Engineering Commons^™

Evaluating The Impact Of Bridge Deck Removal Method On The Performance Of Precast/Prestressed Concrete I-Girders, Shaddi Assad

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Wide flange precast/prestressed concrete I-girders have been widely used by several State Departments of Transportation (DOTs) in the last two decades. These girders have many advantages over standard AASHTO I-girders. Their wide and thick bottom flange accommodates a large number of prestressing strands and their wide and thin top flange provides a shorter deck span, reduced girder weight, greater stability in construction, and adequate platform for workers. Despite these advantages, the wide and thin top flange might be disadvantageous when it comes to deck removal, as it is more susceptible to damage. Therefore there is a need to investigate the …

Evaluation Of Earthquake Hazard For Las Vegas Valley, Nevada Incorporating Probabilistic Hazard Assessment And Non--Linear Site Response, Suchan Lamichhane

UNLV Theses, Dissertations, Professional Papers, and Capstones

Abstract from Manuscript 1, "An alternative analysis of the probabilistic seismic hazard for Las Vegas Valley, Nevada": Probabilistic seismic hazard calculations relevant for rock-site conditions in the Las Vegas Valley, Nevada (LVV) have been computed that account for seismic sources that are not included in the current (2008) USGS national seismic hazard model (NSHM) because of insufficient knowledge or documentation, using the commercial software package EZ-FRISK. The LVV is underlain by a system of mapped, active normal faults that comprise the Las Vegas Valley Fault System (LVVFS), with maximum potential earthquakes to M6.8. The 2008 NSHM explicitly includes only one …

Transport Properties Of Nano-Silica Contained Self-Consolidating Concrete, Borhan Moradi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this research study, transport properties of various self-consolidating concretes (SCCs) containing nano-particles (SiO2) were investigated. Nano-silica replaced a portion of the cementitious materials at different replacement levels ranging from 1.5 to 7.5% by weight. For the purpose of this investigation, flow, bulk, and transport properties of SCCs were studied. The investigated transport properties were absorption, water penetration, rapid chloride permeability, capillary absorption, rapid migration, and chloride diffusion. Transport properties of nano-silica SCCs were also compared to those of equivalent silica fume (micro silica) contained concretes, as well as those of control mixture (concrete without nano or micro silica).

Test …

Infiltration And Runoff Parameters For Tilled And No-Till Row Crops, Andrew J. Volkmer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Infiltration and runoff are hydrologic processes that effect the amount of water available to plants, for groundwater recharge, and for stream flow. No-till planting (NT) is a management practice used to reduce soil erosion, increase water infiltration, and reduce soil water evaporation, and can have great impact on infiltration and runoff. An investigation was conducted to determine the impact of NT on infiltration and runoff when compared to tilled conditions.

Runoff and precipitation data was gathered from sites at Fillmore County, NE, Phelps County, NE, the USDA-ARS North Appalachian Experimental Watersheds (NAEW) near Coshocton, OH, and the Lennoxville Research Station …

Learning From Earthquakes: 2014 Napa Valley Earthquake Reconnaissance Report, Erica Fischer

Lyles School of Civil Engineering Graduate Student Reports

Structural damage was observed during reconnaissance after the 2014 South Napa Earthquake, and included damage to wine storage and fermentation tanks, collapse of wine storage barrel racks, unreinforced masonry building partial or full collapse, and residential building damage. This type of damage is not unique to the South Napa Earthquake, and was observed after other earthquakes such as the 1977 San Juan Earthquake, and the 2010 Maule Earthquake. Previous research and earthquakes have demonstrated the seismic performance of cylindrical fluid-filled tanks is controlled by both the tank and the sloshing motion of the liquid inside. Unlike building structures, steel tanks …

Dual-State Kalman Filter Forecasting And Control Theory Applications For Proactive Ramp Metering, Brian Richard Portugais

Boise State University Theses and Dissertations

Deterioration of freeway traffic flow condition due to bottlenecks can be ameliorated with ramp metering. A challenge in ramp metering is that it is not possible to process data in real-time and use the output in a control algorithm. This is due to the fact that by the time processing is completed and a control measure applied, the traffic state will have changed. A solution to this problem is to forecast the traffic state and implement a control measure based on the forecast.

A dual-state Kalman filter was used to forecast traffic data at two locations on a freeway (I-84). …

Can Tidal Perturbations Associated With Sea Level Variations In The Western Pacific Ocean Be Used To Understand Future Effects Of Tidal Evolution?, Adam T. Devlin, David A. Jay, Stefan A. Talke, Edward D. Zaron

Civil and Environmental Engineering Faculty Publications and Presentations

This study examines connections between mean sea level (MSL) variability and diurnal and semidiurnal tidal constituent variations at 17 open-ocean and 9 continental shelf tide gauges in the western tropical Pacific Ocean, a region showing anomalous rise in MSL over the last 20 years and strong interannual variability. Detrended MSL fluctuations are correlated with detrended tidal amplitude and phase fluctuations, defined as tidal anomaly trends (TATs), to quantify the response of tidal properties to MSL variation. About 20 significant amplitude and phase TATs are found for each of the two strongest tidal constituents, K₁ (diurnal) and M₂ (semidiurnal). …

Modeling And Analyzing The Impact Of Advanced Technologies On Transit Performance Measures In Arterial Corridors, Miguel A. Figliozzi, Wei Feng

Civil and Environmental Engineering Faculty Publications and Presentations

Transportation and transit agencies have implemented advanced technologies like transit signal priority (TSP) and Sydney Coordinated Adaptive Traffic System (SCATS) to reduce travel times and improve reliability. However, due to the lack of detailed empirical data, the joint impact of these factors and improvement strategies on bus travel time has not been studied at the stop-to-stop segment level. With the aim of assessing the performance of an existing TSP/SCATS system, this study had access to a unique set of high-resolution bus and traffic signal data. Novel algorithms and performance measures to measure TSP performance are proposed. Results indicate that a …

Application Of Bamboo For Flexural And Shear Reinforcement In Concrete Beams, Nathan Schneider

All Theses

As the developing world is industrializing and people migrate to cities, the need for infrastructure is growing quickly and concrete has become one of the most widely used construction materials. One poor construction practice observed widely across the developing world is the minimal use of reinforcement for concrete structures due to the high cost of steel. As a low-cost, high-performance material with good mechanical properties, bamboo has been investigated as an alternative to steel for reinforcing concrete. The goal of this research is to add to the knowledge base of bamboo reinforced concrete (BRC) by investigating a unique stirrup design …

Assessment Of Nitrifying Bacteria In Massard Plant Using Molecular Tools, Jennifer Puanani Holmes-Smith

Civil Engineering Undergraduate Honors Theses

The discharge of nutrients (such as nitrogen and phosphorus) from wastewater treatment plants (WWTP) has become an increasingly important issue in the United States. Ammonia (NH3) is a common contaminant found in domestic wastewater and agricultural runoff. It can cause toxicity in fish if left untreated. The United States Environmental Protection Agency (EPA) recommends low national criteria for ammonia limits in freshwater. With these greater restrictions, ammonia-nitrogen limit compliance (5 mg/L) has become an issue at the Massard WWTP in Fort Smith, Arkansas. The purpose of this research is to assess the ammonia removal in the Massard WWTP in order …

Building Envelope Failure Assessment Of Residential Developments Subjected To Hurricane Wind Hazards, James Grayson

All Dissertations

An unfortunate global precedent has been set by hurricane wind hazard events that illustrate the importance of building resilient coastal communities. Although community resilience is heavily dependent upon the socioeconomic response of the community before, during, and after a hazard event, it is also dependent on the vulnerability of the community to a disaster. Therefore, one way that structural engineers can assist communities in becoming more resilient is to investigate and implement methods that mitigate the 'initial shock' experienced by a residential development subjected to a hazard event. The focus of this research was to develop a mechanics-based building envelope …

Projections Of Future Us Design Wind Speeds Due To Climate Change For Estimating Hurricane Losses, Fangqian Liu

All Dissertations

Hurricane is among the most dangerous and costliest natural hazards that affect the coastal environment of the United States (U.S.) every year. Hurricane activities have been observed to change in many aspects since the last century including the changes in both intensity and annual storm frequency. The extent to which aspect of climate change contributes to the variation in hurricane activities from long-term historical statistics is still not clearly understood at this point. This study examines the impacts of two climate change effects (change in annual storm frequency and sea surface temperature) on future U.S. design wind speeds for the …

Fluid Mud Gravity Currents Through Emergent Aquatic Vegetation, Nazli Yilmaz

All Dissertations

In this theoretical and experimental investigation, the propagation dynamics of the fluid-mud underflows form in pipeline dredge disposal operations in the designated areas are studied. These areas such as wetlands, nearshore waters are typically covered with stiff, cylindrical, emergent aquatic vegetation. The main goals of this study are to propose mathematical formulations for the bottom shear force and drag force of emergent stiff aquatic vegetation acting on the gravity current, and to present novel propagation modeling approaches. To be able to predict these forces, a friction coefficient (for the bottom shear force), and a drag coefficient (for vegetation skin friction …

Anammox Polishing In Mainstream Wastewater Treatment To Meet Stringent Ammonia And Total Nitrogen Limits, Rebecca Mary Holgate

Civil & Environmental Engineering Theses & Dissertations

As nitrogen discharge limits are becoming more stringent there is a need for new processes that are sustainable and cost effective. Since anaerobic ammonia oxidizing bacteria (anammox) were discovered in the mid 1990s, there has been considerable success implementing anammox in many wastewater treatment plants to treat internally generated nitrogen rich waste streams (e.g. centrate). Recently, there has also been discussion of implementing anammox in mainstream wastewater treatment to exploit the benefits of autotrophic nitrogen removal.

A two stage A/B pilot study was conducted that included a high-rate activated sludge (HRAS) process followed by a two-stage de-ammonification process incorporating nitrite-shunt …

Modot Pavement Preservation Research Program, David Newton Richardson, Neil Lennart Anderson, John Bowders, Andrew Z. Boeckmann, Ronaldo Luna, S. Michael Lusher, Brent Rosenblad, Lesley Sneed

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The following report documents a research project on pavement preservation performed by the Missouri University of Science and Technology (Missouri S&T) and the University of Missouri-Columbia (UMC) on behalf of the Missouri Department of Transportation (MoDOT). the report consists of a Summary Report followed by six detailed technical reports. to achieve the goal of reducing maintenance costs and improving minor road ratings, MoDOT has embarked upon a plan of formalizing its maintenance/preservation planning. to assist in developing the plan, MoDOT contracted with the Missouri S&T and UMC to conduct a research project, entitled "MoDOT Pavement Preservation Research Program". the product …

Increased Span Length For The Mgs Long-Span Guardrail System, Nicholas A. Weiland

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Long-span guardrail systems have been recognized as an effective means of shielding low-fill culverts while minimizing construction efforts and limiting culvert damage and repair. The current MGS long-span design provided the capability to span unsupported lengths up to 25 ft (7.6 m) without the use of nested guardrail. The excellent performance of the MGS long-span system in full-scale crash tests suggested that longer span lengths may be possible with the current design.

A detailed analysis of the MGS long-span guardrail system was performed using the finite element software program LS-DYNA^®. It was shown that the MGS long-span design …

Development Of Improved Electrodeposition Method For Repair Of Reinforced Concrete Structures, Takahiro Nishida, Nobuaki Otsuki, Atsushi Saito

International Conference on Durability of Concrete Structures

Deterioration of reinforced concrete members and their repair methods have been reported in various concrete published reports. Electrodeposition method is one of these repair methods for repairing deteriorated concrete members using an electrochemical mechanism. The purposes of the electrodeposition method are to fill cracks in concrete and to coat the concrete surface by electrodeposits of chemical compounds. This can be accomplished by passing a weak direct current (1.0–3.0 A/m² of concrete surface area) between a reinforcing steel bar (cathode) in concrete and an external electrode (anode) located in an external solution near the concrete surface. This method also accomplishes …

Behavior Of Cfrp Plate In Simulated Iccp System Of Concrete Structures, Jihua Zhu, Miaochang Zhu, Ningxu Han, Feng Xing, Wei Liu, Luca Bertolini

International Conference on Durability of Concrete Structures

An innovative effort was made to utilize carbon fiber reinforced polymer (CFRP) plate as an anode in impressed current cathodic protection (ICCP) of reinforced concrete structure. The feasibility was explored by bonding CFRP strips to concrete and then applying protection current through CFRP strips to steel rebar in concrete. Service life and performance of CFRP plate were investigated in simulated ICCP systems with various configurations. Steel potential results confirmed that the steel rebar in concrete maintained at a satisfactory level with the applied protection current. It is shown that CFRP strips can be successfully used in various solutions as an …

Water–Binder Ratio Monitoring As A Quality Control Tool For The High-Performance Concrete Used In The Construction Of The Submerged Tunnel, Junjie Zeng, Shengnian Wang, Weiqing Lv, Quanke Su, Zhonghe Shui

International Conference on Durability of Concrete Structures

The designed service life of Hong Kong-Zhuhai-Macao Bridge is 120 years. Concrete quality control for the submerged tunnel of the project is an important work to assure the designed service life. This article is to present an advanced concrete performance prediction method based on water–binder ratio (w/b) monitoring, which is used to serve for concrete quality control. During experiments in the lab, the w/b of submerged tunnel concrete mix proportion was designed to fluctuate up and down, while the other compositions were kept constant. Concretes with different w/b were prepared. The w/b of fresh concrete was tested, followed by preparation …

Effect Of Drying Rate On Shrinkage Of Alkali-Activated Slag Cements, Hailong Ye, Christopher Cartwright, Farshad Rajabipour, Aleksandra Radlińska

International Conference on Durability of Concrete Structures

The volumetric instability of alkali-activated slag (AAS) binders has raised concerns and impeded the acceptance of this Portland cement-free material. The objective of this article is to characterize the influence of drying rate on drying shrinkage behavior of AAS mortars to better understand the mechanisms responsible for its large shrinkage deformation. A series of four AAS mortar mixtures with varying activator composition, as well as a reference Portland cement mortar, was cast and dried at different relative humidities, that is, 30, 50, 70, and 85% RH. Drying took place inside nitrogen-purged environmental chambers for the purpose of eliminating the contribution …

Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han

International Conference on Durability of Concrete Structures

In this paper, the influence of fly ash content on concrete surface chloride concentration was investigated through periodical tests of surface chloride concentration of concrete by immersing three kinds of concrete specimens in 5.0 wt.% sodium chloride solution. One kind of specimen is common concrete without fly ash, whereas the other two kinds of specimens are mixed with fly ash. The results show that the surface chloride ion concentration ranges from 0.295 to 0.777 wt.% for the immersed concrete samples in this study; in the initial stage of immersion, the concrete surface chloride ion concentration is affected by added fly …

Effects Of Stirrups On Bond Behavior Between Concrete And Corroded Steel Bars, Hongwei Lin, Yuxi Zhao, Ming Sun

International Conference on Durability of Concrete Structures

Steel corrosion leads to the deterioration of bond between concrete and steel bars. The serviceability and ultimate strength of concrete elements within RC structures are hence affected. Many researchers have studied the bond behavior of corroded steel bars. However, very few studies have investigated the effects of confinements on the degradation of bond strength. The present paper proposed a new kind of beam specimen based on which the effects of stirrups on degradation of bond were investigated. The test results proved that stirrups can effectively increase the bond strength between concrete and corroded steel bars.

Saturation Of Air Entrained Voids And Its Implication On The Transport Of Ionic Species In Concrete, Yiwen Bu, Jason Weiss

International Conference on Durability of Concrete Structures

Air entrainment is commonly used to improve the durability of concrete materials exposed to freezing and thawing. While the influence of air voids on freeze/thaw damage and salt scaling is frequently studied, the influence of entrained air voids on ionic transport has been studied less frequently. Since ionic transport in concrete materials relies on pore fluid as the medium of conduction, only saturated or partially saturated air voids participate in the transport processes. This paper discusses the conditions under which air voids could become saturated. Specifically, the saturation condition of entrained air voids in laboratory tests and in service is …

Visualization And Quantification Of Solute Diffusivity In Cracked Concrete By X-Ray Ct, Michael Henry, T. Sugiyama, I. S. Darma

International Conference on Durability of Concrete Structures

This paper explores the usage of microfocus X-ray computed tomography (CT) for visualization and quantification of diffusion phenomena in cracked concrete. Mortar specimens of varying shapes (prismatic and cylindrical), crack types (artificial and splitting tensile), and binder compositions (OPC and fly ash) were prepared. Cesium carbonate (Cs₂CO₃) was used as a tracer in the diffusion test because it has high X-ray absorption due to its high atomic number and thus contrasts with mortar and air voids in the CT images. Image processing and analysis was carried out to visualize and quantify the diffusion behavior in 3D …

Effect Of Blast Furnace Slag Powder And Fly Ash On Durability Of Concrete Mixed With Seawater, Nobuaki Otsuki, Takahiro Nishida, Chang Yi, Tomohiro Nagata, Hiroki Ohara

International Conference on Durability of Concrete Structures

According to the report of the United Nations, it is said that two-third of world population would be influenced by water shortage before 2050. To use fresh water effectively, the usage of seawater in concrete industry seems imperative. However, the usage of seawater as concrete material is prohibited in almost all the standards or specifications around the world. In this article, the usage of seawater as a material of concrete based on the results of experimental works and deterioration prediction was discussed. Especially, the effects of by-products such as blast furnace slag or fly ash on the durability of concrete …

Surface Treatment Of Cement-Based Materials With Nanosio2, Pengkun Hou, Xin Cheng, Jueshi Qian, Surendra P. Shah

International Conference on Durability of Concrete Structures

A dense surface structure of cement-based material is favorable for its resistance to the impacts of environment. In this work, effectiveness and mechanisms of the surface treatment of cement-based materials with nanoSiO₂ of different states, that is, colloidal nanoSiO₂ (CNS) and the in situ formed nanoSiO₂ gel through the hydrolysis of its precursor of tetraethoxysilane (TEOS), by brushing and soaking techniques, were investigated. Results showed that both CNS and TEOS are capable of reducing the liquid and gaseous transport properties of hardened cement-based materials, although at a different extent. It revealed that the pozzolanic reactivity and the …

Research On Embedded Sensors For Concrete Health Monitoring Based On Ultrasonic Testing, Shifeng Huang, Mimi Li, Yuesheng Xu, Dongyu Xu, Xinchun Xie, Xin Cheng

International Conference on Durability of Concrete Structures

In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage, the sensors were fabricated and embedded into the cement mortar before testing. The results demonstrated that the piezoelectric composite sensor had wider frequency bandwidth than the piezoelectric ceramic sensor. The compressive strength and ultrasonic velocity had a positive linear relationship, with a correlation coefficient of 0.9216. The head …

Review Of Microbially Induced Corrosion And Comments On Needs Related To Testing Procedures, Mitchell House, W. J. Weiss

International Conference on Durability of Concrete Structures

Concrete is the most widely used material for the construction of the wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated Portland cement may make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multistage degradation process known as microbially induced corrosion (MIC). MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate-reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur-oxidizing bacteria Thiobacillus that resides on concrete surfaces …

Numerical Simulation Of The Early Age Three-Dimensional Microstructure Development Of Cement Pastes, Yunsheng Zhang, Zhiyong Liu, Wei Sun

International Conference on Durability of Concrete Structures

The formation process of microstructure in cement pastes was first simulated with a numerical model CEMHYD3D. The influence of water-to-cement ratio and particles size on heat release and degree of hydration were then investigated. In addition, the mass of CH and C–S–H phases simulated have been verified by measuring values by thermogravimetry–differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD)-Rietveld analysis. The evolutions of solids phase percolation and capillary pores de-percolation were also identified by means of a three-dimensional (3D) numerical model. The results show that the simulated values are in good agreement with the available experimental data, indicating a good …

Study On Variable Action Value Standard For Harbor Infrastructures, Xiaoping Zhong, Qianyi Zhao, Weiliang Jin

International Conference on Durability of Concrete Structures

To meet with different levels of requirements from proprietors and users and to offer a basis for variable action value to the designers, associated with the standards, this dissertation studied the value standard of load effect and environmental effect. For load effect, on the foundation of analyzing variable load effect model, we used equal exceeding probability principle to calculate the load adjustment coefficient for the cargo loading in harbor and river port under different designing service life. For environmental effect, according to the ranks of marine chloride environment in standards GB/T 50476-2008, after analyzing and comparing the research achievements on …