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 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 Ultimate Load Behaviour of Steel Box Girders and Their Components written by Paul Alexander Frieze and published by . This book was released on 1976 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Behavior of Horizontally Curved Steel Tubular flange Bridge Girders written by Zhuo Fan and published by . This book was released on 2007 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new type of curved steel bridge girder, called a curved tubular-flange girder, with rectangular tubes as flanges, is proposed and studied in this dissertation. A curved steel tubular-flange girder has much larger torsional stiffness than a curved I-girder and less potential for cross section distortion than a curved box-girder. Therefore, it has potential advantages compared to curved I-girders and box-girders.

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 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 Measurements of Deformations and Stresses Due to Plate Out of flatness in a Steel Twin Box Girder Bridge System written by Omar Rene Espinoza and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steel A New and Traditional Material for Building written by Dan Dubina and published by CRC Press. This book was released on 2006-08-17 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an era of new, composite materials and high-strength concrete, and with an increasing demand for sustainable building technologies, the importance of the role of steel in construction is being challenged.. Nonetheless, steel can successfully be used to refurbish and retrofit historical buildings, as well as being a material of choice for new building structures. Steel can effectively be combined with a variety of other materials to obtain structures which are characterized by a high-performance response under different types of static and dynamic activity. The proceedings contains nine keynote lectures from international experts, and is further divided into five sections: calculation models and methods; studies and advances in design codes; steel and mixed building technology; steel under exceptional actions; and steel in remarkable constructions and refurbishment.

Download or read book Development of Design Specifications and Commentary for Horizontally Curved Concrete Box girder Bridges written by Nutt, Redfield, and Valentine and published by Transportation Research Board. This book was released on 2008 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides specifications, commentary, and examples for the design of horizontally curved concrete box-girder highway bridges. The report details the development of the design procedures. Recommended Load and Resistance Factor Design (LRFD) specifications and design examples illustrating the application of the design methods and specifications are included in appendixes (available on the TRB website at http://trb.org/news/blurb_detail.asp?id=9596).

Download or read book Improved Design Specifications for Horizontally Curved Steel Girder Highway Bridges written by Dann H. Hall and published by Transportation Research Board. This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 1006 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Manuals of Engineering Practice written by and published by . This book was released on 1970 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of Steel Beams in Torsion written by A. F. Hughes and published by . This book was released on 2011 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report written by and published by . This book was released on 2008 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steel concrete Composite Bridges written by David Collings and published by Thomas Telford. This book was released on 2005 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Steel-concrete composite bridges shows how to choose the bridge form and design element sizes to enable the production of accurate drawings and also highlights a wide and full range of examples of the design and construction of this bridge type."--Jacket.