Manual for Design, Construction, and Maintenance of Orthotropic Steel Deck Bridges
Author: Connor, Robert Fisher, John Gatti, Walter Gopalaratnam, Vellore Kozy, Brian Leshko, Brian McQuaid, David L Medlock, Ronald Mertz, Dennis Murphy, Thomas Paterson, Duncan Sorensen, Ove Yadlosky, John | Size: 9.92 MB | Format:PDF | Quality:Original preprint | Publisher: HDR Engineering, Incorporated | Year: 2012 | pages: 291
Precast concrete bridge rail systems offer several advantages over traditional cast-in-place rail designs, including reduced construction time and costs, installation in a wide range of environmental conditions, easier maintenance and repair, improved railing quality, and greater flexibility for aesthetic treatments. The objective of this project was to develop a precast concrete bridge rail system that met the Test Level 4 impact safety standards provided in the American Association for State Highway and Transportation Officials (AASHTO) document entitled Manual for Assessing Safety Hardware (MASH). The design criteria for the new bridge rail system included criteria for barrier geometry, provisions for open and closed rail options, constructability, weight limitations, segment length, design impact loads, connection of barrier segments, and connection to the bridge deck among other factors. The research effort proceeded in several phases. First, the research focused on determining the overall concept for the new bridge rail system in terms of the rail configuration and geometry as well as the required barrier reinforcement. Next, design concepts for the joints connecting adjacent rail segments were designed and subjected to dynamic component testing in order to select a design capable of meeting design criteria for the precast bridge rail system. After selection of an appropriate rail joint, the researchers developed connection details for the attachment of the rail to the bridge deck. Once the design of the various precast bridge rail components was completed, a complete set of computer-aided design (CAD) details for the prototype precast concrete bridge rail system were completed. Following the design effort, recommendations were made regarding the full-scale testing required to implement the new, precast concrete bridge rail system.
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Phase 1 Development of An Aesthetic Precast Concrete Bridge Rail
Author: Rosenbaugh, Scott K Faller, Ronald K Bielenberg, Robert W Sicking, Dean L Reid, John D | Size: 41.66 MB | Format:PDF | Quality:Original preprint | Publisher: University of Nebraska, Lincoln | Year: 2012 | pages: 360
Precast concrete bridge rail systems offer several advantages over traditional cast-in-place rail designs, including reduced construction time and costs, installation in a wide range of environmental conditions, easier maintenance and repair, improved railing quality, and greater flexibility for aesthetic treatments. The objective of this project was to develop a precast concrete bridge rail system that met the Test Level 4 impact safety standards provided in the American Association for State Highway and Transportation Officials (AASHTO) document entitled Manual for Assessing Safety Hardware (MASH). The design criteria for the new bridge rail system included criteria for barrier geometry, provisions for open and closed rail options, constructability, weight limitations, segment length, design impact loads, connection of barrier segments, and connection to the bridge deck among other factors. The research effort proceeded in several phases. First, the research focused on determining the overall concept for the new bridge rail system in terms of the rail configuration and geometry as well as the required barrier reinforcement. Next, design concepts for the joints connecting adjacent rail segments were designed and subjected to dynamic component testing in order to select a design capable of meeting design criteria for the precast bridge rail system. After selection of an appropriate rail joint, the researchers developed connection details for the attachment of the rail to the bridge deck. Once the design of the various precast bridge rail components was completed, a complete set of computer-aided design (CAD) details for the prototype precast concrete bridge rail system were completed. Following the design effort, recommendations were made regarding the full-scale testing required to implement the new, precast concrete bridge rail system.
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This document contains the Appendices A through D for the report Strength and Durability of Near-Surface Mounted CFRP Bars for Shear Strengthening Reinforced Concrete Bridge Girders published in a separate 123-page document.
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Health Monitoring of Precast Bridge Deck Panels Reinforced with Glass Fiber Reinforced Polymer Bars
Author: Pantelides, Chris P Holden, Korin M Ries, James | Size: 3.88 MB | Format:PDF | Quality:Original preprint | Publisher: University of Utah, Salt Lake City | Year: 2012 | pages: 105
The present research project investigates monitoring concrete precast panels for bridge decks that are reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Due to the lack of long term research on concrete members reinforced with GFRP bars, long term health monitoring is important to record the performance and limit states of the GFRP decks and bridge as a whole. In this research, data is collected on concrete strains, bridge deflections, vertical girder accelerations, as well as initial truck load testing and lifting strains.
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Author: Arneson, L A Zevenbergen, L W Lagasse, P F Clopper, P E | Size: 6.55 MB | Format:PDF | Quality:Original preprint | Publisher: Ayres Associates, Incorporated | Year: 2012 | pages: 340
This document is the fifth edition of HEC-18. It presents the state of knowledge and practice for the design, evaluation and inspection of bridges for scour. There are two companion documents, HEC-20 entitled "Stream Stability at Highway Structures," and HEC-23 entitled "Bridge Scour and Stream Instability Countermeasures." These three documents contain updated material from previous editions and continued research by NCHRP, FHWA, State DOTs, and universities. This fifth edition of HEC-18 also contains revisions obtained from further scour-related developments and the use of the 2001 edition by the highway community. The major changes in the fifth edition of HEC-18 are: expanded discussion on the policy and regulatory basis for the FHWA Scour Program, including risk-based approaches for evaluations, developing Plans of Action (POAs) for scour critical bridges, and expanded discussion on countermeasure design philosophy (new vs. existing bridges). This fifth edition includes: a new section on contraction scour in cohesive materials, an updated abutment scour section, alternative abutment design approaches, alternative procedures for estimating pier scour, and new guidance on pier scour with debris loading. There is a new chapter on soils, rock and geotechnical considerations related to scour. Additional changes include: a new approach for pier scour in coarse material, new sections on pier scour in cohesive materials and pier scour in erodible rock, revised guidance for vertical contraction scour (pressure flow) conditions, guidance for predicting scour at bottomless culverts, deletion of the "General Scour" term, and revised discussion on scour at tidal bridges to reflect material now covered in HEC-25 (2nd Edition).
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Settlement and heave related movements of bridge approach slabs relative to bridge decks create a bump in the roadway. Several problems arise from these bumps, which include poor riding conditions, potential vehicle damage, loss of vehicle control causing injuries or even casualities, lowered perception of the department’s road works, increased maintenance works, and constant delays to rehabilitate the distressed lanes. All these make this bump problem a major maintenance problem in Texas. Several mitigation methods have been employed, and the results are not always satisfactory. In the present research, two treatment methods were investigated for controlling settlements of approach slabs of new bridge construction. Researchers from the University of Texas at Arlington and the University of Texas at El Paso performed two phases to accomplish these studies. During the first phase, the documented information that covers various methods used so far for approach slab settlement mitigation technologies was compiled and presented. The second and final phase focused on field evaluation studies of deep soil mixing and lightweight embankment fill treatment methods in reducing settlements. A few other technologies were also evaluated for reducing settlements of existing bridge approach slabs. Both design and construction specifications of the new methods that provided effective treatments in field conditions are presented.
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This Primer is intended to be a practical supplement to NCHRP Report 534, "Guidelines for Inspection and Strength Evaluation of Suspension Bridge Parallel Wire Cables," and FHWA Report No. FHWA-PD-96-001, titled "Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges." This Primer will serve as an initial resource for those involved in the inspection, metallurgical testing, and strength evaluation of suspension bridge cables in addition to providing necessary documentation for recording performed inspections, testing, and strength evaluations. Furthermore, this document is intended to provide field inspectors, technicians, and/or engineers with the necessary forms and information they need to perform an inspection.
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Posted by: mahyarov - 10-29-2012, 06:27 AM - Forum: Concrete
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Validation of Prestressed Concrete I-Beam Deflection and Camber Estimates
Author: O’Neill, Cullen R French, Catherine E | Size: 3.34 MB | Format:PDF | Quality:Original preprint | Publisher: University of Minnesota, Twin Cities | Year: 2012 | pages: 205
The camber at the time of bridge erection of prestressed concrete bridge girders predicted by the Minnesota Department of Transportation (MnDOT) was observed to often overestimate the measured cambers of girders erected at bridge sites in Minnesota, which, in some cases, was causing significant problems related to the formation of the bridge deck profile, the composite behavior of the girders and bridge deck, delays in construction and increased costs. Extensive historical data was collected from two precasting plants and MN counties and it was found that, on average, the measured cambers at release and erection were only 74% and 83.5%, respectively, of the design values. Through data collection, analysis, and material testing, it was found that the primary causes of the low camber at release were concrete release strengths that exceeded the design values, the use of an equation for concrete elastic modulus that greatly under-predicted the measured values, and thermal prestress losses not accounted for in design. Fourteen girders were instrumented and their camber measured and the program PBEAM was used to evaluate the influence of various time-dependent effects (i.e., solar radiation, relative humidity, concrete creep and shrinkage, length of cure and bunking/storage conditions) on long-term camber. Once investigated, these effects were included in long-term camber predictions that were used to create sets of both time-dependent and singlevalue camber multipliers. The use of these multipliers, along with modifications made to the elastic release camber calculations, greatly reduced the observed discrepancy between measured and design release and erection cambers.
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Posted by: mahyarov - 10-29-2012, 06:25 AM - Forum: Concrete
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Lateral Load Distribution for Steel Beams Supporting an FRP Panel
Author: Poole, Harrison Walker | Size: 3.62 MB | Format:PDF | Quality:Original preprint | Publisher: Kansas State University's Center for Transportation Research | Year: 2012 | pages: 162
Fiber Reinforced Polymer (FRP) is a relatively new material used in the field of civil engineering. FRP is composed of fibers, usually carbon or glass, bonded together using a polymer adhesive and formed into the desired structural shape. Recently, FRP deck panels have been viewed as an attractive alternative to concrete decks when replacing deteriorated bridges. The main advantages of an FRP deck are its weight (roughly 75% lighter than concrete), its high strength-to-weight ratio, and its resistance to deterioration. In bridge design, the American Association of State Highway and Transportation Officials (AASHTO) provides load distributions to be used when determining how much load a longitudinal beam supporting a bridge deck should be designed to hold. Depending on the deck material along with other variables, a different design distribution will be used. Since FRP is a relatively new material used for bridge design, there are no provisions in the AASHTO code that provides a load distribution when designing beams supporting an FRP deck. FRP deck panels, measuring 6 ft x 8.5 ft, were loaded and analyzed at Kansas State University (KSU) over the past 4 years. The research conducted provides insight towards a conservative load distribution to assist engineers in future bridge designs with FRP decks. Two FRP panels were tested using two different support configurations. The continuous panel test was completed throughout the year of 2007 while the simple span and cantilever tests were completed November, 2010 through January, 2011. Load increments of 5 kips from 0 to 20 kips were analyzed in this report. From strain results, load ratios for beams were developed and a distribution ratio for each tests setup was determined. Additional testing was completed on the simple span in order to determine the moment curve for a beam with different loading scenarios. These moment curves provided the researchers with insight that would determine an effective load distribution length of the panel bearing on the supporting beam.
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Posted by: mahyarov - 10-29-2012, 06:22 AM - Forum: Concrete
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Nanotechnology-Based System for Damage-Resistant Concrete Pavements
Author: Al-Rub, Rashid K Abu | Size: 3.97 MB | Format:PDF | Quality:Original preprint | Publisher: Texas A&M University | Year: 2012 | pages: 124
The focus of this study was to explore the use of nanotechnology-based nanofilaments, such as carbon nanotubes (CNTs) and nanofibers (CNFs), as reinforcement for improving the mechanical properties of Portland cement paste and creating multifunctional and sensing concrete. Due to their ultra-high strength and very high aspect ratios, CNTs and CNFs have been excellent reinforcements for enhancing the physical and mechanical properties of polymer, metallic, and ceramic composites. Very little attention has been devoted to exploring the use of nanofilaments in the transportation industry, however. Therefore, this study aimed to bridge the gap between nanofilaments and transportation materials. This was achieved by testing the integration of CNTs and CNFs in ordinary Portland cement paste through state-of-the-art techniques. Different mixes in fixed proportions (e.g., water-to-cement ratio, air content, admixtures) along with varying concentrations of CNTs or CNFs were prepared. Different techniques commonly used for other materials (like polymers) were used in achieving uniform dispersion of nanofilaments in the cement paste matrix and strong nanofilament/cement bonding. Small-scale specimens were prepared for mechanical testing in order to measure the modified mechanical properties as a function of nanofilament concentration, type, and distribution. With 0.1% CNFs, the ultimate strain capacity increased by 142%, the flexural strength increased by 79%, and the fracture toughness increased by 242%. A scanning electron microscope was used to discern the difference between crack bridging and fiber pullout. Test results showed that the strength, ductility, and fracture toughness can be improved with the addition of low concentrations of either CNTs or CNFs.
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