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Full-Text Articles in Engineering

Heat Wave Intensity Duration Frequency Curve: A Multivariate Approach For Hazard And Attribution Analysis, Omid Mazdiyasni, Mojtaba Sadegh, Felicia Chiang, Amir Aghakouchak Oct 2019

Heat Wave Intensity Duration Frequency Curve: A Multivariate Approach For Hazard And Attribution Analysis, Omid Mazdiyasni, Mojtaba Sadegh, Felicia Chiang, Amir Aghakouchak

Civil Engineering Faculty Publications and Presentations

Atmospheric warming is projected to intensify heat wave events, as quantified by multiple descriptors, including intensity, duration, and frequency. While most studies investigate one feature at a time, heat wave characteristics are often interdependent and ignoring the relationships between them can lead to substantial biases in frequency (hazard) analyses. We propose a multivariate approach to construct heat wave intensity, duration, frequency (HIDF) curves, which enables the concurrent analysis of all heat wave properties. Here we show how HIDF curves can be used in various locations to quantitatively describe the likelihood of heat waves with different intensities and durations. We then …


Predicting Power-Transformer Bushings’ Seismic Vulnerability: Mounting Stiffness And Coupling, Jon Bender, Arvin Farid Jun 2019

Predicting Power-Transformer Bushings’ Seismic Vulnerability: Mounting Stiffness And Coupling, Jon Bender, Arvin Farid

Civil Engineering Faculty Publications and Presentations

Large power transformers are both expensive and vulnerable to seismic failure. Excessive amplification of earthquake loading to power transformer bushings beyond the bushings’ rated strength can occur if the system’s structural dynamics produce unpredictable and unfavorable resonance behavior. Determining the degree of vulnerability to large seismic amplifications is not straight-forward, and general design recommendations do not always resolve problems that can potentially arise. This paper considers a number of Case studies in an attempt to postulate a set of critical factors, which might facilitate better prediction of bushing amplification. Further, several additional Case studies are summarized in order to add …


A Robust Decision Support Leader-Follower Framework For Design Of Contamination Warning System In Water Distribution Network, Mohammad S. Khorshidi, Mohammad Reza Nikoo, Elham Ebrahimi, Mojtaba Sadegh Mar 2019

A Robust Decision Support Leader-Follower Framework For Design Of Contamination Warning System In Water Distribution Network, Mohammad S. Khorshidi, Mohammad Reza Nikoo, Elham Ebrahimi, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

In recent years, several models have been proposed to inoculate Water Distribution Systems (WDS) against impacts of accidental and/or intentional compromised water quality through optimal deployment of online monitoring sensors in the network, which is referred to as Contamination Warning Systems (CWS). Translating such modeling efforts to real-world practice is, however, a challenge as different involved parties may pursue conflicting goals and modeling-based recommendations may not justify all stakeholders’ criteria. It is, hence, pivotal to develop conflict resolution methodologies to support engagement of different stakeholders in securing a safe water distribution. The decision making structure for CWS design is often …


Climate‐Induced Changes In The Risk Of Hydrological Failure Of Major Dams In California, Iman Mallakpour, Amir Aghakouchak, Mojtaba Sadegh Feb 2019

Climate‐Induced Changes In The Risk Of Hydrological Failure Of Major Dams In California, Iman Mallakpour, Amir Aghakouchak, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Existing major reservoirs in California, with average age above 50 years, were built in the previous century with limited data records and flood hazard assessment. Changes in climate and land use are anticipated to alter statistical properties of inflow to these infrastructure systems and potentially increase their hydrological failure probability. Because of large socioeconomic repercussions of infrastructure incidents, revisiting dam failure risks associated with possible shifts in the streamflow regime is fundamental for societal resilience. Here we compute historical and projected flood return periods as a proxy for potential changes in the risk of hydrological failure of dams in a …


Evaluating Shallow Mixing Protocols As Application Methods For Microbial Induced Calcite Precipitation Targeting Expansive Soil Treatment, Bhaskar C. S. Chittoori, Tasria Rahman, Malcolm Burbank, Arif Ali Baig Moghal Jan 2019

Evaluating Shallow Mixing Protocols As Application Methods For Microbial Induced Calcite Precipitation Targeting Expansive Soil Treatment, Bhaskar C. S. Chittoori, Tasria Rahman, Malcolm Burbank, Arif Ali Baig Moghal

Civil Engineering Faculty Publications and Presentations

Expansive soils, also known as swell-shrink soils, undergo substantial volumetric changes due to moisture fluctuations from seasonal variations. These volumetric changes cause millions of dollars in damages annually. Microbial Induced Calcite Precipitation (MICP) is a promising soil improvement technique, which uses urease producing bacteria to precipitate calcium carbonate. In this study, a stabilization alternative for expansive soils was studied using MICP. Specifically, indigenous bacteria were stimulated by mixing enrichment and cementation solutions with expansive natural soils to precipitate calcium carbonate and make soil stronger and less expansive. This study examined three expansive soils with varying plasticity and mineralogical characteristics. Two …


Coupled Numerical Analysis Of Variations In The Capacity Of Driven Energy Piles In Clay, Arvin Farid, Daniel P. Zimmerman Jan 2019

Coupled Numerical Analysis Of Variations In The Capacity Of Driven Energy Piles In Clay, Arvin Farid, Daniel P. Zimmerman

Civil Engineering Faculty Publications and Presentations

Energy piles are an emerging alternative for the reduction of energy consumption to heat and cool buildings. Most of the research to date has focused on thermodynamic properties or axial and radial stress and strain of piles. This paper focuses on the effects of temperature fluctuation on the capacity of driven energy piles in clayey soils. Consolidation of clay surrounding driven piles affects the pile capacity (i.e., set up in clay). The heating and cooling periods of energy piles can create the excess pore-water pressure (EPWP, ue) or relax the existing one (e.g., due to pile driving or …