Architectural Engineering Commons^™

Foundations For Dynamic Loads, Vijay K. Puri, Shamsher Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Design of foundations in earthquake prone areas needs special considerations. Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. the reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters. in the case of piles, the soil-pile behavior under earthquake loading is generally nonlinear. the nonlinearity must be accounted for by defining soil-pile stiffness in terms of strain dependent soil modulus. a comparison of observed and predicted pile behavior under dynamic loads has attracted the attention of several investigators. the lateral dynamic pile response …

Intricacies Of Professional Certifications For Quality Management (Qm), Edmund R. Martelli

Masters Theses & Specialist Projects

The modern manufacturing marketplace is extremely complex and constantly changing. Career professionals often seek job placement, career advancement, and continuing education through professional certifications. Professional certifications in the United States (U.S.) have been evolving since 1911. In the 1950s, engineering groups established professional certifications and licenses. In the 1980s, administration of accreditation of certification programs proliferated, and by the 1990s, many government and professional organizations sought to standardize procedures for the industry. Currently, professional certifications are available for virtually every profession and issued by multitudes of organizations.

Quality management (QM) encompasses an extensive combination ofprofessional abilities. Providers of professional certifications …

Seismic Assessment Of An Existing Non-Seismically Designed Major Bridge-Abutment-Foundation System, Aman Mwafy, Oh Sung Kwon, Amr Elnashai

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A comprehensive study carried out to assess the seismic response of a 59-span bridge using a refined inelastic modeling approach and considering Soil-Structure Interaction (SSI) is summarized in this paper. the focus is on describing the methodology adopted to idealize the bridge and its foundation system, while only highlights from the extensive elastic and inelastic analyses are presented. the bridge represents a typical case of vulnerable complex bridges since it was built in the early seventies with minimal seismic design requirements at a distance of about 5 km from a major fault. the SSI analysis is significant in this study …

Cyber-Physical Codesign Of Distributed Structural Health Monitoring With Wireless Sensor Networks, Gregory Hackmann, Weijun Guo, Guirong Yan, Chenyang Lu, Shirley Dyke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Our Deteriorating Civil Infrastructure Faces the Critical Challenge of Long-Term Structural Health Monitoring for Damage Detection and Localization. in Contrast to Existing Research that Often Separates the Designs of Wireless Sensor Networks and Structural Engineering Algorithms, This Paper Proposes a Cyber-Physical Co-Design Approach to Structural Health Monitoring based on Wireless Sensor Networks. Our Approach Closely Integrates (1) Flexibility-Based Damage Localization Methods that Allow a Tradeoff between the Number of Sensors and the Resolution of Damage Localization, and (2) an Energy-Efficient, Multi-Level Computing Architecture Specifically Designed to Leverage the Multi-Resolution Feature of the Flexibility-Based Approach. the Proposed Approach Has Been Implemented …

Low Viscosity Pore Fluid To Manufacture Transparent Soil, Honghua Zhao, Louis Ge, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Transparent soil has been investigated for its potential as a substitute research media for natural soil. the mechanism for manufacturing the transparent soil is through adding an appropriate pore fluid to silica gel particles with the same refractive index. Two types of high viscosity pore fluids were identified by Iskander in 1994. However, because of the high viscosity of these two pore fluids, air was easily entrapped, which made the manufacture of a large mass of transparent soil difficult. in addition, the identified pore fluids caused serious membrane deterioration during triaxial laboratory testing. This research presented herein is an experimental …

Static And Fatigue Bond Characteristics Of Frp Rebars Embedded In Fiber-Reinforced Concrete, Huanzi Wang, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A research project was initiated to develop a nonferrous hybrid reinforcement system for concrete bridge decks by using continuous fiber-reinforced polymer (FRP) rebars and discrete randomly distributed polypropylene fibers. This hybrid system may eliminate problems related to the corrosion of steel reinforcement while providing requisite strength, stiffness, and desired ductility, which are shortcomings of FRP reinforcing system in plain concrete. This article presents the results of a part of this research program, i.e., the bond behaviors of this hybrid reinforcing system under monotonic and fatigue loading. Test results indicate that the addition of polypropylene fibers does not increase the ultimate …

Structural Damage Detection Robust Against Time Synchronization Errors, Guirong Yan, Shirley J. Dyke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Structural Damage Detection based on Wireless Sensor Networks Can Be Affected Significantly by Time Synchronization Errors among Sensors. Precise Time Synchronization of Sensor Nodes Has Been Viewed as Crucial for Addressing This Issue. However, Precise Time Synchronization over a Long Period of Time is Often Impractical in Large Wireless Sensor Networks Due to Two Inherent Challenges. First, Time Synchronization Needs to Be Performed Periodically, Requiring Frequent Wireless Communication among Sensors at Significant Energy Cost. Second, Significant Time Synchronization Errors May Result from Node Failures Which Are Likely to Occur during Long-Term Deployment over Civil Infrastructures. in This Paper, a Damage …

Investigation Of The Thermal Conductivity Of Compacted Silts And Its Correlation To The Elastic Modulus, Robert D. Hotz, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Thermal conductivity measurement is a quick and easy test for compacted soils. This study presents the results of thermal conductivity testing on silt compacted under standard and modified Proctor efforts. a comparison of moisture content measurements from both lab oven and field oven is also presented and discussed. Measured thermal conductivity was correlated to the bulk density and water content. It is further correlated to Young's modulus and Shear modulus of the compacted silt, which were determined through ultrasonic pulse velocity measurements. Several trends were observed which may be used to correlate soil thermal conductivity of the compacted silt to …

On The Turbulent Prandtl Number In Homogeneous Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Derek D. Stretch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this paper, we derive a general relationship for the turbulent Prandtl number Prt for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Prt, is developed in terms of a mixing length scale LM and an overturning length scale LE, the ratio of the mechanical (turbulent kinetic energy) decay time scale TL to scalar decay time scale Tp and the gradient Richardson number Ri. We show that our formulation for Prt is appropriate even for non-stationary (developing) stratified flows, since it does not include the reversible contributions in …

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 …

Estimation Of Flight Delay Costs For U.S. Domestic Air Passengers, Hojong Baik, Tao Li, Naveen K. Chintapudi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Evaluating the economic value of flight delays has always been a keen interest of research groups as well as of federal agencies such as the U.S. Department of Transportation and FAA. However, because of the complexity of the question as well as the incompleteness of available data sets, the estimation of flight delay costs is considered a challenging task in practice. This paper presents a method for estimating domestic air passengers' delay costs incurred by flight delays in U.S. airports. a unique feature of the method is that the costs incurred by flight delays relative to the original flight schedules …

Some Comments On The Protection Of Lunar Habitats Against Damage From Meteoroid Impacts, William P. Schonberg, F. Schäfer, R. Putzar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The establishment of human habitats on the Moon and on Mars will require protecting them from the hazards of near-Earth and interplanetary space. in addition to solar radiation, another hazard to be faced by these habitats is the damage that can result from the high-speed impact of a meteoroid on a critical structural component. Therefore, lunar habitats and their accompanying support facilities need to be designed with adequate levels of protection that will allow them to also withstand the damage that can result from a meteoroid impact. in this paper we discuss some approaches to shielding for lunar habitats, focusing …

A Study Of The Economical Feasibility Of Installing Heating, Ventilation, And Air-Conditioning Condensate Recovery System, Rafid M. Kully

Theses

The objective of this study is to establish a guide line or an analytical frame work to predetermine the economic benefits associated with the installation of Heating, Ventilation, and Air-Conditioning (HVAC) condensate recovery systems to capture the air-handler’s condensate water and use it as makeup water for the cooling tower. Some factors should be considered such as; the location, building operation, amount of outside air required, type of energy recovery system, and indoor conditions setup. Experimental data was used from Emory University in Georgia, where a condensate recovery system was installed and the condensate water from four air-handler units at …

Evaluation Of A Web-Based Learning Tool For Teaching Gis Within The Context Of Transportation Engineering, Ashley Banaszek, Hong Sheng, Richard H. Hall, Ronaldo Luna, Ghulam Bham

Business and Information Technology Faculty Research & Creative Works

An Exploratory Study Was Conducted to Evaluate a Web-Based Learning Module for Teaching Geographic Information Systems to Civil Engineering Students within the Context of a Problem Related to Crash Data Analysis. This Module is One Part of a National Science Foundation Course, Curricula, and Laboratory Improvement Project in Which GIS Modules Are Being Developed for Several Areas of Civil Engineering. the Module Was Used as a Laboratory Assignment in a Transportation Engineering Course. Two Days Later Students Completed Both an Objective Multiple-Choice Quiz over the Material Covered in the Lab and a Subjective Questionnaire. Quantitative Analysis Was Carried Out on …

Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Quantifying diapycnal mixing in stably stratified turbulence is fundamental to the understanding and modeling of geophysical flows. Data of diapycnal mixing from direct numerical simulations of homogeneous stratified turbulence and from grid turbulence experiments, are analyzed to investigate the scaling of the diapycnal diffusivity. In these homogeneous flows the instantaneous diapycnal diffusivity is given exactly by Kd= ∈ρ/ (∂ ρ /∂z)²where ∈ρ is the dissipation rate of density fluctuations, and ∂ ρ /∂z is the mean density gradient. The diffusivity Kd may be expressed in terms of the large-scale properties of the turbulence as K d = γLE …

Control Force Estimation In Seismic Building Design, Xiaozhe Zhang, Franklin Y. Cheng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents two approaches of estimating the control force magnitude in the building structure's seismic design. One is by spectrum average in frequency domain, and the other is by nondeterministic Monte Carlo analysis in time domain. the spectrum method is proposed to find the estimation by averaging the system's frequency response with an earthquake spectrum as a weighting factor. the nondeterministic method is based on sets of potential ground motions generated numerically. the approaches are developed in the concept of performance design, with studies based on the site potential seismic hazard and presenting results at different levels of displacement …

Modeling Permanent Deformation Of Unbound Granular Materials Under Repeated Loads, Cheng Chen, Louis Ge, Jiansheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Finite-element analysis on a pavement structure under traffic loads has been a viable option for researchers and designers in highway pavement design and analysis. Most of the constitutive drivers used were nonlinear elastic models defined by empirical resilient modulus equations. Few isotropic/kinematic hardening elastoplastic models were used but applying thousands of repeated load cycles became computationally expensive. in this paper, a cyclic plasticity model based on fuzzy plasticity theory is presented to model the long-term behavior of unbound granular materials under repeated loads. the discussion focuses on the model parameters that control long-term behavior such as elastic shakedown. the performance …

Special Issue On Modeling In Geotechnical Engineering For Design And Materials, R. A. Tarefder, D. H. Chen, Y. N. Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Finite Element Modeling Of A Field-Scale Shored Mechanically Stabilized Earth Wall, Cheng Chen, Louis Ge, Jia Sheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The shored mechanically stabilized earth (SMSE) walls are typically used in steep terrain to allow construction of a new road or widening of an existing narrow-road by constructing the wall on the outboard of the roadway. the state-of-practice suggests a minimum bench width and MSE reinforcement length equivalent to seventy percent of the design height of the MSE wall. It has been shown recently that shorter reinforcement length is sufficient when the SMSE wall system is constructed, and the retaining benefits provided by the shoring component should be taken into consideration. in this paper, a finite element analysis is performed …

Simulation Prototyping Of An Experimental Solar House, Anna Osborne, Stuart Baur, Katie Grantham

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a comparative analysis between an energy simulation model and an actual solar home. the case study used was the Team Missouri's 2009 Solar Decathlon entry. the home was evaluated using the predicted data developed with the use of Energy-10 Version 1.8. the software simulates the energy use performance of building strategies ranging from building envelope and system efficiency options. the performance data used was collected during the 2009 Solar Decathlon competition. Results comparing energy efficient strategies, consumption and generation are explored with future implications discussed. © 2010 by the authors.

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan of simply supported members be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to address serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength self-consolidating concrete and subjected to compressive fiber stress levels ranging from 65% to 84% of the concrete compressive strength at release of prestressing. Time dependent concrete surface strains were measured …

Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Minimization of the sound pressure field within the shadow zone of a noise barrier is achieved by reducing the pressure gradient along a line, at the top of a barrier, via active noise control. The noise control effectiveness of a barrier is increased by this strategy, especially for specific system configurations. The proposed method was evaluated by numerical simulation. Results indicate that system orientation has little effect on minimizing the pressure gradient at the top of the barrier when the error sensors are invisible to the primary noise disturbance. Highly effective control within the shadow zone and close to the …

Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M. Ronsse, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This project seeks to determine what relationship, if any, exists betweenbackground noise levels in elementary classrooms due to the building mechanicalsystems and student performance on achievement tests. Previous research inclassroom acoustics has clearly identified that lower background noise levelsresult in higher speech intelligibility which is crucial for the learning process;however, there is a lack of data correlating lower noise levels to improved studentachievement scores. For this study, background noise level measurements were madein 14 elementary schools in a public school system in Council Bluffs, Iowa, USA.The measurements were made in unoccupied classrooms with the central buildingmechanical systems activated. Second and …

Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This study investigated the effects of noise from building mechanical systems with tonal components on human task performance and perception. Six different noise conditions based on in-situ measurements were reproduced in an office-like setting; all were set to approximately the same sound level (47 dBA) but could have one particular tonal frequency (120 Hz, 235 Hz, or 595 Hz) at one of two tonal prominence ratios (5 or 9). Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately 1 hour to each noise condition. Results show that the noise …

Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise from building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant …

Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak

Durham School of Architectural Engineering and Construction: Faculty Publications

The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound …

Feasibility Study Of Solar Driven Underground Cooling System, Michel E. Shafik

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

In the United States the peak electrical use occurs during the summer. In addition, the building sector consumes a major portion of the annual electrical energy consumption. One of the main energy consuming components in the building sector is the Heating, Ventilation, and Air-Conditioning (HVAC) systems. This research studies the feasibility of implementing a solar driven underground cooling system that could contribute to reducing building cooling loads. The developed system consists of an Earth-to-Air Heat Exchanger (EAHE) coupled with a solar chimney that provides a natural cool draft to the test facility building at the Solar Energy Research Test Facility …

Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Predicting the insertion loss of an opening backed with an enclosed space is important for building noise control. Recent research in sound transmission through apertures of finite depth in infinite rigid baffles has included the effects of propagating and evanescent modes within the aperture in order to extend models to higher frequencies. The present study extends the model to the case of the aperture backed by a cavity as opposed to sound radiating into half-space. The role of coupling between the aperture modes, radiation modes, and cavity modes in the transmission was investigated. The results were compared to those of …

Modeling Resilient Modulus Of Unbound Granular Materials Under Repeated Loading, Cheng Chen, Louis Ge, Jia Sheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Resilient modulus of unbound granular materials is a key design parameter for mechanistic empirical pavement design. But the complexity of the affected factors has made it challenging and difficult for practical designers and researchers to find an appropriate model to describe the entire stress-strain response where the plastic deformation is accumulated during the repeated loading condition. a cyclic plasticity model based on fuzzy sets plasticity theory is presented in this paper to model the resilient modulus and permanent strain behavior of unbound granular materials under repeated loading. the concept of the fuzzy set plasticity is first introduced, followed by its …

Settlement Of Reinforced Subgrades Under Dynamic Loading, V. K. Puri, S. Kumar, B. M. Das, Shamsher Prakash, B. Yeo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Model tests were conducted in the laboratory to study the settlement behavior of small size footing resting on geogrid reinforced sand layer and subjected to dynamic loads. Tests were conducted by first subjecting the footing to an initial sustained static load and then superimposing additional predetermined dynamic loads. the frequency of dynamic load was kept at 1 Hz which was well below the resonant frequency of the system. based on the observed test results, the nature of variation of the permanent settlement of the foundation with intensity of static loading and the amplitude of cyclic load are presented in this …