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Acton, MA, United States

Disfani M.M.,Swinburne University of Technology | Arulrajah A.,Swinburne University of Technology | Bo M.W.,DST Consulting Engineers Inc. | Hankour R.,Geocomp Corporation
Waste Management | Year: 2011

A comprehensive suite of geotechnical laboratory tests was undertaken on samples of recycled crushed glass produced in Victoria, Australia. Three types of recycled glass sources were tested being coarse, medium and fine sized glass. Laboratory testing results indicated that medium and fine sized recycled glass sources exhibit geotechnical behavior similar to natural aggregates. Coarse recycled glass was however found to be unsuitable for geotechnical engineering applications. Shear strength tests indicate that the fine and medium glass encompass shear strength parameters similar to that of natural sand and gravel mixtures comprising of angular particles. Environmental assessment tests indicated that the material meets the requirements of environmental protection authorities for fill material. The results were used to discuss potential usages of recycled glass as a construction material in geotechnical engineering applications particularly road works. © 2011 Elsevier Ltd. Source


Govindasamy A.V.,Geocomp Corporation | Briaud J.-L.,Texas A&M University
Geotechnical Special Publication | Year: 2014

Bridge scour is a major cause of damage to bridge foundations and abutments. Approximately 17,000 scour-critical bridges exist in the United States. Scour-critical bridges are bridges with foundations that are unstable for calculated and/or observed scour conditions. This designation comes in part from the use of overconservative methods that predict excessive scour depths in erosion-resistant materials. Other available methods capable of overcoming this overconservatism are relatively uneconomical because they require site-specific erosion testing. This paper presents the assessment of two bridge case histories using the observation method for scour (OMS). OMS is a relatively new quantitative bridge-scour assessment method that accounts for time-dependent scour depth using field measurements. This method, which does not require site-specific erosion testing, was developed as a first-order assessment method for use in combination with routine bridge inspections. OMS uses charts that extrapolate or interpolate measured scour depths at the bridge to obtain the scour depth corresponding to a specified future flood event. The vulnerability of the bridge to scour depends on the comparison between the predicted and allowable (threshold) scour depths. The case histories presented in this paper consist of two Texas bridges, one designated as scour critical and the other as stable by the Texas Department of Transportation (TxDOT). Both stable and scour-critical bridges were selected to test OMS and also compare it with TxDOT's scour designation. These case histories serve to demonstrate the validity and applicability of OMS to full-scale bridges and to provide practitioners with two potentially useful real-life case histories that could serve as examples for engineering practice. A validation process was performed on the two case histories using historical scour measurements and flow data. The validation exercise showed that there was good agreement between predicted scour depths using OMS and field measurements. OMS was then applied as a bridge-scour assessment tool to both bridges using the 100-year flood as the future flood and the outcome of OMS compared with the original TxDOT designation. As a result of this, the originally scour-critical bridge was found to be stable according to OMS. The bridge originally designated as stable was also found to be stable according to OMS. © 2014 American Society of Civil Engineers. Source


Brady J.J.,Geocomp Corporation
North American Tunneling - 2014 Proceedings, NAT 2014 | Year: 2014

This paper discusses an important topic where early participation by Owners in an Active Risk Management Process will both save money and mitigate risks while maximizing an Owner's ability to manage program funds. The area explored is the development and management of program-level and project-level Contingency budgets; including recommendations on how best to use project Allowances as well as some long-term strategies for managing Program-level contingencies from inception to commissioning. The ideas and recommendations presented in this paper are based upon first-hand observations of the inner workings (and areas for improvement) of many of the recent larger tunneling programs in the United States. Source


Marr W.A.,Geocomp Corporation
Geotechnical Special Publication | Year: 2013

Instrumentation and monitoring of earth structures has experienced phenomenal change and growth since the last slope stability conference some twenty years ago. This paper gives an overview of the current state-of-practice of instrumentation and monitoring for slopes and embankments and other structures that involve global instability considerations. Reasons to monitor performance, technological revolutions in instrumentation and monitoring over the past 20 years and some recommended practices are presented and discussed. A principal theme of this paper is the important role of instrumentation and monitoring in helping to identify and manage risk. When considered as a part of a risk management program, the role and value of instrumentation and monitoring program becomes much clearer to all involved. © 2013 American Society of Civil Engineers. Source


Govindasamy A.V.,Geocomp Corporation | Briaud J.-L.,Texas A&M University | Kim D.,Hongik University | Olivera F.,Texas A&M University | And 2 more authors.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

Bridge scour can cause damage to bridge foundations and abutments. Bridges with foundations that are unstable for calculated and/or observed scour conditions are termed scour-critical bridges. There are approximately 17,000 scour-critical bridges in the United States. This designation comes in part from the use of overly conservative methods that predict excessive scour depths in erosion-resistant materials. Other methods capable of overcoming this overconservatism are relatively uneconomical because they require site-specific erosion testing. This paper proposes a new bridge scour assessment method. The new method, termed the observation method for scour (OMS), was developed for the Texas Department of Transportation's statewide bridge scour assessment program. The proposed method does not require site-specific erosion testing and accounts for time-dependent scour in erosion-resistant materials. OMS was developed for use as a first-order assessment in combination with a routine bridge inspection program. OMS uses charts that extrapolate or interpolate measured scour depths at the bridge to obtain the scour depth corresponding to a specified future flood event. The scour vulnerability depends on the comparison between the predicted and allowable scour depths. This paper also includes a new hydraulic-hydrologic analysis procedure for the determination of flow parameters required in OMS. This procedure was developed specifically for the state of Texas. The new hydraulic-hydrologic analysis procedure could possibly be applied to other regions that have sufficient flow gauges. The nine case histories used to validate OMS showed good agreement between predicted and measured values. OMS was then applied to 16 bridges, 10 of which were scour-critical bridges that had sufficient information for OMS to be carried out. Six out of these 10 bridges were found to be stable according to OMS. © 2013 American Society of Civil Engineers. Source

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