Engineering Commons^™

การประเมินวิธีการหาค่าความถี่น้ำท่ารายปีสูงสุดจากข้อมูลน้ำฝนตรวจวัดรายวันในพื้นที่ลุ่มแม่น้ำเจ้าพระยาตอนบน, ชิดสุมน ศศิรัตน์

Chulalongkorn University Theses and Dissertations (Chula ETD)

การศึกษานี้มีวัตถุประสงค์เพื่อเปรียบเทียบความแตกต่างของค่าความถี่น้ำท่ารายปีสูงสุดจากข้อมูลน้ำฝนตรวจวัดรายวัน 2 วิธี ได้แก่ วิธีน้ำท่าสูงสุดจากแบบจำลองและวิธีความถี่น้ำฝน กับค่าความถี่น้ำท่าสูงสุดที่ได้จากข้อมูลน้ำท่าตรวจวัดโดยตรง (วิธีน้ำท่าสูงสุดตรวจวัด) เนื่องจากการวิเคราะห์ค่าความถี่น้ำท่ามีความสำคัญต่อการประเมินความเสี่ยงจากอุทกภัยและการออกแบบโครงสร้างทางชลศาสตร์ ในการศึกษานี้ได้ทำการวิเคราะห์ค่าความถี่น้ำท่าสูงสุดจากวิธีน้ำท่าสูงสุดตรวจวัด, วิธีน้ำท่าสูงสุดจากแบบจำลอง และวิธีความถี่น้ำฝน โดยใช้ข้อมูลตรวจวัดจากสถานีน้ำท่าและสถานีน้ำฝน แล้วทำการวิเคราะห์ความถี่น้ำท่ารายปีสูงสุดและความถี่น้ำฝนรายวันสูงสุดจากฟังก์ชันการแจกแจงความน่าจะเป็นที่เหมาะสมที่สุดสำหรับแต่ละสถานีน้ำท่าและสถานีน้ำฝน ที่ผ่านการทดสอบด้วยแผนภาพอัตราส่วนโมเมนต์เชิงเส้น อีกทั้งในการศึกษานี้ได้ประยุกต์ใช้แบบจำลอง HEC-HMS ในการจำลองกระบวนการน้ำฝน-น้ำท่า เพื่อจำลองปริมาณน้ำท่ารายวันสำหรับวิธีน้ำท่าสูงสุดจากแบบจำลอง และจำลองความถี่น้ำท่าสูงสุดสำหรับวิธีความถี่น้ำฝน ซึ่งแบบจำลองนี้ได้ผ่านกระบวนการทดสอบความอ่อนไหว และผ่านการปรับเทียบและสอบทานแบบจำลองสำหรับแต่ละสถานีน้ำท่า ด้วยค่าสัมประสิทธิ์การตัดสินใจ (R2) ของทุกสถานีอยู่ในช่วง 0.71 ถึง 0.99 ค่าเปอร์เซ็นต์ความเอนเอียงของค่าสูงสุด (PpeakBIAS) ของทุกสถานีน้อยกว่า "±25%" ยกเว้นสถานี W.17 ผลการวิเคราะห์ความแตกต่างของค่าความถี่น้ำท่าสูงสุดระหว่างวิธีน้ำท่าสูงสุดตรวจวัดและวิธีน้ำท่าสูงสุดจากแบบจำลอง พบว่ามีเพียงสถานีเดียว คือ สถานี P.17 ที่ค่าความถี่น้ำท่าสูงสุดระหว่าง 2 วิธีการมีความแตกต่างอย่างมีนัยสำคัญ ที่ระดับนัยสำคัญ 0.05 ในขณะที่ค่าความถี่น้ำท่าสูงสุดระหว่างวิธีน้ำท่าสูงสุดตรวจวัดและวิธีความถี่น้ำฝน พบว่ามีความแตกต่างกันอย่างมีนัยสำคัญ ที่ระดับนัยสำคัญ 0.05 ถึง ที่ 8 สถานี ได้แก่คือ สถานี P.21, P.1, P.17, W.4A, W.17, N.1, N.67 และ C.2 ที่ค่าความถี่น้ำท่าสูงสุดระหว่าง 2 วิธีการมีความแตกต่างกันอย่างมีนัยสำคัญ ที่ระดับนัยสำคัญ 0.05 นอกจากนี้พบว่า ผลการวิเคราะห์ค่าความถี่น้ำท่าสูงสุดจากวิธีความถี่น้ำฝนทุกสถานีให้ค่าความถี่น้ำท่าสูงสุดสูงกว่าวิธีน้ำท่าสูงสุดตรวจวัด โดยเฉพาะสถานีที่บริเวณจุดรวมตอนล่างของลุ่มแม่น้ำเจ้าพระยาตอนบน ได้แก่ สถานี P.17, N.67 และ C.2 และเมื่อพิจารณาเพิ่มเติมถึงผลกระทบของโครงสร้างอ่างเก็บน้ำขนาดใหญ่ในลุ่มน้ำ พบว่าการมีโครงสร้างอ่างเก็บน้ำส่งผลให้ค่าความถี่น้ำท่าสูงสุดลดลงแปรผันกับอิทธิพลของสัดส่วนขนาดพื้นที่รับน้ำเหนือเขื่อนกับพื้นที่ลุ่มน้ำทั้งหมด ในบริบทของการเปลี่ยนแปลงสภาพภูมิอากาศที่เพิ่มความรุนแรงและความถี่ของเหตุการณ์สุดขีด การเลือกวิธีประเมินค่าความถี่น้ำท่าที่เหมาะสมจึงมีความสำคัญต่อการลดความเสี่ยงในโครงการและเพิ่มประสิทธิภาพในการบริหารทรัพยากร วิศวกรผู้ใช้งานจึงควรตระหนักถึงความเสี่ยงและความคุ้มค่าที่จะเกิดขึ้นจากการเลือกใช้งานวิธีการใดวิธีการหนึ่ง

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Pakunihanich Nicoli Martin

Cal Poly Humboldt theses and projects

The integration of Indigenous and Western science plays an essential role in Tribally led collaborations for land management. This process of woven sciences is rooted in reciprocal relations and partnerships guided by Tribal Nations. Our cohort was invited by Wiyot Tribal Representatives to investigate a culvert located within the wetlands of Mouralherwaqh— a parcel of land reacquired by the Wiyot Tribe in 2022. This document seeks to share our experience and analysis as part of the Wiyot Tribe’s broader journey in navigating ecocultural restoration projects within Mouralherwaqh. The four community interests we investigated for the wetland crossing included a resized …

A Resilient Decarbonization Package For The Hoopa Shopping Center, Esther Obikoya

Cal Poly Humboldt theses and projects

The Hoopa Shopping Center, located within the Hoopa Valley Tribe Reservation, faces significant energy cost fluctuations and reliability issues. Given the susceptibility of remote communities to power disruptions, the Tribe's move toward achieving a sustainable and resilient power infrastructure is essential. This study investigates the technical and economic decarbonization strategies for the Hoopa Shopping Center, focusing on reducing energy bills, energy consumption, and greenhouse gas emissions through electrification and energy efficiency improvements, as well as the integration of renewable energy sources.

This decarbonization could be done in a way consistent with the development of a microgrid to energize the community …

Direct Blue 86 Textile Dye Removal From Aqueous Solution Using Rice Husk-Based Adsorbent, M. Zulbahari M. Zua, Muhammad Raza Ul Mustafa, Mohamed Hasnain Isa, Teh Sabariah Binti Abd Manan, Naimah Ibrahim, Rozeana Hj Md Juani, Wida Susanty Hj Suhaili, Asmaal Muizz Sallehhin Bin Hj Mohammad Sultan, Zuliana Binti Hj Nayan

ASEAN Journal on Science and Technology for Development

Adsorption by activated carbon is an effective method of dye removal. However, due to high production and regeneration costs of activated carbon, various studies on low-cost adsorbents have been conducted. Agricultural waste such as rice husk (RH) is seen to be a good adsorbent for dye removal. Moreover, rice husk is readily available. In this study, rice husk-based adsorbents were prepared by chemical and thermal treatments. Standard curve (colour vs absorbance) for Direct Blue 86 (DB 86) was prepared to determine the concentration of dye before and after adsorption. The adsorption potential of the adsorbent for textile dye DB 86 …

Stormwater Responses To Climatic And Land Cover Changes In Lowly Urbanized Subcoastal Environments, Md Tanvirul Islam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Stormwater runoff is widely considered a significant factor in coastal inundation and water quality degradation. The main objective of this thesis is to determine the potential impacts on stormwater runoff in lowly urbanized coastal/subcoastal environments under a changing climate and land use/cover. The East Fork San Jacinto River Basin (Area = 2577 of southern Texas, USA was considered a pilot area for this study. Given the sparse availability of high-resolution precipitation data in space and time, this research first evaluated four remotely sensed and/or reconstructed precipitation products (CMORPH-CDR, MERRA, PERSIANN-CDR, and PRISM) by comparing the data with the historical gauge …

Mouralherwaqh: Coastal Wetland Road Crossing Da’Luk, Filip Amborski

Cal Poly Humboldt theses and projects

The integration of Indigenous and Western science plays an essential role in Tribally led collaborations for land management. This process of woven sciences is rooted in reciprocal relations and partnerships guided by Tribal Nations. Our cohort was invited by Wiyot Tribal Representatives to investigate a culvert located within the wetlands of Mouralherwaqh— a parcel of land reacquired by the Wiyot Tribe in 2022. This document seeks to share our experience and analysis as part of the Wiyot Tribe’s broader journey in navigating ecocultural restoration projects within Mouralherwaqh. The four community interests we investigated for the wetland crossing included a resized …

Field Scale Evaluation Of A Flow-Through Filtration System With Mixed Media To Remove E. Coli From Stormwater, Ankur Debnath

Electronic Theses and Dissertations

The main goal of this research was to establish a field-scale stormwater filtration system which is flow-through and cost-effective in terms of construction and maintenance. The filter is constructed in a downstream drainage of a retention pond where the stormwater goes through the porous space of media so that it maintains low retention time with minimum disturbance in flow. The filter consists of two 20ft long sections with concrete channel and ripraps on the inlet & outlet side. 30% Steel chips and 70% steel slags in the size range of 6.00-12.5 mm have been used as media which has been …

Development Of A New Green Infrastructure By Using Biochar Amended Topsoil For On-Site Stormwater Runoff Treatment, Ayesha Sadia

College of Graduate Studies: Theses & Dissertations

This Research Project aimed to design, build, operate and maintain, and monitor a new green infrastructure (GI) using biochar-amended topsoil for on-site stormwater runoff treatment in urban areas. The project involved evaluating the removal efficiencies of pollutants from stormwater runoff such as total suspended solid (TSS), nutrients including nitrogen and phosphorous, heavy metals including lead (Pb), zinc (Zn) and copper (Cu) and oil and grease etc. from the media of biochar amended topsoil. In this Project, a full-scale Field Test Site with a total area of 500 and 1 ft depth was built to on-site treat stormwater runoff from a …

Evaluation Of The Physicochemical Properties And Soil Biogeochemistry Of Fire Residues, Lingqun Zeng

Electronic Theses & Dissertations (2024 - present)

Wildland fire is a main driving force in the Earth system and affects ecosystem properties and processes across spatio-temporal scales. The burning of biomass and production of solid fire residues (conventionally termed fire ash) that are a mixture of completely and incompletely burned materials (inorganic ash and pyrogenic carbon), represent the direct and prominent changes by fires. Cycling of the fire residues is an integral component of elemental cycles and can mediate other biogeochemical processes.

This dissertation aims to fill important knowledge gaps in understanding the disturbance of wildland fires to biogeochemical processes in soils. First, this work characterized and …

A Practical Framework For Component-Level Structural Health Monitoring Of The Gerald Desmond Bridge, Mehran Rahmani, Vesna Terzic, Andrea Calabrese, Brittany Cambell

Mineta Transportation Institute

Bridges serve as critical transportation infrastructure, but traditional maintenance inspection to ensure their safety is time-consuming, costly, and labor-intensive, especially for larger and more complex structures. This study presents a practical framework for the instrumentation, data acquisition, and remote condition assessment of the Gerald Desmond Bridge, California’s largest cable-stayed bridge. The framework aims to establish a foundation for real-time or near real-time remote health monitoring of the bridge’s critical elements. The study highlights the advantages of remote monitoring in terms of efficiency, cost-effectiveness, and early detection of damage.

Novel Membrane Materials For Nutrient Recovery From Nutrient-Rich Resources, Km Prottoy Shariar Piash

Graduate Theses, Dissertations, and Problem Reports (ETD)

Global demand for fertilizer production is expanding substantially to meet the food demand of an increasing world population. Anaerobic digestate (AD) of various centralized wastewater facilities contains substantial amounts of ammonium (NH₄⁺) (300-800 mg/L), potassium (K⁺) (13-120 mg/L), and phosphorus (P) (30-100 mg/L)- based nutrients. In addition to reducing energy costs and CO₂ emissions compared to conventional fertilizing raw material manufacturing, recovering nutrients from these waste streams could help mitigate problems such as eutrophication, which otherwise incurs billions of dollars losses to US economy annually. Apart from nutrients, wastewater streams also contain organic pollutants …

Static Response Of Frp Structural Systems – Piles, Platforms, And Poles, Manish Adhikari

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study addresses the static response of three Fiber Reinforced Polymer (FRP) structural systems (piles, platforms, and poles) under static loads. This research aims to improve safety and sustainability in modern infrastructure by bridging the knowledge gap currently that exists between the experimental behavior and theoretical predictions.

FRP round piles (18-inch in diameter) were tested under axial compression, shear, four-point bending and fatigue. Both the load-deflection and stress-strain responses were analyzed. Coupon tests were conducted and related to the outcomes of full-scale test data. Two major differences were observed in the response of the bending test specimens with modulus of …

An Integrated Framework For Establishing Long-Term Transportation Management Strategies Promoting Sustainable Urban Growth, M Imtiaz Rahman

Graduate Theses, Dissertations, and Problem Reports (ETD)

Urban land areas are experiencing a more rapid expansion compared to their population growth on a global scale. This phenomenon, known as urban sprawl, is characterized by low-density development in the outskirts of cities. This unplanned urban growth leads to changing urban transportation patterns, posing a threat to sustainable development. In response, government agencies implement growth management practices, with transportation management strategies playing a crucial role in achieving sustainable urban growth. However, developing effective growth management strategies is difficult because of several challenges, including limited understanding of the key influencing factors, the complex interdependencies among these factors, and the uncertainties …

Performance Evaluation Of Composite Utility Structures Under Wildfires And Mitigation Methods, Siddhant Sitoula

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Fiber Reinforced Polymer (FRP) composite utility poles and crossarms have been getting wider attention from the utility industries because of their advantages over the traditional wooden, concrete, and steel poles. Wood is vulnerable to fire, rot, and animal damage. Concrete poles are heavier, increasing both transportation and installation costs of the poles, in addition to limited-service life (40-50 years). Similarly, steel poles have durability and safety concerns because of their inherent corrosive nature and conductivity. These disadvantages are significantly reduced by the use of FRP composites in utility structures because of FRP’s strength, specific gravity, flexibility, non-conductivity and durability …

Understanding Learners' Perception Of Virtual Reality-Assisted Learning In Engineering Education, Mohammad Samin Mansur

Graduate Theses, Dissertations, and Problem Reports (ETD)

Virtual reality (VR)-assisted learning may facilitate an immersive and interactive learning environment and enable learners to explore and interact with learning content at their own pace and interest. However, it is still unknown how well VR is received in engineering learning while empowering autonomy and personalization. The objective of this study is to investigate learners' perceptions of VR-assisted learning in engineering education while allowing learners to learn at their own pace, driven by their personal preference. To this end, experiments were conducted, in which thirty engineering students were recruited and immersed in a VR setting designed to deliver an interactive …

A Structure From Motion Photogrammetric Method For Continuously Measuring And Tracking The Deformations Of Soils During Triaxial Testing, Xiaolong Xia

Doctoral Dissertations

"Measuring soil deformation characteristics during triaxial testing is an important part of characterizing the stress-strain behavior of both saturated and unsaturated soils. The total and local deformations and volume changes of a soil specimen are indispensable parameters that need to be measured and are of great significance for understanding volume change and shear strength characteristics of the soil. Over the past several decades, numerous efforts have been made to measure the soil deformations during triaxial testing. However, it remains a great challenge for researchers to measure the volume-changes of unsaturated soils due to the existence of the air phase.

This …

Comprehensive Investigation Of Using Tire-Derived Aggregate In Chip Seal Subjected To Various Traffic And Environmental Conditions, Alireza Pourhassan

Doctoral Dissertations

"Chip seal is one of the most cost- and performance-effective pavement preservation treatments commonly used in the United States. Using crumb rubber obtained from scrap tires as a partial or full replacement for mineral aggregate has been proposed as a sustainable solution to reduce the negative environmental impacts of scrap tire accumulation and excessive consumption of natural resources. However, there was no data available regarding the performance of rubberized chip seal under traffic loads and environmental conditions. An extensive study using laboratory specimens and conditioning as well as field implementation and assessments were conducted to bridge this gap. Different traffic …

Improving Decision-Making Processes In Construction And Infrastructure Bidding: Qualitative And Quantitative Approaches Including Graph Theory, Game Theory, And Machine Learning, Muaz Osman Elzubeir Ahmed

Doctoral Dissertations

"Construction and infrastructure bidding is a highly competitive process that entails various uncertainties faced by contractors. Contractors weigh various factors to determine the expected benefits of a construction project and decide their bid value. However, the situation is more complex in multi-stage bidding (MSG), where general contractors must account for the bids of their subcontractors and face a greater threat of the winner’s curse (i.e., situation where the winning contractor underestimates the actual cost of the project). As such, bidding-related complexities, risks, and uncertainties, if uncontrolled, can lead to the rise of claims and disputes between stakeholders. Existing research falls …

Analysis Of Traffic Conflicts With Right Turning Vehicles At Unsignalized Intersections In Suburban Areas, Abbas Sheykhfard, Farshidreza Haghighi, Sarah Bakhtiari, Sara Moridpour, Kun Xie, Grigorios Fountas

Civil & Environmental Engineering Faculty Publications

Right-turn collisions at intersections are one of the most dominant crash types in suburban areas, especially at unsignalized intersections. There is, however, a lack of comprehensive research on the speed patterns of vehicles during right-turn manoeuvres and their impact on crashes. To provide an in-depth investigation of the factors determining the safety of right-turn manoeuvres, driving behaviour data were collected through an instrumented vehicle study. Using this data, binary logistic regression models were developed to identify the factors affecting the probability of Vehicle-Vehicle (V-V) and Vehicle-Pedestrian (V-P) conflicts at six suburban intersections in Babol, Iran, during right-turn stage manoeuvres. In …

Urban Flood Extent Segmentation And Evaluation From Real-World Surveillance Camera Images Using Deep Convolutional Neural Network, Yidi Wang, Yawen Shen, Behrouz Salahshour, Mecit Cetin, Khan Iftekharuddin, Navid Tahvildari, Guoping Huang, Devin K. Harris, Kwame Ampofo, Jonathan L. Goodall

Civil & Environmental Engineering Faculty Publications

This study explores the use of Deep Convolutional Neural Network (DCNN) for semantic segmentation of flood images. Imagery datasets of urban flooding were used to train two DCNN-based models, and camera images were used to test the application of the models with real-world data. Validation results show that both models extracted flood extent with a mean F1-score over 0.9. The factors that affected the performance included still water surface with specular reflection, wet road surface, and low illumination. In testing, reduced visibility during a storm and raindrops on surveillance cameras were major problems that affected the segmentation of flood extent. …

Small-Strain Site Response Of Soft Soils In The Sacramento-San Joaquin Delta Region Of California Conditioned On Vₛ₃₀ And Mhvsr, Tristan E. Buckreis, Jonathan P. Stewart, Scott J. Brandenberg, Pengfei Wang

Civil & Environmental Engineering Faculty Publications

Sites located in the Sacramento-San Joaquin Delta region of California typically have peaty-organic soils near the ground surface, which are characteristically soft, with shear wave velocities as low as 30 m/s. These unusually soft geotechnical conditions, which are outside the range of applicability of existing ergodic site amplification models, can be anticipated to produce significant site effects during earthquake shaking. We evaluate site response for 36 seismic stations in the Delta region using non-ergodic methods with low-amplitude ground motion data. We model first-order site effects using a period-dependent relation conditioned on the 30 m time-averaged shear wave velocity (V …

A Review On Biochar As An Adsorbent For Pb(Ii) Removal From Water, Pushpita Kumkum, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

Heavy metal contamination in drinking water is a growing concern due to its severe health effects on humans. Among the many metals, lead (Pb), which is a toxic and harmful element, has the most widespread global distribution. Pb pollution is a major problem of water pollution in developing countries and nations. The most common sources of lead in drinking water are lead pipes, faucets, and plumbing fixtures. Adsorption is the most efficient method for metal removal, and activated carbon has been used widely in many applications as an effective adsorbent, but its high production costs have created the necessity for …

De-Risking Pretreatment Of Microalgae To Produce Fuels And Chemical Co-Products, Jacob S. Kruger, Skylar Schutter, Eric P. Knoshaug, Bonnie Panczak, Hannah Alt, Alicia Sowell, Stafanie Van Wychen, Matthew Fowler, Kyoko Hirayama, Anuj Thakkar, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

Conversion of microalgae to renewable fuels and chemical co-products by pretreating and fractionation holds promise as an algal biorefinery concept, but a better understanding of the pretreatment performance as a function of algae strain and composition is necessary to de-risk algae conversion operations. Similarly, there are few examples of algae pretreatment at scales larger than the bench scale. This work aims to de-risk algal biorefinery operations by evaluating the pretreatment performance across nine different microalgae samples and five different pretreatment methods at small (5 mL) scale and further de-risk the operation by scaling pretreatment for one species to the 80 …

Automated Flood Depth Estimation On Roadways, Kwame Ampofo, Megan A. Witherow, Alex Glandon, Monibor Rahman, Ahmed Temtam, Mecit Cetin, Khan M. Iftekharuddin

Civil & Environmental Engineering Faculty Publications

Recurrent nuisance flooding is common across many parts of the globe and causes extensive challenges for drivers on the roadways. The prevailing monitoring methods for roadway flooding are costly and not automated or effective. The ubiquity of visual data from cameras and advancements in computing such as deep learning may offer cost-effective methods for automated flood depth estimation on roadways based on reference objects such as cars. However, flood depth estimation faces challenges due to the limited amount of data annotated with water levels and diverse scenes showing reference objects at various scales and perspectives. This study proposes a novel …

Implications Of Alternative Communications And Sensing Technologies For Implementing Variable Speed Limit Control Through Connected Vehicles: Sag Curve As A Case Study, Reza Vatani Nezafat, Mecit Cetin, Elizabeth Williams, George F. List

Civil & Environmental Engineering Faculty Publications

Connected vehicles (CVs) will enable various applications to improve traffic flow. This paper's focus is to investigate how the potential implementation of variable speed limit (VSL) through different types of communication and sensing technologies on CVs makes it possible to mitigate congestion at a sag curve bottleneck. A VSL algorithm is developed and implemented in a simulation environment for controlling the inflow of vehicles to a sag curve to minimize delays and increase throughput. Both vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) options for CVs are investigated when implementing the VSL control strategy in a simulation environment. Also, for measuring traffic density …

Investigating The Viability Of Low Frequency Mhvsr Estimates Using Deep Shear Wave Velocity Profile, T. Mai, C. C. Nweke, P. Wang, F. J. Ornelas

Civil & Environmental Engineering Faculty Publications

Site response describes the alterations of seismic energy due to its interaction with subsurface geological interfaces and structures, which is usually estimated by one dimensional (1D) ground response analysis (GRA). However, 1D GRA requires subsurface information (e.g., shear wave velocity profile), which makes it not widely applicable, particularly for the sites where subsurface information is unavailable. Alternatively, the microtremor horizontal-to-vertical spectral ratio (mHVSR) from three-component recordings of ambient noise on the ground surface is easily measured and is believed to have the potential for site response prediction (the peaks in mHVSR are strongly associated with the site resonant frequencies). However,the …

Contribution Of High Turbidity To Tidal Dynamics In A Curved Channel In Zhoushan Islands, China, Li Li, Fangzhou Shen, Zhiguo He, Gangfeng Ma, Jiachen Wang, Kailong Huangfu

Civil & Environmental Engineering Faculty Publications

The curved tidal channel, Luotou Deep-water Navigational Channel, is the main channel of the Ningbo Zhoushan Port, which is ranked first in the world. Tidal dynamics in the channel are spatially and temporally asymmetric. In this study, the three-dimensional tidal dynamics in the channel were analyzed using field data and simulated using FVCOM. The results show that the tides in the channel flood/ebb along the northern/southern bank near the bottom/surface layer and these asymmetries are due to the imbalanced Coriolis force, centrifugal force, sea-level gradient, and density gradient. Residual current velocity peaks (0.7 m/s) in the middle of the channel …

Modeling Coupled Driving Behavior During Lane Change: A Multi-Agent Transformer Reinforcement Learning Approach, Hongyu Guo, Mehdi Keyvan-Ekbatani, Kun Xie

Civil & Environmental Engineering Faculty Publications

In a lane change (LC) scenario, the lane change vehicle interacts with surrounding vehicles. The interactions not only affect their driving behaviors but also influence the traffic flow. This study aims to model the coupled behavior of the lane changer and the follower in the target lane during LC. Large-scale real-world connected vehicle (CV) data from the Safety Pilot Model Deployment (SPMD) program are used to extract LCs and study vehicle interactions. A multi-agent Transformer-based deep deterministic policy gradient (MA-TDDPG) method is proposed to model the coupled behaviors during LC. The multi-agent framework can handle the multiple agents’ behaviors with …

A General Framework For Modeling Subregional Path Effects, T. E. Buckreis, P. Wang, S. J. Brandenberg, J. P. Stewart

Civil & Environmental Engineering Faculty Publications

Next Generation Attenuation (NGA) West2 ground motion models (GMMs) include regional path adjustments for broad jurisdictional regions, which necessarily averages spatially variable path effects within those regions. We extend that framework to account for systematic variations in attenuation within subregions defined in consideration of geologic differences. In recent years, cell-based methods which systematically account for spatial variations by summing the attenuation effects over a fine discretization of uniform-rectangular cells (e.g., Dawood and Rodriquez-Marek 2013; Kuehn et al. 2019) have been shown to be an effective alternative to regionalization and a step towards modelling non-ergodic path effects. The main drawbacks of …

Compound Flooding Hazards Due To Storm Surge And Pluvial Flow In A Low-Gradient Coastal Region, Sunghoon Han, Navid Tahvildari

Civil & Environmental Engineering Faculty Publications

Flood risk analyses often focus on a single flooding source, typically storm surge or rainfall-driven flooding, depending on the predominant threat. However, hurricanes frequently cause compound flooding through significant storm surges accompanied by heavy rainfall. This study employs a hydrodynamic model based on Delft3D-Flexible Mesh that couples flow, waves, and rainfall-driven flow to simulate five historical tropical cyclones in Virginia's southeast coastal region. These storms produced varying intensities of storm surge and rainfall in the study area. Model simulations, incorporating rainfall through a rain-on-grid approach, account for the dynamic interaction between storm tides, and pluvial flow and enable the definition …