Engineering Commons^™

Numerical Study Of Cone Penetration In Calcareous Sands: Investigating Cone Tip Resistance Correction Factors For Crushable Soils, Stephanie Michelle Hyder

Dissertations and Theses

The cone penetration test (CPT) is used to characterize the behavior and properties of soils, including the susceptibility to earthquake liquefaction triggering. The cone tip resistance relates to liquefaction susceptibility through relative density, where relative density is closely related to both cone tip resistance and liquefaction susceptibility. Currently, published methods of estimating liquefaction potential (i.e., cyclic resistance ratio) are based on silica sands and do not properly characterize calcareous sands. The measured cone tip resistance in calcareous sands is lower than in silica sands at the same relative density; this difference is generally attributed to the higher compressibility of calcareous …

Uncertainty Quantification Of Live Load Effect In Buried Rc Box Culverts, Mohd Firoj

Dissertations and Theses

Although buried and mostly invisible to the traveling public, bridge-sized culverts (i.e., culverts with span around or longer than 20 ft) account for a large proportion of state-managed bridges. As per Oregon Department of Transportation inventory, there are approximately 35,000 culverts in the state highway system. Among them, 10,862 are in poor conditions and need to be analyzed for load rating purposes. The prediction and understanding of live load effects in culverts are crucial to the design, evaluation, and life-cycle maintenance of culverts. These live load effects include maximum bending moments and shear forces at different critical cross sections.

This …

Probability Distribution Fitting For Censored Data: A Practical Guide For Survival Analysis Of Nbi Data For Concrete Bridge Decks In Oregon, Asmaa Almeshaileh

Dissertations and Theses

Many sophisticated statistical models and analyses have been proposed to analyze datasets derived from the national bridge inventory (NBI). These objectives range from creating an understanding of the factors that drive the deterioration of bridge members to providing agencies with quantitative information for their maintenance and repair decisions. As these models become increasingly sophisticated and difficult to comprehend and implement, practicing engineers and owners are less likely to use them. Often, however, grouping data intuitively, for example, per a select structure type or condition rating and analyzing them using prescriptive statistics such as distribution fitting, does not only lie in …

A Bayesian Network-Based Methodology For Improved Bridge Load Rating And Asset Management, Jeffery Mark Roberts

Dissertations and Theses

From the day a new structure is made available for use, to the day that the structure is no longer able to fulfill an intended purpose, structural safety is a vital interest. Managing a portfolio of structures can be a difficult undertaking for an asset manager, particularly if different types of structures are being maintained. The goal is to manage assets in the most efficient manner which can be influenced by, at a minimum, safety and financial concerns.

A potential tool for an asset manager or owner is the use of Bayesian Networks (BNs). When a BN is used to …

Uncertainty Quantification And Fragility Development Of Deteriorating Rc Bridge Piers, Ayush Bhandari

Dissertations and Theses

Corrosion can reduce structural capacity and increase the risk of bridge damage/failure under extreme events. The impact of corrosion on seismic fragility of bridges has been well studied. However, the methodology used in most existing studies requires detailed information on the structural design and condition of a bridge, which is a major hindrance in conducting seismic risk assessment for a large population of bridges. Furthermore, existing studies do not adequately address the time-dependency of uncertainties associated with fragility curve development. This study presents a methodology to generate time-dependent seismic fragility curves for deteriorating highway bridges based only on the limited …

Seismic Performance Design Criteria Of Existing Bridge Bent Plastic Hinge Region And Rapid Repair Measures Of Earthquake Damaged Bridges Considering Future Resilience, A K M Golam Murtuz

Dissertations and Theses

The main objective of this research was to evaluate the seismic performance of existing sub-standard reinforced concrete (RC) bridge column-spread footing subassemblies and to quantify the material strain limits through a full-scale experimental program. A total of six column-footing test specimens with pre-1990 construction details were subjected to reverse cyclic lateral loading, utilizing a conventional three-cycle symmetric loading protocol and a protocol representing the demands expected from a CSZ earthquake. Additionally, the tests were designed so that variable axial loading could be applied to simulate the secondary load effects experienced during an earthquake in a column that is part of …

Towards Simulation Of Complex Ocean Flows: Analysis And Algorithm For Computation Of Coupled Partial Differential Equations, Wenbin Dong

Dissertations and Theses

The hybrid CFD models which usually consist of 2 sub-models, develop our capability to simulate many emerging problems with multiphysics and multiscale flows, especially for the coastal ocean flows interacted with local phenomena of interest. For most cases, the sub-models are connected with direct interpolation which is easy and workable. It becomes urgently needed to investigate the inner mechanism of such model integration as this simple method does not work well if the two sub-models are different in governing equations, numerical methods, and computational grids. Also, it can not treat complex flow structures as well as the balance in mass …

On A New Framework For Detecting, Classifying, And Forecasting Floods For Large-Scale Flood Risk Analysis, Equisha Glenn

Dissertations and Theses

Increasing trends in flooding events are projected to continue as climate changes have increased the chance of extreme weather events. Given the significant, damaging impacts of extreme floods, the ability to effectively model floods is crucial for risk management and mitigation of the impacts of these extreme flooding events. This dissertation presents a new framework for detecting and predicting large-scale flood risk in the United States using climate information. This methodology categorizes regional, simultaneous floods into an index that is used to forecast the risk of extreme flooding a season ahead. The index proposed herein, named the Spatial Flood Index …

A Citizen-Science Approach For Urban Flood Risk Analysis Using Data Science And Machine Learning, Candace Agonafir

Dissertations and Theses

Street flooding is problematic in urban areas, where impervious surfaces, such as concrete, brick, and asphalt prevail, impeding the infiltration of water into the ground. During rain events, water ponds and rise to levels that cause considerable economic damage and physical harm. The main goal of this dissertation is to develop novel approaches toward the comprehension of urban flood risk using data science techniques on crowd-sourced data. This is accomplished by developing a series of data-driven models to identify flood factors of significance and localized areas of flood vulnerability in New York City (NYC). First, the infrastructural (catch basin clogs, …

Determinant Factors Of Bicyclist Injury Severity At Signalized And Unsignalized Intersections, Apy Das

Dissertations and Theses

Bicycling is becoming increasingly popular in Oregon and the US in general due to its environment friendliness as well as health benefits. With Oregon's population projected to increase by more than 30% over the next 30 years, improving the safety of the transportation network for persons on bicycles is important. In Oregon, majority of the bicyclist crashes occur at intersections. This thesis seeks to identify the determinant factors that significantly impact bicyclist crash injury severity at intersections. A mixed logit framework that accounts for any unobserved heterogeneity in the data and allows the estimated parameters to randomly vary across observations …

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 …

Kinematic Demands On Pile-Supported Wharves Due To Liquefaction-Induced Lateral Ground Deformations, Thomas John Torkelson Ii

Dissertations and Theses

Kinematic demands from lateral soil deformations can be a major cause of damage to maritime and highway transportation structures such as wharves, ports, and bridges. Data from five centrifuge tests on pile-supported wharves were used to evaluate the accuracy of Newmark Sliding Block Analysis in estimating the kinematic demands on piles. The piles in the centrifuge tests were subjected to varying degrees of liquefaction-induced lateral ground deformations. Pile-pinning effects were included in the analysis by incorporating the lateral pile resistance in the limit-equilibrium slope stability analysis. The results of the analysis have shown that the median Newmark displacements better estimated …

Field Trials And Long-Term Monitoring Of Microbially-Induced Desaturation For The Treatment Of Liquefiable Silty Soils, Kayla Rae Sorenson

Dissertations and Theses

Earthquake liquefaction hazards in silty soils are a critical problem in Portland, Oregon, and other areas around the world. This is a particular problem for existing facilities founded on liquefiable soils, for which there exists no cost-effective liquefaction mitigation solution at the present time. It is essential from both a seismic safety and a seismic resilience perspective to be able to mitigate potentially liquefiable soils underneath existing structures, and to do so in a cost-effective manner. Recent studies suggest that liquefaction mitigation using microbially-induced desaturation (MID) may provide this capability.

The objective of MID is to reduce earthquake-induced excess pore …

Using Quantitative Stereology On High Resolution Sem Images To Estimate Diatom Percentages, Ariadna Covarrubias Ornelas

Dissertations and Theses

Diatoms are single-celled organisms of various shapes and sizes typically found in aquatic environments. When diatoms die, the organic material decomposes, and the outer skeletons (i.e., frustules) settle and accumulate as sedimentary deposits. These soils, called diatomaceous soils, exhibit nontraditional behavior since the diatom particles are typically hollow skeletons composed of amorphous silica with intricately patterned and abrasive surfaces. Recent studies have shown that diatomaceous soils are challenging geomaterials since even a small percentage of diatom particles will notably affect engineering behavior. Furthermore, laboratory studies on diatomaceous soil mixtures have demonstrated that many engineering soil properties depend on the percentage …

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 …

Analyzing Freight Congestion And Transportation Performance Measures Using The National Performance Management Research Data Set (Npmrds), Yaxin Zhang

Dissertations and Theses

Traffic congestion is common in urban areas. It results in loss of productivity, increased risk of passenger safety, increased fuel consumption, environment pollution, etc. Improving performance measurement is a tool to improve traffic flow and capacity planning.

The main data source in this research is the National Performance Management Research Data Set (NPMRDS) for 2018. NPMRDS is a form of commercial GPS probe data, obtained from vehicles with on-board probe technologies. This dataset is licensed by the Federal Highway Administration and is made available to State Departments of Transportation (DOTs) and Metropolitan Planning Organizations (MPOs) for the purpose of federally …

Structural Robustness Of Long-Span Cable-Supported Bridges, Qian Chen

Dissertations and Theses

As a critical part of the current infrastructure system, long-span bridges are directly exposed to adverse environments, such as floods, scours, hurricanes, etc., and dynamic loads such as earthquakes and vehicular impacts. Additionally, recent long-span cable-supported collapse examples show that many bridges suffered progressive collapse when local damage occurred, and they are highly vulnerable to severe damages in the event of a localized failure. However, the traditional design approaches are unable to provide explicit measures of residual safety of bridges, especially after an abnormal event. Currently available redundancy and robustness evaluation approaches, which were developed mainly for short-span bridges, are …

Understanding The Effect Of Climate And Hydrometeorological Extremes On Natural And Human-Induced Hydrosystems, Jeongwoo Hwang

Dissertations and Theses

The contemporary hydrosystems of the United States involve a complex combination of natural and modified basins in the presence of changing climate and anthropogenic impacts. An enhanced understanding of the interdependence between climate forcings, human-induced interventions, and water balance in both natural and modified basins are essential for developing reliable and resilient hydrosystems and for better water resources management. In response, this dissertation focuses on investigating the hydroclimatology of natural and modified basins across the contiguous United States. It has three research objectives: (1) to explain flow alterations due to anthropogenic activities, especially dam operations, in modified basins and understand …

Alternate Load Paths And Retrofits For Long-Span Truss Bridges Under Sudden Member Loss And Blast Loads, Huihui Li

Dissertations and Theses

In current bridge design practices, due to the existence of alternate load paths (ALPs), continued stability and progressive collapse-resistance of long-span bridges following the initialed loss of a critical member can be attributed to “redundancy”. However, “redundancy”, also indicated as the post member failure behavior of long-span bridges is not well understood and is not explicitly considered, especially for long-span truss bridges. As one of the most famous collapse events that took place recently, collapse of the I-35W truss bridge has demonstrated the vulnerabilities of long-span truss bridges, and their societal and economic consequences under the abnormal events, such as …

Use Of Carbon Fiber Reinforced Polymer (Cfrp) Including Sheets, Rods, And Ropes In Strengthening And Repairing Long Reinforced Concrete Columns, Yasir Matloob Saeed

Dissertations and Theses

The use of FRP materials in strengthening and repairing of reinforced concrete (RC) structures has increased in the past two decades. Recently, FRP materials have become one of the most used materials in rehabilitation engineering. For seismic retrofitting of RC structures, usually the process involves strengthening or repairing the vertical support elements of the buildings or bridges. Several studies focused on the use of FRP materials in strengthening and repairing RC columns. Externally bonded (EB) FRP sheets or laminates and near-surface-mounted (NSM) FRP rods have been used for enhancing the strength and ductility of RC columns. Although glass FRP (GFRP) …

Dynamic Response Of Highway Bridge Superstructures Subjected To Wave Action: Experimental Analysis And Numerical Modeling, Alaa Waleed Hameed

Dissertations and Theses

Bridges are critical lifeline components of the infrastructure network, enabling economies to function under normal conditions and disaster response and recovery missions to take place after extreme events. Therefore, ensuring satisfactory performance increases community resilience and minimizes both human and economic losses. Coastal bridges, which are the focus of this PhD dissertation, are vulnerable to coastal storms. High failure rates of these bridges during two major hurricane events in the mid-2000s have spurred research activities to better understand the wave-induced forces of coastal bridges.

This PhD research represents a continuation effort to build, implement, and introduce new fundamental concepts and …

Robust Maximum Flow Network Interdiction Problem, Darshan Rajesh Chauhan

Dissertations and Theses

In this thesis, a maximum flow-based network interdiction problem considering uncertainties in arc capacities and interdiction resource consumption is solved. The problem consists of two entities with opposing objectives: the goal of the adversary is to maximize the flow of illicit drugs through the network, while the goal of the interdictor is to minimize the maximum flow by completely interdicting arcs given a specified amount of resources. Lack of complete information about the usage patterns of the transportation network by the adversary results in an uncertain estimate of arc capacity and resources required for interdiction by the interdictor. To account …

Computational Fluid Dynamics Simulation Of Rain-Wind-Induced Vibration Of Stay Cables, Hongfan Wang

Dissertations and Theses

Due to the large amplitude, frequent occurrence and severe consequences, the rain-wind induced vibration (RWIV) of stay cables in cable-stayed bridges has been investigated extensively by researchers around the world. However, the underlying excitation mechanism is still unclear. Recently, computational fluid dynamics (CFD) simulation has been widely applied in the research on structure vibrations due to dynamic wind loads, with great potential as an alternative tool for wind tunnel testing. It has also been adopted to investigate the RWIV, but only a few studies have been conducted so far. Furthermore, most of the CFD simulations reported in literatures are two-dimensional, …

Using Statistical Learning Approaches To Understand Trends And Variability Of Tornadoes Across The Continental United States, Niloufar Nouri

Dissertations and Theses

The annual frequency of tornadoes during 1950-2018 across the major tornado-impacted states were examined and modeled using anthropogenic and large-scale climate covariates in a hierarchical Bayesian inference framework. Anthropogenic factors include increases in population density and better detection systems since the mid-1990s. Large-scale climate variables include El Niño Southern Oscillation (ENSO), Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Arctic Oscillation (AO), and Atlantic Multi-decadal Oscillation (AMO). The model provides a robust way of estimating the response coefficients by considering pooling of information across groups of states that belong to Tornado Alley, Dixie Alley, and Other …

Concrete Bridge Deck Performance Data And Metrics For The State Of Oregon, Jael Wettach-Glosser

Dissertations and Theses

Bridge decks are a critical element of a bridge that support and distribute vehicle loads to the superstructure. Because of the requirements of this role, bridge decks are exposed to severe conditions that typically lead to structural deficiency in bridges which is both costly and disruptive. Therefore, to keep bridges and highways in good repair, developing optimal preservation decisions for concrete bridge decks is key. In order to develop effective performance monitoring and preservation schedules, the parameters affecting bridge deck deterioration need to be better understood.

With guidance from the literature and Oregon Department of Transportation (ODOT) personnel, two datasets …

Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz

Dissertations and Theses

Concrete is widely used for civil infrastructure structures and they experience deterioration and degradation due to aging, increases in the traffic loads, harsher environmental conditions, use of deicing chemicals, etc. Therefore, evaluating the integrity of reinforced concrete structures has become of increasing interest for infrastructure owners and managers. A number of non-destructive testing (NDT) and structural health monitoring (SHM) methods have been developed in recent decades to aid in evaluating structures and provide input for asset management. One family of these methods uses the dynamic response of a structural member: stress waves (high frequency) and structural vibrations (low frequency). Both …

Seismic Behavior Of Screen Grid Core Insulated Concrete Form Walls, Anwer Sabah Mohammed Mohammed

Dissertations and Theses

The use of the insulated concrete form (ICF) walls in residential buildings has increased over the past few decades. Much research has been conducted to evaluate the lateral strength of these walls by applying monotonic and cyclic loadings. In the current study, full-scale shake table experiments were employed to evaluate the in-plane behavior of four screen grid insulated concrete form (SGICF) walls. The first two wall specimens utilized dry fit insulated form blocks made from recycled expanded polystyrene granules that were bonded together with cement. When stacked, the cavities in the blocks formed a grid of cores that are evenly …

A Dynamic Risk Management Framework For Water And Environmental Sustainability, Arun Ravindranath

Dissertations and Theses

The risks and vulnerabilities facing reservoir systems in river basins shift dynamically over time and space. These risks involve regime changes and shifts, throughout which one observes the transition of water availability from prolonged dry periods to prolonged wet periods. Ensuring reliability of water supply under these hydrological regime shifts involves understanding how these regime shifts can be identified, characterized, and quantified. This dissertation describes a dynamic risk management (DRM) framework for water management at the basin level whose main features are (1) a system of updating risk assessments and policy recommendations on a yearly basis, where the risk assessments …

Global Food Security Under Climate-Water-Energy Nexus, Ehsan Najafi

Dissertations and Theses

During the last few decades, the global agricultural production has risen and technology enhancement is still contributing to yield growth. However, population growth, water and energy crisis, and extreme weather, climate change, etc. threaten the global food security. The focus of this study is to advance the understanding of the associations between crops productivity and large scale and local scale climatic variables, climate change, technology enhancement and assessing food-water-energy nexus to enhance global food security in a sustainable manner considering current available resources. As decision-makers try to improve food security, it is important to identify the impact of technology enhancement …

Heavy Truck Collision With Bridge Piers, Ran Cao

Dissertations and Theses

Based on bridge failure data compiled by the New York State Department of Transportation, collision, both caused by vessels and vehicles, is the second leading cause of bridge failures after hydraulic. The current AASHTO-LRFD (2017) specification recommends designing a bridge pier vulnerable to vehicular impacts for an equivalent static force of 2,670-kN (600 kips) applied in a horizontal plane at a distance of 1.5 m (5.0 feet) above the ground level. The vast majority of research studies on vehicular collision with bridge piers have been carried out with single-unit trucks, which are typically classified as medium-duty vehicles weighing about 89 …