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.
Conlee C.T.,Geocomp Corporation |
Gallagher P.M.,Drexel University |
Boulanger R.W.,University of California at Davis |
Kamai R.,University of California at Davis
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012
This paper reports the results of two centrifuge tests that were conducted to evaluate the effectiveness of colloidal silica for liquefaction mitigation. Colloidal silica has been selected as a stabilizer material in soils because of its permanence and ability to increase the strength of soils over time. The centrifuge model geometry was selected to study the effects of lateral spreading in a 4.8-m-thick liquefiable layer overlain by a silty clay sloping toward a central channel. The centrifuge test evaluates the response of untreated loose sands versus loose sands treated with 9, 5, and4%colloidal silica concentrations (by weight). The models were subjected to a series of peak horizontal base accelerations ranging from 0.007 up to 1:3g (prototype) with a testing centrifugal acceleration of 15g. The results show a reduction in both lateral spreading and settlement in colloidal silica-treated sands versus untreated sands. The shear modulus at low strains was determined from shear wave velocity measurements for the untreated and treated loose sands. The hysteretic response during cyclic loading was also determined for various levels of shaking. The results from the centrifuge tests show an increase in cyclic resistance ratios and a decrease in cyclic shear strains for increasing colloidal silica concentrations. © 2012 American Society of Civil Engineers.
Sivathayalan S.,Carleton University |
Ha D.,Geocomp Corporation
Canadian Geotechnical Journal | Year: 2011
An experimental study of the effect of (initial) static shear stress on the undrained simple shear response of sands is presented. Liquefaction resistance of two sands, one generally contractive and the other dilative, over a wide range of density and effective stress levels was evaluated at various density and stress states. At a given density, the effect· of static shear on the cyclic resistance of sands is dependent on the type of stress-strain response that ensues during loading. The general notion that static shear increases the cyclic resistance of sands at relatively high densities is not valid if the sand is contractive at the denser state. The Kα correction factor for sand at 80% relative density may be as low as about 0.6 for strain-softening sand depending on the initial stress state. The routine industry practice of disregarding the Kα factor in dense sands may thus lead to unsafe designs in such materials. The Kα values measured under cyclic simple shear loading are compared to the Kα values reported in the literature based on cyclic triaxial tests. Test results clearly indicate that Kα is also dependent on the loading mode. Kα correction factors proposed in the literature, in general, have been derived either from empirical data or from laboratory tests under triaxial loading mode. Extra attention is required when using those correction factors, as they may not appropriately account for the loading mode effects.
News Article | December 8, 2016
DUBLIN--(BUSINESS WIRE)--Research and Markets has announced the addition of the "Structural Health Monitoring Market: Global Industry Analysis and Opportunity Assessment, 2016-2026" report to their offering. The global structural health monitoring market is estimated to register a value CAGR of 13.8% over the 10-year forecast period 2016 - 2026 and is expected to be valued at US$ 5,771.5 Mn by 2026 end. In 2015, the global structural health monitoring market was valued at US$ 1,405.2 Mn and this is estimated to reach US$ 1,590.6 Mn by the end of 2016, reflecting a Y-o-Y growth rate of 13.2%. Wide availability of low-cost sensors, growing infrastructural development across the globe, and increasing government initiatives towards public safety and structural health monitoring system standardisation are factors expected to drive growth of the global structural health monitoring market over the forecast period. However, complexity in implementing structural health monitoring solutions for massive structures coupled with a lack of trained professionals could hamper overall market growth to a certain extent during the forecast period. The global structural health monitoring market is also likely to witness certain key trends such as an increasing focus of solution providers on low-cost energy harvesting monitoring systems and increasing adoption of distributed optic fibre in structural health monitoring solutions. Some of the well-known companies operating in the global structural health monitoring market are National Instruments Corporation, Advitam Inc. (Vinci SA), Digitexx Data Systems, Inc., Acellent Technologies, Inc., Strainstall UK Limited (James Fisher & Sons PLC), Nova Metrix LLC, COWI A/S, Geocomp Corporation, Hottinger Baldwin Messtechnik GmbH, and Kinemetrics Inc. For more information about this report visit http://www.researchandmarkets.com/research/5k8s5x/structural_health
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.
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.
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.
Marr W.A.,Geocomp Corporation
Geotechnical Special Publication | Year: 2011
Active risk management, (ARM™), is a systematic process of identifying, analyzing, planning, monitoring and responding to project risk over the life of the project. It involves processes, tools, and techniques that help the project team minimize the probability and consequences of adverse events (threats) and maximize the probability and consequences of positive events (opportunities) throughout the life of the project. It is especially useful in projects with significant geotechnical risks. It provides the project team with more complete information on the risks they face in a format understandable to non-specialists - cost and schedule impacts. It identifies the uncertainties and potential events that create the most risk to the project and develops ways to minimize these uncertainties as they affect final project cost and schedule. The concept of Active Risk Management applied to civil engineering projects has been developed by the author on a variety of projects over 35 years. This paper lays out the steps of Active Risk Management and discusses how they are applied in geotechnical engineering. It illustrates the use of the method with a practical example that shows the value of obtaining additional geotechnical information to reduce risk. © 2011 ASCE.
Marr W.A.,Geocomp Corporation |
Hawkes M.,Geocomp Corporation
Geotechnical Special Publication | Year: 2010
Many structures located close to excavations are damaged by excessive ground movements during construction. This is partly due to limitations of commonly used methods to design the excavation support system. The authors propose using a displacement-based design method that focuses on designing to keep movements within allowable values. A step-by-step approach for the method is described and illustrated for a deep excavation into soft clay. © ASCE 2010.
Geocomp Corporation | Date: 2014-11-04
Computer hardware and software for collecting data about natural and man-made environments from sensors and instruments at a remote site. Telecommunication services, namely, provide access via the Internet to data collected from sensors and instruments from natural and man-made environments at a remote location; Electronic data transmission services in the field of geo-engineering.