Geotechnical Engineering Commons^™

Cyclic Behavior Of Transitional Fine-Grained Soils In Northern Willamette Valley, Frank Jarman

Civil and Environmental Engineering Master's Project Reports

As discussed within studies from Idriss and Boulanger (2008) and Bray and Sancio (2006), the undrained cyclic shear behavior of low-plasticity fine-grained soils will transition between liquefaction (sand-like behavior) to cyclic softening (clay-like behavior) over a narrow range of plasticity index (PI). Despite not being sufficiently understood, the cyclic behavior of low plasticity silts has become an increasingly important field of study due to the significant impact it has on ground deformations and infrastructure failure in areas that are seismically active. Laboratory tests were performed on soils by third party consultants on a site located in the northern Willamette Valley, …

Liquefaction Triggering In Low-Plasticity Silts And Effects Of Liquefaction-Induced Lateral Spreading On A Reinforced-Concrete Pile, Jared A. Martinez

Civil and Environmental Engineering Master's Project Reports

Liquefaction triggering and post-liquefaction effects on lateral loading of deep foundations is an emerging area of study. This project presents: the results of cyclic direct simple shear (CDSS) testing on a low-plasticity alluvial silt collected in Portland, Oregon; and analysis of the combined effects of liquefaction-induced lateral spreading on a reinforced-concrete pile using data collected from a shake table test. The former research determines the liquefaction susceptibility and post-liquefaction characteristics of a local transitional soil using stress-controlled CDSS testing, the latter explores the complex lateral loading a reinforced-concrete pile undergoes during seismic loading with liquefaction-induced lateral spreading of the ground …

Cascadia Subduction Zone Earthquake Vertical Ground Acceleration Investigation And Potential Impact On Bridges In The Pacific Northwest, Rachel Caroline Bassil

Civil and Environmental Engineering Master's Project Reports

The effects of vertical ground accelerations during subduction zone earthquakes currently are not sufficiently understood. There are numerous case studies and evidence that effects of vertical ground accelerations can significantly impact the performance of bridges during a seismic event, but most previous research has been focused on shallow crustal earthquakes. Current bridge design codes provide little guidance for accounting for vertical ground accelerations in seismic design, in part because additional information is needed about the characteristics of vertical ground motions during Cascadia Subduction Zone (CSZ) earthquakes in the Pacific Northwest.

For this study, recorded seismic data from recent subduction zone …

Undrained Cyclic Loading Of Low Plasticity Silty Soils In The Pacific Northwest Using Laboratory And Field Cyclic Shear Testing, Angelica Melissa Preciado Reyes

Dissertations and Theses

The cyclic behavior of a fine-grained low plasticity silty soil (plasticity index of approximately 15) at a site in Portland, Oregon, is characterized using a field and laboratory cyclic shear test program. The field cyclic tests were performed using the NHERI@UTexas large mobile shakers T-Rex and Rattler. The laboratory tests were performed using resonant column torsional shear and cyclic direct simple shear devices. This testing program's results were used to evaluate the soil's potential to develop excess pore water pressure with cyclic shear strains ranging from 0.00001% to 3%. The laboratory cyclic test results are compared against field cyclic test …

Numerical Simulation Of Continuous Cone Penetration And Interpretation Of Cptu Dissipation Tests, Andrew Phillip Eugene Huffman

Dissertations and Theses

The piezocone penetration test (CPTu) is a commonly used method of geotechnical site investigation. The CPTu is especially useful because it provides a nearly continuous data profile of in-situ soil behavior, which can be correlated to useful engineering parameters. However, limitations exist for interpretation of geotechnical properties from CPTu data and for numerical analysis of cone penetration problems. The research presented in this thesis examines interpretation of coefficient of consolidation from CPTu dissipation test data and implementation of an algorithm to advance numerical simulation of cone penetration problems. This thesis presents analysis of CPTu dissipation responses from field-measured and numerically …

Relationships Between In-Situ Tests And Soil Cyclic Strength For Earthquake Hazard Characterization In The Pacific Northwest, Tanner Scott Bryantt

Dissertations and Theses

Strong earthquake shaking is a natural hazard threat in the Pacific Northwest. Soil failure due to strong earthquake shaking -- known as cyclic soil failure or liquefaction -- is expected to cause large ground deformations and damage to roads, bridges, and other civil infrastructure. Cyclic soil strength (CRR) is often characterized with in-situ geotechnical tests including the cone penetration test (CPT). Relationships between CRR and in-situ test data are not well established for soils in the Pacific Northwest. Portland State University, in partnership with New Albion Geotechnical has compiled a database of cyclic lab tests for Pacific Northwest soils to …

Undrained Cyclic Shear Resistance Of Low Plastic Silts, Rawan Almoumen

Dissertations and Theses

A magnitude 9 Cascadia Subduction Zone earthquake is expected to trigger widespread liquefaction in loose material in Oregon. The geotechnical engineering studies have determined that the Willamette Silts may be susceptible to liquefaction or cyclic softening, as their plasticity indices ranges between non-plastic to low plasticity. While the majority of past studies have focused on liquefaction of sand and cyclic behavior of clays, there is not enough data on the cyclic response behavior of silty soils and the liquefaction susceptibility of these soils. A research focus in the geotechnical engineering program at Portland State University revolves around is performing cyclic …

An Analysis Of The Optimal Mix Of Global Energy Resources And The Potential Need For Geoengineering Using The Ceagom Model, John George Anasis, M. A. K. Khalil, George G. Lendaris, Christopher L. Butenhoff, Randall Bluffstone

Systems Science Faculty Publications and Presentations

Humanity faces tremendous challenges as a result of anthropogenic climate change caused by greenhouse gas emissions. The mix of resources deployed in order to meet the energy needs of a growing global population is key to addressing the climate change issue. The goal of this research is to examine the optimal mix of energy resources that should be deployed to meet a forecast global energy demand while still meeting desired climate targets. The research includes the unique feature of examining the role that geoengineering can play in this optimization. The results show that some form of geoengineering is likely to …

Optimization Of Single- And Double-Flash Cycles And Space Heating Systems In Geothermal Engineering, Talal Hussein Hassoun

Dissertations and Theses

Two different problems of optimization in the utilization of geothermal energy are presented: First, the thermodynamic optimization for a geothermal power plant using a single- or double-flash process is considered; in this analysis, the optimum flash temperature giving the maximum power output is determined. Second, an economic optimization for space heating systems using geothermal energy is developed to obtain operating conditions for which the total (capital and operating) cost is a minimum.

Both graphical and analytical methods are used in the thermodynamic optimization to determine the optimum flash temperature. The graphical method is based on thermodynamic data provided by an …