Applied Technology Council A Nonprofit Corporation Advancing Engineering Applications for Hazard Mitigation California - Washington, DC Area

The ATC/MCEER Joint Venture, a partnership of the Applied Technology Council (ATC) and the Multidisciplinary Center for Earthquake Engineering Research (MCEER), State University of New York at Buffalo, is pleased to announce the immediate availability of two new publications:  the MCEER/ATC-49-1 Liquefaction Study Report, and the MCEER/ATC-49-2 Design Examples report, both of which are companion documents to the 2-volume MCEER/ATC-49 Recommended LRFD Guidelines for the Seismic Design of Highway Bridges, which was released by the ATC/MCEER Joint Venture in June 2004.

The MCEER/ATC-49-1 Liquefaction Study Report documents a comprehensive study of the effects of liquefaction and the associated hazards — lateral spreading and flow.  The motivation for the study was the recommended change in the design return period for ground motions for a rare or “Maximum Considered Earthquake” (MCE) used in the Recommended LRFD Guidelines for the Seismic Design of Highway Bridges.  With the increase in return period comes an increase in the potential for liquefaction and liquefaction-induced ground movements, which could damage bridges and were cause for concern that the Recommended Guidelines may prove to be too costly to accommodate in construction. 

The purpose of the study was to investigate liquefaction hazard implications for the design of bridges using real sites and real structures.  The study scope was limited to two sites and bridges in relatively high seismicity locations, one in the western U.S. in Washington state and one in the central U. S. in Missouri .  The resulting MCEER/ATC-49-1 Liquefaction Study Report contains detailed discussions on:

• Recommended procedures to evaluate liquefaction potential and lateral spread effects;
• Ground mitigation design approaches and procedures to evaluate the beneficial effects of pile pinning in straining lateral spread;
• Results from the studies of the western U. S. and central U. S. bridge sites, including (1) an assessment of liquefaction effects based on simplified analyses, nonlinear response analysis of the soil column, estimates of lateral spreading using traditional Newmark charts and site-specific Newmark analyses; (2) an assessment of implications of predicted lateral spread/flow using a pushover-type analysis; and (3) development and evaluation of structural and/or geotechnical mitigation alternatives if the structure did not produce acceptable performance for the ground motion levels and site conditions; and
• Study conclusions, including cost implications.

The MCEER/ATC-49-2 Design Examples report contains two design examples that illustrate use of the Recommended LRFD Guidelines for the Seismic Design of Highway Bridges.  These design examples are the eighth and ninth in a series originally developed for the Federal Highway Administration (FHWA) to illustrate the use of the American Association of State Highway and Transportation Officials (AASHTO) Division 1-A Standard Specifications for Highway Bridges.  Each of the nine design examples, including the seven previously developed, were carried out and reported on in a consistent manner, using the same calculation and report formatting procedures.  Design Example 8 was performed on a five-span continuous cast-in-place concrete box girder bridge and the ninth design example (Design Example 2LRFD) was performed on a three-span continuous steel girder bridge.  The design examples contain flow charts and detailed step-by-step procedures, including:

• Preliminary design;
• Basic requirements;
• Determination of seismic design and analysis procedure;
• Determination of elastic seismic forces and displacements;
• Determination of design forces;
• Design displacements and checks;
• Design of structural components;
• Design of foundations;
• Design of abutments; and
• Consideration of liquefaction

The MCEER/ATC-49-1 Liquefaction Study Report, Recommended LRFD Guidelines for the Seismic Design of Highway Bridges, and the MCEER/ATC-49-2 Design Examples, Recommended LRFD Guidelines for the Seismic Design of Highway Bridges, are available from both ATC and MCEER at a cost of $50.00 per report (plus the cost of shipping and sales tax, if applicable).  To order from MCEER, contact MCEER Publications at (716) 645-3391, ext. 105, email: mceer@mceermail.buffalo.edu, or visit the MCEER website, http://mceer.buffalo.edu. To order from ATC, contact ATC Publication Sales at (650) 595-1542, email: ATC@ATCouncil.org, or use ATC’s Online store on the ATC website.

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