Engineering Commons^™

Finite Element Analysis Of Frp Debonding Failure At The Tip Of Flexural/Shear Crack In Concrete Beam, Tayyebeh Mohammadi, Baolin Wan, Kent Harries

Civil and Environmental Engineering Faculty Research and Publications

One of the most common failure modes of strengthened RC beams with externally bonded FRP is intermediate crack (IC) debonding of FRP initiated at the tip of flexural/shear cracks. This study presents a method, using extended finite element method (XFEM), to model IC debonding in an FRP-strengthened concrete beam. In XFEM, as soon as a damage initiation criterion is reached in an element, additional degrees of element freedom are added to model crack initiation. Crack propagation is then modeled using fracture energy criterion. This method can be used to simulate debonding failure along an arbitrary, solution-dependent path without the requirement …

Heavy Vehicle Performance During Recovery From Forced-Flow Urban Freeway Conditions Due To Incidents, Work Zones And Recurring Congestion, Alexander Drakopoulos, Yue Liu, Alan Horowitz

Civil and Environmental Engineering Faculty Research and Publications

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the 2010 Manual heavy vehicle impact is evaluated based on “passenger car equivalent” values for buses, recreational vehicles and trucks. These values were calibrated for relatively uncongested freeway conditions (levels of service A through C) since inadequate field data on heavy vehicle behavior under congested conditions were available. A number of field data collection efforts, that were not included in deriving the passenger car equivalent values …

Timoshenko Beam Effects In Lateral-Mode Microcantilever-Based Sensors In Liquids, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by actuating microcantilevers in the lateral flexural mode, especially for microcantilevers having larger width-to-length ratios. However, experimental results show that for these geometries the resonant characteristics predicted by the existing analytical models differ from the measurements. A recently developed analytical model to more accurately predict the resonant behaviour of these devices in viscous fluids is described. The model incorporates viscous fluid effects via a Stokes-type fluid resistance assumption and `Timoshenko beam' effects (shear deformation and rotatory inertia). Unlike predictions based on Euler-Bernoulli beam …

Conditional Spectrum-Based Ground Motion Selection. Part I: Hazard Consistency For Risk-Based Assessments, Ting Lin, Curt B. Haselton, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

The conditional spectrum (CS, with mean and variability) is a target response spectrum that links nonlinear dynamic analysis back to probabilistic seismic hazard analysis for ground motion selection. The CS is computed on the basis of a specified conditioning period, whereas structures under consideration may be sensitive to response spectral amplitudes at multiple periods of excitation. Questions remain regarding the appropriate choice of conditioning period when utilizing the CS as the target spectrum. This paper focuses on risk-based assessments, which estimate the annual rate of exceeding a specified structural response amplitude. Seismic hazard analysis, ground motion selection, and nonlinear dynamic …

Conditional Spectrum-Based Ground Motion Selection. Part Ii: Intensity-Based Assessments And Evaluation Of Alternative Target Spectra, Ting Lin, Curt B. Haselton, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

In a companion paper, an overview and problem definition was presented for ground motion selection on the basis of the conditional spectrum (CS), to perform risk-based assessments (which estimate the annual rate of exceeding a specified structural response amplitude) for a 20-story reinforced concrete frame structure. Here, the methodology is repeated for intensity-based assessments (which estimate structural response for ground motions with a specified intensity level) to determine the effect of conditioning period. Additionally, intensity-based and risk-based assessments are evaluated for two other possible target spectra, specifically the uniform hazard spectrum (UHS) and the conditional mean spectrum (CMS, without variability).It …

Anaerobic Co-Digestion Planning And Research For Green Bay, Wi, Jonathan Kusowski

Master's Theses (2009 -)

The aspiration to find an alternative sustainable fuel source is an ever growing concern. Anaerobic digestion might hold the answer to finding an alternative sustainable energy source. Anaerobic digestion does not only provide a renewable resource in the form of biogas, but also stabilizes wastes, preventing large amounts from being landfilled or incinerated. Anaerobic digestion of municipal wastewater sludges can often be improved by the addition of high strength industrial wastes, in a process called co-digestion. High strength industrial wastes provide an additional carbon source for the microbes to utilize and convert into usable biogas. Co-digestion also offers the opportunity …

Ion Exchange Nutrient Recovery From Municipal Wastewater, Allen Williams

Master's Theses (2009 -)

Nitrogen and phosphorus discharge is regulated due to eutrophication. Typically ammonium-nitrogen is removed through nitrification which requires energy and phosphorus (P) is removed by metal salt addition to precipitate P. A more sustainable approach may be to implement nutrient recovery to form fertilizers. Most nitrogen fertilizer is formed through the energy intensive Haber-Bosch process. Phosphate rock, a limited resource, is mined for P fertilizer. Discharge regulations and the fertilizer production costs provide an economic driver for recovery. The current project used anionic and cationic ion exchange (IX) to concentrate the nutrients with recovery by struvite precipitation. Previous work lacks direct …

Industrial Symbiosis: Corn Ethanol Fermentation, Hydrothermal Carbonization, And Anaerobic Digestion, Patrick J. Mcnamara, Lindsey R. Jader, Frederick J. Schendel, Nicholas J. Hahn, Brandon M. Wood, Kenneth J. Valentas, Paige M. Novak, Steven J. Heilmann

Civil and Environmental Engineering Faculty Research and Publications

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and …

Validation Of Earthquake Simulations And Their Effects On Tall Buildings Considering Spectral Shape And Duration, Ting Lin, Gregory Deierlein, Nenad Bijelic

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Young’S Modulus And Volume Porosity Relationships For Additive Manufacturing Applications, John Anthony Choren, Stephen M. Heinrich, M. Barbara Silver-Thorn

Civil and Environmental Engineering Faculty Research and Publications

Recent advancements in additive manufacturing (or rapid prototyping) technologies allow the fabrication of end-use components with defined porous structures. For example, one area of particular interest is the potential to modify the flexibility (bending stiffness) of orthopedic implants through the use of engineered porosity (i.e., design and placement of pores) and subsequent fabrication of the implant using additive manufacturing processes. However, applications of engineered porosity require the ability to accurately predict mechanical properties from knowledge or characterization of the pore structure and the existence of robust equations characterizing the property–porosity relationships. As Young’s modulus can be altered by variations in …

Developing A Model To Enhance Labor Productivity Using Bridge Construction Benchmark Data, Seonghoon Kim, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

The Labor Working Status Monitoring (LWSM) Model that incorporates the WRITE and the industry benchmark data was developed through the five steps to enhance labor productivity in bridge construction operations. The first step of the development process was to conduct a literature review, followed by the second step which was to develop the WRITE. During the development, the authors identified the necessary hardware and software for the WRITE and outlined a schematic to show the connection of major hardware components. The third step was to develop the LWSM Model for monitoring the on-site construction labor working status by comparing data …

Resonant Characteristics Of Rectangular Hammerhead Microcantilevers Vibrating Laterally In Viscous Liquid Media, Jinjin Zhang, Fabien Josse, Stephen M. Heinrich, Nicholas J. Nigro, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

The resonant characteristics of laterally vibrating rectangular hammerhead microcantilevers in viscous liquid media are investigated. The rectangular hammerhead microcantilever is modeled as an Euler-Bernoulli beam (stem) and a rigid body (head). A modified semi-analytical expression for the hydrodynamic function in terms of the Reynolds number, Re, and aspect ratio, h/b, is proposed to rapidly evaluate the sensing characteristics. Using this expression, the resonance frequency, quality factor and normalized surface mass sensitivity are investigated as a function of the dimensions of the microcantilever and liquid properties. Guidelines for design of hammerhead microcantilever geometry are proposed to achieve efficient sensing platforms for …

Triclosan Enriches For Dehalococcoides-Like Chloroflexi In Anaerobic Soil At Environmentally Relevant Concentrations, Patrick J. Mcnamara, Mark J. Krzmarzick

Civil and Environmental Engineering Faculty Research and Publications

Triclosan is an antimicrobial agent that is discharged to soils with land-applied wastewater biosolids, is persistent under anaerobic conditions, and yet its impact on anaerobic microbial communities in soils is largely unknown. We hypothesized that triclosan enriches for Dehalococcoides-like Chloroflexi because these bacteria respire organochlorides and are likely less sensitive, relative to other bacteria, to the antimicrobial effects of triclosan. Triplicate anaerobic soil microcosms were seeded with agricultural soil, which was not previously exposed to triclosan, and were amended with 1 mg kg⁻¹ of triclosan. Triplicate control microcosms did not receive triclosan, and the experiment was run for …

Starting A Construction Engineering Program At Marquette University, Mark O. Federle

Civil and Environmental Engineering Faculty Research and Publications

Marquette University decided to start a Construction Engineering and Management program during the 2007 academic year. An endowed chair, titled the McShane Chair in Construction Engineering and Management, was funded by Jim and Kelly McShane to run the program. After a national search, Mark Federle, an executive with a large construction firm and previous academic experience at Iowa State University, was hired to start the program. The first class of students were enrolled in the fall of 2008. This paper will present the opportunities/challenges in starting a Construction Engineering and Management program. Lessons learned, comparisons to other programs, and other …

Conditional Spectrum Computation Incorporating Multiple Causal Earthquakes And Ground‐Motion Prediction Models, Ting Lin, Stephen C. Harmsen, Jack W. Baker, Nicolas Luco

Civil and Environmental Engineering Faculty Research and Publications

The Conditional Spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions as well as the epistemic uncertainties in ground motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are …

Development Of The Chinese Construction Industry After The Cultural Revolution: Administration Framework, Economic Growth, And Market Structure, Yilei Huang, Yi Lan, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

This paper presents the results of an investigation on the development of the Chinese construction industry after the Cultural Revolution in terms of administration framework, economic growth, and market structure, with the consideration of Chinese currency inflation. The development was divided into three stages based on Chinese government policy changes on the construction industry. In each stage, the reform of administration framework was reviewed, and the market size and market structure in both the domestic and the international markets were analyzed. Value added and gross output value of domestic market, the number of contracts, contracting value, total turnover, and turnover …

Fatigue Risks In The Connections Of Sign Support Structures, Christopher M. Foley, Joseph A. Diekfuss, Baolin Wan

Transportation Reports with the Wisconsin Department of Transportation

This research effort develops a reliability-based approach for prescribing inspection intervals for mast-arm sign support structures corresponding to user-specified levels of fatigue-induced fracture risk. The resulting level of risk for a particular structure is dependent upon its geographical location, the type of connection it contains, the orientation of its mast-arm relative to north and the number of years it has been in service. The results of this research effort indicate that implementation of state-of-the-art reliability-based assessment procedures can contribute very valuable procedures for assigning inspection protocols (i.e. inspection intervals) that are based upon probabilities of finding fatigue-induced cracking in these …

Evening Methane Emission Pulses From A Boreal Wetland Correspond To Convective Mixing In Hollows, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Spatial and temporal heterogeneity of methane flux from boreal wetlands makes prediction and up-scaling challenging, both within and among wetland systems. Drivers of methane production and emissions are also highly variable, making empirical model development difficult and leading to uncertainty in methane emissions estimates from wetlands. Previous studies have examined this problem using point-scale (static chamber method) and ecosystem-scale (flux tower methods) measurements, but few studies have investigated whether different processes are observed at these scales. We analyzed methane emissions from a boreal fen, measured by both techniques, using data from the Boreal Ecosystem-Atmosphere Study. We sought to identify driving …

Timoshenko Beam Effects In Lateral-Mode Microcantilever-Based Sensors In Liquids (Proceedings), Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Probabilistic Sea-Level Rise Hazard Analysis, Ting Lin

Civil and Environmental Engineering Faculty Research and Publications

This paper proposes a framework termed Probabilistic Sea-Level Rise Hazard Analysis (PSLRHA), to integrate the sea-level rise knowledge of current climate change scientific communities for informed engineering and policy decisions that affect coastal infrastructure, populations, and ecosystems. PSLRHA combines probabilities of all emission scenarios with predictions of the resulting sea-level rise over time, in order to compute sea-level rise hazard. PSLRHA also incorporates uncertainties in those sea-level rise predictions, by considering multiple Sea-Level Rise Prediction Models (SLRPMs). The output of the PSLRHA framework could be a Global Sea-Level Rise Hazard Map (GSLRHM) that can be used for Performance- Based Sea-Level …

Abundance And Diversity Of Organohalide-Respiring Bacteria In Lake Sediments Across A Geographical Sulfur Gradient, Patrick J. Mcnamara, Benjamin B. Crary, Paige J. Novak, Mark J. Krzmarzick

Civil and Environmental Engineering Faculty Research and Publications

Across the U.S. Upper Midwest, a natural geographical sulfate gradient exists in lakes. Sediment grab samples and cores were taken to explore whether this sulfur gradient impacted organohalide-respiring Chloroflexi in lake sediments. Putative organohalide-respiring Chloroflexi were detected in 67 of 68 samples by quantitative polymerase chain reaction. Their quantities ranged from 3.5 × 10⁴ to 8.4 × 10¹⁰ copies 16S rRNA genes g⁻¹ dry sediment and increased in number from west to east, whereas lake sulfate concentrations decreased along this west-to-east transect. A terminal restriction fragment length polymorphism (TRFLP) method was used to corroborate this inverse relationship, …

Reliability-Based Fatigue Assessment Of Mast-Arm Sign Support Structures, Joseph A. Diekfuss

Dissertations (1934 -)

Over the past few decades, there have been issues of poor fatigue performance (the main failure mechanism) of the welded, tube-to-transverse plate connections within sign support structures. Review of the literature has indicated that a considerable amount of research has been devoted to identifying the structural response characteristics of these signs. Others have tried to identify how these connections may be repaired, retrofitted or simply better designed to sustain longer fatigue lives. However, little attention has been given to using a systematic reliability-based approach to assess the risk of fatigue-induced fracture in these structures.

Using a reliability-based approach to solve …

Effect Of Support Compliance On The Resonant Behavior Of Microcantilever-Based Sensors In Viscous Fluids, Rabin Maharjan

Dissertations (1934 -)

Resonant microcantilevers are often considered for use in chemical sensing and biosensing applications. However, when excited in the conventional transverse flexural mode, their performance in liquids is severely compromised. Theoretical and experimental studies have shown that the detrimental effects of the liquid may be mitigated by operating the microcantilever in lateral flexure, especially for microbeams having smaller length-to-width (L/b) ratios. However, for these most promising geometries the predictions of existing models tend to diverge from experimental data for resonant frequency (f_res) and quality factor (Q). A likely reason for these discrepancies is support compliance, which has been neglected …

Influence Of Fluid-Structure Interaction On Microcantilever Vibrations: Applications To Rheological Fluid Measurement And Chemical Detection, Isabelle Dufour, E. Lemaire, B. Caillard, H. Debeda, C. Lucat, Stephen M. Heinrich, Fabien Josse, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

At the microscale, cantilever vibrations depend not only on the microstructure’s properties and geometry but also on the properties of the surrounding medium. In fact, when a microcantilever vibrates in a fluid, the fluid offers resistance to the motion of the beam. The study of the influence of the hydrodynamic force on the microcantilever’s vibrational spectrum can be used to either (1) optimize the use of microcantilevers for chemical detection in liquid media or (2) extract the mechanical properties of the fluid. The classical method for application (1) in gas is to operate the microcantilever in the dynamic transverse bending …

Introducing Adaptive Incremental Dynamic Analysis: A New Tool For Linking Ground Motion Selection And Structural Response Assessment, Ting Lin, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

Adaptive Incremental Dynamic Analysis (AIDA) is a novel ground motion selection scheme that adaptively changes the ground motion suites at different ground motion intensity levels to match hazard-consistent properties for structural response assessment. Incremental DynamicAnalysis (IDA), a current dynamic response history analysis practice in Performance-Based Earthquake Engineering (PBEE), uses the same suite of ground motions at all Intensity Measure (IM) levels to estimate structural response. Probabilistic Seismic Hazard Analysis (PSHA) deaggregation tells us, however, that the target distributions of important ground motion properties change as the IM levels change. To match hazard-consistent ground motion properties, ground motions can be re-selected …

Comparative Evaluation Of Operating Life For Phosphate-Specific Ion Exchange Resins, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

A Simple Model For The In-Plane Rotational Response Of A Disk Resonator In Liquid: Resonant Frequency, Quality Factor, And Optimal Geometry, Mohomad S. Sotoudegan, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Development Of An Aquaponics Research Program, Richard W. Marklin Jr., Margaret Mathison, Brooke K. Mayer, Mark L. Nagurka, Vikram Cariapa, Michael Schläppi

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Cantilever-Based Resonant Gas Sensors With Integrated Recesses For Localized Sensing Layer Deposition, C. Carron, P. Getz, J. J. Su, D. S. Gottfried, Fabien Josse, Stephen M. Heinrich

Civil and Environmental Engineering Faculty Research and Publications

This work presents mass-sensitive hammerhead resonators with integrated recesses as a gas-phase chemical microsensor platform. Recesses are etched into the head region of the resonator to locally deposit chemically sensitive polymers by ink-jet printing. This permits the sensing films to be confined to areas that (a) are most effective in detecting mass loading and (b) are not strained during the in-plane vibrations of the resonator. As a result of the second point, even 5-μm thick polymer coatings on resonators with a 9-12 μm silicon thickness barely affect the Q-factor in air. This translates into higher frequency stability and ultimately higher …

Evaluation Of Bridge Maintenance Interventions Under Changing Deterioration Rates: A Markovian-Based Methodology, Dilum Fernando, Baolin Wan, Scott Walbridge

Civil and Environmental Engineering Faculty Research and Publications

Markovian transition probability matrices employing condition states are often used in bridge management systems to determine optimal intervention strategies. This approach assumes a constant deterioration matrix throughout the entire analysis period. However, in order to adequately model and evaluate intervention options such as fiber-reinforced polymer (FRP) strengthening, it is necessary to model the impact of the intervention on the deterioration rate. This paper presents a Markovian based approach to model interventions that impact deteriorating rates. A model employing this approach is proposed. A methodology to determine the optimal intervention strategy based on steady state probabilities is then presented. The proposed …