dampers

R.S. Rao, P. Gergely and R.N. White, 12/22/95, NCEER-95-0020, 190 pp., $15.00

This report extends the knowledge base concerning friction damping devices, suggests design solutions that are feasible from both engineering and economic perspectives, and evaluates the performance of these designs. The seismic retrofit scheme proposed was experimentally evaluated using shake-table tests. Several time history analyses were performed to study the effectiveness of using friction dampers for retrofit. The analysis showed that introducing the friction dampers improved the performance for a wide range of ground motions. The success of the retrofit scheme, however, depends on the slip load setting in the friction dampers. A simplified design methodology, called the Inelastic Demand Spectrum (IDS), was proposed and developed for obtaining the optimum slip load.

Parametric Results for Seismic Response of Pile-Supported Bridge Bents
G. Mylonakis, A. Nikolaou and G. Gazetas, 12/22/95, NCEER-95-0021,242 pp., $20.00

This is the first of three reports in which the authors develop design aids and tools for estimating: 1) the effect of pile deformation on the response of bridge piers; and 2) assessing the interplay between soil, pile and pier in the seismic response of a number of different bridge types under varying soil conditions and input ground motions. The report presents a complete set of parametric results in the form of graphs and tables for the seismic response of bridge bents supported either on a single drilled pile or on a 4x5 pile group embedded in three actual layered soil deposits. The input excitation, in the form of vertically propagating S waves, is described through real and artificial accelerograms. Both kinematic and inertial interaction are taken into account; and results are in both the time and frequency domains. The authors present accelerations and displacements for the bridge and pile cap, as well as for internal forces along the piles. They investigate potential errors that may arise when one ignores: 1) radiation damping produced by piles and elastic bedrock; 2) pile cap rotations; 3) the cross-swaying and rocking component of pile foundation response. The results presented in this report are strictly applicable to linear soils and structures.

Kinematic Bending Moments in Seismically Stressed Piles
A. Nikolaou, G. Mylonakis and G. Gazetas, 12/23/95, NCEER-95-0022, 260 pp., $20.00

This is the second of three reports describing studies on the behavior of bridge piles and piers. It studies the kinematic deformation of a free-head and fixed-head pile embedded in layered soil. A comprehensive parametric study is presented aimed at developing a fundamental understanding of the problem, and design aids for inexpensively computing the peak bending moments in a pile, under an arbitrary seismic time history. It is demonstrated that peak kinematic moments during earthquakes can be correlated with the amplitudes of steady-state harmonic moments, and that simple formulae presented in the report would lead to satisfactory estimates of the largest peak bending moments in actual piles.

Seismic Evaluation of a 30-Year-Old Non-Ductile Highway Bridge Pier and Its Retrofit
J.B. Mander, B. Mahmoodzadegan, S. Bhadra and S.S. Chen, 5/31/96, NCEER-96-0008, 202 pp., $20.00

This report presents an experimental investigation of the seismic behavior of a full-scale highway bridge cap beam-to-column subassemblage and its retrofit. Retrofitting consisted of strengthening the joint core and cap beam by providing a high strength concrete jacket and longitudinal prestress. Following experimental testing, the ATC 6-2 evaluation method and the evaluation method recommended by Priestley et al. (1992) were analyzed to determine their compatibility with the experimental results. An energy-based evaluation methodology is introduced to overcome shortcomings in the current evaluation methods.

Seismic Performance of a Model Reinforced Concrete Bridge Pier Before and After Retrofit
J.B. Mander, J.H. Kim and C.A. Ligozio, 5/31/96, NCEER-96-0009, 208 pp., $20.00

A series of experimental and analytical studies were performed on a 1/3 scale model pier before and after retrofit. The scale model represented a typical eastern U.S. non-seismically designed concrete bridge pier. The pre-retrofitted model pier was tested under quasi-static inelastic loading. A seismic retrofit philosophy - "capacity analysis and redesign" - was introduced and implemented to retrofit the damaged model pier. The experimental behavior of the retrofitted model pier demonstrated that failure due to joint shear and bond/anchorage could be avoided. Comparison with the experimental and analytical study on the companion prototype pier subassemblage before and after retrofit showed the failure mode to be similar to that of the scaled model. The model pier was evaluated before and after retrofit using the capacity/demand method and the equivalent lateral strength method, both advocated by the FHWA Retrofitting Manual for Highway Bridges.

Estimation of the Economic Impact of Multiple Lifeline Disruption: Memphis Light, Gas and Water Division Case Study
S.E. Chang, H.A. Seligson and R.T. Eguchi, 8/16/96, NCEER-96-0011, 204 pp., $20.00

This report focuses on estimating economic losses from urban lifeline disruption in seismic events. A methodological approach is developed and applied to estimating losses that would be incurred in Memphis/Shelby County, Tennessee in the event of a large hypothetical earthquake in the New Madrid Seismic Zone. Disruption to the natural gas, electric power and water lifeline systems is considered. Economic loss is evaluated for each of the three lifelines individually, as well as for the case of multiple lifeline disruption. The scope includes evaluation of four types of economic loss: lifeline facility repair costs, revenue losses to the utility provider, direct economic loss suffered by utility customers, and the consequent indirect economic loss in the region.

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