DOCSLIB.ORG

Why Steel Box Girders

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Why Steel Box Girders BRIDGE No. 6, April 1997 CROSSINGS Practical Information For The Bridge Industry for easy ingress. Given these issues, steel box gird- Why Steel Box ers have been slow to catch on as a viable form for a spectrum of bridge sites. Girders? Since a bridge’s primary purpose is to support loads, its structurally efficiency is its most impor- By Dann H. Hall tant feature. However, there are other concomi- Bridge design utilizes the imaginative applica- tant requirements placed on modern bridges: tion of changing technology to meet changing Functionality; serviceability; maintainability; aes- demands. Steel box girders are widely acknowl- thetic appeal and; buildability. After examining edged to be attractive but have been perceived to trade-offs that exist with regard to various forms be more expensive than comparable I girders. Box meeting the sometimes paradoxical demands girder design generally has required more labor placed on modern bridges, the engineer chooses a than the design of comparable I girder bridges and bridge form. Increasingly, the steel box girder computer analysis software has not been readily form is being chosen. available. Some fabricators have not been anxious to undertake box girder fabrication. Background Straight welded steel box girders were first Also, several large steel box girder bridges failed added to the AASHTO Standard Specifications for during construction in Europe during the 1960s. Highway Bridges in the early 1970s. Torsion is not Steel box girders in the United States have been included in these provisions. Instead, a formula associated with metal fatigue in the webs due to providing wheel load factors for a limited number box distortion near connection plate welds. of boxes per traffic lane and limited spacing Shipping limitations on the highway have elimi- between webs is given such that torsion is believed nated the steel box girders form from considera- to be negligible. tion. Inspection of in situ box girders has been a problem when the box cross sections are too small Two of the earliest curved steel box girder bridges in the United States were built in Massachusetts in the early 1960s. Welded box girders were selected to provide the torsional stiff- ness and strength necessary to satis- fy a demanding horizontal radii of 150 feet. Contemporaneously, a straight steel box girder bridge was designed to carry a railroad across the Missouri River at Kansas City. A steel box was selected to take advan- tage of the torsional stiffness that permitted the girders to be launched without additional bracing and to be placed in service quickly. The Poplar Street Bridge, which carries I-70 across the Mississippi River at St. Louis, consists of dual bridges, each having an orthrotropic steel decks, each supported on twin steel box girders. Box sections were A steel box ramp in Seattle (photo courtesty of Parsons Brinkerhoff) selected to provide stability of widely Reprinted from Modern Steel Construction spaced girders of great span. Serviceability These earlier bridges utilized true steel boxes Serviceability requires bridges to be rigid made with steel plates forming the four box sides, enough to prevent excessive vibration and deflec- whereas the Atlanta Area Rapid Transit Authority tion. Bridges must function without excessive (MARTA) design utilized single steel “tub” girders. repairs and minimal shut-downs during their “Tub” girders have webs and bottom flange of steel design lives. plates with separate steel top flanges attached to a Limitation of deflections is the standard tech- composite concrete deck which completes the box. nique available to engineers to improve serviceabil- Again, the box shape provided the torsional stiff- ity. Steel’s superior stiffness permits relatively ness to permit large deck overhangs so that a sin- shallow bridges. Box girders can provide an addi- gle box can carry two commuter trains side by side. tional advantage in this regard to horizontal The AASHTO Guide Specifications for curves because the box acts as two I girders, thus Horizontally Curved Bridges was introduced in heavier load characteristically applied to the out- 1980. These provisions require a rational analysis side girder of a curved I girder bridge is resisted by which must consider torsion. These specifications a box girder which has the flexural stiffness and opened up new bridge forms, including the single strength of two I girders. box cross section and widely spaced boxes with Fatigue caused by inadequate design and poor large overhangs. For the first time, the design details can lead to cracking that can require expen- code recognized the torsional resistance of steel sive repairs. Internal cross bracing has caused boxes; thus permitting the form to match that of fatigue distress in box girders when forces were not the prestressed segmental concrete box girder properly considered and a path provided to proper- bridge. ly transmit cross frame forces to the girder flanges. Aesthetics Maintainability As the highway system has become ubiquitous Maintainability relates to the ease and cost of in nearly all cities, aesthetics has become increas- maintenance over the life of the bridge. The bridge ingly important. A region’s residents and visitors must be accessible for inspection and repairs with- often sense that the quality and appearance of the out excessive disruptions to traffic and excessive bridges reflect its style. cost. Decisions with respect to aesthetics can be divid- The box configuration provides benefits with ed into those relating to detail and those relating regard to maintenance through minimization of to form. Box girders can provide a smooth appear- exposed bracing details and flanges that would oth- ance because they hide bracing and stiffening erwise collect debris that should be removed. Steel while minimizing exposed steel surface. Thus, the box girders have even been specified to eliminate engineer can design a detail-clean structure with roosting birds over pedestrian areas. few visible appurtenances. The elimination of exposed horizontal flange Replacing pairs of I girders with a box girder surfaces and bracing is especially beneficial for does not change the essential form of the bridge. weathering steel applications when accumulation However, fewer boxes, with large deck overhangs, of debris which can hold moisture should be avoid- or at a minimum, a single box cross section, reveals ed. Repainting also is simplified when there is the torsional effectiveness of the box. Torsional almost no bracing to be painted. Fewer boxes leads action can draw load to a central pier shaft rather to fewer webs and they need paint on only one side. than using expensive redundant pier columns to take loads straight down from the deck. This use Buildability of torsion to reduce the number of components exemplifies the inherent beauty of efficient struc- Bridges must be buildable with the existing tural form as proposed by David Billington in his technology and facilities with minimal disruption book, The Bridge and the Tower. to the existing highway system and without unex- pected delays and claims. Functionality Bridge fabrication shops on navigable water- Functionality relates to traffic volume, speed ways in the much of the central and eastern U. S. and safety. Heavy traffic volume demands numer- have been shut. The Kansas City railroad bridge ous grade separation structures. Increased speeds and the Popular Street bridge were fabricated in demand smoothly curved alignments with ade- one of these now defunct shops and shipped by quate visibility and setback of supports for safety. barge to the bridge site. The Interstate System provides an alternate means of transportation but Curved steel box girder bridges can provide long box size is limited in weight, length and width. curved spans with fewer supports than would be required for segmented straight girder bridges. To overcome shipping limitations, boxes can be A steel box ramp near Miami designed with a bolted seam along the bottom webs provide a narrower, more efficient, bottom flange permitting halves of wide boxes to be flange which permits reduction of steel in regions shipped by highway or rail. of low stress and a more compact flange for higher compressive strength which requires less stiffen- Modern fabrication equipment including com- ing. Tub girders are more practical with regard to puter controlled burning and drilling have made welding inside compared to a closed box with its the welded steel box more economical to fabricate. limited accessibility. Curved, haunched inclined webs are being faithful- ly burned from plates using torches driven by com- The use of single box cross sections for ramps is puters which have been fed data from the design possible because the torsional stiffness permits drawings. Numeric controlled drilling permits the large deck overhangs. The single box usually production of multiple bolt holes in near perfect needs a single pier shaft with one or two bearings. location again with data from the design drawings. Large deck overhangs and girder spacings usually require transverse post-tensioning (PT) with a Economy vaulted deck. The savings in girder and substruc- Many of the items discussed above relate to the ture costs usually exceed any added deck cost. life-cost of a bridge. However, the initial cost is The twin-steel box MacMillan Yard Bridge in extremely important and certainly the most deter- Toronto, with a transversely PT vaulted concrete minable. The total bridge cost, including the sub- deck nearly 100’ wide successfully competed structure cost, should be considered. Economical against a similar segmental concrete design. The box bridges have a minimal number of girders and numerous single box ramps used on the Boston no more than one pier shaft per box. Since fabrica- Central Artery also have led to recent successes of tion cost per pound of steel box girders is higher steel box designs when competing with similar con- than for I girders, the box weight should be less crete designs.
Load more

Recommended publications
  • Evaluation of a High Performance Concrete Box Girder Bridge
    Evaluation of a High Performance Concrete Box Girder Bridge Andreas Greuel T. Michael Baseheart, Ph. D. Graduate Research Assistant Associate Professor of Civil University of Cincinnati Engineering Cincinnati, Ohio University of Cincinnati Cincinnati, Ohio Bradley T. Rogers Engineer LJB, Inc. As part of the FHWA (Federal Highway Admin- Dayton, Ohio istration) High Performance Concrete Bridge Program, two full-scale truckload tests of Bridge GUE-22-6.57 were carried out. The main ob- jectives of these tests were to investigate the static and dynamic response of the high perfor- Richard A. Miller, Ph. D. mance concrete (HPC) structure. A secondary Associate Professor of Civil Engineering objective was to investigate the load transfer University of Cincinnati between the box girders through experimental Cincinnati, Ohio middepth shear keys. The structure was loaded using standard Ohio Department of Transporta- tion (ODOT) dump trucks. A model test of the bridge was conducted as well. It was found that the bridge behavior is well predicted using sim- ple models. The bridge behaves as a single unit and all girders share the load almost equally. Bahram M. Shahrooz, Ph. D. The dynamic behavior of the bridge is typical Associate Professor of Civil for comparable structures. Engineering University of Cincinnati Cincinnati, Ohio 60 PCI JOURNAL he use of high performance con- located on US Route 22, a heavily in that the Ohio box girder has only a crete (HPC) can lead to more traveled two-lane highway near Cam- 5 in. (127 mm ) thick bottom flange Teconomical bridge designs be- bridge, Ohio. rather than the 5.5 in.
    [Show full text]
  • Review on Applicability of Box Girder for Balanced Cantilever Bridge Sneha Redkar1, Prof
    International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 05 | May-2016 www.irjet.net p-ISSN: 2395-0072 Review on applicability of Box Girder for Balanced Cantilever Bridge Sneha Redkar1, Prof. P. J. Salunke2 1Student, Dept. of Civil Engineering, MGMCET, Maharashtra, India 2Head, Assistant Professor, Dept. of Civil Engineering, MGMCET, Maharashtra, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - This paper gives a brief introduction to the 1874. Use of steel led to the development of cantilever cantilever bridges and its evolution. Further in cantilever bridges. The world’s longest span cantilever bridge was built bridges it focuses on system and construction of balanced in 1917 at Quebec over St. Lawrence River with main span of cantilever bridges. The superstructure forms the dynamic 549 m. India can boast of one such long bridge, the Howrah element as a load carrying capacity. As box girders are widely bridge, over river Hooghly with main span of 457 m which is used in forming the superstructure of balanced cantilever fourth largest of its kind. bridges, its advantages are discussed and a detailed review is carried out. Concrete cantilever construction was first introduced in Europe in early 1950’s and it has since been broadly used in design and construction of several bridges. Unlike various Key Words: Bridge, Balanced Cantilever, Superstructure, bridges built in Germany using cast-in-situ method, Box Girder, Pre-stressing cantilever construction in France took a different direction, emphasizing the use of precast segments. The various advantages of precast segments over cast-in-situ are: 1. INTRODUCTION i. Precast segment construction method is a faster method compared to cast-in-situ construction method.
    [Show full text]
  • Bridges for Planes, Trains, but Not Automobiles by David A
    bridges for Planes, Trains, buT noT auTomobiles By David A. Burrows, P.E., LEED AP BD+C ® British Airways 747 crossing beneath the Taxiway “R” bridge, June, 2012. Courtesy of City of Phoenix Aviation Department. Copyright s described in the August edition of STRUCTURE® maga- zine, Phoenix Sky Harbor International Airport opened the first stage of their automated transit system, PHX Sky Train™, on April 8, 2013. Thousands of passengers have already boarded the Sky Train and experienced the comfortable five A th minute ride from the 44 Street Station through the East Economy Lot Station, over Taxiway “R” (more than 100 feet above Sky Harbor Blvd.), ending at Terminal 4. The next phase, known as Stage 1A, is currently under con- struction and continues Sky Train’s route from Terminal 4 to Terminal 3. Scheduled to be open in early 2015, Stagemagazine 1A, similar to the Stage 1 construction,S faces theT task ofR crossing U an active C T U R E taxiway. Unlike the first Stage’s crossing above Taxiway “R”, the current phase of construction crosses beneath Taxiways “S” and “T”. Both Stages’ taxiway crossings presented several design and construction challenges. A US Airways jet passes beneath the Taxiway R crossing with the PHX Sky Train overhead. Courtesy of City of Phoenix Aviation Department. The World’s First In addition to the challenging geometry was the schedule constraint On Oct. 10, 2010, a celebration to mark the re-opening of Taxiway for constructing the bridge. Because the construction required the “R” was held by the City of Phoenix with members of the City’s taxiway to be closed, a limited shutdown period of six months was Aviation Department, designers, contractors and media watching possible due to airport operations.
    [Show full text]
  • Steel Bridge Design Handbook Vol. 13
    U.S. Department of Transportation Federal Highway Administration Steel Bridge Design Handbook Bracing System Design Publication No. FHWA-HIF-16-002 - Vol. 13 December 2015 FOREWORD This handbook covers a full range of topics and design examples intended to provide bridge engineers with the information needed to make knowledgeable decisions regarding the selection, design, fabrication, and construction of steel bridges. Upon completion of the latest update, the handbook is based on the Seventh Edition of the AASHTO LRFD Bridge Design Specifications. The hard and competent work of the National Steel Bridge Alliance (NSBA) and prime consultant, HDR, Inc., and their sub-consultants, in producing and maintaining this handbook is gratefully acknowledged. The topics and design examples of the handbook are published separately for ease of use, and available for free download at the NSBA and FHWA websites: http://www.steelbridges.org, and http://www.fhwa.dot.gov/bridge, respectively. The contributions and constructive review comments received during the preparation of the handbook from many bridge engineering processionals across the country are very much appreciated. In particular, I would like to recognize the contributions of Bryan Kulesza with ArcelorMittal, Jeff Carlson with NSBA, Shane Beabes with AECOM, Rob Connor with Purdue University, Ryan Wisch with DeLong’s, Inc., Bob Cisneros with High Steel Structures, Inc., Mike Culmo with CME Associates, Inc., Mike Grubb with M.A. Grubb & Associates, LLC, Don White with Georgia Institute of Technology, Jamie Farris with Texas Department of Transportation, and Bill McEleney with NSBA. Joseph L. Hartmann, PhD, P.E. Director, Office of Bridges and Structures Notice This document is disseminated under the sponsorship of the U.S.
    [Show full text]
  • Steel Bridge Design Handbook
    U.S. Department of Transportation Federal Highway Administration Steel Bridge Design Handbook Design Example 4: Three-Span Continuous Straight Composite Steel Tub Girder Bridge Publication No. FHWA-HIF-16-002 - Vol. 24 December 2015 FOREWORD This handbook covers a full range of topics and design examples intended to provide bridge engineers with the information needed to make knowledgeable decisions regarding the selection, design, fabrication, and construction of steel bridges. Upon completion of the latest update, the handbook is based on the Seventh Edition of the AASHTO LRFD Bridge Design Specifications. The hard and competent work of the National Steel Bridge Alliance (NSBA) and prime consultant, HDR, Inc., and their sub-consultants, in producing and maintaining this handbook is gratefully acknowledged. The topics and design examples of the handbook are published separately for ease of use, and available for free download at the NSBA and FHWA websites: http://www.steelbridges.org, and http://www.fhwa.dot.gov/bridge, respectively. The contributions and constructive review comments received during the preparation of the handbook from many bridge engineering processionals across the country are very much appreciated. In particular, I would like to recognize the contributions of Bryan Kulesza with ArcelorMittal, Jeff Carlson with NSBA, Shane Beabes with AECOM, Rob Connor with Purdue University, Ryan Wisch with DeLong’s, Inc., Bob Cisneros with High Steel Structures, Inc., Mike Culmo with CME Associates, Inc., Mike Grubb with M.A. Grubb & Associates, LLC, Don White with Georgia Institute of Technology, Jamie Farris with Texas Department of Transportation, and Bill McEleney with NSBA. Joseph L. Hartmann, PhD, P.E.
    [Show full text]
  • Single-Span Cast-In-Place Post-Tensioned Concrete
    LRFD Example 1 1-Span CIPPTCBGB 1-Span Cast-in-Place Cast-in-place post-tensioned concrete box girder bridge. The bridge has a 160 Post-Tensioned feet span with a 15 degree skew. Standard ADOT 32-inch f-shape barriers will Concrete Box Girder be used resulting in a bridge configuration of 1’-5” barrier, 12’-0” outside [CIPPTCBGB] shoulder, two 12’-0” lanes, a 6’-0” inside shoulder and a 1’-5” barrier. The Bridge Example overall out-to-out width of the bridge is 44’-10”. A plan view and typical section of the bridge are shown in Figures 1 and 2. The following legend is used for the references shown in the left-hand column: [2.2.2] AASHTO LRFD Specification Article Number [2.2.2-1] AASHTOLRFD Specification Table or Equation Number [C2.2.2] AASHTO LRFD Specification Commentary [A2.2.2] AASHTO LRFD Specification Appendix [BDG] ADOT LRFD Bridge Design Guidelines Bridge Geometry Bridge length 160.00 ft Bridge width 44.83 ft Roadway width 42.00 ft Superstructure depth 7.50 ft Web spacing 9.25 ft Web thickness 12.00 in Top slab thickness 8.50 in Bottom slab thickness 6.00 in Deck overhang 3.33 ft Minimum Requirements The minimum span to depth ratio for a single span bridge should be taken as 0.045 resulting in a minimum depth of 7.20 feet. Use 7’-6” [Table 2.5.2.6.3-1] The minimum top slab thickness shall be as shown in the LRFD Bridge Design Guidelines. For a centerline spacing of 9.25 feet, the effective length is 8.25 feet resulting in a minimum thickness of 8.50 inches.
    [Show full text]
  • Recent Technology of Prestressed Concrete Bridges in Japan
    IABSE-JSCE Joint Conference on Advances in Bridge Engineering-II, August 8-10, 2010, Dhaka, Bangladesh. ISBN: 978-984-33-1893-0 Amin, Okui, Bhuiyan (eds.) www.iabse-bd.org Recent technology of prestressed concrete bridges in Japan Hiroshi Mutsuyoshi & Nguyen Duc Hai Department of Civil and Environmental Engineering, Saitama University, Saitama 338-8570, Japan Akio Kasuga Sumitomo Mitsui Construction Co., Ltd., Tokyo 104-0051, Japan ABSTRACT: Prestressed concrete (PC) technology is being used all over the world in the construction of a wide range of bridge structures. However, many PC bridges have been deteriorating even before the end of their design service-life due to corrosion and other environmental effects. In view of this, a number of innova- tive technologies have been developed in Japan to increase not only the structural performance of PC bridges, but also their long-term durability. These include the development of novel structural systems and the ad- vancement in construction materials. This paper presents an overview of such innovative technologies on PC bridges on their development and applications in actual construction projects. Some noteworthy structures, which represent the state-of-the-art technologies in the construction of PC bridges in Japan, are also pre- sented. 1 INTRODUCTION Prestressed concrete (PC) technology is widely being used all over the world in construction of wide range of structures, particularly bridge structures. In Japan, the application of prestressed concrete was first introduced in the 1950s, and since then, the construction of PC bridges has grown dramatically. The increased interest in the construction of PC bridges can be attributed to the fact that the initial and life-cycle cost of PC bridges, including repair and maintenance, are much lower than those of steel bridges.
    [Show full text]
  • Over Jones Falls. This Bridge Was Originally No
    The same eastbound movement from Rockland crosses Bridge 1.19 (miles west of Hollins) over Jones Falls. This bridge was originally no. 1 on the Green Spring Branch in the Northern Central numbering scheme. PHOTO BY MARTIN K VAN HORN, MARCH 1961 /COLLECTION OF ROBERT L. WILLIAMS. On October 21, 1959, the Interstate Commerce maximum extent. William Gill, later involved in the Commission gave notice in its Finance Docket No. streetcar museum at Lake Roland, worked on the 20678 that the Green Spring track west of Rockland scrapping of the upper branch and said his boss kept would be abandoned on December 18, 1959. This did saying; "Where's all the steel?" Another Baltimore not really affect any operations on the Green Spring railfan, Mark Topper, worked for Phillips on the Branch. Infrequently, a locomotive and a boxcar would removal of the bridge over Park Heights Avenue as a continue to make the trip from Hollins to the Rockland teenager for a summer job. By the autumn of 1960, Team Track and return. the track through the valley was just a sad but fond No train was dispatched to pull the rail from the memory. Green Spring Valley. The steel was sold in place to the The operation between Hollins and Rockland con- scrapper, the Phillips Construction Company of tinued for another 11/2 years and then just faded away. Timonium, and their crews worked from trucks on ad- So far as is known, no formal abandonment procedure jacent roads. Apparently, Phillips based their bid for was carried out, and no permission to abandon was the job on old charts that showed the trackage at its ' obtained.
    [Show full text]
  • Framework for Improving Resilience of Bridge Design
    U.S. Department of Transportation Federal Highway Administration Framework for Improving Resilience of Bridge Design Publication No. FHWA-IF-11-016 January 2011 Notice This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for use of the information contained in this document. This report does not constitute a standard, specification, or regulation. Quality Assurance Statement The Federal Highway Administration provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement. Framework for Improving Resilience of Bridge Design Report No. FHWA-IF-11-016 January 2011 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA-IF-11-016 4. Title and Subtitle 5. Report Date Framework for Improving Resilience of Bridge Design January 2011 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Brandon W. Chavel and John M. Yadlosky 9. Performing Organization Name and Address 10. Work Unit No. HDR Engineering, Inc. 11 Stanwix Street, Suite 800 11. Contract or Grant No. Pittsburgh, Pennsylvania 15222 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Office of Bridge Technology Technical Report Federal Highway Administration September 2007 – January 2011 1200 New Jersey Avenue, SE Washington, D.C. 20590 14.
    [Show full text]
  • Glulam Timber Bridges for Local Roads Zachary Charles Carnahan South Dakota State University
    South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange Theses and Dissertations 2017 Glulam Timber Bridges for Local Roads Zachary Charles Carnahan South Dakota State University Follow this and additional works at: http://openprairie.sdstate.edu/etd Part of the Civil and Environmental Engineering Commons Recommended Citation Carnahan, Zachary Charles, "Glulam Timber Bridges for Local Roads" (2017). Theses and Dissertations. 1173. http://openprairie.sdstate.edu/etd/1173 This Thesis - Open Access is brought to you for free and open access by Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. GLULAM TIMBER BRIDGES FOR LOCAL ROADS BY ZACHARY CHARLES CARNAHAN A thesis in partial fulfillment of the requirements for the Master of Science Major in Civil Engineering South Dakota State University 2017 iii DISCLAIMER The contents of this report, funded in part through grant(s) from the Federal Highway Administration, reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the South Dakota Department of Transportation, the State Transportation Commission, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. iv ACKNOWLEDGEMENTS This study was funded by the South Dakota Department of Transportation (SDDOT) and the Mountain Plains Consortium (MPC) University Transportation Center.
    [Show full text]
  • Strengthening of a Long Span Prestressed Segmental Box Girder Bridge
    Strengthening of a Long Span Prestressed Segmental Box Girder Bridge Bruno Massicotte The Grand-Mere Bridge in the province of Ph.D., P.Eng. Quebec, Canada, is a 285 m (935 ft) long, Associate Professor cast-in-place, segmental box girder bridge that Department of Civil Engineering Ecole Polytechnique de Montreal experienced several problems which resulted Montreal , Quebec, Canada in distress characterized by an increasing de­ Formerly, Bridge Design Engineer at the Quebec Ministry of Transportation flection combined with localized cracking. These defects were due mainly to insufficient prestressing causing high tensile stresses in the deck and possible corrosion of the pre­ stressing steel. To remedy this situation, the Quebec Ministry of Transportation strength­ ened the bridge by adding external prestress­ Andre Picard ing equivalent to 30 percent of the remaining Ph.D., P.Eng. internal prestressing. The paper describes the Professor Department of Civil Engineering causes of the distress and focuses on the as­ Universite Laval sumptions adopted in the analyses to deter­ Quebec City, Quebec, Canada mine the current state of the bridge. The tech­ Yvon Gaumond, P.Eng. nique and design criteria used in strengthening Bridge Design Chief Engineer the Grand-Mere Bridge are described. Also, Bridge Department the construction aspects and the various prob­ Quebec Ministry of Transportation lems met during the external prestressing op­ Quebec City, Quebec, Canada eration are discussed. The new technology and experience gained in strengthening this structure can be applied to both pretensioned and post-tensioned concrete bridges. he Grand-Mere Bridge, a 285 m (935 ft) long, cast-in­ Claude Ouellet, P.Eng.
    [Show full text]
  • Steel Bridge Design Handbook
    U.S. Department of Transportation Federal Highway Administration Steel Bridge Design Handbook Design Example 2A: Two-Span Continuous Straight Composite Steel I-Girder Bridge ArchivedPublication No. FHWA-IF-12-052 - Vol. 21 November 2012 Notice This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for use of the information contained in this document. This report does not constitute a standard, specification, or regulation. Quality Assurance Statement The Federal Highway Administration provides high-quality information to serve Government, industry, and the publicArchived in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement. Steel Bridge Design Handbook Design Example 2A: Two-Span Continuous Straight Composite Steel I-Girder Bridge Publication No. FHWA-IF-12-052 - Vol. 21 November 2012 Archived Archived Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA-IF-12-052 - Vol. 21 4. Title and Subtitle 5. Report Date Steel Bridge Design Handbook Design Example 2A: Two-Span November 2012 Continuous Straight Composite Steel I-Girder Bridge 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Karl Barth, Ph.D. (West Virginia University) 9. Performing Organization Name and Address 10. Work Unit No. HDR Engineering, Inc. 11 Stanwix Street 11. Contract or Grant No. Suite 800 Pittsburgh, PA 15222 12.
    [Show full text]