Download or read book Behavior of Steel Tub Girders with Optimized Bracing Layouts written by Stalin Vinicio Armijos Moya and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composite steel tub girders are a popular alternative for straight and horizontally curved bridges due to their high torsional stiffness and aesthetic appearance. While the closed girder in the finished bridge has a high torsional stiffness, prior to curing of the concrete deck the steel girder alone is relatively flexible. Consequently, steel tub girders require extensive amounts of bracing to avoid instability and cross section distortion due to the relatively low torsional stiffness during construction. The primary bracing systems include a top flange lateral truss as well as internal and external cross frames. The quasi-closed shape that results with the added bracing, results in a stiff girder system capable of resisting significant torsional moments and deformations. However, current design and detailing practices for steel tub girders commonly include several aspects that may lead to unnecessary fabrication costs and structural inefficiencies. The top flange lateral truss is commonly installed along the entire length of steel tub girders to increase the girder torsional stiffness. However, the horizontal truss is mainly effective near the ends of the girders where the shear deformations are the largest. Thus, partial top lateral bracing systems can be an alternative for straight and mildly horizontally curved bridge applications. Additionally, the internal K-frame braces are usually installed at every panel point to control cross-sectional distortion of the girders. However, the amount of internal K-frames can be significantly reduced with little impact on the structural performance. By optimizing the amount of bracing depending on the application, steel tub girders can be more cost-effective without undermining their structural integrity. In addition to modifications in the bracing, current AASHTO Specifications have several geometric restrictions for the section geometry of steel tub girders that may not be warranted. AASHTO restricts the web slope not to exceed the limit of 1 Horizontal to 4 Vertical. Tub girders with flatter web slopes can result in girders with higher tributary widths that could potentially reduce the number of girder lines on a bridge. In addition, top flanges are required to be centered on the top of the webs. If the top flanges are permitted to offset towards inside of the tub, more space would be available to connect directly the horizontal truss and avoid undesired eccentricities due to large gusset plates. Since these cross-sectional and bracing details are not currently allowed by AASHTO Specifications, a TxDOT-sponsored research project was performed to evaluate the impact of the aforementioned details using large-scale experimental tests and parametric finite element analyses. This dissertation evaluates the feasibility of optimized bracing layouts for straight and horizontally curved steel tub girders, in addition to analyzing the impact of modified cross-sectional geometries in the ultimate flexural capacity of steel tub girders

Download or read book Behavior of Steel Tub Girders with Modified Cross sectional Geometry written by Yang Wang (Ph. D.) and published by . This book was released on 2019 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steel trapezoidal box girders, also referred to as steel tub girders, have been an attractive design option for long-span horizontally curved highway bridges. The completed composite bridge system presents an aesthetic appeal profile as well as large torsional stiffness. However, during construction, the open U-shaped steel girder section is relatively flexible in torsion and requires extensive bracing. A recent application on straight bridge system in Waco, Texas showed potential wider utilization of tub girders for span length normally reserved for precast concrete beams. Current design and fabrication practices have several relatively inefficient aspects regarding the section geometry and bracing details. These details include the restrictions on the slope ratio of the webs and the top flange-web attachment. Due to the use of empirical equation for live load distribution factor, the slopes of tub girder webs are restricted to be no greater than 1 Horizontal: 4 Vertical in current AASHTO specification. Significant economy can be achieved by utilizing flatter webs. While keeping the width of bottom flange constant, the use of flatter webs increases the tributary width of individual girder. This leads to potential reduction of the required number of girder lines to support traffic live loads and considerable savings on fabrication time and cost. Additionally, the webs of the tub girder are usually attached at the mid-width of the top flanges. This leaves limited flange width to connect the top lateral braces directly with the flange. Therefore, large gusset plates are frequently used to provide sufficient space for the connection. However, the use of gusset plates leads to poor load transfer and unnecessary fabrication cost. If the top flanges are allowed to offset toward the inside of the box, more flange width would be available for simple bolted bracing connection without using gusset plates. Since these proposed details are not currently permitted by AASHTO Specification, a TxDOT-sponsored research project has been conducted at UT Austin to demonstrate the impact of these improved tub girder details using large-scale experimental study and finite element analyses. This dissertation presents part of the results of this research project to provide better understanding of tub girder behavior as well as design recommendations to improve the efficiency and economy of the steel tub girder system

Download or read book Cross frame Diaphragm Bracing of Steel Bridge Girders written by W. M. Kim Roddis and published by . This book was released on 2008 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steel plate girder bridges make use of traditional cross-frame diaphragms to stabilize the compression flange of girders. These braces are required during construction, especially during deck placement, to prevent lateral torsional buckling of bridge girders. Girder buckling capacity is a function of cross-frame diaphragm spacing as well as strength and stiffness. Recent developments in bridge design may cause the governing girder limit state to shift from one of strength to one of stability. These developments include the elimination of in-plan bracing, composite girders, High Performance Steels, and phased deck replacements. In addition, the American Association of State Highway and Transportation Officials (AASHTO) has changed its code requirement for cross-frame diaphragm spacing in the 1998 AASHTO LRFD Bridge Design Specifications. The requirement for 25-foot maximum brace spacing has been removed. The current requirement is for a "rational analysis" to determine cross-frame diaphragm spacing. Explanations of the problems these changes cause in design are discussed. A case study is presented of a bridge that suffered construction difficulties during deck placement. This investigation found that the cross-frame diaphragms were not stiff enough to brace the plate girders during the deck placement. Suggestions are given as to an efficient, economical design and spacing for cross-frame diaphragms on plate girder bridges.

Download or read book Steel Box Girder Bridges written by and published by Thomas Telford Publishing. This book was released on 1973 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Behavior and Design of Large Steel Box Girder Bridges written by Ernst H. Petzold and published by . This book was released on 1973 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Guidelines for Steel Trapezoidal Box Girder Systems written by and published by . This book was released on 2007 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Composite Action During Construction of Steel Trapezoidal Box Girder Bridges written by and published by . This book was released on 2005 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: In steel trapezoidal box girder bridge systems, the U-shaped steel girder is designed to act compositely with the concrete deck to form a closed box for live loading. During the construction stage, however, the behavior is not well understood. The usual practice of assuming the system to be non-composite during construction requires substantial top flange bracing to form a quasi-closed box section. Composite box girders with live loading, and girders during construction, have to be evaluated during the design of curved steel trapezoidal box girder bridges. Considering both cases, the design for construction loading is the least understood and is the most important. Stresses due to construction loading can reach up to 60-70 percent of the total design stress for a given cross section. A three-phase study was undertaken to investigate the behavior of curved trapezoidal box girders during construction.

Download or read book Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges written by and published by Transportation Research Board. This book was released on 2012 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's National Cooperative Highway Research Program (NCHRP) Report 725: Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges offers guidance on the appropriate level of analysis needed to determine the constructability and constructed geometry of curved and skewed steel girder bridges. When appropriate in lieu of a 3D analysis, the guidelines also introduce improvements to 1D and 2D analyses that require little additional computational costs."--Publication information.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1989 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Steel Designer s Handbook written by R. L. Brockenbrough and published by McGraw-Hill Companies. This book was released on 1994 with total page 1056 pages. Available in PDF, EPUB and Kindle. Book excerpt: This sourcebook reflects advances in standard design specifications and industry practices. The third edition offers access to reliable data on the material properties of steel, with coverage of the trend towards load- resistance-factor design (LRFD) in both bridges and buildings.

Download or read book Guide to Stability Design Criteria for Metal Structures written by Ronald D. Ziemian and published by John Wiley & Sons. This book was released on 2010-02-08 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive guide to stability design criteria, fully updated and incorporating current research Representing nearly fifty years of cooperation between Wiley and the Structural Stability Research Council, the Guide to Stability Design Criteria for Metal Structures is often described as an invaluable reference for practicing structural engineers and researchers. For generations of engineers and architects, the Guide has served as the definitive work on designing steel and aluminum structures for stability. Under the editorship of Ronald Ziemian and written by SSRC task group members who are leading experts in structural stability theory and research, this Sixth Edition brings this foundational work in line with current practice and research. The Sixth Edition incorporates a decade of progress in the field since the previous edition, with new features including: Updated chapters on beams, beam-columns, bracing, plates, box girders, and curved girders. Significantly revised chapters on columns, plates, composite columns and structural systems, frame stability, and arches Fully rewritten chapters on thin-walled (cold-formed) metal structural members, stability under seismic loading, and stability analysis by finite element methods State-of-the-art coverage of many topics such as shear walls, concrete filled tubes, direct strength member design method, behavior of arches, direct analysis method, structural integrity and disproportionate collapse resistance, and inelastic seismic performance and design recommendations for various moment-resistant and braced steel frames Complete with over 350 illustrations, plus references and technical memoranda, the Guide to Stability Design Criteria for Metal Structures, Sixth Edition offers detailed guidance and background on design specifications, codes, and standards worldwide.

Download or read book Transactions of the American Society of Civil Engineers written by American Society of Civil Engineers and published by . This book was released on 2005 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. 29-30 contain papers of the International Engineering Congress, Chicago, 1893; v. 54, pts. A-F, papers of the International Engineering Congress, St. Louis, 1904.

Download or read book Design of Steel Structures written by Elias G. Abu-Saba and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended for classroom teaching in architectural and civil engineering at the graduate and undergraduate levels. Although it has been developed from lecture notes given in structural steel design, it can be useful to practicing engineers. Many of the examples presented in this book are drawn from the field of design of structures. Design of Steel Structures can be used for one or two semesters of three hours each on the undergraduate level. For a two-semester curriculum, Chapters 1 through 8 can be used during the first semester. Heavy emphasis should be placed on Chapters 1 through 5, giving the student a brief exposure to the consideration of wind and earthquakes in the design of buildings. With the new federal requirements vis a vis wind and earthquake hazards, it is beneficial to the student to have some under standing of the underlying concepts in this field. In addition to the class lectures, the instructor should require the student to submit a term project that includes the complete structural design of a multi-story building using standard design procedures as specified by AISC Specifications. Thus, the use of the AISC Steel Construction Manual is a must in teaching this course. In the second semester, Chapters 9 through 13 should be covered. At the undergraduate level, Chapters 11 through 13 should be used on a limited basis, leaving the student more time to concentrate on composite construction and built-up girders.

Download or read book Engineering for Structural Stability in Bridge Construction written by Federal Highway Federal Highway Administration and published by . This book was released on 2020-07-19 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual is intended to serve as a reference. It will provide technical information which will enable Manual users to perform the following activities:Describe typical erection practices for girder bridge superstructures and recognize critical construction stagesDiscuss typical practices for evaluating structural stability of girder bridge superstructures during early stages of erection and throughout bridge constructionExplain the basic concepts of stability and why it is important in bridge erection* Explain common techniques for performing advanced stability analysis along with their advantages and limitationsDescribe how differing construction sequences effect superstructure stabilityBe able to select appropriate loads, load combinations, and load factors for use in analyzing superstructure components during constructionBe able to analyze bridge members at various stages of erection* Develop erection plans that are safe and economical, and know what information is required and should be a part of those plansDescribe the differences between local, member and global (system) stability

Download or read book STESSA 2000 Behaviour of Steel Structures in Seismic Areas written by Federico Mazzolani and published by CRC Press. This book was released on 2021-07-28 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a review of developments in the behaviour and design of steel structures in seismic areas. The proceedings look at the analytical and experimental research on the seismic response of steel structures, and cover topics such as global behaviour and codification, design and application.

Download or read book Structural Stability of Steel written by Theodore V. Galambos and published by John Wiley & Sons. This book was released on 2008-04-18 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Practical guide to structural stability theory for the design of safe steel structures Not only does this book provide readers with a solid foundation in structural stability theory, it also offers them a practical, working knowledge of how this theory translates into design specifications for safe steel structures. Structural Stability of Steel features detailed discussions of the elastic and inelastic stability of steel columns, beams, beam-columns, and frames alongside numerous worked examples. For each type of structural member or system, the authors set forth recommended design rules with clear explanations of how they were derived. Following an introduction to the principles of stability theory, the book covers: * Stability of axially loaded planar elastic systems * Tangent-modulus, reduced-modulus, and maximum strength theories * Elastic and inelastic stability limits of planar beam-columns * Elastic and inelastic instability of planar frames * Out-of-plane, lateral-torsional buckling of beams, columns, and beam-columns The final two chapters focus on the application of stability theory to the practical design of steel structures, with special emphasis on examples based on the 2005 Specification for Structural Steel Buildings of the American Institute of Steel Construction. Problem sets at the end of each chapter enable readers to put their newfound knowledge into practice by solving actual instability problems. With its clear logical progression from theory to design implementation, this book is an ideal textbook for upper-level undergraduates and graduate students in structural engineering. Practicing engineers should also turn to this book for expert assistance in investigating and solving a myriad of stability problems.

Download or read book Redundancy in Highway Bridge Superstructures written by Michel Ghosn and published by Transportation Research Board. This book was released on 1998 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: