Description: Description: Description: Description: C:\Users\Nicholas Sitar\Documents\sitar3.jpgNICHOLAS SITAR
Edward G. and John R. Cahill Professor
Civil and Environmental Engineering
Phone: (510) 643-8623
Campus Office: 449 Davis Hall

sitar@ce.berkeley.edu

 

 

 

CURRENT COURSES:

Fall 2012

o    CEE 281 ENGINEERING GEOLOGY - Lectures: Tu, Th 9:30-11 a.m., 406 Davis Hall

o     Lab: F  1-4 p.m., 406 Davis Hall, Field Trips - TBA

Spring 2012

o    CEE 176 ENVIRONMENTAL GEOTECHNICS - Tu, Th 12:30- 2 p.m., 406 Davis Hall

 

OFFICE HOURS - Spring 2012:

o    Tu, W 10 - 11:30 a.m.

EDUCATION AND EXPERIENCE

B.A.Sc. Geological Engineering, University of Windsor, 1973.

M.S. Geology - Hydrogeology, Stanford University, 1975.

Ph.D. Civil Engineering - Geotechnical, Stanford University, 1979.

Registered Geological Engineer in British Columbia.

TEACHING AND RESEARCH

On the undergraduate level, Professor Sitar has taught introductory courses in Engineering Geology, Soil Mechanics and Foundation Engineering, and Groundwater and Seepage. On the graduate level he currently teaches Engineering Geology and Advanced Topics in Geological Engineering. His current research interests include seismic slope stability, seismic response of reinforced soil structures, analysis of seismically induced earth pressures on retaining structures, behavior of discontinuous rock masses, and the application of GIS to seismic slope stability. In Environmental Geotechnics his research interests are in groundwater remediation and in probabilistic risk assessment applied to groundwater flow and contaminant transport. The emphasis is on developing methodologies for practical field applications.

 

Application of Wireless Sensor Technology to Environmental Monitoring

 

Ubiquitous wireless sensor networks have numerous potential applications in many areas. The main objective of this research is to develop affordable, reliable wireless instrumentation for a variety of applications such as wild fire monitoring, landslide and rock fall monitoring, and monitoring on underground space.

 

Monitoring of Rock Mass Response to Environmental Loading

 

Rock masses deform in response to changes in atmospheric pressure and temperature. These deformations can be monitored using a variety of sensors. In this effort acoustic emissions are being tracked at a site in Yosemite in order to establish correlation between the intensity of acoustic emissions and the expansion and contraction of rock blocks. In a related effort, seismic monitoring has been successfully used to monitor rock falls and rock fall impacts.  The ultimate goal is to develop rock fall hazard warning system for high rock walls.

Effect of Vegetation and Rodent Activity on Levee Performance

The effect of roots from woody vegetation on long term performance of levees, specifically their susceptibility to seepage induced failures is being investigated as a part of this study. Similarly the burrowing activity of rodents is being evaluated as it pertains to habitat preferences, ability of grouting to mitigate the damage, and potential for inducing catastrophic levee failures.

Application of Reliability Methods to Probabilistic Slope Stability Analysis

It is well recognized that the natural heterogeneity of the subsurface environment introduces a significant level of uncertainty in making predictions of the expected contaminant pathways and concentration levels. The approach taken in this work is to use reliability methods developed primarily in structural engineering and to apply them to slope stability analyses in soil and rock. These techniques appear to offer considerable computational advantage in the analysis of events with a very low probability of occurrence. The current emphasis is on development of new applications.

Earthquake Engineering

Evaluation of Seismically Induced Earth Pressures on Retaining Structures

It is generally accepted that retaining structures are subject to increased loads due to seismic loading.  However, observations in a number of recent earthquakes suggest that well designed retaining structures perform quite well even if they are not particularly designed for seismic loading. Most recent results from dynamic centrifuge experiments show that the magnitude of the dynamic pressure is significantly lower than has been assumed previously. The current effort is concentrating on the evaluation of basement and underground structures and numerical modeling.

 

Seismic Response of Improved Ground

Ground improvement using different techniques is extensively used to mitigate the seismically induced liquefaction hazard. In this project, dynamic centrifuge tests were being used to evaluate the influence of the geometry of the improved zone on the expected performance of the improved ground.

 

 

RECENT PUBLICATIONS

  • Sitar, N., MacLaughlin, M.M., and Doolin, D.M., Influence of Kinematics on Landslide Mobility and Failure Mode, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 131, No. 6, June, 2005.

  •  Collins, B.D., and Sitar, N., "Failure Mode Identification and Hazard Quantification for Coastal Bluff Landslides," Proceedings 2005 International Conference on Landslide Risk Management, Editors O. Hungr and R. Fell R. Couture, and E. Eberhardt, Vancouver, BC, Canada, June 2005, pp. 487-496.

  •  Jimenez-Rodriguez R. and Sitar N., "Probabilistic rock wedge stability analysis using system reliability methods", Paper J0880, CD Proceedings 2005 International Conference on Landslide Risk Management, Editors O. Hungr and R. Fell, R. Couture, and E. Eberhardt, Vancouver, BC, Canada, June 2005.

  •  Jimenez-Rodriguez R. and Sitar, N. "Probabilistic identification of removable wedges in rock slopes: Influence of stochastic model parameters, Proceedings, Eurorock 2005 - Impact of Human Activity on Geological Environment, P. Konecny ed., A.A. Balkema, Netherlands, May 2005.

  •  Jimenez-Rodriguez R. and Sitar, N. "Maximum likelihood inference of discontinuity trace lengths based on observations at rock outcrops", GeoEngineering Report No. UCB/GE-2005/01.

  •  Jimenez-Rodriguez R. and Sitar, N. "Probabilistic identification of removable wedges in rock slopes: Influence of stochastic model parameters," GeoEngineering Report No. UCB/GE-2005/02, May 2005, 51 p.

  •  Jimenez-Rodriquez R., Sitar, N., and Bartlett, P. "Maximum likelihood estimation of trace length distribution parameters using the EM algorithm", in Prediction, Analysis and Design in Geomechanical Applications: Proceedings of the Eleventh International Conference on Computer Methods and Advances in Geomechanics (IACMAG-2005), G. Barla and M. Barla, eds., Torino, Italy, 19-24 June, 2005, pp. 619-626.

  • Jimenez-Rodriguez, R.,  Sitar, N., and Chacon, J. "Caracterizacion de discontinuidades en macizos rocosos mediante modelos graficos probabilisticos" [Characterization of discontinuities in rock masses by means of probabilistic graphical models], Metodos Numericos en Ingenieria 2005, J.L. Perez Aparicio, A. Rodriguez Ferran, J.A.C. Martins, R. Gallego and J. Cesar de Sa editors, SEMNI, Sociedad Espanola de Metodos Numericos en Ingenieria, publisher, Extended abstract in Proceedings; full paper on CD-Rom, 2005.

  •  Wang G, Liu X.H., Li S.F., Sitar, N., "Smart element method II. An element based on the finite Eshelby tensor," Int. J. for Numerical Methods in Engineering, 64 (10): 1303-1333, Nov. 2005.

  •  Nova-Roessig, L. and Sitar, N., "Centrifuge Model Studies of the Seismic Response of Reinforced Soil Slopes," Journal of Geot. and Geoenv. Engrg., Vol. 132, No. 3, March 1, 2006.

  •  Kasali, G. and Sitar, N., "Field Evaluation of Axial Response of Drilled Shafts to Dynamic Loads," Proceedings of the 8th U.S. National Conference on Earthquake Engineering, April 18-22, 2006, San Francisco, California, USA, Paper No. 1428. (CD)

  •  Wang, G. and Sitar, N., "Nonlinear Finite Element Analysis of Drilled Piers Under Dynamic and Static Axial Loading," Proceedings of the 8th U.S. National Conference on Earthquake Engineering, April 18-22, 2006, San Francisco, California, USA, Paper No. 1452. (CD)

  •  Doolin, D.M. and Sitar, N., Wildfire Monitoring Using Wireless Sensor Networks, Fire Management Today, Spring 2006, Vol. 66, No. 2, 44-47.

  •  Jimenez-Rodriguez, R., Sitar, N.; and Chacon, J., "System reliability approach to rock slope stability", International Journal of Rock Mechanics and Mining Sciences, v 43, n 6, September, 2006, p 847-859.

  •  Jimenez-Rodriguez, R. and Sitar, N., "Inference of discontinuity trace length distributions using statistical graphical models", International Journal of Rock Mechanics and Mining Sciences, v 43, n 6, September, 2006, p 877-893.

  •  Jimenez-Rodriguez, R. and Sitar, N., "A spectral method for clustering of rock discontinuity sets", International Journal of Rock Mechanics and Mining Sciences, v 43, n 7, October, 2006, p 1052-1061.

  •  Wang, G. and Sitar, N., "Nonlinear Analysis of a Soil-Drilled Pier System under Static and Dynamic Loading," Pacific Earthquake Engineering Research Center Report, PEER 2006/06, November 2006, 183 p.

  •  Wang, G., Li, S., Nguyen, H-N. and Sitar, N., "Effective Elastic Stiffness for Periodic Masonry Structures via Eigenstrain Homogenization," ASCE, Journal of Materials in Civil Engineering,Vol. 19, No. 3, March 2007, pp. 269-277.

  •  Collins, B.D., Kayen, R. and Sitar, N. "Process-based empirical prediction of landslides in weakly lithified coastal cliffs, San Francisco, California, USA," in McInnes, R., Jakeways, J., Fairbank, H., Mathie, E., eds., Landslides and climate change, Proceedings of the International Conference on Landslides and Climate Change, Isle of Wight, United Kingdom, May 2007: London, Taylor & Francis, p. 175-184, 2007.

  • Al Atik L. and Sitar, N. "Dynamic centrifuge study of seismically induced lateral earth pressures," Proceedings, 4th International Conference on Earthquake Geotechnical Engineering, Thessaloniki, Greece, June 25-28, 2007.

  •  Al Atik, L. and Sitar, N. "Development of Improved Procedures for Seismic Design of Buried and Partially Buried Structure", Pacific Earthquake Engineering Research Center Report, PEER 2007/06, June 2007, 170 p.

  •  Jimenez-Rodriguez, R. and Sitar, N. "Rock Wedge Stability Analysis Using System Reliability Methods", Technical Note, Rock Mechanics and Rock Engineering, Springer Verlag, Vol. 40, No. 4, August 2007, pp. 419-427.

  • Collins, B. D., Kayen, R., Reiss, T., and Sitar, N., 2007. Terrestrial Lidar Investigation of the 2003 and 2007 Activations of the Northridge Bluff Landslide, Daly City, California: U.S. Geological Survey, Open File Report 2007-XXXX,  [http://pubs.usgs.gov/of/2007/XXXX/ ].

  •  Collins, B.D. and Sitar, N. "New Approaches to Stability Analysis of Steep Coastal Bluffs", Proceedings, GeoCongress 2008: Geosustainability and Geohazard Mitigation (GSP 178), ASCE, New Orleans, March 9-12, 2008, pp. 507-513.

  •  Al Atik, L. and Sitar, N. "Dynamic Centrifuge Study of Seismically Induced Lateral Earth Pressures on Retaining Structures", Proceedings, GEESD IV, Sacramento, CA, May, 2008, ASCE GSP 181, 2008.

  •  Collins, B.D. and Sitar, N. "Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA", Geomorphology, Vol. 97, Issues 3-4, 15 May 2008, pp. 483-501.

  •  Jimenez-Rodriguez, R. and Sitar, N. "Influence of Stochastic Discontinuity Network Parameters on the Formation of Removable Blocks in Rock Slopes", Rock Mechanics and Rock Engineering, Springer Verlag, Vol. 41, No. 4, August 2008, pp. 563-585. 

  • Al Atik, L. and Sitar, N. "Experimental and Analytical Study of Seismic Performance Retaining Structures." PEER Report 2008/104, UC Berkeley, March 2009.

  • Jimenez-Rodriguez, R. and Sitar, N. "The importance of distribution types on finite element analyses of foundation settlement", Computers and Geotechnics, Elsevier, Vol. 36, No. 3, April 2009, pp. 474-483.

  •  Sitar, N. and Al Atik, L. "On Seismic Response of Retaining Structures." Proceedings, Int. Conf. on Performance Based Earthquake Geotechnical Engineering, IS Tokyo 2009, June 2009.

  •  Al Atik, L. and Sitar, N. "Seismically Induced Lateral Earth Pressures: A New Approach. Proceedings", 17th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Alexandria, Egypt, Oct. 2009.

  •  Collins, B. and Sitar, N. "Geotechnical Properties of Cemented Sands in Steep Slopes." J. of Geotech. and Geoenvir. Engrg, ASCE, Vol. 135, No. 10, October, 2009, pp. 1359-1366.

  •  Al Atik, L. and Sitar, N. "Numerical Study of Seismic Earth Pressures in Centrifuge Model Experiments." Proc. 9th U.S. National and 10th Canadian Conf. on Earthquake Engineering, July 25-29, 2010, Toronto, Ont., Canada, Paper No. 968.

  •  Lew, M., Sitar, N., and Al Atik, L. "Seismic Earth Pressures: Fact or Fiction." Invited Keynote Paper, Earth Retention Conference, ER 2010, ASCE, Seattle, August, 2010.

  •  Lew, M., Sitar, N., Al Atik, L., Pourzanjani, M., Hudson, M.B. "Seismic Earth Pressures on Deep Building Basements." Structural Engineers Association of California, Proceedings of the Annual Convention, September, 2010.

  •  Al Atik, L. and Sitar, N. "Seismic Earth Pressures on Cantilever Retaining Structures." J. Geotech. and Geoenvir. Engrg., ASCE, Volume 136, No. 10, October 2010, pp. 1324-1333.

  •  Collins, B.D. and Sitar N. "Stability of Steep Slopes in Cemented Sands." J. Geotech. and Geoenvir. Engrg., ASCE, Volume 137, No. 1, January 2011, pp. 43-51.

  • Shriro, M., Cobos Roa, D., Bray, J.D., Sitar, N., Lichter, J., Evans, R.,  Kroll, R. "Study of Levee Seepage and Slope Stability in Relation to Roots,"  Association of Dam Safety Officials 2011 Conference, Washington D.C., September, 2011.

  •  Wang, G., Kasali, G. and Sitar, N. "Static and Dynamic Axial Response of Drilled Piers. I: Field Tests.":  J. of Geotech. and Geoenvir. Engrg., ASCE, Vol. 137, No. 12, Dec., 2011, pp. 1133-1142.

  •  Wang, G. and Sitar, N. ":Static and Dynamic Axial Response of Drilled Piers. II: Numerical Simulation."  J. of Geotech. and Geoenvir. Engrg., ASCE, Vol. 137, No. 12, Dec., 2011, pp. 1143-1153.

  •  Zimmer, V.L, Collins, B.D., Stock, G.M., and Sitar, N. "Rock fall dynamics and deposition: an integrated analysis from the 2009 Ahwiyah Point rock fall, Yosemite National Park, USA," Earth Surface Processes and Landforms 37, 680-691, 2012. DOI: 10.1002/esp.3206

  •  Sitar, N., Geraili Mikola, R., and Candia, G. "Seismically Induced Lateral Earth Pressures on Retaining Structures and Basement Walls", Keynote Lecture, Geotechnical Engineering State of the Art and Practice, Keynote Lectures from GeoCongress 2012, GSP 226, ASCE, 2012.

  • Cobos-Roa, D., Shriro, M., Sitar, N., Bray, J.D., Bawden, G., Lichter, J., and Evans, R. "3-D Stratigraphy and Root Geometry From Trench and Ground-Based LiDAR Mapping," Proceedings, GeoCongress 2012, ASCE, March, 2012. 

 

 

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