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.