1、Report on Analysis and Design of Seismic-Resistant Concrete Bridge SystemsReported by ACI Committee 341ACI 341.2R-14First PrintingJune 2014ISBN: 978-0-87031-896-2Report on Analysis and Design of Seismic-Resistant Concrete Bridge SystemsCopyright by the American Concrete Institute, Farmington Hills,
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11、 in the annually revised ACI Manual of Concrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331Phone: +1.248.848.3700Fax: +1.248.848.3701www.concrete.orgThis report is intended for use by practicing engineers and provides a summary of the state-of-the-art
12、 analysis, modeling, and design of concrete bridges subjected to strong earthquakes. It is intended to supplement and complement existing documents from the American Association of State Highway and Transporta-tion Officials (AASHTO), California Department of Transportation (Caltrans), and various b
13、uilding codes and guidelines. Procedures and philosophies of codes and guidelines are summarized. Linear and nonlinear seismic analysis methods are also discussed, and important modeling considerations for different bridge elements, including curved girders and skewed abutments, are highlighted. The
14、 report also includes a summary of general seismic-resistant design and construction considerations for concrete bridges, as well as analysis and design considerations for bridges with seismic isolation.Keywords: abutment; bridge; column; connections; design; earthquake; footing; girder; hinge; rest
15、rainer; seismic; seismic analysis; seismic isolation.CONTENTSCHAPTER 1INTRODUCTION, p. 21.1General, p. 21.2Lessons learned from earthquake damage to bridges, p. 3CHAPTER 2NOTATION AND DEFINITIONS, p. 62.1Notation, p. 62.2Definitions, p. 6CHAPTER 3CODES, p. 73.1Historical perspective, p. 7CHAPTER 4SE
16、ISMIC HAZARDS, p. 74.1Introduction, p. 74.2Probabilistic seismic hazard analysis , p. 84.3Multi-level earthquake ground motions, p. 94.4USGS probabilistic ground motion maps and design value maps, p. 94.5Vertical accelerations, p. 104.6Near-fault ground motions and residual ground displacements near
17、 faults, p. 104.7Load combinations, p. 11Sri Sritharan*, Chair Mark A. Aschheim, SecretaryACI 341.2R-14Report on Analysis and Design of Seismic-Resistant Concrete Bridge SystemsReported by ACI Committee 341Hossam M. AbdouNagi A. Abo-ShadiRobert B. Anderson*Bassem AndrawesDino BagnariolAbdeldjelil Be
18、larbiSarah L. BillingtonJoAnn P. BrowningRigoberto BurguenoW. Gene CorleyShukre J. Despradel*Angel E. HerreraDavid HieberRiyadh A. HindiEric Michael HinesAhmed M. M. IbrahimMervyn J. KowalskySena Kumarasena*Dawn E. LehmanKevin R. MackieAdolfo B. MatamorosStavroula J. PantazopoulouBradley N. RobsonMa
19、rio E. Rodriguez*M. Saiid SaiidiAyman E. Salama*David H. SandersPedro F. SilvaGlenn R. SmithBozidar StojadinovicMatthew J. TobolskiRaj Valluvan*Ronald J. WatsonNadim I. WehbeMaged A. YoussefQun Zhong-BrisboisConsulting MembersY. Frank ChenEdward P. WassermanStewart C. Watson*Task Group members who p
20、repared this report.Task Group leaderDeceasedThe committee would like to thank the following people for their contri-butions to this report: M. Aydemir, P. Amin, V. Chandra, W.-F. Chen, B. Chung, T. Cooper, E. He, M. Hosseini, N. Johnson, P. Lipscombe, E. M. Lui, E. Matsumoto, H. Mutsuyoshi, V. Nuge
21、nt, M. Raoof, P. Somerville, S. Zhu, and N. Zoubi.ACI Committee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitati
22、ons of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom.Refere
23、nce to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 341.2R-14 supersedes ACI 341.2R-97(
24、03) and was adopted and published June 2014.Copyright 2014, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or
25、recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.14.8Combining effects of orthogonal components of earthquakes, p. 114.9Ground motion time histories, p. 114.10Geotechnical co
26、nsiderations, p. 12CHAPTER 5ANALYSIS, p. 125.1Overview, p. 125.2Single-mode spectral analysis, p. 135.3Pushover analysis, p. 135.4Multi-mode spectral analysis, p. 145.5Time-history analysis, p. 145.6Nonlinear analysis, p. 14CHAPTER 6MODELING, p. 206.1General, p. 206.2Superstructure modeling, p. 226.
27、3Substructure modeling, p. 236.4Abutment and foundation modeling, p. 236.5Bearings, p. 27CHAPTER 7DESIGN, p. 277.1General, p. 277.2Multi-level seismic design, p. 277.3AASHTO force-based design methods, p. 287.4Displacement-based design methods, p. 297.5Seismic conceptual design, p. 307.6Design consi
28、derations, p. 317.7Seismically isolated bridges, p. 357.8Construction, p. 39CHAPTER 8REFERENCES, p. 39Authored references, p. 39CHAPTER 1INTRODUCTION1.1GeneralThe stated objectives of seismic design provisions in major codes have evolved considerably over the last 20 years. The initial focus of prev
29、enting structural collapse under the design earthquake to prevent loss of life has shifted to broader design objectives, such as achieving a level of serviceability following a major earthquake that allows for emergency response and ensures that transportation life-lines remain operational. These ne
30、wer design objectives focus on the need for structures to remain operational after an earthquake, particularly for structures important to emer-gency response and those housing emergency and high-risk facilities. Critical structures include bridges on key response routes, hospitals, public safety he
31、adquarters, communication centers, and nuclear power stations.Bridge seismic design philosophies may use a traditional single seismic design level (AASHTO 2012; AASHTO LRFDSEIS-2-M) or a two-level approach (MCEER-ATC-49) where both functional-level and safety-level hazards are considered. Performanc
32、e objectives for each level are composed of a performance level or functional requirement at a seismic hazard level. The functional-level event consid-ered in this two-level approach is typically a lower-level event with relatively high probability of exceedance (PE), and the safety-level event is t
33、ypically a major seismic event with a very low PE. The typical performance objectives for the two-level approach tolerate only slight damage to ensure uninter-rupted service of the bridge under the lower-level event, and allow only easily repairable damage under the higher-level event to ensure mini
34、mal or no disruption of lifelines.In setting minimum performance standards, design codes recognize that it is not practical to design a structure to resist a large earthquake elastically; therefore, some degree of damage is typically permitted under the higher-level event (Fig. 1.1). For critical st
35、ructures, however, depending on expectations of how quickly the particular structure can be put back in service and repaired, the damage can be further restricted by tighter requirements defined by the owner.Design performance level requirements have become more general and are not always tied to tr
36、aditional notions of force and strength. Thus, analysis requirements have also evolved beyond the traditional methods involving equiva-lent static forces representing the design event. The extent of damage in different bridge components is commonly quanti-fied using performance quantities such as st
37、rains, curvatures, and displacements. Limiting damage requires imposing appropriate limits on these parameters in the critical sections of the structural members. In addition, the response of the structural system should be evaluated as a whole to assess functionality and operability. This requires
38、a higher level of sophistication in both system modeling as well as sectional and material-level analysis. Reinforced concrete structural members, in particular, require greater attention to detail when moving beyond elastic or equivalent elastic analysis Fig. 1.1Acceptable damage (spalling of cover
39、 concrete) to a bridge column for large earthquake.American Concrete Institute Copyrighted Material www.concrete.org2 REPORT ON ANALYSIS AND DESIGN OF SEISMIC-RESISTANT CONCRETE BRIDGE SYSTEMS (ACI 341.2R-14)because of the interaction of concrete and reinforcing bar, nonhomogeneity of the concrete m
40、aterial, and the progres-sion of cracking and yielding of the section with increasing strains. For example, a pushover analysis accounting for the pier or bent moment-curvature relationships at different axial loads is commonly used to develop a better under-standing of the nonlinear behavior of the
41、 structure and the type of damage that might be expected.For bridge structures, damage permitted under the design seismic event is limited primarily to elements with ductile capacity that can experience dependable flexural inelastic response such as the columns or pier walls. In addition, nominal da
42、mage may be tolerated in other parts of the bridge such as at the abutment, shear keys, and in-span hinges or expansion joints. These bridge elements are easy to inspect and repair, should damage be sustained during a seismic event. The use of a capacity design approach is also intended to prevent d
43、amage to elements, such as foundation piling, that are difficult to inspect and repair following a seismic event. Acceptable damage depends on the param-eters discussed previously and the expectations of the bridge owners and stakeholders; however, in all cases, loss of girder support, column failur
44、e, foundation failure, and connection failure are unacceptable.Performance-driven design requirements, especially for structures in areas of high seismicity, make the modeling of the bridge structural system very important. The bridge structural system being modeled should not only include the colum
45、ns, but also the abutment and foundation systems. Modeling should account for interaction between these different components (for example, superstructure impact on abutment gap closure) as well as with the surrounding soil (for example, transmission of base rock motion to the foundation elements thr
46、ough the surrounding soil).Although the discussions presented herein are in principle applicable to all bridges, the intent is to address short- and medium-span bridges with span lengths less than 500 ft (150 m). Long-span and specialty bridges involving addi-tional design considerations are outside
47、 the scope of this document. The information presented in this document has largely been extracted from design specifications, codes, and other references. This document should be considered as a guide to be used by a responsible design professional with the proper background and in conjunction with
48、 experience and judgment of the designer.1.2Lessons learned from earthquake damage to bridgesEarthquakes over the last 40 years, including the 1971 San Fernando, 1989 Loma Prieta, and 1994 Northridge earth-quakes in the United States; the 1995 Hyogo-Ken Nanbu Earthquake in Japan; the 1999 Ji-Ji Eart
49、hquake in Taiwan; and the 1999 Kocaeli Earthquake in Turkey, are reminders of the vulnerability of existing bridges and their impacts on society when they perform poorly during earthquakes (Chen and Duan 2014; Yashinsky 2000). Collapse or severe damage to several bridges occurred in each of these events, some examples of which are shown in Fig. 1.2a, 1.2b, and 1.2c. Although research to improve bridge seismic performance has been ongoing for several decades, research with signifi-cant experimental emphasis intensified in the United Sta
