Civil Engineering Commons^™

Early-Age Hydration Studies Of Portland Cement, Fengjuan Liu

Electronic Theses and Dissertations

Our current knowledge on cement hydration during setting is based on the discrete observation of hydrated paste. An advanced micro/nano-level technique which can perform the in-situ observation on the continuous hydration of cement paste is demanded. In this study, Raman spectroscopy (RS) was chosen as such a method to continuously investigate wet pastes. The objective of this research is to explore the hydration process and microstructural development of fresh pastes with this technique. This research was conducted in three phases. First, the RS analysis was used to continuously observe the cement hydration from 20 minutes after mixing to 9 hours. …

Economic Analysis Of Michigan Commercial Vehicle Enforcement Strategies, Randy José Jorge Díaz

Masters Theses

Transportation infrastructure is an essential component of a nation’s success as it allows efficient transportation of goods to all economic markets, providing economic stability and ensuring trade competiveness. Nearly 70 percent of all of Michigan’s freight is shipped by truck and Michigan is ranked eighth in the USA in terms of the value of its exports with $50 billion per year. Unfortunately, commercial vehicles also contribute to the deterioration of pavement, reducing air quality and potentially influencing road safety. To enforce commercial vehicle laws and regulations, most states utilize fixed weigh stations supplemented with other enforcement strategies. Although fixed weigh …

Performance Of Frp-Retrofitted Concrete Bridge Columns Under Blast Loading, R. Zheng, P. Zohrevand, H. Erdogan, Amir Mirmiran

Civil Engineering Faculty Publications and Presentations

Contrary to military or essential government buildings, most bridges are designed without any consideration for blast resistance. Fiber-reinforced polymers (FRPs) can provide an effective means for strengthening of critical bridges against such loading. This study has focused on the effectiveness of FRP retrofitting in the dynamic response of reinforced concrete bridge columns under blast loading. Using a simplified equivalent I-section with a virtual material lumped at the two flanges; a lightly meshed uniaxial finite element model was developed and successfully validated against previous studies. The proposed model was then used for a thorough parametric study on the blast resistance of …

Gis Framework For Spatiotemporal Mapping Of Urban Flooding And Analyze Watershed Hydrological Response To Land Cover Change, Sayed Joinal Hossain Abedin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban flooding is a manmade disaster, and a recurrent problem in cities around the globe. Increased surface imperviousness due to urbanization along with inadequate drainage infrastructure system are the chief culprits for urban flooding. Flooding in an urban area brings about severe economic, structural, and environmental damages, and can be associated with casualties too. In order to evade flooding, an efficient flood model is imperative to study current flooding, and analyze flooding behavior to urban surface characteristics.

This research aims to develop a framework using Geographic Information System (GIS) to perform modeling and mapping of flood spatiotemporal variation in urban …

Effect Of Caliche On The Behavior Of Drilled Shafts, Rouzbeh Afsharhasani

UNLV Theses, Dissertations, Professional Papers, and Capstones

The current design methodology for a drilled shaft foundation in cohesionless soil is primarily based on ultimate skin friction values of drilled shafts. In order to obtain these values for each soil type, load tests such as Osterberg test are designed and performed. The Osterberg test layout is designed to estimate the capacity of drilled shaft by applying an upward load during the test and then calculating the downward capacity assuming the upward and downward capacity are the same. This method is appropriate for soils not containing caliche layers because caliche layers bond to the shaft and prevent skin friction …

Investigation Of Chloride Induced Corrosion Of Bridge Pier And Life-Cycle Repair Cost Analysis Using Fiber Reinforced Polymer Composites, Dinesh Dhakal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MR&R) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier …

Modeling Pavement Distress Rates Within U.S. Air Force Airfields, Lauren Sahagun

UNLV Theses, Dissertations, Professional Papers, and Capstones

Through the review of Pavement Condition Index (PCI) surveys completed at Air Force installations scattered across the continental United States, pavement engineers at the Air Force Civil Engineer Center propose that the predominant factor contributing to pavement distress development is climate. They suggest that within each pavement distress type (i.e. alligator cracking, rutting, spalling, etc.) a geographic pattern exists that is strongly correlated to the conventional climate zones within the US. Knowledge of these geographic patterns would equip pavement engineers and asset managers with a powerful tool to develop purposeful maintenance strategies specific to each distress type.

The following approach …

Exact Controllability Of The Lazer-Mckenna Suspension Bridge Equation, Lanxuan Yu

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is well known that suspension bridges may display certain oscillations under external aerodynamic forces. Since the collapse of the Tacoma Narrows suspension bridge in 1940, suspension bridge models have been studied by many researchers. Based upon the fundamental nonlinearity in suspension bridges that the stays connecting the supporting cables and the roadbed resist expansion, but do not resist compression, new models describing oscillations in suspension bridges have been developed by Lazer and McKenna [Lazer and McKenna (1990)]. Except for a paper by Leiva [Leiva (2005)], there have been very few work on controls of the Lazer-McKenna suspension bridge models …

Robust Geotechnical Design - Methodology And Applications, Lei Wang

All Dissertations

This dissertation is aimed at developing a novel robust geotechnical design methodology and demonstrating this methodology for the design of geotechnical systems. The goal of a robust design is to make the response of a system insensitive to, or robust against, the variation of uncertain geotechnical parameters (termed noise factors in the context of robust design) by carefully adjusting design parameters (those that can be controlled by the designer such as geometry of the design). Through an extensive investigation, a robust geotechnical design methodology that considers explicitly safety, robustness, and cost is developed. Various robustness measures are considered in this …

Virtual Analysis And Evaluation Of Roundabout Safety And Operational Features, Elisha Jackson Wankogere

Masters Theses

Roundabouts can be a solution to safety concerns present at other types of intersections. Recently in the United States, there has been an increase in conversion of problematic intersections to roundabouts to improve their safety. However, it is difficult to make these roundabouts, especially multi-lane roundabouts, safe to all ranges of users. Roundabout features such as advance warning and signage play an important role in determining driver performance as they navigate the roundabout.

This research is an effort to evaluate new and existing roundabout safety and operational features such as signs and pavement markings and how they influence performance of …

Robust Design Of Shield Tunnels ‒ Considering The Longitudinal Variation Of Input Parameters, Wenping Gong

All Dissertations

This dissertation, aimed at developing an improved design methodology for shield tunnels that explicitly considers design robustness against longitudinal variation of input parameters (such as soil parameters). To this end, a new solution model for shield tunnel performance analysis was first developed. In this new model, the random field concept was employed to model the longitudinal variation of input parameters. The input parameters (in the longitudinal domain) that had been generated with Monte Carlo simulation (MCS) were used as inputs for the tunnel longitudinal behavior analysis. Here, the finite element method (FEM) based upon Winkler elastic foundation theory was employed. …

Estimating Field At-Rest Lateral Stress Coefficient And Liquefaction Resistance Of Aged Sands, Md Hossian

All Dissertations

Published results of laboratory tests to evaluate the influence of the at-rest lateral stress coefficient (K0) and the overconsoildation ratio (OCR) on liquefaction resistance of sands are reviewed in this dissertation. It is found that significant increase in liquefaction resistance can occur with high K0 and/or high OCR. A unique relationship between liquefaction resistance of isotropic and anisotropic normally consolidated sands exists based on the published laboratory data. Relationships between liquefaction resistance of overconsolidated sands and normally consolidated sands also have been shown in previous laboratory studies. Based on the previous studies, expressions for K0 and OCR correction factors (KK0 …

Sensitivity Of Columbia Basin Runoff To Long-Term Changes In Multi-Model Cmip5 Precipitation Simulations, Mehmet Demirel, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

In this study, we used precipitation elasticity index of streamflow, to reflect on the sensitivity of streamflow to changes in future precipitation. We estimated precipitation elasticity of streamflow from: (1) simulated streamflow by the VIC model using observed precipitation for the current climate (1963–2003); (2) simulated streamflow by the VIC model using simulated precipitation from 10 GCM - CMIP5 dataset for the future climate (2010–2099) including two different pathways (RCP4.5 and RCP8.5) and two different downscaled products (BCSD and MACA). The hydrological model was calibrated at 1/16 latitude-longitude resolution and the simulated streamflow was routed to the subbasin outlets of …

Vulnerability Functions For Seismic Loss Assessment Of The Modern Multi-Story Buildings In Dubai, Abdul Rahman Abdul Aziz Ashri Hassan

Theses

The rapid developments in the United Arab Emirates along with the repeated seismic activity confirm the significance of planning for the possible damage that may hit earthquake-prone areas in order to mitigate earthquake losses. The contemporary buildings are the most important when estimating the potential losses from earthquakes since they represent concentrated economic and human assets. This study aims at developing vulnerability functions for a wide range of modern building inventory in a highly-populated and earthquake-prone area in the UAE. Ten reference buildings with varying heights from 2 to 100 stories and three different lateral force resisting systems are selected …

Cal Poly India Project, Derek Babine, Austen Hibler, Alex Hernandez

Mechanical Engineering

This report documents the research, ideation, and development of a solution, implemented by the Cal Poly India Sanitation Team per the request of Mr. Harish Bhutani, to solve the problem of hazardous human waste management in poor villages in India. The sponsor envisioned a universal design that would give each household in those villages access to a private toilet system because the current solution is open defecation in water sources and farming fields. The initial constraints required the project be low cost, not use of electricity or water, have the ability to cater to an 8-10 person household, and be …

Stochastic Wavenumber Estimation: Damage Detection Through Simulated Guide Lamb Waves, Garrison Stevens

All Theses

Structural Health Monitoring (SHM) is a field of research that seeks to identify the onset of damage in infrastructure systems such that catastrophic failures can be averted. Acoustic Wavenumber Spectroscopy (AWS) is an emerging SHM technique that can identify and locate change of thickness resulting from damage in thin plates through the estimation of the characteristic wavenumber. AWS measures the ultrasonically induced vibrations of thin plates by laser scanners and monitors the propagation of Rayleigh-Lamb waves through the structure. This method is particularly suitable for thin-walled structures such as those contained in pipes, airplanes, and wind turbine blades. While AWS …

Geotechnical Analysis Of The Foundation Of Fort Sumter National Monument Using Numerical Modeling, Daniel Kyser

All Theses

The foundational condition of the historical coastal fortification of Fort Sumter in Charleston, SC was analyzed though the use of numerical modeling. In this study, two-dimensional Finite Element (FE) analyses were conducted to assess the stability of the foundation-casemates-wall system in a coupled manner subjected to potential loadings such as ocean waves, storm surge and earthquake. The finite element model was verified by modeling the historical events (construction between 1820 and 1860, demolition due to artillery bombardment, reconstruction, earthquake, building of the Battery Huger, and the removal of fill from the parade ground) since the construction of the fort in …

Combined Numberical And Experimental Assessment Of Steel Roof Decks Subjected To Windborne Debris, Robert Roper

All Theses

In the summer of 2013, a steel roof deck manufacturer (Company A) approached Clemson University about testing their steel roof decking product to evaluate the performance of the steel roof deck to resist impact from tornado windborne debris using FEMA P-361 Design and Construction Guidance for Community Safe Rooms. To assist Company A in better serving their customers in areas prone to severe wind events and to facilitate use of their products in community safe rooms, debris impact tests were conducted on two cold-formed corrugated steel roof decking products. Community safe rooms are buildings that are constructed in accordance with …

Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie

All Dissertations

This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate 'environmental thinking' into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …