Engineering Commons^™

Investigating Wood Welding Parameters Using A Prototype Welding Machine, Timothy R. Melin

Master's Theses

Understanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling.

The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects …

An Investigation Of Initially Delaminated Composite Sandwich With Delamination Arrest Mechanism Under Buckling Loading, Tony D. Tran

Master's Theses

This thesis involves the development of a fiberglass-foam composite sandwich structure with the introduction of delamination arrestment keys; therefore, a study of an initially delaminated composite sandwich structure was the experimental analysis on multiple configurations in how the arrestment keys are placed.

The first part of this thesis research was to the experimental design and manufacturing of the composite sandwich plates. These plates were later cut down to the specific test dimensions and manufacturing processes for the composite sandwich plates and test specimens were created. The composite sandwich plates were manufactured using a vacuum resin infusion process. The dimensions of …

Anaerobic Co-Digestion Of Wastewater Treatment Pond Algae With Wastewater Sludge, Daniel Eric Heimel

Master's Theses

Microalgae harvested from wastewater treatment ponds can be anaerobically digested to produce biogas, a renewable fuel resource. However, past experiments have shown some limitations of algae digestion. Algal cell walls are thought to be resistant to digestion, and the high protein content of algae can lead to ammonia toxicity in digesters. Co-digestion of algae with substrates containing higher C:N ratios (e.g., waste paper) can be used to maintain non-inhibitory ammonia concentrations and increase methane production. However, high carbon waste co-substrates have become costly or are not readily available in many communities. Although domestic wastewater sludge has only a marginally higher …

An Investigation Of The Influence Of Diaphragm Flexibility On Building Design Through A Comparison Of Forced Vibration Testing And Computational Analysis, Blake Alan Roskelley

Master's Theses

An assessment of the validity of idealizing a concrete diaphragm as rigid was performed through the modal analysis of three existing buildings. Modal analysis was performed both by physical experimentation and computational analysis. Experimental determination of the mode shapes shows that two of the three buildings’ diaphragms exhibited flexible behavior. The experimental results were compared to computational analysis results and were shown to be similar, confirming that that the two building diaphragms are not rigid. As a standard, diaphragms with aspect ratios less than three are permitted to be idealized as rigid per ASCE 7-05. To determine the effect of …

Assessment Of State Recycling Regulations In The United States, Nazli Yesiller, James L. Hanson, Samuel A. Vigil

Civil and Environmental Engineering

This investigation was conducted to identify the current status of state recycling regulations in U.S. using an extensive survey. Questions were included regarding: baseline waste generation and recycling trends; recycling regulatory trends; quantitative thresholds; integration of science, engineering, and economic principles; material properties; and legislative status of regulations. The majority of the surveyed states had regulations for recycling activities, which were less strict than solid waste regulations, and required permits for operation of recycling facilities. A low percentage of the states regulated generators, transporters, and handlers and a high percentage regulated recyclers. In general, transfer stations and recycling centers were …

A Realistic Technology And Engineering Assessment Of Algae Biofuel Production, T. J. Lundquist, I. C. Woertz, N. W. T. Quinn, J. R. Benemann

Civil and Environmental Engineering

This report assesses the economics of microalgae biofuels production through an analysis of five production scenarios. These scenarios, or cases, are based on technologies that currently exist or are expected to become available in the near-term, including raceway ponds for microalgae cultivation, bioflocculation for algae harvesting, and hexane for extraction of algae oil. Process flow diagrams, facility site layouts, and estimates for the capital and operations costs of each case were developed de novo. This report also reviews current and developing microalgae biofuel technologies for both oil and biogas production, provides an initial assessment of the US and California …

A Classification Tree Based Modeling Approach For Segment Related Crashes On Multilane Highways, Anurag Pande, Mohamed Abdel-Aty, Abhishek Das

Civil and Environmental Engineering

Introduction: This study presents a classification tree based alternative to crash frequency analysis for analyzing crashes on mid-block segments of multilane arterials.

Method: The traditional approach of modeling counts of crashes that occur over a period of time works well for intersection crashes where each intersection itself provides a well-defined unit over which to aggregate the crash data. However, in the case of mid-block segments the crash frequency based approach requires segmentation of the arterial corridor into segments of arbitrary lengths. In this study we have used random samples of time, day of week, and location (i.e., milepost) …

Traffic Safety Investigations For Local Agencies, Jacob D. Hudson

Master's Theses

National and statewide (California) collision numbers are currently on the

decline; however, the U.S. is declining at a much slower rate than most other

developed countries, and in some aspects is actually regressing in terms of traffic

safety. Although state highway safety is improving, local roadway safety may

actually be regressing. Approximately three-quarters of all U.S. public roadways,

and approximately 80% of all injury accidents fall under the jurisdiction of cities.

However, cities may not be allocating the proper level of resources, or operating

under the proper administrative methodologies to adequately address these

safety issues.

This research finds that on …

Base Shear Estimated From Floor Accelerations And Column Shears, Rakesh K. Goel

Civil and Environmental Engineering

This paper compares base shear computed from floor accelerations (inertial base shear) and column shears (structural base shear) for several single-degree-of-freedom (SDF) systems and two mid-rise, multi-story buildings due to a suite of 30 earthquake ground motions. The presented results show that the inertial base shear is close to structural base shear in short-period (<1 >sec) SDF systems but may significantly exceed the structural base shear for individual ground motions in longer period (> 1 sec) SDF systems. Furthermore, the inertial base shear exceeds the structural base shear in the median by 10% to 20% and may exceed the structural …

Performance-Based Analysis Of Steel Buildings: Special Concentric Braced Frame, Scott Michael Adams

Master's Theses

The performance-based analysis methods and evaluation criteria in ASCE 41-06 were used to evaluate a special concentric braced frame building based on the design standards in ASCE 7-05. A rectangular, six-story office building was evaluated using linear static, linear dynamic, nonlinear static, and nonlinear dynamic procedures. The results showed that the linear procedures underestimated damage compared to the nonlinear procedures, with the building performing to Life Safety for the linear procedures, and the nonlinear procedures indicating component damage beyond the intended Life Safety limit for the 2/3 maximum considered earthquake (MCE) hazard. This trend continued to the maximum considered earthquake …

Evaluating Effectiveness Of Best Management Practices To Control Accelerated Sedimentation Of The Morro Bay Estuary, Misgana K. Muleta

Civil and Environmental Engineering

The Morro Bay estuary, located on the central Coast of California approximately half way between Los Angeles and San Francisco, is one of the most important wetlands on the west Coast as it supports wide variety of habitats including numerous sensitive and endangered plant and animal species. Various studies have identified accelerated erosion and subsequent sedimentation as a major threat for sustainability of the bay. Watershed disturbances caused by agricultural activities are believed to be one of the major causes of the accelerated erosion and sedimentation. More than 200 conservation practices have been installed in the watershed since the mid-1990 …

Compaction Characteristics Of Municipal Solid Waste, James L. Hanson, Nazli Yesiller, Shawna A. Von Stockhausen, Wilson W. Wong

Civil and Environmental Engineering

Compaction characteristics of municipal solid waste (MSW) were determined in the laboratory and in the field as a function of moisture content, compactive effort, and seasonal effects. Laboratory tests were conducted on manufactured wastes using modified and 4X modified efforts. Field tests were conducted at a MSW landfill in Michigan on incoming wastes without modifications to size, shape, or composition, using typical operational compaction equipment and procedures. Field tests generally included higher efforts and resulted in higher unit weights at higher water contents than the laboratory tests. Moisture addition to wastes in the field was more effective in winter than …

Spatial And Temporal Temperature Distributions In Municipal Solid Waste Landfills, James L. Hanson, Nazli Yesiller, Nicolas K. Oettle

Civil and Environmental Engineering

Long-term spatial and temporal variations in temperatures have been investigated in covers, wastes, and liners at four municipal solid waste landfills located in different climatic regions: Alaska, British Columbia, Michigan, and New Mexico. Temperatures were measured in wastes with a broad range of ages from newly placed to old (up to 40 years). The characteristic shape of waste temperature versus depth relationships consisted of a convex temperature profile with maximum temperatures observed at central locations within the middle third fraction of the depth of the waste mass. Lower temperatures were observed above and below this central zone, with seasonal fluctuations …

Simplified Procedures For Seismic Analysis And Design Of Piers And Wharves In Marine Oil And Lng Terminals, Rakesh K. Goel

Civil and Environmental Engineering

No abstract provided.

Scale Model Shake Table Testing Of Underground Structures In Soft Clay, Victor A. Crosariol

Master's Theses

Underground structures perform an important role in transportation systems in many seismically active regions around the world, but empirical data regarding the seismic behavior of these structures is limited. This research works towards filling that empirical gap through the use of scale model shake table testing. Underground seismic soil-structure interaction (USSSI) effects were investigated for a stiff rectangular tunnel cross-section embedded within soft clay. San Francisco Young Bay Mud was used as a prototype soil for developing a scale model soil mixture consisting of kaolinite, bentonite, class C fly ash, and water. A single cell Bay Area Rapid Transit (BART) …

Geo-Engineering Reconnaissance Of The 2010 Maule, Chile Earthquake, Pedro Arduino, Scott Ashford, Dominic Assimaki, Jonathan Bray, Terry Eldridge, David Frost, Youssef Hashash, Tara Hutchinson, Laurie Johnson, Keith Kelson, Robert Kayen, Christian Ledezma, Robb Moss, George Mylonakis, Scott Olson, Kyle Rollins, Nicholas Sitar, Jonathan Stewart, Alfredo Urzua, Ramon Verdugo, Rob Witter, Nick Zoa

Civil and Environmental Engineering

No abstract provided.

Shake Table Testing To Quantify Seismic Soil Structure Interaction Of Underground Structures, Robb E.S. Moss, Vic Crosariol, Steven Kuo

Civil and Environmental Engineering

This research uses shake table testing of scale soil-structure models to mimic the coupled seismic response of underground structures and surrounding/supporting soil (termed soil-structural-interaction or SSI). Currently the seismic design of subways and other critical underground infrastructure rely on little to no empirical data for calibrating numerical simulations. This research is working towards filling that empirical data gap. The research is composed of two phases, the first a validation of the free-field response of a flexible wall barrel filled with model soil, the second a test to measure the “racking” deformations induced in a model subway cross-section embedded in the …

Comparison Of Model Evaluation Methods To Develop A Comprehensive Watershed Simulation Model, Misgana K. Muleta

Civil and Environmental Engineering

Comprehensive environmental models such as the Soil and Water Assessment Tool (SWAT) are becoming an integral part of decision making processes for effective planning and management of natural resources. Before their use as decision making aid, however, models must be properly evaluated to improve their prediction accuracy and reduce the likelihood of making decisions that could lead to undesirable policy outcomes. Model evaluation refers to practices such as quality analysis of input data, sensitivity analysis, calibration and verification, and uncertainty analysis. Many methodologies have been developed for model evaluations over the years. One of the major limitations of the existing …

Spatial Variability Of Levees As Measured Using The Cpt, Robb E.S. Moss, J. C. Hollenback, J. Ng

Civil and Environmental Engineering

The spatial variability of a soil deposit is something that is commonly discussed but difficult to quantify. The heterogeneity as a function of lateral distance can be critical to the design of long engineered structures such as highways, bridges, levees, and other lifelines. This paper presents a methodology for using CPT measurements to quantifying the spatial variability of cone tip resistance along a levee in the California Bay Delta. The results, presented in the form of a general relative variogram, identify the distance at which the maximum spatial variability is achieved for a given soil strata. This information helps define …

Simplified Procedure For Seismic Evaluation Of Piles With Partial-Moment Connection To The Deck In Marine Oil Terminals, Rakesh K. Goel

Civil and Environmental Engineering

This paper presents development of a simplified procedure for seismic evaluation of piles with partial-moment connection typically used in marine oil terminals. The current seismic evaluation procedure of the piles in marine oil terminals includes monitoring material strains specified in the Marine Oil Terminal Engineering and Maintenance Standard (MOTEMS) during the nonlinear static pushover analysis to estimate the displacement capacity of piles. This investigation developed closed-form formulas for estimating the displacement capacity of piles by using a simple pile-deck connection system. The displacement capacity estimated from these formulas ensures that the material stain limits specified in the MOTEMS is not …

Flexural Cracks In Fiber-Reinforced Concrete Beams With Fiber-Reinforced Polymer Reinforcing Bars, Won K. Lee, Daniel C. Jansen, Kenneth B. Berlin, Ian E. Cohen

Civil and Environmental Engineering

Fiber-reinforced polymer (FRP) reinforcing bars have attracted considerable attention for applications where corrosion of steel reinforcement is problematic. Due to the generally low elastic modulus and poor bond characteristics of FRP as compared to steel reinforcing bars, the use of FRP results in larger crack widths under service loads. Fiber-reinforced concrete (FRC) is proposed for use with FRP to reduce crack widths. The work presented herein includes the results from 16 beams tested under four-point bending with either Grade 420 (Grade 60) steel or FRP reinforcing bars, and either plain concrete or FRC. A modified Gergely-Lutz model was applied to …

The Concept Of Proactive Traffic Management For Enhancing Freeway Safety And Operation, Mohamed Abdel-Aty, Anurag Pande, Liang Hsia

Civil and Environmental Engineering

No abstract provided.

New Approach For Surface N Factors, James L. Hanson, Nazli Yesiller, Gareth E. Swarbrick, Wei-Lien Liu

Civil and Environmental Engineering

Air and surface freezing and thawing indexes and prediction of ground temperatures from air temperatures were investigated. A new method for applying n factors on a daily basis to capture localized temperature extremes is presented and compared to conventional seasonal n-factor analysis. Measured air temperatures from five locations and measured air and surface temperatures from one location were used. Freezing and thawing indexes were determined using daily and monthly average temperatures, different time frames, and seasonal and daily applications of n factors. Air and surface freezing indexes (I_af and I_sf) varied more than air and surface …

Performance Of A Stormwater Filter And Bacteria Inactivation Using Biocidal Media, Alexander Scott Bowerman

Master's Theses

There are many possible ways to mitigate stormwater pollution, but this study focused on the DrainPacTM catchment basin insert and the feasibility of integrating N-halamine biocidal brominated beads into the filter system. This study was divided into three sections. The first section involved testing a DrainPacTM filter for treatable flow rates, head loss, and removal of solids, oil, and bacteria. The DrainPacTM filter is designed to be installed in a stormwater catch basin. The filter is composed of a 12 x 41 inch metal frame with textile filter media attached to it in a basket shape. The upper portion of …

Influence Of Material Type, Aggregate Size, And Unconfined Compressive Strength On Water Jetting Of Cidh Pile Anomalies, Joseph Carl Heavin

Master's Theses

Water jetting as a means for removing anomalous materials from cast-in-drilled-hole (CIDH) piles was examined. The primary objective of this research was to establish empirical relationships between different jetting parameters and the removal of commonly occurring anomalous zone materials, including low-strength concrete, slurry mixed concrete, grout, and clay soil. Also investigated was the current standard-of-practice used by water jetting contractors within California. The testing specimens consisted of typical anomalous material with unconfined compressive strengths between 5 and 6,000 psi. The experimental work consisted of water blasting submerged specimens using rotary jets, nozzles, and pumping equipment typically used in construction practice. …

City Of Davis Greenbelt Master Plan, Brandon Haydu

Master's Theses

The City of Davis is currently updating its Parks and Recreation Facilities Master Plan. During the update, greenbelts were identified as a highly used and desired facility. This Greenbelt Master Plan serves as a plan focused on the opportunities greenbelts can provide as recreational and transportation facilities. This report has analyzed community feedback, greenbelt coverage, greenbelt capacity, and existing local, state, and federal design guidelines. The final plan is a set of goals, objectives, policies, and programs, along with a greenbelt map, which is aimed at improving the greenbelt infrastructure in Davis through the year 2020.

Identification Of Physical Changes To A Steel Frame, Daniel Eric Means

Master's Theses

The thesis utilized physical testing and computer modeling to determine the feasibility of identifying a change to the mass or stiffness of a steel frame. Physical testing was performed using an accelerometer, linear shaker, and arbitrary function generator. Two methods of laboratory testing were developed: ambient vibration testing (AVT) and forced vibration testing (FVT). AVT was able to preliminarily identify the natural frequencies and mode shapes of the frame. FVT was able to precisely identify four distinct natural frequencies, mode shapes, and damping ratios. The baseline frame then underwent two physical changes: the addition of mass to its roof, and …

Beneficial Reuse Of Corrugated Board In Slurry Applications, James L. Hanson, Nazli Yesiller, Jagjit Singh, Greg M. Stone, Adam Stephens

Civil and Environmental Engineering

Use of virgin and post-consumer corrugated board as a replacement for bentonite in slurry mixes was investigated. The effectiveness of the slurry mixes was assessed using typical tests including Marsh funnel viscosity, density, and filtrate loss. Filter cake permeability was also determined. Corrugated board was fiberized for the test program. Test results indicated that corrugated board could be used to replace 9 to 27% (0.5 to 1.5% corrugate content) of bentonite in slurry mixes with a total solids content of 5.5%. Slurry applications provide a new and viable beneficial reuse alternative for paper/paperboard products, which constitute the largest weight and …

Genetic Programming To Investigate Design Parameters Contributing To Crash Occurence On Urban Arterials, Abhishek Das, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Nonlinear models were developed to estimate crash frequency on urban arterials with partial access control. These multilane arterials consist of midblock segments joined by signalized and unsignalized intersections (or access points). Crashes included in the analysis are of three major types: rear-end, angle, and head-on. Each crash type is further sorted into mutually exclusive categories on the basis of the roadway element responsible for the crashes: midblock segment, signalized intersection, and access point. Genetic programming (GP) is adopted for predicting crash frequency. GP, which is primarily based on genetic algorithms, uses the concept of evolution to develop models through the …

Dual Axis Solar Tracker, Weston Sapia, Jason Birnie

Electrical Engineering

No abstract provided.