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Elmekati A.,Mueser Rutledge Consulting Engineers | Shamy U.E.,Southern Methodist University
Computers and Geotechnics | Year: 2010

The particulate nature of granular soils can be accurately simulated at a microscale level. However, due to the huge spatial extent of geotechnical systems, a model fully constructed at such a scale is almost impossible with current computing technologies. Hence, continuum-based approaches are considered as the practical scale for modeling the majority of problems. Combining both scales enables benefiting from the advantages of both techniques while trying to overcome their drawbacks. Although a significant number of publications have addressed coupling both scales, only a few provide information regarding implementing the proposed procedures. In this study, an efficient co-simulation framework for conducting multiscale analysis is introduced. The framework is based on integrating existing continuum and micromechanical modeling software packages and therefore benefitting from already existing codes. A computational simulation of a rigid pile in contact with granular soil demonstrating the capabilities of such technique is presented. The near-field zone surrounding the pile is modeled using DEM whereas FEM is utilized to model far-field zones that are not affected by the presence of the pile. Results of conducted simulations resemble those obtained from experimental results. The proposed approach appears to be a very effective and promising tool to model boundary value problems of geotechnical systems. © 2010 Elsevier Ltd. Source


Malekmohammadi M.,Mueser Rutledge Consulting Engineers | Pezeshk S.,University of Memphis
Earthquake Spectra | Year: 2015

In this study, site amplification factors for the deep soil deposits of the Mississippi embayment are computed using a nonlinear site response analysis program first to develop a model for nonlinear soil response for possible use by ground motion developers and second to address site amplification estimation. The effects of geology, sediment depth, and average shear wave velocity at the upper 30 m of soil ranging 180-800m/s, as well as the effect of peak ground acceleration at the bedrock on nonlinear ground motion amplification for the upper embayment, are investigated. The site response computations cover various site conditions, sediment depth of 70-750 m, and peak acceleration of input rock motions of 0.01-0.90 g. The amplification (or de-amplification) at various frequencies implied by the sediment depth is greater than that implied just by site classification of the top 30 m of soil. © 2015, Earthquake Engineering Research Institute. Source


Cermak J.,Mueser Rutledge Consulting Engineers | Evans J.,Bucknell University
Geotechnical Special Publication | Year: 2012

Results of a comprehensive evaluation of construction and performance of an in-situ mixed soil-cement-bentonite (SCB) wall constructed at a Florida site are presented and discussed. Cracking of boreholes during verification drilling resulted in in-hole permeability test results higher than specified limits in contract documents. The evaluation indicated that fluid pressures associated with certain verification drilling techniques (e.g., coring) may result in longitudinal stresses in the SCB wall of sufficient magnitude to exceed the tensile strength of the wall backfill resulting in cracking. Also, transverse cracking away from boreholes was observed many months after construction within the top portion of the wall. The investigation of internal stresses in the wall indicated that drying shrinkage which occurred above a moisture zone together with thermal shrinkage had the capacity to induce tension stresses which exceeded the tensile strength of the wall backfill, and caused the observed transverse cracking at the top portion of the wall. The study found that cracks did not affect the overall performance of the SCB wall. © 2012 American Society of Civil Engineers. Source


Carr P.,Judy Company | Quasarano M.,Mueser Rutledge Consulting Engineers
Geotechnical Special Publication | Year: 2012

During replacement of the center bascule span of the Amtrak Thames River Bridge with a lift span structure, significant settlement occurred in the bascule pier. The pier was stabilized by solidifying the underlying soil by methodological injection of grout. This paper describes the construction aspects of an unusually large permeation grouting program which was undertaken to arrest settlement of a 92-year-old bridge pier. © 2012 American Society of Civil Engineers. Source


Zaniewski J.P.,West Virginia University | Knihtila S.F.,Mueser Rutledge Consulting Engineers | Rashidi H.N.,West Virginia University
Airfield and Highway Pavements 2015: Innovative and Cost-Effective Pavements for a Sustainable Future - Proceedings of the 2015 International Airfield and Highway Pavements Conference | Year: 2015

One of the imperative components contributing to longevity and performance of asphalt concrete overlays is sufficient bond strength between the new overlay and existing surface. If the multi-layered asphalt pavement does not have ample bond strength to endure dynamic loads from traffic, surface distresses may develop. Surface distresses may occur in areas of, but not limited to, stopping, starting, and turning. These surface distresses are, but not limited to, de-bonding, delamination, slippage, or fatigue cracking. Therefore, the objective of this study was to develop a test method and testing device for measuring the bond strength between pavement layers. The research evaluated tack coat materials and HMA mix designs commonly used by West Virginia Division of Highways. The project was conducted in both laboratory and field. The effects of mix design, tack coat type, surface condition, and moisture damage were evaluated. Initial testing concluded that laboratory compaction using Superpave Gyratory Compactor affected bond strength. It was also found that the cut face which represents the worn surface and the new HMA face of the sample exhibit different bond strengths. Increased nominal maximum aggregate size of the mix design increased bond strength, but not a significant amount. Cut faced samples exhibited higher bond strength than milled samples on average. The bond strengths of samples with or without tack coat were not statistically different. For milled and cut faced samples, trackless tack coat was superior to a standard SS-1h emulsion. Set time from 0.25 to 2.0 hours, was statistically significant for both milled and cut faced samples. The difference in bond strength for moisture damage was statistically significant. © ASCE. Source

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