Ph.D. Civil Engineering, University of Colorado Boulder, 2006
M.S. Civil Engineering, University of Colorado Boulder, 2000
B.S. Civil Engineering, University of Colorado Boulder, 1997
Foundations of bridges and structures
Soil dynamics and dynamic soil-foundation-structure interaction
Nondestructive evaluation of foundations, aggregate roads, pavements and bridge decks
Aggregate roadway stabilization and performance
Advancements in geophysical surface wave testing methods
Development of instruments and techniques for in-situ and laboratory soil testing
Advances in experimental and analytical techniques for resonant column testing
Use of recycled materials in geotechnical engineering
Dr. Ashlock has performed research in instrumentation development, dynamics of soils and foundations, deep foundations, computational mechanics, non-destructive surface wave testing of soils and pavements and granular road stabilization. He developed the automated version of the soil borehole shear testing device, which is now sold by Handy Geotechnical Instruments Inc. He also developed a servo-hydraulic inertial shaker system for full-scale testing of pile foundations for the National Science Foundation (NSF) Network for Earthquake Engineering Simulation (NEES), and he developed a custom resonant column testing device for soil and rock. Dr. Ashlock currently serves as vice chair of ASTM Committee D18.09 on Cyclic and Dynamic Properties of Soils and is a member of ASTM Committee D18.02 on Sampling and Related Field Testing for Soil Evaluation.
CAREER: A Framework for Integrated Computational and Physical Simulation of Dynamic Soil-Pile Group Interaction. Funding agency: National Science Foundation.
Performance Based Evaluation of Cost Effective Aggregate Options for Granular Roadways. Funding agency: Iowa DOT.
Cost-Effective Field Test Methods for LRFD Resistance Factors of Drilled Shafts. Funding agencies: Midwest Transportation Center and Iowa DOT.
Intermodal Gantry Crane Pavement and Foundation Design Improvement. Funding agencies: Union Pacific Railroad and Midwest Transportation Center.
Feasibility of Gravel Road and Shoulder Recycling. Funding agency: Iowa DOT Highway Research Board.
Verification of LRFD Resistance Factors for Drilled Shafts Using Field Tests. Funding agencies: Iowa Highway Research Board and Midwest Transportation Center.
Design and Performance Verification of a Bridge Column/Footing/Pile System for Accelerated Bridge Construction (ABC). Funding agencies: Iowa Highway Research Board and Midwest Transportation Center
Honors and Awards
National Science Foundation CAREER Award #1351828: “CAREER: A Framework for Integrated Computational and Physical Simulation of Dynamic Soil-Pile Group Interaction”, 2014.
Charles W. Schafer Faculty Award for Excellence in Teaching, Research and Service, Iowa State University Department of Civil, Construction and Environmental Engineering, 2012.
Black & Veatch Making a World of Difference Faculty Fellow, 2011-2014.
Tau Beta Pi, Chi Epsilon, Golden Key Honor Societies
U.S. Department of Education Graduate GAANN Fellowship, University of Colorado Boulder, 2001-2006.
"Software Control Program for Automated Borehole Shear Soil Testing Device (ABST)." ISURF #03908, March 2011.
J. C. Ashlock and T. Bechtum, "ABST_V1.0," Automated Borehole Shear Test Control Program Version 1.0, Submitted to Handy Geotechnical Instruments, Inc. and ISU Institute for Physical Research and Technology, March 2011.
Websites and Data Dissemination
Documentation, authoring of metadata, and archival of NSF NEES project data for online dissemination to earthquake engineering community via the NEEShub Project Warehouse. Curation completed early 2012, public release scheduled for summer 2012. nees.org/warehouse/project/940
Lin S and JC Ashlock, “Surface-wave testing of soil sites using multichannel simulation with one-receiver”, Soil Dynamics and Earthquake Engineering, 87, 82-92 (2016). DOI: 10.1016/j.soildyn.2016.04.013.
Lin S, JC Ashlock and RC Williams, “Nondestructive quality assessment of asphalt pavements based on dynamic modulus”, Construction and Building Materials, 112, 836-847 (2016). DOI: 10.1016/j.conbuildmat.2016.02.189.
Lin S and JC Ashlock, “Comparison of MASW and MSOR for Surface Wave Testing of Pavements”, Journal of Environmental & Engineering Geophysics, 20(4), 277–285 (2015). DOI: 10.2113/JEEG20.4.277.
Chen C, RC Williams, MG Marasinghe, JC Ashlock, O Smadi, S Schram and A Buss, “Assessment of Composite Pavement Performance by Survival Analysis”, Journal of Transportation Engineering (2015). DOI: 10.1061/(ASCE)TE.1943-5436.0000784.
Ashlock JC and S Lin, “Critical Depths for Higher Modes by Minimally-invasive Multimodal Surface Wave Method (MMSW): Simulations and Field Test”, Journal of Environmental & Engineering Geophysics, 20(2), 195-202 (2015). DOI: 10.2113/JEEG20.2.195.
Drnevich VP, S Werden, JC Ashlock and JR Hall, Jr., “Applications of the New Approach to Resonant Column Testing,” Geotechnical Testing Journal, 38(1), 1–17 (2015). DOI:10.1520/GTJ20140222.
Lin S and JC Ashlock, “Multi-Mode Rayleigh Wave Profiling by Hybrid Surface and Borehole Methods”, Geophysical Journal International, 197(2), 1184-1195, Royal Astronomical Society/Oxford Press (2014). DOI: 10.1093/gji/ggu05.
Ashlock JC, V Drnevich and RYS Pak, “Strain Measures for Transfer Function Approaches to Resonant Column Testing”, ASTM Geotechnical Testing Journal, 36(4), 455-465, ASTM International (2013). DOI:10.1520/GTJ20120130.
Pak RYS, JC Ashlock, S Kurahashi and M Soudkhah, “Physical Characteristics of Dynamic Vertical-Horizontal-Rocking Response of Surface Foundations on Cohesionless Soils”, Géotechnique, 61(8), 687-697, ICE (2011). DOI: 10.1680/geot.8.P.072.
Pak RYS and JC Ashlock, “A Fundamental Dual-Zone Continuum Theory for Dynamic Soil–Structure Interaction”, Earthquake Engineering and Structural Dynamics, 40, 1011–1025 (2011). DOI: 10.1002/eqe.1075Ashlock JC and RYS Pak, “Experimental Response of Piles in Sand under Compound Motion”, Journal of Geotechnical and Geoenvironmental Engineering, 135(6), 799-808, ASCE (2009). DOI: 10.1061/(ASCE)GT.1943-5606.0000038.
Ashlock JC and S Lin, “Critical Depths for Higher Modes by Minimally-Invasive Seismic Profiling: Simulations and Field Test”, SAGEEP 2014, 27th Symposium on the Application of Geophysics to Engineering and Environmental Problems, Boston, Massachusetts, March 16-20, 2014, expanded abstract, 412-420.
Lin S and JC Ashlock, “Comparison of MASW and MSOR for Surface Wave Testing of Pavements”, SAGEEP 2014, 27th Symposium on the Application of Geophysics to Engineering and Environmental Problems, Boston, Massachusetts, March 16-20, 2014, expanded abstract, 265-273.
Ashlock JC and MK Fotouhi, “Thermal Integrity Profiling and Crosshole Sonic Logging of Drilled Shaft with Artificial Defects”, GeoCongress 2014, Geo-Characterization and Modeling for Sustainability, Atlanta, GA, Feb. 23-26, 2014, 1795-1805.
Ashlock JC and MK Fotouhi, “Analysis of Full-Scale Random Vibration Pile Tests in Soft and Improved Clays”, Proc. 18th International Conference on Soil Mechanics and Geotechnical Engineering, International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE), Paris, France, Sep. 2-6, 2013, 4 pp.
Phipps JN, JC Ashlock and S Sritharan, “Experimental Results of Foundation Rocking on a Natural Clay Deposit”, 15th World Conference on Earthquake Engineering, Lisbon, Portugal, September 24-28, 2012, 10 pp.
Fotouhi MK and JC Ashlock, “Analysis of Experimental Dynamic Soil-Pile Interaction by Approximate Numerical Solutions”, 15th World Conference on Earthquake Engineering, Lisbon, Portugal, September 24-28, 2012, 10 pp.
Ashlock JC and N Lu, “Interpretation of Borehole Shear Strength Tests of Unsaturated Loess by Suction Stress Characteristic Curves”, GeoCongress 2012, State of the Art and Practice in Geotechnical Engineering, Oakland, CA, March 25-29, 2012, 10 pp.
Lin S and JC Ashlock, “A Study on Issues Relating to Testing of Soils and Pavements by Surface Wave Methods”, 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2011), Burlington, VT, July, 2011. AIP Conf. Proc. 1430, 1532-1539 (2012); DOI: 10.1063/1.4716397.
Ashlock JC and JN Phipps, “Experimental Multi-modal Foundation Vibrations and Comparison with Benchmark Half-space Solutions”, GeoFrontiers 2011, Advances in Geotechnical Engineering, Dallas, TX, Paper No. 1616, 10 pp., DOI:10.1061/41165(397)319, March, 2011.
Ashlock JC and RYS Pak, (2010a), “Application of Random Vibration Techniques to Resonant Column Testing”, ASCE GeoFlorida 2010 Conference, Paper No. 750, 11 pp., February, 2010.
Ashlock JC and RYS Pak, (2010b), “Multi-modal Synthesis and Variable Modulus Effects in Resonant Column tests by Random Excitations”, 5th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics and Symposium in Honor of Professor I. M. Idriss, San Diego, CA, Paper No. 1.31b, 9 pp., May, 2010.
J. C. Ashlock and N. Lu, "Interpretation of Borehole Shear Strength Tests of Unsaturated Loess by Suction Stress Characteristic Curves," GeoCongress 2012, State of the Art and Practice in Geotechnical Engineering, Oakland, CA, March 25-29, 2012 (Accepted).
S. Lin and J. C. Ashlock, "A Study on Issues Relating to Testing of Soils and Pavements by Surface Wave Methods," 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2011), Burlington, Vermont, July 17-22, 2011, American Institute of Physics, Melville, NY, 8 pp (Accepted).
J. C. Ashlock and J. N. Phipps, "Experimental Multi-modal Foundation Vibrations and Comparison with Benchmark Half-space Solutions," GeoFrontiers 2011, Advances in Geotechnical Engineering, Dallas, TX, Paper No. 1616, 10 pgs., March 2011. DOI: 10.1061/41165(397)319.
R. Y. S. Pak, J. C. Ashlock, S. Kurahashi and M. Soudkhah, "Physical characteristics of dynamic vertical-horizontal-rocking response of surface foundations on cohesionless soils," Géotechnique, 61(8), 687-697, ICE, 2011. DOI: 10.1680/geot.8.P.072.
R. Y. S. Pak and J. C. Ashlock, "A Fundamental Dual-Zone Continuum Theory for Dynamic Soil–Structure Interaction," Earthquake Engineering and Structural Dynamics, 40:1011–1025, 2011. DOI: 10.1002/eqe.1075.