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Book Effect of Diaphragms in Skew Prestressed Concrete Box Girder Bridges microform

Download or read book Effect of Diaphragms in Skew Prestressed Concrete Box Girder Bridges microform written by Gamal Abdel-Aziz Mohamed Ghoneim and published by National Library of Canada. This book was released on 1986 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Steel Diaphragms in Prestressed Concrete Girder Bridges

Download or read book Steel Diaphragms in Prestressed Concrete Girder Bridges written by Robert Emil Abendroth and published by . This book was released on 2004 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Diaphragms in Skew Box Girder Bridges

Download or read book Diaphragms in Skew Box Girder Bridges written by and published by . This book was released on 1988 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper documents a study on the effect of diaphragms on the reactions, internal forces, and behaviour of skew box girder bridges. three different cases were examined: 1) the traditional skew diaphragms, 2) orthogonal diaphragms, and 3) no diaphragms. based on the results of the study, the following conclusions are drawn: 1) diaphragms are not required in skew box girder bridges; 2) in the absence of diaphragms, slab thickness in the end zones should be increased to deal with relatively high transverse moments which develop in the vicinity of the obtuse end supports; 3) eliminating the diaphragms results in more easily constructed boxes and better access to the inside of the box for inspection and installation of utility lines; and 4) orthogonal diaphragms are superior to skew diaphragms, with regards to ease of construction, reduction and simplication of diaphragm reinforcement, and reduction in transverse bending stresses.

Book Lateral Load Resistance of Diaphragms in Prestressed Concrete Girder Bridges

Download or read book Lateral Load Resistance of Diaphragms in Prestressed Concrete Girder Bridges written by R. E. Abendroth and published by . This book was released on 1991 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each year several prestressed concrete girder bridges in Iowa and other states are struck and damaged by vehicles with loads too high to pass under the bridge. Whether or not intermediate diaphragms play a significant role in reducing the effect of these unusual loading conditions has often been a topic of discussion. A study of the effects of the type and location of intermediate diaphragms in prestressed concrete girder bridges when the bridge girder flanges were subjected to various levels of vertical and horizontal loading was undertaken. The purpose of the research was to determine whether steel diaphragms of any conventional configuration can provide adequate protection to minimize the damage to prestressed concrete girders caused by lateral loads, similar to the protection provided by the reinforced concrete intermediate diaphragms presently being used by the Iowa Department of Transportation. The research program conducted and described in this report included the following: A comprehensive literature search and survey questionnaire were undertaken to define the state-of-the-art in the use of intermediate diaphragms in prestressed concrete girder bridges. A full scale, simple span, restressed concrete girder bridge model, containing three beams was constructed and tested with several types of intermediate diaphragms located at the one-third points of the span or at the mid-span. Analytical studies involving a three-dimensional finite element analysis model were used to provide additional information on the behavior of the experimental bridge. The performance of the bridge with no intermediate diaphragms was quite different than that with intermediate diaphragms in place. All intermediate diaphragms tested had some effect in distributing the loads to the slab and other girders, although some diaphragm types performed better than others. The research conducted has indicated that the replacement of the reinforced concrete intermediate diaphragms currently being used in Iowa with structural steel diaphragms may be possible.

Book The Behaviour of Continuous Prestressed Concrete Box Girder Bridges microform

Download or read book The Behaviour of Continuous Prestressed Concrete Box Girder Bridges microform written by Bruce Wilfrid Golley and published by National Library of Canada. This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Behaviour of a Two cell Prestressed Concrete Box Girder Bridge

Download or read book Behaviour of a Two cell Prestressed Concrete Box Girder Bridge written by Amar Khaled and published by . This book was released on 1988 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Barrier Joint and Diaphragm Effects on Force Distribution in Prestressed Concrete Girder Bridges

Download or read book Barrier Joint and Diaphragm Effects on Force Distribution in Prestressed Concrete Girder Bridges written by Jonathan Darren Chipperfield and published by . This book was released on 2010 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The purpose of this research was to create two finite element models (FEM) using ANSYS 11.0 and calibrate them to the measured test results. After the calibrated models were validated a parametric study was performed comparing the effects of secondary elements on live load distribution. Included in this parametric study are the effects of the barrier, the barrier joint, and the diaphragms, on the girders, both interior and exterior. The results of this project show the effects of secondary elements and whether they are localized or global on the longitudinal span of the bridge, as well as tell how the live load is being distributed. Also, for load testing, recommendations on placement of strain gages will be discussed.

Book Adjacent Precast Prestressed Concrete Box Girder Bridges Transversely Post tensioned at Top Flanges Only

Download or read book Adjacent Precast Prestressed Concrete Box Girder Bridges Transversely Post tensioned at Top Flanges Only written by Shady Nasry Badie Labib and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adjacent precast, prestressed concrete box girders are widely used in short and medium span bridges in North America. Adjacent box girders are connected at their interface using partial- or full-depth grouted shear keys. Typically, transverse post-tensioning (TPT) is applied through diaphragms at discrete locations along the bridge span to improve the transverse load distribution and control differential deflections. Nevertheless, diaphragms only reduce the differential deflection between girders and do not eliminate it. In addition, the provision of transverse diaphragms is associated with an increased cost and time. The main objective of this research program is to investigate the feasibility of eliminating the transverse diaphragms by applying TPT in the top flange of the girders. The effect of applying TPT in the top flange of the girders, instead of being accommodated in discrete rigid diaphragms, on the transverse load distribution is studied. The research program comprised two phases: experimental and numerical. The experimental phase consisted of four different tests on a one-third scale bridge model, (1) Strain distribution test - uncracked shear key, (2) Load distribution test - uncracked shear key, (3) Load distribution test - cracked shear key, and (4) Ultimate load test. On the other hand, the numerical phase included the construction of a finite element model (FEM) to validate the experimental results of the tested bridge. The validated FEM was then used to study the influence of varying several parameters including the presence of concrete topping, wheel load location and the width of the bridge on the transverse load distribution behavior of box girder bridges. Results demonstrated the efficiency of distributing the TPT force at a shorter spacing along the length of the bridge in producing the minimum required concrete prestress. In addition, the influence of TPT force and spacing on the transverse load distribution behavior was found insignificant during the simulated service condition (fully-intact or partially-cracked shear keys). However, at failure, the presence of TPT added redundancy to the bridge model and mitigated any sudden failure when shear keys were fully cracked. Furthermore, the presence of concrete topping reduced mid-span deflection up to 25%.

Book Assessing the Needs for Intermediate Diaphragms in Prestressed Concrete Bridges

Download or read book Assessing the Needs for Intermediate Diaphragms in Prestressed Concrete Bridges written by and published by . This book was released on 2008 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reinforced concrete Intermediate Diaphragms (IDs) are currently being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed in the bridge community because the use of IDs increases the cost and time of construction. There is no consistency in the practice of providing IDs among various states and codes of practice, and the overall effectiveness of IDs, as well as the need for them in prestressed concrete bridges, is unclear. The objectives of this research were (1) to assess the need of reinforced concrete (RC) IDs in PC girder bridges and to determine their effectiveness, and (2) to search for a possible alternative steel diaphragm configuration that could replace concrete diaphragms if necessary. The research team has examined and reviewed state-of-the-art technology and current practices from many sources of information on IDs. Through a survey questionnaire and review of the Louisiana Department of Transportation and Development (LADOTD) Bridge Design Manual, the research team obtained relevant information regarding the ID practices in Louisiana. Through the LADOTD data base for all state bridges, and from direct interaction with district engineers, several of the bridges that are of interest for this study were selected for field inspection. From these field trips to various bridge locations, much information has been acquired from the bridges themselves, as well as from the district engineers. Systematic parametric studies for various bridge configurations, which are representative of an entire range of bridge geometries with different parameters, were analyzed through simplified and solid finite element models. This study was performed on right and skewed bridges, which are simply supported and continuous. A reduction factor that could be multiplied by the AASHTO load distribution factor to account for the influence of the diaphragm in load distribution was developed. A finite element analysis was carried out using 3-D solid models to assess the effectiveness of various diaphragms in protecting the girders against the lateral impact and to determine the design forces in the steel bracing members during construction of deck. The results from the parametric studies indicated that several parameters such as skew, span length, spacing, stiffness of diaphragm and girder have different levels of influence on the effectiveness of diaphragms in live load distribution for bridges. Correction factors that could quantify the ID influence on load distribution were developed. Results from various studies indicated that a steel diaphragm section can possibly replace the RC diaphragms. A prestressed concrete bridge was tested in the field. This bridge was selected by an inspection team comprised of personnel from FHWA, LADOTD, and the LSU research team and is located over Cypress Bayou on LA 408 East, in District 61. A comprehensive instrumentation and loading scheme is presented and illustrated in this report. The instrumentation consists of LVDTs - Linear Variable Differential Transformers (to measure the midspan deflection of each girder), accelerometers, strain gauges, and acoustic emission sensors. The measured results are presented, and comparisons are made between the finite element model and the field tests.

Book Lateral Impact Response for Prestressed Concrete Girder Bridges with Intermediate Diaphragms

Download or read book Lateral Impact Response for Prestressed Concrete Girder Bridges with Intermediate Diaphragms written by Bassem Onsi Andrawes and published by . This book was released on 2001 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each model was analyzed with either one RC or two different types of steel intermediate diaphragms. The bridge models were analyzed for a lateral impact load applied at different locations along the bottom flange of an exterior girder. A comparison was made between the induced strains and displacements in the girders for each diaphragm case. This study revealed that intermediate diaphragms have an effect on reducing girder damage in PC girder bridges. When a lateral impact load was applied at a diaphragm location, the RC diaphragm provided more damage protection for the girders than that provided by either of the two selected steel diaphragms. The three types of diaphragms studied essentially provided the same degree of damage protection when a lateral impact load was applied away from a diaphragm location.