East E.W.,Research Civil Engineer |
Bogen C.,Engineer Research and Development Center
Congress on Computing in Civil Engineering, Proceedings | Year: 2012
The authors' efforts to improve the quality of Industry Foundation Class (IFC) building information exchanges has highlighted needed for defensible verification methods. The tools and techniques needed to meet these efforts requirements would also improve research that requires building information. This paper announces the open publication of a series of models and tools produced and used by the authors for their research. Widespread use of common models and shared tools are expected to improve the quality of research that requires building information. © 2012 American Society of Civil Engineers.
Doyle J.D.,Research Civil Engineer |
Howard I.L.,Mississippi State University |
Gartrell C.A.,Research Civil Engineer |
Anderton G.L.,Engineer Research and Development Center |
And 2 more authors.
International Journal of Geomechanics | Year: 2014
Matting systems are used for temporary applications on soft soils to reduce ground pressure exerted by aircraft, heavy equipment, vehicles, and construction material. They have been used for military airfields, construction platforms, and similar applications. Previous evaluation studies of matting systems have typically consisted of full-scale testing, with only a limited amount of numerical modeling found in the literature. This paper presents results of full-scale accelerated testing of 21 test sections encompassing five matting systems, five soil-support conditions, and two aircraft loadings. One of the soil-support conditions was instrumented and tested in conjunction with three matting systems and one aircraft loading. Three-dimensional finite-element modeling was performed on the instrumented sections using the measured test data for calibration. Good matches of measured soil stresses were obtained with the model for two of the mats, whereas the model underpredicted stresses in the third mat. Modeling of the type performed in this paper was capable of correctly ranking the performance of the matting systems modeled relative to the full-scale test results. © 2014 American Society of Civil Engineers.
Kayen R.,Research Civil Engineer |
Kayen R.,University of California at Los Angeles |
Moss R.E.S.,California Polytechnic State University, San Luis Obispo |
Thompson E.M.,Tufts University |
And 5 more authors.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013
Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to build a global catalog of 422 case histories of Vs liquefaction performance. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Where possible, uncertainties of the variables comprising both the seismic demand and the soil capacity were estimated and included in the analysis, resulting in greatly reduced overall model uncertainty relative to previous studies. The presented data set and probabilistic analysis also help resolve the ancillary issues of adjustment for soil fines content and magnitude scaling factors. © 2013 American Society of Civil Engineers.
Doyle J.D.,Mississippi State University |
Mejias-Santiago M.,Research Civil Engineer |
Brown E.R.,Research Civil Engineer |
Howard I.L.,Mississippi State University
Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions | Year: 2011
This paper presents test results on warm mix asphalt (WMA) mixtures containing high amounts of reclaimed asphalt pavement (RAP) to evaluate performance when used as a surface mixture. The evaluation considered permanent deformation, durability, non-load associated cracking, and moisture damage. Crushed gravel and limestone mixtures were tested with 0 to 50% RAP in conjunction with three warm mix asphalts. Test results indicated high RAP-WMA to be a potentially viable product for surface mixtures. WMA was shown capable of producing rut resistant mixtures with high RAP contents. A more intriguing finding was that while increasing rut resistance the high RAP mixtures did not affect the low temperature properties as much as the high temperature properties. Mixtures with high RAP content appear to be only slightly more susceptible to thermal cracking. Warm mixes have been shown to be susceptible to water. In general it was shown that WMA technology can be used with high RAP content to produce mixtures that are more resistant to moisture damage. Increasing the RAP content generally increased the resistance of the mix to moisture damage. Gravel mixtures produced with foamed asphalt, however, did not perform well with respect to moisture damage, especially with no RAP in the mixture. Testing indicated high RAP content WMA mixes may be more susceptible to durability issues than low RAP mixes. To date this has not been observed in the field, but additional monitoring of high RAP sections is needed to determine if and to what extent durability on the surface is a cause of concern.