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Book Development of a Rational Design Method for Shear Keys at In span Hinges in Multi frame Highway Bridges A rational seismic analysis method for in span hinge shear keys

Download or read book Development of a Rational Design Method for Shear Keys at In span Hinges in Multi frame Highway Bridges A rational seismic analysis method for in span hinge shear keys written by Masoud Mehr and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Time dependent Deflection of In span Hinges in Prestressed Concrete Box Girder Bridges

Download or read book Time dependent Deflection of In span Hinges in Prestressed Concrete Box Girder Bridges written by Ahmed Akl and published by . This book was released on 2015 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Post-tensioned multi-cell reinforced concrete bridges with in-span hinges in California have been experiencing undesirable and unexpected differential movements at expansion joints during and after construction. The deformation of in-span hinges in cast-in-place (CIP) prestressed concrete (PS) box girder bridges is referred to as "hinge curl" and is due to post tensioning forces. The difference between the elevations of the two sides of the hinge creates a bump on the road and presents a road hazard with risk to the travelling public safety. Accurate prediction of instantaneous and time-dependent deformation of superstructure in-span hinges is important to avoid mismatch at the intermediate expansion joints of bridges. A method to estimate hinge curl was developed by the California Department of Transportation (Caltrans) through Memo to Designers (MTD) No. 11-34 and has been used in design. However, this method often leads to estimate of deformations that are different from those in the field. Hence, grinding of the superstructure at the hinge and other remedial measures are often necessary, and this results in extra cost and delay. The principal aims of this study was to evaluate the MTD method based on field measurements and analytical studies, identify the extent and sources of discrepancy between the estimated and actual "hinge curl" deflections, and propose a new method to more accurately estimate short-term and long-term hinge curl. The research presented in this dissertation consisted of six parts: (1) field measurement of hinge movements in five bridges, (2) analysis of data and comparison with the estimated movements using the current method, (3) analytical studies of the five bridges using relative simple models utilizing software package SAP2000, (4) analytical studies of the five bridges using detailed finite element models utilizing ABAQUS, (5) analytical parametric studies of the effect of superstructure skew at abutments and horizontal curvature on the hinge curl, and (6) development of a new, practical method to improve on estimation of hinge curl. Deflections of superstructures were measured and monitored for five bridges in the state of California during construction until bridges were opened to traffic. Temperature and relative humidity data were also collected during field measurements. The field data were analyzed and the correlation with the current method for estimating hinge curl was investigated. Hinge curls were estimated according to Caltrans MTD 11-34 with the aid of computer models developed using CTBridge software. Substantial differences between the field data and estimated hinge curls were noted due to the inaccurate boundary condition assumption and other issues determined in the current design equations. Analytical studies were conducted using two modelling approaches, stick model and finite element model, to further investigate the deformation behavior of the bridges. SAP2000 was utilized for the first modelling approach and a more sophisticated program, ABAQUS, was utilized for the second approach to capture the three-dimensional deformation behavior. Construction sequence and material time-dependent effects were modelled in both approaches. Parametric studies of the effect of skewed abutments and horizontal curvature on hinge curl were performed using the finite element approach on ABAQUS. A new method was developed for estimating the immediate hinge curl. Modifications of the time-dependent deflection multipliers were proposed to improve prediction of the long term hinge curl. Hinge curls were calculated according to the proposed method and compared to those measured for verification. The study validated the applicability of the proposed method for hinge curl prediction. The new method and the modifications were summarized in addition to a design example in a new proposed document with MTD format to facilitate adoption of the new method by Caltrans.

Book Integrated Numerical and Field Approachs to Improve Bridge Designs

Download or read book Integrated Numerical and Field Approachs to Improve Bridge Designs written by Inmar Badwan and published by . This book was released on 2005 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Bridge design codes provide a set of technical requirements for safe and acceptable design. However, several design requirements need evaluation and field verification to asses their accuracy. Those associated with the full-depth shear key joints in multi-beam decks, load distribution in highly skew continuous bridges, and permit load bridge rating are reviewed in the context. Multi-beam decks can be made by precast units that are post-tensioned together with shear keys and transverse post-tensioning. The performance of the longitudinal joints with regards to load transfer and water tightness is one of the design features of interest. To transfer load between the adjacent units, the joints are filled with grout material. The transverse post-tensioning stress is employed to prevent excessive opening of these joints. Live load tests on multi-beam bridge were performed to obtain actual load distribution data. The study presents the test results and an associated finite element analyses. A simplified method based upon grillage analogy is developed to quantify required transverse post-tensioning stresses in the longitudinal joints. The efficiency of the joints was evaluated by comparing with a hypothetical monolithic slab structure and by the distribution of loads in the transverse direction. The post-tensioning stresses as calculated according to the method were compared with the requirements of the AASHTO LRFD provisions. Estimation of the span and support moment is required to develop a realistic design for skew continuous bridges. Distribution factors recommended by the code provide convenience and simplistic methods to calculate the moments on bridge girders. Refined formulas for estimating the load distribution factors are provided in the current AASHTO LRFD Bridge Design Specifications. A considerable amount of literature is available on field verification studies of right angle steel girder bridges; however studies on highly skew bridges are relatively limited. Previous studies on highly skew bridges have verified the distribution characteristics either analytically or experimentally using prototype bridges. The current study presents a live load field test carried out on a 60-degree skew three-span continuous steel girder bridge. The results are used to derive quantitative information regarding the actual transverse load distribution characteristics of the bridge to asses the accuracy of the current methods. To account for the application of overloads, the LRFR permit load rating was modified by introducing the fatigue damage of overloads. The study used a modification factor referred to as the fatigue index to point to the damage causing effect of overloads. A method is developed to calculate the modification factor. The method considers the fatigue damage that may be caused by overloads as well as the stresses induced by normal traffic. The approach assumes that fatigue index for a specific overload is proportional to the total number of stress cycles required to increase the crack size to the crack threshold at stress induced by normal traffic. The number represents the overload stress cycles that would produce a crack size at which normal traffic stress cycle is able to contribute to the crack growth. The fatigue index as determined by the method reflects the severity of an overload and its potential for causing fatigue damage."--P. iii-iv.

Book Evaluation of Improved Shear Key Designs for Multi beam Box Girder Bridges

Download or read book Evaluation of Improved Shear Key Designs for Multi beam Box Girder Bridges written by and published by . This book was released on 1997 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory tests were conducted to investigate the problem of shear key failure in multi-beam prestressed box girder bridges and to propose a new shear key design. Failure of shear keys will typically not only compromise the load-sharing mechanism between adjacent girders, but also may lead to the failure of the deck waterproofing system, with attendant corrosion problems. The tests consisted of monitoring relative displacements occurring across intergirder joints, produced by a simulated concentrated wheel load.

Book Intermediate Expansion Hinges in Multiple span Rigid Frame Bridges

Download or read book Intermediate Expansion Hinges in Multiple span Rigid Frame Bridges written by Dan Henry Pletta and published by . This book was released on 1938 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Strengthening of an Existing Continuous span Steel stringer Concrete deck Bridge

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 AASHTO Guide Specifications for LRFD Seismic Bridge Design

Download or read book AASHTO Guide Specifications for LRFD Seismic Bridge Design written by and published by AASHTO. This book was released on 2011 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work offers guidance on bridge design for extreme events induced by human beings. This document provides the designer with information on the response of concrete bridge columns subjected to blast loads as well as blast-resistant design and detailing guidelines and analytical models of blast load distribution. The content of this guideline should be considered in situations where resisting blast loads is deemed warranted by the owner or designer.

Book Guide Specifications for Seismic Isolation Design

Download or read book Guide Specifications for Seismic Isolation Design written by and published by AASHTO. This book was released on 2010 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edition is based on the work of NCHRP project 20-7, task 262 and updates the 2nd (1999) edition -- P. ix.

Book Engineering for Structural Stability in Bridge Construction

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

Book Recommended Seismic Design Criteria for New Steel Moment Frame Buildings FEMA 350

Download or read book Recommended Seismic Design Criteria for New Steel Moment Frame Buildings FEMA 350 written by Federal Emergency Agency and published by FEMA. This book was released on 2013-03-16 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report, FEMA-350 - Recommended Seismic Design Criteria for New Steel Moment-Frame Buildings has been developed by the SAC Joint Venture under contract to the Federal Emergency Management Agency (FEMA) to provide organizations engaged in the development of consensus design standards and building code provisions with recommended criteria for the design and construction of new buildings incorporating moment-resisting steel frame construction to resist the effects of earthquakes. It is one of a series of companion publications addressing the issue of the seismic performance of steel moment-frame buildings. The set of companion publications includes: FEMA-350 - Recommended Seismic Design Criteria for New Steel Moment-Frame Buildings. This publication provides recommended criteria, supplemental to FEMA-302 - 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, for the design and construction of steel moment-frame buildings and provides alternative performance-based design criteria. FEMA-351 - Recommended Seismic Evaluation and Upgrade Criteria for Existing Welded Steel Moment-Frame Buildings. This publication provides recommended methods to evaluate the probable performance of existing steel moment-frame buildings in future earthquakes and to retrofit these buildings for improved performance. FEMA-352 - Recommended Postearthquake Evaluation and Repair Criteria for Welded Steel Moment-Frame Buildings. This publication provides recommendations for performing postearthquake inspections to detect damage in steel moment-frame buildings following an earthquake, evaluating the damaged buildings to determine their safety in the postearthquake environment, and repairing damaged buildings. FEMA-353 - Recommended Specifications and Quality Assurance Guidelines for Steel Moment-Frame Construction for Seismic Applications. This publication provides recommended specifications for the fabrication and erection of steel moment frames for seismic applications. The recommended design criteria contained in the other companion documents are based on the material and workmanship standards contained in this document, which also includes discussion of the basis for the quality control and quality assurance criteria contained in the recommended specifications. The information contained in these recommended design criteria, hereinafter referred to as Recommended Criteria, is presented in the form of specific design and performance evaluation procedures together with supporting commentary explaining part of the basis for these recommendations.

Book Performance based Seismic Bridge Design

Download or read book Performance based Seismic Bridge Design written by M. Lee Marsh and published by Transportation Research Board. This book was released on 2013 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 440, Performance-Based Seismic Bridge Design (PBSD) summarizes the current state of knowledge and practice for PBSD. PBSD is the process that links decision making for facility design with seismic input, facility response, and potential facility damage. The goal of PBSD is to provide decision makers and stakeholders with data that will enable them to allocate resources for construction based on levels of desired seismic performance"--Publisher's description.

Book Design of Highway Bridges

Download or read book Design of Highway Bridges written by Richard M. Barker and published by John Wiley & Sons. This book was released on 2013-02-04 with total page 1194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Up-to-date coverage of bridge design and analysis revised to reflect the fifth edition of the AASHTO LRFD specifications Design of Highway Bridges, Third Edition offers detailed coverage of engineering basics for the design of short- and medium-span bridges. Revised to conform with the latest fifth edition of the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications, it is an excellent engineering resource for both professionals and students. This updated edition has been reorganized throughout, spreading the material into twenty shorter, more focused chapters that make information even easier to find and navigate. It also features: Expanded coverage of computer modeling, calibration of service limit states, rigid method system analysis, and concrete shear Information on key bridge types, selection principles, and aesthetic issues Dozens of worked problems that allow techniques to be applied to real-world problems and design specifications A new color insert of bridge photographs, including examples of historical and aesthetic significance New coverage of the "green" aspects of recycled steel Selected references for further study From gaining a quick familiarity with the AASHTO LRFD specifications to seeking broader guidance on highway bridge design Design of Highway Bridges is the one-stop, ready reference that puts information at your fingertips, while also serving as an excellent study guide and reference for the U.S. Professional Engineering Examination.