Download or read book Improved Load Rating of Reinforced Concrete Slab Bridges written by David Villegas Jãuregui and published by . This book was released on 2007 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diagnostic testing for improved load rating of reinforced concrete slab bridges written by Loyl Clyde Bussell and published by . This book was released on 1997 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Load Distribution and Rating Assessment of Variable Depth Continuous Slab Bridges written by Ahmadudin Burhani and published by . This book was released on 2021 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many in-service reinforced concrete slab bridges in the United States have thicknesses that change along the span, leading to variation in flexural rigidity. Despite being commonly used, determining their live load carrying capacity has remained routinely uncertain. The variabilities are often ignored, and typical programs, such as AASHTOWare Bridge Rating (BrR), are used to assess such bridges’ structural capacity. In turn, this resulted in the entire analysis being subjected to erroneous results. Moreover, many of these structures are susceptible to weight restrictions due to shortened termination of reinforcements used in the negative moment regions. It is not always clear to which degree the reinforcement length affects such bridges’ structural capacity. It is also uncertain whether other parameters, such as bridge geometry, play role in improving the structural capacity. The objective of this study was to use experimental results and three-dimensional finite element simulations to assess the structural capacity of LOG-47-1184, a concrete highway bridge in Ohio that has four lanes and three consecutive spans of varying thickness and is subject to load restrictions. The study further provides an appropriate development length that satisfies different levels of section variability. The effect of the bridge’s geometry on the reinforcement was investigated. The experimental response of the bridge was determined, and results were used to calculate sets of load rating factors (LRFs) and to validate a three-dimensional finite element model (FEM). A detailed rating analysis found LRFs using the FEM were greater than those from Midas Civil, which in turn were greater than those from the legacy BrR program used by the Ohio Department of Transportation. The ratios of the BrR LRFs to the other procedure were generally constant across multiple test truck load configurations, with less than 4% variation for BrR/Midas Civil and about 25% for BrR/FEM. The LRFs from the FEM satisfied the operating checks and all LRFs exceeded one; therefore, no load restriction posting was required for the bridge. As a result, this study suggests that similar bridges that are susceptible to load restrictions based on the BrR outputs might have adequate structural capacity. Subsequently, it was found that the haunching increased force effects over intermediate supports, which in turn required longer development length. A total reasonable length was determined to be 4L/7, which can be extended on either side of intermediate supports. The FEM simulations underestimated AASHTO LRFD requirements by an average of 40%. Under HL-93 load configurations and using the LRFR approach, all LRFs exceeded one and satisfied the operating rating checks. The LRFs improved by 30% when the skew angle exceeded 15o as compared with 0o and reached 61% with the skew angle of 30o.
Download or read book Development of Improved Analytical Load Rating Procedures for Flat slab Concrete Bridges written by Timothy J. Poulin and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Procedure for Load Rating Reinforced Concrete Slab Bridges Without Plans written by Alain Michael Cuaron and published by . This book was released on 2016 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridges without plans are a problem in the state of New Mexico since standard bridge load rating techniques cannot be used due to the lack of design plans and documentation that contains the required information such as the amount and location of the reinforcement. A research project was conducted for the New Mexico Department of Transportation (NMDOT) to provide an effective method to load rate reinforced concrete slab bridges without plans using both structural analysis and non-destructive experimental techniques. This thesis presents the evaluation of two simple-span and two continuous-span reinforced concrete slab bridges. Bridge 8486 is a simple-span reinforced concrete slab bridge located in Albuquerque, NM. The bridge was built in 1984. According to the most current bridge inspection report for the bridge, the bridge had a satisfactory condition rating for the deck and superstructure and a good condition rating for the substructure. The bottom reinforcement layout was determined using a Hilti Ferroscan along with an AASHTO-based required steel area estimate while the material properties were determined based on the age of the bridge. The final load ratings from an AASHTOWare BrR analysis show that Bridge 8486 is capable of carrying an HS-20 vehicle safely. Bridge 8282 is a simple-span reinforced concrete slab that was built in 1976. The bridge is located in Albuquerque, NM. The bridge has a satisfactory condition rating for the deck and superstructure while the substructure was given a fair condition rating based on the most current bridge inspection report. The bottom reinforcement layout and material properties were estimated similarly to Bridge 8486. The final BrR load ratings show that the bridge has a load carrying capacity that can safely carry an HS-20 vehicle. Bridge 8827 is a three-span continuous reinforced concrete slab bridge. The bridge was built in 1991 in Albuquerque, NM. The deck, superstructure and substructure were given a fair condition rating in the most current bridge inspection report. Like Bridge 8486 and Bridge 8282, the bottom reinforcement was estimated using a Hilti Ferroscan, however, the scanner did not provide enough data to estimate the top reinforcement layout. Therefore, the top reinforcement layout was estimated using a combination of AASHTO, a top to bottom steel area ratio assumption (i.e., steel area for the top of the slab above the pier is 10% larger than the bottom steel area at midspan), and the Hilti Ferroscan results. Based on the final BrR load ratings, the bridge can carry an HS-20 vehicle safely. Bridge 7489 is a two-span continuous reinforced concrete slab bridge. The bridge was built in 1964 in Albuquerque, NM. The bridge had satisfactory condition ratings for the deck, superstructure, and substructure. The bottom and top reinforcement layout were estimated using the Hilti Ferroscan along with the required steel area estimation following AASHTO. The bridge load rating from BrR showed that the bridge could carry an HS-20 vehicle.
Download or read book Higher Level Load Rating of a Reinforced Concrete Slab Bridge with Barriers written by Kundan Kulkarni and published by . This book was released on 2007 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Characteristics of In Service Bridges for Enhancing Load Ratings Leveraging Refined Analysis Methods written by Devin K. Harris and published by . This book was released on 2021 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge load rating assesses the safe live load carrying capacity of an existing or newly designed structure. In addition to load rating with previously defined standard load rating vehicles, the Federal Highway Administration issued additional guidance to states related to rating requirements for all the bridges with respect to specialized hauling vehicles and emergency vehicles that must be met by the end of 2022. It is recognized that the load effects (bending moment and shear) produced by these vehicle types on certain bridge types and spans might be greater than those caused by the previous rating vehicles. Therefore, a number of bridges within VDOT’s inventory may require posting when rated with these specialized vehicles. The goal of this study was to assess the likelihood of an increase in load rating factors through refined analysis methods for the bridge classes potentially vulnerable to load ratings under consideration of the new federal regulations and when using conventional, simplified equations for load distribution factors. In particular, the study focused on the evaluation of live load distribution factors for girder bridges and effective widths for distributing live loads in slab bridges through refined analysis. Three bridge classes (simple span steel girder bridges, reinforced concrete T-beam bridges, and concrete slab bridges) were selected for this refined analysis. Girder bridges were modeled using the plate-with-an-eccentric-beam analysis approach, while plate elements were used to model slab bridges within the LARSA 4D software package. The selected modeling approaches were validated through the simulation of the bridge structures with available field-testing results from the literature. A total of 71 in-service bridges belonging to the three selected bridge classes were then modeled and analyzed to compute the load distribution factors for girder bridges or effective widths for slab bridges, and the results were compared with those obtained from the code-specified equations. Using the data obtained from these numerical simulations, a series of multi-parameter linear regression models were developed to predict the percent change in distribution factor and effective width, respectively, for girder and slab bridges with different geometrical characteristics if a refined method analysis is implemented. The regression models were limited to four parameters such that the results from regression models could be presented in table format. The developed tables should be used as screening tools to provide guidance on the use of refined methods of analysis to improve the load ratings of bridges vulnerable to posting from previously existing load rating classifications as well as the recently introduced vehicles. Should VDOT use refined methods of analysis, there is good potential that the agency can avoid posting a substantial portion of its inventory, saving resources for more critical needs while safely keeping Virginia’s bridges open for commerce and the traveling public
Download or read book A Comparison of AASHTO Bridge Load Rating Methods written by Mark Mlynarski and published by Transportation Research Board. This book was released on 2011 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB’s National Cooperative Highway Research Program (NCHRP) Report 700: A Comparison of AASHTO Bridge Load Rating Methods documents an analysis of 1,500 bridges that represent various material types and configurations using AASHTOWareTM Virtis® to compare the load factor rating to load and resistance factor rating for both moment and shear induced by design vehicles, American Association of State Highway and Transportation Officials (AASHTO) legal loads, and eight additional permit/legal vehicles.
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.
Download or read book Estimating the Load Rating of Reinforced Concrete Bridges Without Plans written by Edgardo Ruiz and published by . This book was released on 2020 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are over 250,000 reinforced concrete bridges in the U.S. many of which do not have a load rating on record nor the plans required to perform the calculations. The U.S. Army owns and maintains hundreds of these bridges throughout the U.S. This dissertation describes the development of multiple regression models to estimate the load rating of reinforced concrete bridges. An exploratory data analysis of the 2017 NBI data was performed for the selection of a representative data sample. The data was found to have multiple errors and required significant processing in order to extract a reliable sample for modeling. After processing, a data sample of 31,112 bridges remained, providing sufficient sample for model training and testing. A six-variable model (Model A) was determined to provide the best performance while maintaining a desired low level of complexity. The model was tested by comparing the percentage of cases that fell within its 95% prediction interval, which resulted in 94.9% of the real values falling within the prediction interval. Given the concerns that arose of the quality of the 2017 NBI data during its exploration, as built-drawings from 50 slab bridges throughout the U.S. were collected. With these drawings a new data sample was generated by calculating the load rating of each bridge. Availability of the as-built drawings provided the opportunity to investigate other variables not available in the 2017 NBI, most notably the slab thickness. This data sample was significantly smaller than the previous one, therefore a repeated 10-fold cross-validation approach was taken to evaluate model performance. It was determined that a five-variable model (Model B) provided the best trade-off between complexity and performance. Model B performed significantly better than Model A due to the inclusion of the slab thickness variable. The models presented in this dissertation provide a valuable tool for reinforced concrete bridge owners tasked with the assigning a load rating when no structural plans are available helping.
Download or read book Rapid Strengthening of Reinforced Concrete Bridges written by and published by . This book was released on 2002 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Load Test for the Evaluation and Rating of Short span Reinforced Concrete Slab Bridges written by Amy Eitel and published by . This book was released on 2002 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: There exists in the state of Ohio a large inventory of short span reinforced concrete bridges, particularly on rural secondary highways, whose actual structural reliability cannot be accurately ascertained. Quite often little or no documentation exists to assist the responsible local jurisdictions in assessing the ability of these bridges to safely carry modern truck loading.
Download or read book Strength and Serviceability Criteria Reinforced Concrete Bridge Members written by E. G. Paulet and published by . This book was released on 1966 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluating Bridge Performance Load Rating Bridges Without Plans and Experimental Displacement Influence Lines written by Jun Huang and published by . This book was released on 2007 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the best alternatives for bridges which need accurate load rating, is through field testing. Presented in this dissertation are two studies on evaluating the performance of bridges based on the results of a diagnostic load test. The first topic is focused on load rating bridges without plans using the results of a diagnostic test. The second topic is focused on utilizing measured displacements from a field test to evaluate the bridge performance.
Download or read book Strength Evaluation of Existing Reinforced Concrete Bridges written by Roy A. Imbsen and published by Transportation Research Board National Research. This book was released on 1987 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Manual for Bridge Evaluation written by American Association of State Highway and Transportation Officials. Subcommittee on Bridges and Structures and published by AASHTO. This book was released on 2011 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bridge Load Rating written by Rafael Armendariz and published by . This book was released on 2018-08-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The inspection and evaluation of bridges in Indiana is critical to ensure their safety to better serve the citizens of the state. Part of this evaluation includes bridge load rating. Bridge load rating, which is a measure of the safe load capacity of the bridge, is a logical process that is typically conducted by utilizing critical information that is available on the bridge plans. For existing, poorly-documented bridges, however, the load rating process becomes challenging to adequately complete because of the missing bridge information. Currently, the Indiana Department of Transportation (INDOT) does not have a prescribed methodology for such bridges. In an effort to improve Indiana load rating practices INDOT commissioned this study to develop a general procedure for load rating bridges without plans. The general procedure was developed and it was concluded that it requires four critical parts. These parts are bridge characterization, bridge database, field survey and inspection, and bridge load rating. The proposed procedure was then evaluated on two bridges in Indiana that do not have plans as a proof of concept. As a result, it was concluded that load rating of bridges without plans can be successfully completed using the general procedure. A flowchart describing the general procedure was created to make the load rating process more user-friendly. Additional flowcharts that summarize the general procedure for different type of bridges were also provided.
