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Strengthening Of An Existing Continuous Span Steel Beam Concrete Deck Bridge By Post Tensioning
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Book Synopsis Strengthening of an Existing Continuous-span, Steel-beam, Concrete-deck Bridge by Post-tensioning by :
Download or read book Strengthening of an Existing Continuous-span, Steel-beam, Concrete-deck Bridge by Post-tensioning written by and published by . This book was released on 1990 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to upgrade a large number of understrength and obsolete bridges in the U.S. has been well documented in the literature. Through several Iowa DOT projects, the concept of strengthening simple-span bridges by post-tensioning has been developed. The purpose of the project described in this report was to investigate the use of post-tensioning for strengthening continuous composite bridges. In a previous, successfully completed investigation, the feasibility of strengthening continuous, composite bridges by post-tensioning was demonstrated on a laboratory 1/3-scale-model bridge (3 spans: 41 ft 11 in. x 8 ft 8 in.). This project can thus be considered the implementation phase. The bridge selected for strengthening was in Pocahontas County near Fonda, Iowa, on County Road N28. With finite element analysis, a post-tensioning system was developed that required post-tensioning of the positive moment regions of both the interior and exterior beams. During the summer of 1988, the strengthening system was installed along with instrumentation to determine the bridge's response and behavior. Before and after post-tensioning, the bridge was subjected to truck loading (1 or 2 trucks at various predetermined critical locations) to determine the effectiveness of the strengthening system. The bridge, with the strengthening system in place, was inspected approximately every three months to determine any changes in its appearance or behavior. In 1989, approximately one year after the initial strengthening, the bridge was retested to identify any changes in its behavior. Post-tensioning forces were removed to reveal any losses over the one-year period. Post-tensioning was reapplied to the bridge, and the bridge was tested using the same loading program used in 1988. Except for at a few locations, stresses were reduced in the bridge the desired amount. At a few locations flexural stresses in the steel beams are still above 18 ksi, the allowable inventory stress for A7 steel. Although maximum stresses are above the inventory stress by about 2 ksi, they are about 5 ksi below the allowable operating stress; therefore, the bridge no longer needs to be load-posted.
Book Synopsis Strengthening of Existing Single Span Steel Beam and Concrete Deck Bridges by : K. F. Dunker
Download or read book Strengthening of Existing Single Span Steel Beam and Concrete Deck Bridges written by K. F. Dunker and published by . This book was released on 1985 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unifying objective of Phases I and II of this study was to determine the feasibility of the post-tensioning strengthening method and to implement the technique on two composite bridges in Iowa. Following completion of these two phases, Phase III was undertaken and is documented in this report. The basic objectives of Phase III were further monitoring bridge behavior (both during and after post-tensioning) and developing a practical design methodology for designing the strengthening system under investigation. Specific objectives were: to develop strain and force transducers to facilitate the collection of field data; to investigate further the existence and effects of the end restraint on the post-tensioning process; to determine the amount of post-tensioning force loss that occurred during the time between the initial testing and the retesting of the existing bridges; to determine the significance of any temporary temperature-induced post-tensioning force change; and to develop a simplified design methodology that would incorporate various variables such as span length, angle-of-skew, beam spacing, and concrete strength. Experimental field results obtained during Phases II and III were compared to the theoretical results and to each other. Conclusions from this research are as follows: (1) Strengthening single-span composite bridges by post-tensioning is a viable, economical strengthening technique. (2) Behavior of both bridges was similar to the behavior observed from the bridges during field tests conducted under Phase II. (3) The strain transducers were very accurate at measuring mid-span strain. (4) The force transducers gave excellent results under laboratory conditions, but were found to be less effective when used in actual bridge tests. (5) Loss of post-tensioning force due to temperature effects in any particular steel beam post-tensioning tendon system were found to be small. (6) Loss of post-tensioning force over a two-year period was minimal. (7) Significant end restraint was measured in both bridges, caused primarily by reinforcing steel being continuous from the deck into the abutments. This end restraint reduced the effectiveness of the post-tensioning but also reduced midspan strains due to truck loadings. (8) The SAP IV finite element model is capable of accurately modeling the behavior of a post-tensioned bridge, if guardrails and end restraints are included in the model. (9) Post-tensioning distribution should be separated into distributions for the axial force and moment components of an eccentric post-tensioning force. (10) Skews of 45 deg or less have a minor influence on post-tensioning distribution. (11) For typical Iowa three-beam and four-beam composite bridges, simple regression-derived formulas for force and moment fractions can be used to estimate post-tensioning distribution at midspan. At other locations, a simple linear interpolation gives approximately correct results. (12) A simple analytical model can accurately estimate the flexural strength of an isolated post-tensioned composite beam.
Book Synopsis Strengthening of an Existing Continuous-span, Steel-stringer, Concrete-deck Bridge by : Fred Wayne Klaiber
Download or read book Strengthening of an Existing Continuous-span, Steel-stringer, Concrete-deck Bridge written by Fred Wayne Klaiber and published by . This book was released on 1993 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Feasibility Study of Strengthening Existing Single Span Steel Beam Concrete Deck Bridges by : F. W. Klaiber
Download or read book Feasibility Study of Strengthening Existing Single Span Steel Beam Concrete Deck Bridges written by F. W. Klaiber and published by . This book was released on 1981 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: No method is as economical and promising for strengthening unsafe bridges as strengthening by post-tensioning of the steel beams.
Book Synopsis Evaluation of Post-tension Strengthened Steel Girder Bridge Using FRP Bars by : Terry J. Wipf
Download or read book Evaluation of Post-tension Strengthened Steel Girder Bridge Using FRP Bars written by Terry J. Wipf and published by . This book was released on 2003 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many state, county, and local agencies are faced with deteriorating bridge infrastructure composed of a large percentage of relatively short to medium span bridges. In many cases, these older structures are rolled or welded longitudinal steel stringers acting compositely with a reinforced concrete deck. Most of these bridges, although still in service, need some level of strengthening due to increases in legal live loads or loss of capacity due to deterioration. Although these bridges are overstressed in most instances, they do not warrant replacement; thus, structurally efficient but cost-effective means of strengthening needs to be employed. In the past, the use of bolted steel cover plates or angles was a common retrofit option for strengthening such bridges. However, the time and labor involved to attach such a strengthening system can sometimes be prohibitive. This project was funded through the Federal Highway Administration's Innovative Bridge Research and Construction program. The goal is to retrofit an existing structurally deficient, three-span continuous steel stringer bridge using an innovative technique that involves the application of post-tensioning forces; the post-tensioning forces were applied using fiber reinforced polymer post-tensioning bars. When compared to other strengthening methods, the use of carbon fiber reinforced polymer composite materials is very appealing in that they are highly resistant to corrosion, have a low weight, and have a high tensile strength. Before the post-tensioning system was installed, a diagnostic load test was conducted on the subject bridge to establish a baseline behavior of the unstrengthened bridge. During the process of installing the post-tensioning hardware and stressing the system, both the bridge and the post-tensioning system were monitored. The installation of the hardware was followed by a follow-up diagnostic load test to assess the effectiveness of the post-tensioning strengthening system. Additional load tests were performed over a period of two years to identify any changes in the strengthening system with time. Laboratory testing of several typical carbon fiber reinforced polymer bar specimens was also conducted to more thoroughly understand their behavior. This report documents the design, installation, and field testing of the strengthening system and bridge.
Book Synopsis Alternate Methods of Bridge Strengthening by :
Download or read book Alternate Methods of Bridge Strengthening written by and published by . This book was released on 1989 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for upgrading a large number of understrength and obsolete bridges in the United States has been well documented in the literature. Through the performance of several Iowa DOT projects, the concept of strengthening bridges (simple and continuous spans) by post-tensioning has been developed. The purpose of this project was to investigate two additional strengthening alternatives that may be more efficient than post-tensioning in certain situations. The research program for each strengthening scheme included a literature review, laboratory testing of the strengthening scheme, and a finite-element analysis of the scheme. For clarity the two strengthening schemes are presented separately. In Part 1 of this report, the strengthening of existing steel stringers in composite steel beam concrete-deck bridges by providing partial end restraint was shown to be feasible. Part 2 of this report summarizes the research that was undertaken to strengthen the negative moment regions of continuous, composite bridges. Two schemes were investigated: post-compression of stringers and superimposed trusses within the stringers.
Book Synopsis Strengthening of existing single span steel beam and concrete deck bridges by :
Download or read book Strengthening of existing single span steel beam and concrete deck bridges written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Practical Solutions for Bridge Strengthening & Rehabilitation by :
Download or read book Practical Solutions for Bridge Strengthening & Rehabilitation written by and published by . This book was released on 1993 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Bridge Evaluation, Repair and Rehabilitation by : A.S. Nowak
Download or read book Bridge Evaluation, Repair and Rehabilitation written by A.S. Nowak and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evaluation, repair and rehabilitation of bridges are increasingly important topics in the effort to deal with the deteriorating infrastructure. For example, in the United States about 40 percent of the nation's 570,000 bridges are classified, according to the Federal Highway Administra tion's (FHW A) criteria, as deficient and in need of rehabilitation and replacement. In other countries the situation is similar. FHW A estimates the cost of a bridge replacement and reha bilitation program at 50 billion dollars. The major factors that have contributed to the present situation are: the age, inadequate maintenance, increasing load spectra and environmental contamination. The deficient bridges are posted, repaired or replaced. The disposition of bridges involves clear economical and safety implications. To avoid high costs of replacement or repair, the evaluation must accurately reveal the present load carrying capacity of the struc ture and predict loads and any further changes in the capacity (deterioration) in the applicable time span. Accuracy of bridge evaluation can be improved by using the recent developments in bridge diagnostics, structural tests, material tests, structural analysis and probabilistic methods. There is a need for an international exchange of advanced experience to increase the research effi ciency. The Workshop is organized on the premise that the exchange of existing American and European experience in the area of bridge evaluation, repair and rehabilitation is beneficial for both parties involved.
Book Synopsis Methods for Increasing Live Load Capacity of Existing Highway Bridges by : Roger A. Dorton
Download or read book Methods for Increasing Live Load Capacity of Existing Highway Bridges written by Roger A. Dorton and published by Transportation Research Board. This book was released on 1997 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This synthesis will be of interest to state department of transportation bridge design and structural engineers, bridge consultants, and others involved in applied and research methods for increasing the live load capacity of existing highway bridges. The synthesis describes the current state of the practice for the various methods used to increase the live load capacity of existing highway bridges. This is done predominantly for bridges in the short- to medium-span range. Information on the more common bridge material types is presented. There is an emphasis on superstructure rather than substructure strengthening.
Book Synopsis Strengthening of Existing Continuous Composite Bridges by :
Download or read book Strengthening of Existing Continuous Composite Bridges written by and published by . This book was released on 1987 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Cost-effective Practices for Off-system and Local Interest Bridges by : F. W. Klaiber
Download or read book Cost-effective Practices for Off-system and Local Interest Bridges written by F. W. Klaiber and published by Transportation Research Board. This book was released on 2004 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 327: Cost-Effective Practices for Off-System and Local Interest Bridges examines off-system bridge design, construction, maintenance, financing, rehabilitation, and replacement. For this report, 'off-system' refers to those bridges typically owned and maintained by local agencies, and by state agencies on rural and other low-volume roads.
Book Synopsis Developments in fiber-reinforced polymer (FRP) composites for civil engineering by : M. Dawood
Download or read book Developments in fiber-reinforced polymer (FRP) composites for civil engineering written by M. Dawood and published by Elsevier Inc. Chapters. This book was released on 2013-05-15 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter summarizes the recent advances in the use of fiber-reinforced polymer (FRP) materials for repair, rehabilitation, and strengthening of steel structures. Conventional methods of strengthening and repairing steel structures are presented. The advantages and limitations of using FRP materials are summarized. Topics presented include strengthening of flexural members, strengthening with prestressed FRP materials, stress-based and fracture mechanics-based approaches to evaluating bond behavior, repair of cracked steel members, and strengthening of slender members subjected to compression forces. The chapter concludes with a brief discussion of future trends in this field and a summary of other resources for further information.
Book Synopsis Strengthening Continuous Steel Girder Bridges with Post-installed Shear Connectors and Inelastic Moment Redistribution by : Kerry Kreitman
Download or read book Strengthening Continuous Steel Girder Bridges with Post-installed Shear Connectors and Inelastic Moment Redistribution written by Kerry Kreitman and published by . This book was released on 2016 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many continuous steel bridges constructed prior to the 1970s have floor systems consisting of a non-composite concrete deck over steel beams with no shear connectors. While many of these bridges are still in good condition, the structures may not satisfy current load requirements and thus may need to be strengthened or replaced to avoid load-posting and to maintain structural safety. One potentially economical method of extending the service life of such bridges is to post-install adhesive anchor shear connectors to create composite action between the existing steel beams and concrete deck. This is efficient in regions dominated by positive flexural demands where the concrete deck is in compression. Inelastic moment redistribution away from the interior pier sections can be considered to address strength deficiencies in these regions, which are dominated by negative flexural demands. This dissertation explores this method of strengthening continuous non-composite steel girder bridges. Of particular interest is the “shakedown” behavior of partially composite strengthened girders under large repeated loads requiring moment redistribution. These concepts are commonly referred to as “autostress” design. After conducting preliminary studies on the feasibility of this strengthening method for typical bridges in the state of Texas, an extensive large-scale experimental program was conducted in conjunction with finite element modeling. The results of the testing and modeling are discussed in detail. Design recommendations and a design example are also provided.
Book Synopsis Developments in Fiber-Reinforced Polymer (FRP) Composites for Civil Engineering by : Nasim Uddin
Download or read book Developments in Fiber-Reinforced Polymer (FRP) Composites for Civil Engineering written by Nasim Uddin and published by Elsevier. This book was released on 2013-05-15 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of fiber-reinforced polymer (FRP) composite materials has had a dramatic impact on civil engineering techniques over the past three decades. FRPs are an ideal material for structural applications where high strength-to-weight and stiffness-to-weight ratios are required. Developments in fiber-reinforced polymer (FRP) composites for civil engineering outlines the latest developments in fiber-reinforced polymer (FRP) composites and their applications in civil engineering. Part one outlines the general developments of fiber-reinforced polymer (FRP) use, reviewing recent advancements in the design and processing techniques of composite materials. Part two outlines particular types of fiber-reinforced polymers and covers their use in a wide range of civil engineering and structural applications, including their use in disaster-resistant buildings, strengthening steel structures and bridge superstructures. With its distinguished editor and international team of contributors, Developments in fiber-reinforced polymer (FRP) composites for civil engineering is an essential text for researchers and engineers in the field of civil engineering and industries such as bridge and building construction. Outlines the latest developments in fiber-reinforced polymer composites and their applications in civil engineering Reviews recent advancements in the design and processing techniques of composite materials Covers the use of particular types of fiber-reinforced polymers in a wide range of civil engineering and structural applications
Book Synopsis Strengthening of Simple Span and Continuous Span Plate Girder Bridges by Post-tensioning by : Parmjit S. Parmar
Download or read book Strengthening of Simple Span and Continuous Span Plate Girder Bridges by Post-tensioning written by Parmjit S. Parmar and published by . This book was released on 1987 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Strengthening Techniques for Reinforced Concrete Bridge Superstructures by : Frieder Seible
Download or read book Strengthening Techniques for Reinforced Concrete Bridge Superstructures written by Frieder Seible and published by . This book was released on 1990 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
