Civil and Environmental Engineering Commons^™

Effects Of Wind Turbine Rotor Positioning On Tornado Induced Loads, Juan P. Lopez Ortiz

Electronic Thesis and Dissertation Repository

This study investigates the loads induced by a large-scale tornado simulation on a horizontal axis wind turbine (HAWT) to assess the influence of three-dimensional flows with respect to the HAWT position. The loads were analyzed under two rotor operational conditions, idling and parked, at five radial distances. Subsequently, experimental validation of the numerical code HIW-TUR was conducted by evaluating the induced moments for various yaw and pitch angles. The experimental results demonstrated that the bending moment was the most important in terms of magnitude and variation with respect to the HAWT position. Furthermore, The HIW-TUR code accurately identified the magnitude …

Spatial Data Analysis For The Development Of Expected Adverse Weather Charts For Transportation Construction Projects, S M Rahat Rashedi, Akosua Ofosua Okyere-Addo

SDSU Data Science Symposium

Problem - Seasonal and daily weather events impact construction projects across the various climate regions of South Dakota in differing fashions. Additionally, the impacts for similar weather events can impact grading, surfacing, and structural construction activities in various ways. Adverse weather conditions can cause major delays which may lead to time extensions and increase project cost.

Purpose – To address these issues, South Dakota Department of Transportation (SDDOT) developed Working Day Weather Charts in 1998. However, advances in construction practices and weather prediction as well as climatic changes have occurred over the interim 25 years. This study is focused on …

Spatial Data Analysis For Traffic Safety Network Screening, Akosua Okyere-Addo, S. M. Rahat Rashedi

SDSU Data Science Symposium

Problem - The roadway system represents a major investment, both public and private, and a valuable resource that enables mobility and accessibility to users. Due to degradation of aging infrastructure and increasing traffic, transportation agencies are seeking to effectively update or improve the system. With rising costs, tight budgets, and limited land resources, agencies are seeking effective techniques for identifying critical mobility and safety concerns. Historically, assignment of crashes to portions of the network, whether segments or intersections, has been the primary manner to link crash and road elements.

Purpose – The primary goal is to explore a potentially more …

Homogeneous Flow Performance Of Steel-Fiber Reinforced Self-Consolidating Concrete For Repair Application: A Biphasic Approach, Naimeh Nouri, Masoud Hosseinpoor, Ammar Yahia, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, fiber-reinforced self-consolidating concrete (FR-SCC) was considered as a diphasic suspension of fiber and coarse aggregate (F-A ≥ 5 mm) skeleton in mortar suspension with solid particles finer than 5 mm. The coupled effect of the volumetric content of fibers, coarse aggregate particle-size distribution, and rheological properties of the mortar on the passing ability and dynamic stability of various FR-SCC mixtures was investigated. Nine high-strength and 10 conventional-strength FR-SCC mixtures for repair application were proportioned with water-to-binder ratios (W/B) of 0.35 and 0.42, respectively, and macro steel fibers of 0.1%–0.5% volumetric contents. The dosages of high-range water-reducer (HRWR) …

Effect Of Additional Water Or Superplasticizer On Key Characteristics Of Cement Paste Made With Superabsorbent Polymer And Other Shrinkage Mitigating Materials, Kamran Aghaee, Ricarda Sposito, Karl Christian Thienel, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of superabsorbent polymer (SAP) coupled with expansive agent (EA) or shrinkage-reducing admixture (SRA) can effectively reduce shrinkage of cement-based materials. However, SAP particles at high contents can adversely affect rheological and mechanical properties. Securing proper workability can be accomplished by additional water or adjusting the superplasticizer (SP) demand. There is an uncertainty about the efficiency of these approaches to workability compensation. This study evaluates the effect of additional water or SP on key properties of cement paste made with SAP and relatively high content of EA or SRA. Macro and micro mechanisms underlying the effect of combined shrinkage …

Numerical Modeling Of A Pile-Supported Wharf Subjected To Liquefaction-Induced Lateral Ground Deformations, Milad Souri, Arash Khosravifar, Stephen Dickenson, Nason Mccullough, Scott Schlechter

Civil and Environmental Engineering Faculty Publications and Presentations

Fully-coupled nonlinear dynamic analysis is increasingly used for assessing the seismic performance of pile-supported wharf structures subjected to liquefaction-induced lateral ground deformations. Several numerical challenges exist for analysis of this highly nonlinear soil-structure interaction, which require robust, yet practical, solutions that are validated with experimental data. This study presents a numerical model of a pile-supported wharf and evaluates the applicability of a soil constitutive model, and modeling assumptions and methods by using recorded data from a well-instrumented, large-scale centrifuge test. The objectives of this study include: (a) evaluating the performance of a recently developed pressure-dependent multi-yield surface constitutive soil model …

Effect Of Class C And Class F Fly Ash On Early-Age And Mature-Age Properties Of Calcium Sulfoaluminate Cement Paste, Sukanta K. Mondal, Carrie Clinton, Hongyan Ma, Aditya Kumar, Monday Uchenna Okoronkwo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

To Promote the Sustainable Development of Eco-Efficient Calcium Sulfoaluminate (CSA) Cements through the Partial Replacement of the CSA Clinker with Supplementary Cementitious Waste Products, the Effects of Coal Fly Ashes on the Early-Age and Mature-Age Properties of a Calcium Sulfoaluminate (CSA)-Based Cement Paste Were Investigated. the Impacts of Both Class C and Class F Fly Ashes on the Rheological Properties, Hydration Kinetics, and Compressive Strength Development of CSA Cement Paste Were Studied. Rheology-Based Workability Parameters, Representing the Rate of Loss of Flowability, the Rate of Hardening, and the Placement Limit, Were Characterized for the Pastes Prepared with Fixed Water-To-Cement (W/c) …

Rheological Characterization Of Ultra-High Performance Concrete For 3d Printing, Arun R. Arunothayan, Behzad Nematollahi, Kamal Khayat, Akilesh Ramesh, Jay G. Sanjayan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The authors recently developed a 3D-printable ultra-high performance fiber-reinforced concrete (3DP-UHPFRC) for additive construction of structural members with significantly reduced reliance on steel bars. This study investigates the rheological behavior of the developed 3DP-UHPFRC. The effects of two major factors affecting the performance of 3DP-UHPFRC, namely steel fiber volume (0, 1%, and 2%) and nano-clay (NC) content (0, 0.1%, and 0.2% by binder mass) on workability, static yield stress, dynamic yield stress, and apparent viscosity were determined. Test results showed that the inclusion of steel fibers and NC reduced the workability and led to a significant increase in the static …

Electrochromic Smart Glass: Supplier Comparison Return On Investment Analysis, Hayden Stewart Owens

Construction Management

In recent years, sustainability in construction has become the focus of how the industry can progress with minimal environmental impact. As sustainability certifications become more desirable, key companies in the construction industry have started to seek greener alternatives to standard building systems. There are many sustainable products that are released, but these products are typically so complex that members of the industry are not familiar with these new systems. One novel piece of technology introduced to the industry is electrochromic glass, or smart glass. Electrochromic glass windows examine sunlight and heat exposure from the surrounding environment and change their opacity …

Evaluation, Comparison, And Improvement Recommendations For Caltrans Financial Programming Processes And Tools, Wenbin Wei, Nigel Blampied, Raajmaathangi Sreevijay

Mineta Transportation Institute Publications

The California Transportation Improvement Program System (CTIPS) is the main tool used by Caltrans’ Division of Financial Programming to support the business of transportation programming. It is a multi-agency joint-use project programming database system applied to develop and manage various state and federal transportation programming documents. The goal of this project is to evaluate CTIPS and explore various new options that will maintain the current functionality of CTIPS, meet legislative guidelines for ADA compliance, ensure security of the system, and have sufficient scalability and capabilities for integration with other systems in the future. The research is based on the review …

Behaviour And Material Properties Of Versaloc Semi-Interlocking Mortarless Masonry, Sonam Dorji, Hossein Derakhshan, David P. Thambiratnam, Tatheer Zahra, Alireza Mohyeddin

Research outputs 2022 to 2026

Masonry construction is popular around the world, but the use of mortared masonry presents numerous challenges. In recent decades, masonry construction systems incorporating interlocking masonry units have been proposed to eliminate mortar. The interlocking between masonry units can be achieved using specially shaped units. This paper presents a comprehensive experimental study to determine the behaviour as well as basic material properties of one such semi-interlocking mortarless masonry. The experiments included testings of ungrouted masonry units, prisms, and wallets. In addition, masonry prisms and wallets with grouted cores were also investigated to study the effect of grouting. A detailed description of …

An Artificial Intelligence Framework To Contractor Financial Prequalification, Salah Elgamal

Theses and Dissertations

Financial distress in the construction industry always causes major disruptions that

usually result in a rippling effect on the economy. Avoiding such defaults is a top priority for employers to meet their demands. Artificial Intelligence (AI) models have provided increased accuracy in predicting financial distress compared to statistical, fuzzy and logistic regression models, and other classification models. The main objective of this work is to support project employers in pre-qualifying contractors by predicting the status of construction contractors during a bid analysis to disqualify contractors with a high probability of experiencing financial distress during the project duration. Eight financial indicators …

Estimating Solar Energy Production In Urban Areas For Electric Vehicles, Shaimaa Ahmed

Theses and Dissertations

Cities have a high potential for solar energy from PVs installed on buildings' rooftops. There is an increased demand for solar energy in cities to reduce the negative effect of climate change. The thesis investigates solar energy potential in urban areas. It tries to determine how to detect and identify available rooftop areas, how to calculate suitable ones after excluding the effects of the shade, and the estimated energy generated from PVs. Geographic Information Sciences (GIS) and Remote Sensing (RS) are used in solar city planning. The goal of this research is to assess available and suitable rooftops areas using …

An Artificial Intelligence Tool For The Selection Of Delay Analysis Technique In Construction, Mostafa Farouk

Theses and Dissertations

The increasing complexity and magnitude of projects impose greater impact of delays on stakeholders. Construction delays are a major source of disputes in construction projects. Since a construction project depends on interactions and shared responsibilities among parties, research works were directed toward identifying delay causes, quantifying their impacts, and proposing ways to deal with them. Several delay analysis techniques (DATs) are available, but when applied to the same project’s delays provide different results. Thus, the selection of the DAT to use in evaluating delays becomes vital. Reviewing the literature, it has been realized that often there are disagreements, which lead …

Design Of A Non-Destructive System For Arctic Permafrost Detection Via High Frequency Electromagnetic Induction, Gray Dominic Thurston

Theses and Dissertations

Electromagnetic induction (EMI) sensors have been utilized in the past by the United States Army Corps of Engineers as a method of detecting unexploded ordnance (UXO). Recently, an EMI instrument was constructed that extended the traditional EMI frequency range from 100 kHz to 15 MHz to aid in the detection of nonmetallic ordnance, landmines, and improvised explosive devices. Building on this research, the iFROST mapper project aims to use the same high-frequency (HF) EMI technique to characterize arctic soil and subsurface permafrost deposits. Based on a device used by the US Army for UXO detection, an HF EMI instrument was …

Monitoring Fluid Migration Using In-Situ Nuclear Magnetic Resonance Core Flooding System Integrated With Fiber Optic Sensors: A Proof Of Concept, Bruno Da Silva Falcão, Lionel Esteban, Ausama Giwelli, Yevhen Kovalyshen, Stephen Banks, Ahmed Al-Yaseri, Alireza Keshavarz, Stefan Iglauer

Research outputs 2022 to 2026

In-situ nuclear magnetic resonance (NMR) core flooding system has enabled researchers to monitor several rock properties such as porosity, pore size distribution, and fluid saturation along the tested samples with high resolutions and under reservoir conditions. However, spatially resolved rock strength/mechanical property alteration coupled to fluid migration/substitution remains poorly characterized. To this end, Fiber Bragg Grating (FBG) multiplex sensors were integrated with NMR core flooding system to monitor rock strength changes, or generally speaking, to observe hydro-mechanical-chemical coupling mechanisms during core flooding tests. In this study, we present a novel approach on how to conduct core flooding experiments, while simultaneously …

Driver And Bicyclist Comprehension Of Blue Light Detection Confirmation Systems, Douglas P. Cobb, Hisham Jashami, Christopher Monsere, Sirisha Kothuri, David S. Hurwitz

Civil and Environmental Engineering Faculty Publications and Presentations

This study analyzed motorist and bicyclist understanding and preference of positive confirmation of detection of a bicycle by the traffic signal infrastructure using a blue light detection confirmation (BLDC). The research analyzed results of an online survey of 1,123 respondents and intercept survey of 337 respondents. The study initially found that participants of the survey did not understand the meaning of the blue light itself, but comprehension of the system rose from 40% to 50% when supplemental signs were used. Respondents overwhelmingly indicated that they preferred the sign option that included symbols, text, and a representation of the blue light, …

Development And Prediction Of A Construction Price Index In Egypt, Mohamed Ramadan

Theses and Dissertations

Cost overrun is one of the most recurring issues in the Egyptian construction industry. The effect is not only on the construction industry ,but also influences the overall economy of a country like Egypt. Therefore, a construction performance index and a construction price index could be an integral indicator of the performance of the industry. These indices can reduce construction companies’ losses and decrease the effect of any sudden economic depression on the construction industry. Several research were conducted to predict construction indices. However, many uncertainties disturb the prediction of these indices. The trend in the prediction models for construction …

Co-Culture Models Of Endothelial Cells, Macrophages, And Vascular Smooth Muscle Cells For The Study Of The Natural History Of Atherosclerosis, Martin Liu, Saurabhi Samant, Charu Hasini Vasa, Ryan M. Pedrigi, Usama Oguz, Sangjin Ryu, Timothy Wei, Daniel R. Anderson, Devandra K. Agrawal, Yiannis Chatzizisis

Biological Systems Engineering: Papers and Publications

Background

This work aims to present a fast, affordable, and reproducible three-cell co-culture system that could represent the different cellular mechanisms of atherosclerosis, extending from atherogenesis to pathological intimal thickening.

Methods and results

We built four culture models: (i) Culture model #1 (representing normal arterial intima), where human coronary artery endothelial cells were added on top of Matrigel-coated collagen type I matrix, (ii) Culture model #2 (representing atherogenesis), which demonstrated the subendothelial accumulation and oxidative modification of low-density lipoproteins (LDL), (iii) Culture model #3 (representing intimal xanthomas), which demonstrated the monocyte adhesion to the endothelial cell monolayer, transmigration into the …

Assessing The Predictive Capability Of The Nno Ballistic Limit Equation For Low-Density Projectile Impact, William P. Schonberg

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of nearly all Earth-orbiting spacecraft includes some sort of added shielding that protects the spacecraft against impacts by meteoroids and orbital debris. The effectiveness of the shielding is typically assessed using ballistic limit equations (BLEs) that are developed using data from high-speed impact tests on key spacecraft components and elements. These equations predict whether or not a particular system or structural element will sustain a critical failure following a specific impact event. As such, they are essential components of spacecraft system design as well as any quantitative spacecraft risk assessments that may need to be performed as part …