@article{gajan_kayser_2019, title={Quantification of the influence of subsurface uncertainties on the performance of rocking foundations during seismic loading}, volume={116}, ISSN={["1879-341X"]}, DOI={10.1016/j.soildyn.2018.09.029}, abstractNote={The major objective of this paper is to quantify the effects of uncertainties in soil properties and loading conditions on the performance of rocking foundations during seismic loading. Probabilistic numerical simulations were carried out using a validated soil-foundation Contact Interface Model in OpenSees finite element framework. Results indicate that for relatively larger static vertical factor of safety systems, the moment capacity of rocking foundations mainly depends on the applied vertical load on the foundation as opposed to the bearing capacity, while the energy dissipation and settlement are more sensitive to initial vertical stiffness of soil-foundation system and applied vertical load.}, journal={SOIL DYNAMICS AND EARTHQUAKE ENGINEERING}, author={Gajan, Sivapalan and Kayser, Mohammad}, year={2019}, month={Jan}, pages={1–14} }
 @inproceedings{kebede_gabr_kayser_2014, title={Scour Zone Characterization by Deep Impinging Jet}, DOI={10.1115/omae2014-24257}, abstractNote={Scour downstream of many hydraulic structures such as culverts and spillways may be treated as analogues to jet scour. This study presents the characterization of a fluidized zone by an impinging jet using a recently developed In Situ Erosion Evaluation Probe (ISEEP). Jet embedment was varied from 0.61 m (2 ft) to 2.43 m (8 ft) in the laboratory with a jet velocity ranging from 3 m/s to 6 m/s using an external pump. A number of piezometers were installed radially and with depth around the probe to characterize the extent of the fluidized zone (zone where effective stress reaches zero). Results indicated that the shape of the embedded fluidized zone changes from spherical to elliptical with increasing impinging distance. The nature of the zone expansion was categorized into three phases: initial, transition, and steady state. A jet velocity of 3.8 m/s resulted in a lateral distance of the fluidization zone that extended 0.3 m from the probe. At jet velocities of 4.2 m/s and 4.5 m/s, the lateral distance of the fluidization zone reached about 0.40 m and 0.45 m, respectively. Vertically, a jet velocity of 4.2 m/s fluidized the soil up to 0.3 m above the jet (probe tip) at 2.4 m embedment depth. At an embedment depth of 2.4 m, this maximum fluidization zone occurs as a closed fluidization. The dimensions of this zone are a function of the applied jet velocity (considering the values used in this study).}, booktitle={Volume 8B: Ocean Engineering}, publisher={ASME International}, author={Kebede, Yulian A. and Gabr, Mohammed A. and Kayser, Mohammad F.}, year={2014}, month={Jun} }
 @article{kayser_gabr_2013, title={Assessment of Scour on Bridge Foundations by Means of In Situ Erosion Evaluation Probe}, volume={2335}, ISSN={["2169-4052"]}, DOI={10.3141/2335-08}, abstractNote={ The work in this paper presents the use of an in situ erosion evaluation probe (ISEEP) to assess scour depth at bridge piers. Numerical modeling and deployment of the device at a North Carolina Outer Banks site damaged by Hurricane Irene in 2011 demonstrates the applicability of the proposed concept. Computational fluid dynamics software, FLOW-3D, was used to assess the scour depth at a bridge pier, and the results were compared with values based on ISEEP-estimated parameters by using an excess-stream power model. The scour depth was also calculated from empirical equations that assumed the same conditions as those used in the numerical analysis. Parametric analysis using FLOW-3D indicated that of the parameters for defining the scour depth, the entrainment coefficient had the largest effect, whereas the drag coefficient had the smallest effect on the scour magnitude within the range of values included in this analysis. The estimated scour depths that were based on ISEEP data agreed relatively well with the scour magnitudes obtained from the numerical analysis, as the ISEEP data reflected the changes in the properties of the sand layer with depth. In contrast, the scour magnitude calculated from the empirical equations underestimated the scour depth, mainly because these equations had no provision for a layered-soil profile. Further validation of both the field-testing procedure and the data reduction approach, including the assessment of the applicability in soils that contain an appreciable percentage of fines, is recommended. }, number={2335}, journal={TRANSPORTATION RESEARCH RECORD}, publisher={Transportation Research Board}, author={Kayser, Mohammad and Gabr, Mohammed A.}, year={2013}, pages={72–78} }