Download or read book Seismic Behaviour of Highway Bridges with Base Isolation written by and published by . This book was released on 1988 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study is made on the seismic behaviour of highway bridges with lead-rubber isolation. the system of base isolation is considered as a bilinear spring. single and twin span highway bridges subjected to representative strong earthquake ground motion records were analyzed. the effect of various parameters such as the isolator's stiffness, pier stiffness, and pier eccentricity on the system response was evaluated. it was found that the use of base isolation shifts the fundamental frequency of the bridge system towards the longer period. proper design of the base isolation tends to reduce the design forces on the bridge piers and is accompanied by larger displacements. simplified design guidelines are adequate as long as the bridge system can be represented by a single degree of freedom model. the reduction in pier stiffness of a two-span bridge may increase the displacement and the force transmitted the abutment. the increased forces at the abutments are accompanied by reduction in the shear force transmitted to the pier. increased displacements and forces may also result when the location of the pier departs from the centre and unequal spans are created. in this case, the maximum displacements and forces occur at the abutment adjacent to the long span.

Download or read book Seismic Design of Base isolated Highway Bridges Utilizing Lead rubber Bearings written by and published by . This book was released on 1990 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study is made of the seismic behaviour of base-isolated highway briges with the objective of developing design procedures in the form of code-type approach. The recommendations of current codes concerning the use of energy dissipation mechanisms for the seismic design of bridges are reviewed. A model representing the bridge deck, piers, and the base-isolation system is used to evaluate the response of the bridge to a selected earthquake time history record and to evaluate the effects of various design parameters on the dynamic response. The results of this analysis are used in the development of design guidelines for the isolated bridge system. It was found that base isolation affects the design forces on piers and abutments as well as the deck displacements. An optimum design should provide a reasonable balance between the shear forces on supports and tolerable displacements. Two design procedures are proposed based on the time history and inelastic response spectra approaches. Simplified charts are presented which aid in the seismic design of new bridges as well as in the upgrading of existing ones.

Download or read book Guide Specifications for Seismic Isolation Design written by American Association of State Highway and Transportation Officials and published by . This book was released on 1999 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of United States and New Zealand Seismic Design Practices for Highway Bridges written by Applied Technology Council and published by . This book was released on 1982 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bridge Engineering written by W.F. Chen and published by CRC Press. This book was released on 2003-02-27 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mitigating the effects of earthquakes is crucial to bridge design. With chapters culled from the best-selling Bridge Engineering Handbook, this volume sets forth the principles and applications of seismic design, from the necessary geotechnical and dynamic analysis background to seismic isolation and energy dissipation, active control, and retrofit

Download or read book Guide Specifications for Seismic Isolation Design written by and published by AASHTO. This book was released on 2010 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edition is based on the work of NCHRP project 20-7, task 262 and updates the 2nd (1999) edition -- P. ix.

Download or read book Guide Specifications for Seismic Isolation Design written by American Association of State Highway and Transportation Officials and published by . This book was released on 2014 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: These Guide Specifications address major changes in the way seismic hazard is now defined in the United States, as well as changes in the state of the art of seismic isolation design for highway bridges. It also reflects changes in the definition of the seismic hazard as now defined in the AASHTO LRFD Bridge Design Specifications and the Guide Specifications for LRFD Seismic Bridge Design, industry trends in the design and construction of isolators, and provisions in the design specifications that impact the design and testing of isolation bearings. This new edition has been revised and greatly expanded with the addition of Appendix B, which contains 14 design examples: two benchmark bridges and six design variations of each one.

Download or read book Seismic Design and Retrofitting of Reinforced Concrete Bridges written by G. Michele Calvi and published by . This book was released on 1991 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Specification for the Seismic Design of Bridges written by National Cooperative Highway Research Program and published by Transportation Research Board. This book was released on 2002 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Protection of Bridge Structures Using Shape Memory Alloy based Isolation Systems Against Near field Earthquakes written by Osman Eser Ozbulut and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The damaging effects of strong ground motions on highway bridges have revealed the limitations of conventional design methods and emphasized the need for innovative design concepts. Although seismic isolation systems have been proven to be an effective method of improving the response of bridges during earthquakes, the performance of base-isolated structures during near-field earthquakes has been questioned in recent years. Near-field earthquakes are characterized by long period and large- velocity pulses. They amplify seismic response of the isolation system since the period of these pulses usually coincides with the period of the isolated structures. This study explores the feasibility and effectiveness of shape memory alloy (SMA)-based isolation systems in order to mitigate the response of bridge structures against near-field ground motions. SMAs have several unique properties that can be exploited in seismic control applications. In this work, uniaxial tensile tests are conducted first to evaluate the degree to which the behavior of SMAs is affected by variations in loading rate and temperature. Then, a neuro-fuzzy model is developed to simulate the superelastic behavior of SMAs. The model is capable of capturing rate- and temperature-dependent material response while it remains simple enough to carry out numerical simulations. Next, parametric studies are conducted to investigate the effectiveness of two SMA-based isolation systems, namely superelastic-friction base isolator (S-FBI) system and SMA/rubber-based (SRB) isolation system. The S-FBI system combines superelastic SMAs with a flat steel-Teflon bearing, whereas the SRB isolation system combines SMAs with a laminated rubber bearing rather than a sliding bearing. Upon evaluating the optimum design parameters for both SMA-based isolation systems, nonlinear time history analyzes with energy balance assessment are conducted to compare their performances. The results show that the S-FBI system has more favorable properties than the SRB isolation system. Next, the performance of the S-FBI systems is compared with that of traditional isolation systems used in practice. In addition, the effect of outside temperature on the seismic response of the S-FBI system is assessed. It is revealed that the S-FBI system can successfully reduce the response of bridges against near-field earthquakes and has excellent re-centering ability.

Download or read book Performance based Seismic Bridge Design written by M. Lee Marsh and published by Transportation Research Board. This book was released on 2013 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 440, Performance-Based Seismic Bridge Design (PBSD) summarizes the current state of knowledge and practice for PBSD. PBSD is the process that links decision making for facility design with seismic input, facility response, and potential facility damage. The goal of PBSD is to provide decision makers and stakeholders with data that will enable them to allocate resources for construction based on levels of desired seismic performance"--Publisher's description.

Download or read book Fundamentals of Seismic Protection for Bridges written by Mark Yashinsky and published by National Information Centre of Earthquake Engineering. This book was released on 2003 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: With special reference to United States.

Download or read book Design Analysis and Seismic Performance of a Hypothetical Seismically Isolated Bridge on Legacy Highway written by Keri Lynn Ryan and published by . This book was released on 2011 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to maintain the functionality of critical transportation lifelines after a large seismic event motivates the strategy to design certain bridges for performance standards beyond the minimum required by bridge design codes. To design a bridge to remain operational, one may stiffen and strengthen the load carrying members to increase the capacity, or alternatively use response modification devices such as seismic isolators to shift the dynamic characteristics of the bridge, henceforth reducing the seismic demands. Seismic isolation systems are attractive because they are directly conducive to accelerated bridge construction techniques. The two strategies are compared for a typical Utah highway bridge, using a three-span, pre-stressed concrete girder bridge that crosses Legacy Highway as a case study example.

Download or read book Advanced Models for Sliding Seismic Isolation and Applications for Typical Multi span Highway Bridges written by Murat Eroz and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The large number of bridge collapses that have occurred in recent earthquakes has exposed the vulnerabilities in existing bridges. One of the emerging tools for protecting bridges from the damaging effects of earthquakes is the use of isolation systems. Seismic isolation is achieved via inserting flexible isolator elements into the bridge that shift the vibration period and increase energy dissipation. To date, the structural performance of bridges incorporating sliding seismic isolation is not well-understood, in part due to the lack of adequate models that can account for the complex behavior of the isolators. This study investigates and makes recommendations on the structural performance of bridges utilizing sliding type seismic isolators, based on the development of state-of-the-art analytical models. Unlike previous models, these models can account simultaneously for the variation in the normal force and friction coefficient, large deformation effects, and the coupling of the vertical and horizontal response during motion. The intention is to provide support for seismic risk mitigation and insight for the analysis and design of seismically isolated bridges by quantifying response characteristics. The level of accuracy required for isolator analytical models used in typical highway bridges are assessed. The comparative viability of the two main isolator types (i.e. sliding and elastomeric) for bridges is investigated. The influence of bridge and sliding isolator design parameters on the system s seismic response is illustrated.

Download or read book Seismic Isolation of Highway Bridges written by and published by . This book was released on 2006 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Analysis and Response of Highway Bridges with Hybrid Isolation written by Chunli Wei and published by . This book was released on 2013 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transportation Infrastructure written by and published by DIANE Publishing. This book was released on 1993-07 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on threats that earthquakes pose to the nation1s bridges.