New PEER Reports

The following reports are available from the National Information Service for Earthquake Engineering (NISEE). To order, please contact the Pacific Earthquake Engineering Research Center, 1301 South 46th Street, Richmond, California 94804-4698. Tel: (510) 231-9468; Fax: (510) 231-9461; Email: eerclib@nisee.berkeley.edu; Website: http://nisee.berkeley.edu.      

PEER 2001/02 Seismic Response Analysis of Highway Overcrossings Including Soil-Structure Interaction. Jian Zhang and Nicos Makris.

The development and validation of a simple yet dependable method to estimate the seismic response of freeway overcrossings is presented. The proposed method adopts the substructure approach to address the issue of soil-foundation-superstructure interaction. The various steps of the method are validated with scarce historic records and are compared with the results obtained by other investigators.

The efficiency of the proposed method is validated by comparing the computed time response quantities with records from the Meloland Road and the Painter Street overcrossings located in southern and northern California, respectively. The proposed procedure allows for inexpensive parametric analysis that examines the importance of considering soil-structure interaction at the end abutments and center bent. Results and recommendations presented by past investigations are revisited and integrated into comprehensive tables that improve understanding of the dynamic characteristics and behavior of freeway overcrossings.

PEER 2001/01 Experimental Study of Large Seismic Steel Beam-to-Column Connections. Egor P. Popov and Shakhzod M. Takhirov.

Two large bolted steel moment-resisting connections were studied by experiments. These connections were single-sided beam-column assemblies that are representative of exterior beam-column connections. They were composed of W36x150 Grade 50 beams and W14x257 Grade 50 columns. T-sections were cut from W40x264 sections of Grade 50 steel. The T-section webs were welded to the beams and prestressed by bolts to the beam flanges in the shop. Final beam-to-column assembly required no additional welding: the T-section flanges were bolted to the column and the column shear tab was bolted to the beam web. The specimens had two symmetrically located T-sections with different web geometry: Specimen 1 had rectangular-shaped webs, whereas Specimen 2 had U-shaped webs. During cyclic testing, beam deformation was minimal due to active participation of the T-section flanges: a separation between T-section flanges and the column flanges was observed. This separation occurred due to bending plastic deformation in the T-section flanges. This phenomenon allowed dissipating energy and prevented severe buckling in the beam flanges and beam web.

PEER 2000/09 Structural Engineering Reconnaissance of the August 17, 1999 Earthquake: Kocaeli (Izmit), Turkey. Halil Sezen, Kenneth J. Elwood, Andrew S. Whittaker, Khalid M. Mosalam, John W. Wallace, and John F. Stanton.

In late August and early September 1999, a team of structural engineers representing the Pacific Earthquake Engineering Research (PEER) Center traveled to Turkey to study damaged and undamaged buildings, bridges, industrial facilities, and lifeline infrastructure affected by the August 17, 1999, Izmit earthquake. The PEER reconnaissance team sought to improve understanding of the performance of the built environment and to identify gaps in a PEER research agenda that is developing knowledge and design tools for performance-based earthquake engineering. The Mw7.4 earthquake occurred on the North Anatolian fault in northwestern Turkey at 3:02 a.m. local time. The hypocenter of the earthquake was located near Izmit, 90 km east of Istanbul. Official figures placed the loss of life at approximately 17,225, with more than 44,000 injured. Approximately 77,300 homes and businesses were destroyed and 245,000 more were damaged. The total direct loss was estimated to be more than US$ 6 billion.

PEER 1998/01 Seismic Performance of Well-Confined Concrete Bridge Columns. Dawn E. Lehman and Jack P. Moehle.

Recent earthquakes have provided performance data demonstrating that large losses can result from inadequate performance of highway bridges. An experimental and analytical research program was undertaken to characterize the response of well-confined, circular cross-section, concrete bridge columns subjected to lateral loading. In the experimental investigation, columns with varying longitudinal reinforcement ratios and aspect ratios were tested in the laboratory to characterize the response of modern bridge columns subjected to lateral loads. In the analytical investigation, methods to assess strength, force-displacment response, and element damage were evaluated using the experimental results. The research program results are used to delineate a performance-based seismic design framework for reinforced concrete bridge columns.