Download or read book Evaluation of Passive Force Behavior for Bridge Abutments Using Large scale Tests with Various Backfill Geometries written by Jaycee Cornwall Smith and published by . This book was released on 2014 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge abutments are designed to withstand lateral pressures from thermal expansion and seismic forces. Current design curves have been seen to dangerously over- and under-estimate the peak passive resistance and corresponding deflection of abutment backfills. Similar studies on passive pressure have shown that passive resistance changes with different types of constructed backfills. The effects of changing the length to width ratio, or including MSE wingwalls determine passive force-deflection relationships. The purpose of this study is to determine the effects of the wall heights and of the MSE support on passive pressure and backfill failure, and to compare the field results with various predictive methods.

Download or read book Evaluation of Passive Force on Skewed Bridge Abutments with Large scale Tests written by Aaron Kirt Marsh and published by . This book was released on 2013 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force versus backwall deflection relationship. Current design codes make no allowances for skew effects on the development of the passive force. However, small-scale experimental results and available numerical models indicate that there is a significant reduction in peak passive force as skew angle increases for plane-strain cases. To further explore this issue large-scale field tests were conducted at skew angles of 0°, 15°, and 30° with unconfined backfill geometry. The abutment backwall was 11 feet (3.35-m) wide by 5.5 feet (1.68-m) high, and backfill material consisted of dense compacted sand. The peak passive force for the 15° and 30° tests was found to be 73% and 58%, respectively, of the peak passive force for the 0° test which is in good agreement with the small-scale laboratory tests and numerical model results. However, the small differences may suggest that backfill properties (e.g. geometry and density) may have some slight effect on the reduction in peak passive force with respect to skew angle. Longitudinal displacement of the backfill at the peak passive force was found to be approximately 3% of the backfill height for all field tests and is consistent with previously reported values for large-scale passive force-deflection tests, though skew angle may slightly reduce the deflection necessary to reach backfill failure. The backfill failure mechanism appears to transition from a log spiral type failure mechanism where Prandtl and Rankine failure zones develop at low skew angles, to a failure mechanism where a Prandtl failure zone does not develop as skew angle increases.

Download or read book Large scale Testing of Passive Force Behavior for Skewed Bridge Abutments with Gravel and Geosynthetic Reinforced Soil GRS Backfills written by Amy Fredrickson and published by . This book was released on 2015 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Test results in both sets of backfills confirmed previous findings that there is significant reduction in passive force with skewed abutment configurations. The reduction factor was 0.58 for the gravel backfill and 0.63 for the GRS backfill, compared to the predicted reduction factor of 0.53 for a 30° skew. These results are within the scatter of previous skewed testing, but could indicate that slightly higher reduction factors may be applicable for gravel backfills.

Download or read book Passive Force deflection Behavior for Abutments with MSE Confined Approach Fills written by Kyle M. Rollins and published by . This book was released on 2010 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approach fills behind bridge abutments are commonly supported by wrap-around mechanically stabilized earth (MSE) walls; however the effect of this geometry on passive force development is unknown. This report describes the first large-scale tests to evaluate passive force-deflection curves for abutments with MSE wingwalls. A test was also performed with fill extending beyond the edge of the abutment wall for comparison. The abutment wall was simulated with a pile supported cap 5.5 ft high, 11 ft wide, and 15 ft long in the direction of loading. The backfill behind the pile cap consisted of clean sand compacted to 96% of the modified Proctor maximum density. As the pile cap was loaded laterally, pressure on the MSE wall led to pull-out of the steel reinforcing grids and the MSE wall panels moved outward about 2% of the wall height when the ultimate passive force developed. Despite pullout, the passive force per effective width was 28 kips/ft for the pile cap with MSE wingwalls compared to 22.5 kips/ft for the cap without wingwalls. Nevertheless, the passive force with the MSE wingwalls was still only 76% of the resistance provided by the cap with fill extending beyond the edges. The pile cap with MSE walls required greater movement to reach the ultimate passive force (deflection of 4.2% of wall height vs. 3%). The Caltrans method provided good agreement with the measured passive resistance while the log spiral method required the use of a higher plane strain friction angle to provide reasonable agreement.

Download or read book Large scale Testing of Passive Force Behavior for Skewed Abutments with High Width height Ratios written by Katie Noel Palmer and published by . This book was released on 2013 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of seismic forces and thermal expansion on bridge performance necessitate an accurate understanding of the relationship between passive force and backwall deflection. In past case studies, skewed bridges exhibited significantly more damage than non-skewed bridges. These findings prompted studies involving numerical modeling, lab-scales tests, and large-scale tests that each showed a dramatic reduction in passive force with increased skew. Using these results, a correlation was developed between peak passive force and backwall skew angle. The majority of these tests had length to height ratios of 2.0; however, for several abutments in the field, the length to height ratio might be considerably higher than 2.0. This change in geometry could potentially affect the validity of the previously found passive force reduction correlation.

Download or read book Evaluation of Passive Force on Skewed Bridge Abutments with Controlled Low strength Material Backfill written by Kevin Bjorn Wagstaff and published by . This book was released on 2016 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: To determine the relationship of passive force versus backwall displacement for a CLSM backfilled bridge abutment, two laboratory large-scale lateral load tests were conducted at skew angles of 0 and 30°. The model backwall was a 4.13 ft (1.26 m) wide and 2 ft (0.61 m) tall reinforced concrete block skewed to either 0 or 30°. The passive force-displacement curves for the two tests were hyperbolic in shape, and the displacement required to reach the peak passive resistance was approximately 0.75-2% of the wall height. The effect of skew angle on the magnitude of passive resistance in the CLSM backfill was much less significant than for conventional backfill materials. However, within displacements of 4-5% of the backwall height, the passive force-displacement curve reached a relatively constant residual or ultimate strength. The residual strength ranged from 20-40% of the measured peak passive resistance. The failure plane did not follow the logarithmic spiral pattern as the conventional backfill materials did. Instead, the failure plane was nearly linear and the failed wedge was displaced more like a block with very low compressive strains.

Download or read book Passive Force on Skewed Bridge Abutments with Reinforced Concrete Wingwalls Based on Large scale Tests written by Kyle M. Smith and published by . This book was released on 2014 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comparison of passive force per unit width suggests that MSE wall abutments provide 60% more passive resistance per unit width compared to reinforced concrete wingwall and unconfined abutment geometries at zero skew. These findings suggest that changes should be made to current codes and practices to properly account for skew angle in bridge design.

Download or read book Large Scale Bridge Abutment Tests to Determine Stiffness and Ultimate Strength Under Seismic Loading written by Brian H. Maroney and published by . This book was released on 1995 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Structure Backfill on Stiffness and Capacity of Bridge Abutments written by Azadeh Bozorgzadeh and published by . This book was released on 2007 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge abutments provide resistance to deformation and earthquake induced inertial forces from the bridge superstructure. In order to limit the inertial forces transmitted into the abutment walls and piles, the abutment walls are designed to be sheared off in major seismic events. Therefore, the force-resistance mechanism of bridge abutments in the longitudinal direction is mainly provided by backwall-soil interaction. Current design practice in California makes use of bi-linear load-deformation curve and does not account for the structure backfill properties. An experimental and an analytical research program were conducted at UCSD to further investigate such structure backfill interaction characteristics. In order to meet the objectives of this research project, a field investigation was conducted to develop a proper characterization of the soil types used for abutment structure backfills. The experimental program included five large-scale tests. In the first phase of the experiment, an abutment wall (without a foundation) was built at 50% scale of a prototype diaphragm abutment. The second phase of this research program was performed on a backwall sheared off from wingwalls and stem in seat-type abutments. The specific aims of the experimental program were to examine the effect of structure backfill soil type, backfill height, vertical movement of the wall, and pre-existing cut slope in backfilling on stiffness and capacity of the abutments in the longitudinal direction. An analytical model was developed for evaluating the response of bridge abutments loaded longitudinally. The approach involves calculating maximum passive resistance of the structure backfill material, and creating p-y curves to predict the force-displacement relationship of longitudinally loaded bridge abutments. The finite element program Plaxis 2D was used to model the abutment wall experiments. The procedure was validated by comparing the finite element results with the experimental results. In conclusion, the study indicates that the response of bridge abutments in the longitudinal direction is nonlinear and a function of several factors which need to be considered. The passive resistance of the structure backfill is controlled by the soil shear strength and the interface friction angle. Finally, the vertical movement of the wall has a significant effect on post-peak behavior of abutments.

Download or read book Service Limit State Design and Analysis of Engineered Fills for Bridge Support written by Mahsa Khosrojerdi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineered fills, including compacted granular fill and reinforced soil, are a cost-effective alternative to conventional bridge foundation systems. The Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) is a fast, sustainable and cost-effective method for bridge support. The in-service performance of this innovative bridge support system is largely evaluated through the vertical and lateral deformations of the GRS abutments and the settlements of reinforced soil foundations (RSF) during their service life. While it is a common assumption that granular or engineered fills do not exhibit secondary deformation, it has been observed in in-service bridge abutment applications and large-scale laboratory tests. Evaluation of the secondary, or post-construction, deformation of engineered fills is therefore also needed. The aim of this study is to analyze and quantify the maximum deformations of GRS abutment and RSF under service loads, evaluate the stress distributions within the engineered fills of the GRS abutment and RSF, and investigate the time-dependent behavior of engineered fills for bridge support. The ultimate goal is to provide accurate yet easy-to-use analysis-based design tools that can be used in the performance assessment of GRS abutments and RSF under service loads. It is anticipated that the research performed within the scope of this dissertation will eventually help promote sustainable and efficient design practice of these structures.The research objective was achieved through development of numerical models that employed finite difference solution scheme and simulated the performance of granular backfill and reinforcement material. The backfill soil was simulated using three different constitutive models. Comparison of the simulation results with case studies showed that the behavior of GRS structures under service loads is accurately predicted by the Plastic Hardening model. The developed models were validated through comparison of model predictions with laboratory and field test data reported in the literature. A comprehensive parametric study was conducted to evaluate the effects of backfill soils properties (friction angle and cohesion), reinforcement characteristics (stiffness, spacing, and length), and structure geometry (abutment height and facing batter and foundation width) on the deformations of GRS abutments and RSF. The results of the parametric study were used to conduct a nonlinear regression analysis to develop equations for predicting the maximum lateral deformation and settlement of GRS abutments and maximum settlement of RSF under service loads. The accuracy of the proposed prediction equations was evaluated based on the results of experimental case studies. The developed prediction equations may contribute to better understanding and enable simple calculations in designing these structures. To investigate the time-dependent deformations of GRS abutment and RSF, a numerical model was developed. The time-dependent deformations are also known as secondary deformations and creep. To model the creep behavior of the backfill material, the Burgers creep viscoplastic model that combines the Burgers model and the Mohr-Coulomb model was used in the simulations. To model the creep behavior of geosynthetics, the model proposed by Karpurapu and Bathurst (1995) was used; this model uses a hyperbolic load-strain function to calculate the stiffness of the reinforcement. Results indicated that engineered fills can exhibit noticeable secondary deformation.

Download or read book Numerical Simulations and Shaking Table Tests of Geosynthetic Reinforced Soil Bridge Abutments written by Yewei Zheng and published by . This book was released on 2017 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geosynthetic reinforced soil (GRS) bridge abutments are becoming widely used in transportation infrastructure and provide many advantages over traditional pile-supported designs, including lower cost, faster and easier construction, and smoother transition between the bridge and approach roadway. Seismic events represent a severe loading condition and experimental testing and evaluation are needed to understand the potential issues and performance characteristics. This study involves a comprehensive evaluation of the performance of GRS bridge abutments for the service limit state, the strength limit state, and an extreme event limit state (i.e., seismic loading conditions) using both numerical simulations and physical modeling experiments. A numerical model was developed for GRS bridge abutments under service loading conditions and was validated using field measurements. Simulation results indicate that the horizontal restraining forces generated from the bridge structure can have an important effect on reducing lateral facing displacements and bridge seat settlements of GRS bridge abutments. Parametric studies were conducted to investigate the effects of various design parameters on the performance of GRS bridge abutments for service loading conditions, and the results indicate that reinforcement spacing, reinforcement stiffness, bridge load, and abutment height have the most significant effects on the lateral facing displacements and bridge seat settlements. The numerical model was enhanced by incorporating the strain softening behavior for backfill soil and the rate-dependent behavior for geosynthetic reinforcement to simulate the load-deformation behavior of GRS bridge abutments up to failure condition. A linearly elastic reinforcement model can capture the deformation behavior of GRS bridge abutments for service loads, but not for larger applied loads approaching failure. The geometry parameters for GRS bridge abutments have important effects on the internal failure surface of the GRS bridge abutments, and the internal failure surface manifests as a bilinear surface that starts at the heel of the bridge footing, moves vertically downward to mid-height of the GRS bridge abutment, and then linearly to the toe of the GRS bridge abutment. The seismic response of GRS bridge abutments was evaluated using an experimental testing program. Shaking table tests were conducted on six half-scale GRS bridge abutments by application of a series of shaking events in the directions longitudinal and transverse to the bridge beam. Experimental design of the model specimen followed established similitude relationships for shaking table testing of reduced-scale models in a 1g gravitational field, including scaling of model geometry, geosynthetic reinforcement stiffness, backfill soil modulus, bridge load, and characteristics of the earthquake motions. Experimental results indicate that the seismic facing displacements and bridge seat settlements for GRS bridge abutments are small and will likely not have a major effect on the bridge performance. Reinforcement spacing and stiffness have the most important effects on the seismic performance of GRS bridge abutments.

Download or read book Large scale Testing of Low strength Cellular Concrete for Skewed Bridge Abutments written by Tyler Kirk Remund and published by . This book was released on 2017 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: It was observed that the cellular concrete backfill mainly compressed under loading with no visible failure at the surface. The passive-force curves showed the material reaching an initial peak resistance after movement equal to 1.7-2.6% of the backwall height and then remaining near this strength or increasing in strength with any further deflection. No skew effects were observed; any difference between the two tests is most likely due to the difference in concrete placement and testing.

Download or read book Large scale Testing of Low strength Cellular Concrete for Skewed Bridge Abutments written by Rebecca Eileen Black and published by . This book was released on 2018 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cellular concrete for the 0° skew test had an average wet destiny of 29 pounds per cubic food and a 28-day compressive strength of 120 pounds per square inch. The cellular concrete for the 30° skew test had an average wet density of 31 pounds per cubic foot and a 28-day compressive strength of 132 pounds per square inch. It was observed from the passive force deflection curves of the two tests that skew decreased the peak passive resistance by 29% , from 52.1 kips to 37 kips. Various methods were used to predict the peak passive resistance and compared with observed behavior to verify the validity of each method.

Download or read book Large scale Strength Testing of High speed Railway Bridge Embankments written by Daniel Ethan William Schwicht and published by . This book was released on 2018 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The peak passive force developed was about 2.5 times higher than that predicted with the California HSR design method for granular backfill material with a comparable backwall height and width. The displacement required to develop the peak passive force decreased with skew angle and was somewhat less than for conventional granular backfills. Peak passive force developed with displacements of 3 to 1.8% of the wall height, H in comparison to 3 to 5% of H for conventional granular backfills.

Download or read book Proceedings of the 16th International Conference on Soil Mechanics and Geotechnical Engineering written by The Organizing Committee of the 16th ICSMGE and published by IOS Press. This book was released on 2005-09-12 with total page 3742 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 16th ICSMGE responds to the needs of the engineering and construction community, promoting dialog and exchange between academia and practice in various aspects of soil mechanics and geotechnical engineering. This is reflected in the central theme of the conference 'Geotechnology in Harmony with the Global Environment'. The proceedings of the conference are of great interest for geo-engineers and researchers in soil mechanics and geotechnical engineering. Volume 1 contains 5 plenary session lectures, the Terzaghi Oration, Heritage Lecture, and 3 papers presented in the major project session. Volumes 2, 3, and 4 contain papers with the following topics: Soil mechanics in general; Infrastructure and mobility; Environmental issues of geotechnical engineering; Enhancing natural disaster reduction systems; Professional practice and education. Volume 5 contains the report of practitioner/academic forum, 20 general reports, a summary of the sessions and workshops held during the conference.

Download or read book Development and Implementation of Improved Seismic Design and Retrofit Procedures for Bridge Abutments written by Geoffrey R. Martin and published by . This book was released on 1997 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geosynthetic Reinforced Soil GRS Walls written by Jonathan T. H. Wu and published by John Wiley & Sons. This book was released on 2019-07-10 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to provide a detailed overview of Geosynthetic Reinforced Soil Walls Geosynthetic Reinforced Soil (GRS) Walls deploy horizontal layers of closely spaced tensile inclusion in the fill material to achieve stability of a soil mass. GRS walls are more adaptable to different environmental conditions, more economical, and offer high performance in a wide range of transportation infrastructure applications. This book addresses both GRS and GMSE, with a much stronger emphasis on the former. For completeness, it begins with a review of shear strength of soils and classical earth pressure theories. It then goes on to examine the use of geosynthetics as reinforcement, and followed by the load-deformation behavior of GRS mass as a soil-geosynthetic composite, reinforcing mechanisms of GRS, and GRS walls with different types of facing. Finally, the book finishes by covering design concepts with design examples for different loading and geometric conditions, and the construction of GRS walls, including typical construction procedures and general construction guidelines. The number of GRS walls and abutments built to date is relatively low due to lack of understanding of GRS. While failure rate of GMSE has been estimated to be around 5%, failure of GRS has been found to be practically nil, with studies suggesting many advantages, including a smaller susceptibility to long-term creep and stronger resistance to seismic loads when well-compacted granular fill is employed. Geosynthetic Reinforced Soil (GRS) Walls will serve as an excellent guide or reference for wall projects such as transportation infrastructure—including roadways, bridges, retaining walls, and earth slopes—that are in dire need of repair and replacement in the U.S. and abroad. Covers both GRS and GMSE (MSE with geosynthetics as reinforcement); with much greater emphasis on GRS walls Showcases reinforcing mechanisms, engineering behavior, and design concepts of GRS and includes many step-by-step design examples Features information on typical construction procedures and general construction guidelines Includes hundreds of line drawings and photos Geosynthetic Reinforced Soil (GRS) Walls is an important book for practicing geotechnical engineers and structural engineers, as well as for advanced students of civil, structural, and geotechnical engineering.