Hybrid Of Natural Element Method (Nem) With
Genetic Algorithm (Ga) To Find Critical Slip Surface,
2014
Mississippi State University
Hybrid Of Natural Element Method (Nem) With Genetic Algorithm (Ga) To Find Critical Slip Surface, Shahriar Shahrokhabadi, Vahid Khoshfahm, Hamed Nabizadeh Rafsanjani
Durham School of Architectural Engineering and Construction: Faculty Publications
One of the most important issues in geotechnical engineering is the slope stability analysis for determination of the factor of safety and the probable slip surface. Finite Element Method (FEM) is well suited for numerical study of advanced geotechnical problems. However, mesh requirements of FEM creates some difficulties for solution processing in certain problems. Recently, motivated by these limitations, several new Meshfree methods such as Natural Element Method (NEM) have been used to analyze engineering problems. This paper presents advantages of using NEM in 2D slope stability analysis and Genetic Algorithm (GA) optimization to determine the probable slip surface and …
Development Of A Tribometer To Characterize Lubrication Layer Properties Of Self-Consolidating Concrete,
2014
Missouri University of Science and Technology
Development Of A Tribometer To Characterize Lubrication Layer Properties Of Self-Consolidating Concrete, Dimitri Feys, Kamal Khayat, Aurelien Perez-Schell, Rami Khatib
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The Last Decade, Significant Advances Have Been Made in Investigating, Understanding and Predicting the Flow Characteristics during Pumping of Concrete. Kaplan Developed Theoretical Equations based on the Rheological and Tribological Properties of Concrete to Predict Pumping Pressures. Several Tribometers Were Developed to Characterize the Flow Properties of Concrete Along a Smooth Wall, But None of Them Allows the Use of Highly Workable Concretes. the Main Reason is that for the Calculation of the Yield Stress and Viscous Constant of the Lubrication Layer, the Concrete is Not Allowed to Be Sheared. in This Paper, a New Design for the Concrete Tribometer …
Shear Strength Of Chemically Based Self-Consolidating Concrete Beams: Fracture Mechanics Approach Versus Modified Compression Field Theory,
2014
Missouri University of Science and Technology
Shear Strength Of Chemically Based Self-Consolidating Concrete Beams: Fracture Mechanics Approach Versus Modified Compression Field Theory, Mahdi Arezoumandi, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental investigation was conducted to study the shear strength of full-scale beams constructed with both chemically based self-consolidating concrete (SCC) and conventional concrete (CC). This experimental program consisted of 12 beams without stirrups with three different longitudinal reinforcement ratios. The beams were tested under a simply supported four-point loading condition. The experimental shear strengths of the beams were compared with the shear provisions of both U.S. and international design codes. Furthermore, the shear strengths of the beams were evaluated based on fracture mechanics approaches, modified compression field theory (MCFT), and a shear database of CC specimens. Results of this …
Role Of Solids Retention Time On Complete Nitrification: Mechanistic Understanding And Modeling,
2014
Missouri University of Science and Technology
Role Of Solids Retention Time On Complete Nitrification: Mechanistic Understanding And Modeling, Guoqiang Liu, Jianmin Wang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Effects of solids retention time (SRT) on both steps of the nitrification process (e.g., ammonia oxidation and nitrite oxidation) and the nitrifier community in a complete-mix activated sludge process were studied. At a SRT less than or equal to 20 days, the effluent ammonia concentration was lower than the effluent nitrite concentration. At the 40-day SRT, however, the effluent nitrite concentration became equal to or less than the effluent ammonia concentration. Quantitative Polymerase Chain Reaction (QPCR) assays indicated that increasing SRT significantly increased nitrite-oxidizing bacteria/ammonia-oxidizing bacteria (NOB/AOB) ratio. Further investigation indicated that Nitrosomonas europaea/eutropha were the dominant AOB for ammonia …
Full-Scale Field Testing Of Micropiles In Stiff Clay Subjected To Combined Axial And Lateral Loads,
2014
Missouri University of Science and Technology
Full-Scale Field Testing Of Micropiles In Stiff Clay Subjected To Combined Axial And Lateral Loads, Kyle A. Kershaw, Ronaldo Luna
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A series of full-scale micro piles was installed at a site in mid-Missouri for a load-test program to study the effect of combined loading. The micro piles were installed with a 178-mm (7-in.) outer diameter steel casing to a depth of 4.6 m (15 ft) and a bond zone length of 3.0 m (10 ft). The surficial soils at the site consisted of stiff-to-hard clay underlain by weathered silty/sandy shale where the bond zone of the micro piles was located. The load-test program included axial, lateral, and combined-load tests. The ultimate axial and lateral capacity of the piles was initially …
Effects Of Mix Design Parameters And Rheological Properties On Dynamic Stability Of Self-Consolidating Concrete,
2014
Missouri University of Science and Technology
Effects Of Mix Design Parameters And Rheological Properties On Dynamic Stability Of Self-Consolidating Concrete, B. Esmaeilkhanian, Kamal Khayat, A. Yahia, D. Feys
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Stability is a crucial property for successful placement and performance of self-consolidating concrete (SCC). Dynamic stability refers to the segregation resistance of concrete during flow and is not thoroughly described in literature to date. In this research, a newly developed dynamic stability test, the Tilting-box test, was employed to evaluate the effect of different mix design parameters on the dynamic segregation of SCC. Paste volume, water-to-binder ratio (w/b), maximum size of aggregate (MSA), aggregate density, and aggregate grain-size distribution were shown to affect the dynamic stability of SCC, while the coarse aggregate shape did not have a significant influence. The …
Virtual Surface Temperature Sensor For Multi-Zone Commercial
Buildings,
2014
University of Nebraska-Lincoln
Virtual Surface Temperature Sensor For Multi-Zone Commercial Buildings, Yuebin Yu, Denchai Woradechjumroen, Daihong Yu
Durham School of Architectural Engineering and Construction: Faculty Publications
Multi-zone structure is commonly used in small commercial office buildings, retail stores and supermarket. While there is no adjacent wall between the zones, the impact of a neighbor zone on the current zone can be approximated and analyzed through the application of virtual walls. It is critical to accurately estimate the virtual wall surface temperature in order to evaluate the model uncertainty and apply improved supervisory control on multiple rooftop air-conditioning units (RTUs). We propose an innovative virtual surface temperature sensor based on system-identification to solve this challenge. The validation of the virtual temperature model is processed by the three …
Shallow Flat Soffit Precast
Concrete Floor System,
2014
Omaha, NE
Shallow Flat Soffit Precast Concrete Floor System, George Morcous, Maher Tadros
Durham School of Architectural Engineering and Construction: Faculty Publications
A precast concrete floor system that eliminates the need for column corbels and beam ledges while being very shallow. The main advantages of the present system include a span to-depth ratio of 30, a flat soffit, economy, consistency with prevailing erection techniques, and fire and corrosion protection. The present system consists of continuous precast columns, prestressed rectangular beams, hollow-core planks, and cast-in-place composite topping. Testing results have indicated that a 12 inch deep flat soffit precast floor system has adequate capacity to carry gravity loads (including 100 psf live load) in a 30 ft x 30 ft bay size. Testing …
Summary Of Large-Scale Nonplanar Reinforced Concrete Wall Tests,
2014
Tufts University
Summary Of Large-Scale Nonplanar Reinforced Concrete Wall Tests, Anahid A. Behrouzi, Andrew Mock, Laura Lowes, Dawn Lehman, Daniel Kuchma
Architectural Engineering
Nonplanar wall configurations are prevalent in engineering practice, yet relatively little research has addressed nonplanar walls and the earthquake response of these components remains poorly understood. A recent experimental test program conducted by the authors investigated the earthquake response of modern, ACI Code compliant C‐shaped walls subjected to unidirectional and bidirectional lateral loading. To compare the results of this study with previous experimental investigations conducted by others, this document examines laboratory tests of slender nonplanar walls available in the literature. Response histories, damage patterns, drift capacity and failure mechanisms are used to characterize the behavior of each nonplanar wall test …
Use Of Innovative Techniques To Enhance The Hydraulic Disinfection Efficiency Of Drinking Water Contact Tanks,
2014
Missouri University of Science and Technology
Use Of Innovative Techniques To Enhance The Hydraulic Disinfection Efficiency Of Drinking Water Contact Tanks, J. J. Kattnig, S. K. Venayagamoorthy
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The focus of this study was to understand the complex nature of flow dynamics within water disinfection contact tanks and to use this understanding in the development of beneficial tank modifications. Methods involved in this process included the use of computational fluid dynamics (CFD) and physical conservative tracer studies. Attempted tank alterations included the installation of baffles, inlet modification, and the use of industrial packing material. Tested modifications aimed at altering existing velocity fields to increase the hydraulic disinfection efficiency of a given system. Hydraulic efficiency was measured through the use of residence time distribution (RTD) curves and the well-known …
Empirically Derived Effective Stiffness Expressions For Concrete Walls,
2014
SCA Consulting Engineers
Empirically Derived Effective Stiffness Expressions For Concrete Walls, Andrew Mock, Anahid A. Behrouzi, Laura Lowes, Dawn Lehman, Daniel Kuchma
Architectural Engineering
In most cases, analysis to determine component demands for seismic design of concrete buildings employs linear elastic models in which reduced, effective component stiffnesses are used. This document i) reviews the recommendations for defining the effective flexural, shear and axial stiffness of concrete walls that are included in current design codes, standards and guidelines and ii) compares these recommendations with stiffness expressions derived directly from experimental data by the authors and others. Section 2 reviews existing empirically derived and code‐, standard‐, and guideline‐based expressions for the effective stiffness of concrete walls. Section 3 presents the process used by the authors …
Summary Of Large-Scale C-Shaped Reinforced Concrete Wall Tests,
2014
Tufts University
Summary Of Large-Scale C-Shaped Reinforced Concrete Wall Tests, Anahid A. Behrouzi, Andrew Mock, Laura Lowes, Dawn Lehman, Daniel Kuchma
Architectural Engineering
Flexural concrete walls (i.e., walls the yield in flexural prior to failure) are used commonly as the lateral load resisting system for mid‐ and high‐rise buildings on the West Coast. They are relatively stiff under service‐level loading, can take on various configurations to accommodate architectural constraints, and are generally assumed to exhibit ductile response under severe earthquake loading. Despite heavy reliance on concrete walls, relatively little research has been done to investigate the earthquake performance of walls with modern design details. Few data exist characterizing the performance of modern walls under variable levels of earthquake loading or the impact of …
Form Pressure Generated By Fresh Concrete: A Review About Practice In Formwork Design,
2014
Missouri University of Science and Technology
Form Pressure Generated By Fresh Concrete: A Review About Practice In Formwork Design, Tilo Proske, Kamal Khayat, Ahmed Omran, Olaf Leitzbach
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this paper, several current industrial practices in formwork design are presented focusing on the normative calculation of the form pressure. Most of the current Standards are devoting for the design of the formwork for the normal vibrated concrete. Currently, the Standards are being updated to include provisions for the newly adapted concrete, such as the flowable concrete and self-consolidating concrete. However, the experience with these methods is still limited. The available methods for calculating the formwork pressure for the flowable concrete and SCC are based on measuring the shear strength of concrete using different concepts, such as the setting …
The Potential For Energy Reduction In Uk Commercial Offices Through Effective Management And Behaviour Change,
2014
Technological University Dublin (formerly Uni. of Greenwich)
The Potential For Energy Reduction In Uk Commercial Offices Through Effective Management And Behaviour Change, Mark Mulville, Keith Jones, Gesche Huebner
Articles
eneral office equipment can be responsible for a significant proportion of overall electrical energy consumption in UK offices and this is predicted to rise significantly over the coming years [Webber, C. A., Roberson, J. A., Brown, R. E., Payne, C. T., Nordman, B., & Koomey, J. G. (2001). Field surveys of office equipment operating patterns. Berkley: CA: Lawrence Berkley National Laboratory]. As a significant contributor to overall energy use, this equipment has a corresponding cost and carbon impact. The legally binding requirements of the climate change act [Department of Energy and Climate Change. (2008 Department of Energy and …
Fit For Renting:An Investigation Into Space Standards Of Irish Housing,
2014
Technological University Dublin
Fit For Renting:An Investigation Into Space Standards Of Irish Housing, Jim Roche, Noel Brady
Books/Book Chapters
No abstract provided.
Safety Effect Of Missouri's Strategic Highway Safety Plan: Missouri's Blueprint For Safer Roadways,
2014
Missouri University of Science and Technology
Safety Effect Of Missouri's Strategic Highway Safety Plan: Missouri's Blueprint For Safer Roadways, Mojtaba A. Mohammadi, V. A. Samaranayake, Ghulam H. Bham
Mathematics and Statistics Faculty Research & Creative Works
This study systematically evaluated the changes in motor vehicle crashes that occurred on the Missouri Interstate highway system following the implementation of the Missouri Strategic Highway Safety Plan (MSHSP) between 2004 and 2007. The MSHSP implemented crash injury reduction strategies in enforcement, education, engineering, and public policy. Empirical Bayesian methods were commonly used to evaluate the effects of any change in safety as a result of countermeasures. This paper presents a simple new approach to evaluating the effects of Missouri's safety plans on roadway crashes. For crash data associated with traffic and roadway characteristics, negative binomial regression models were developed …
Behavior Of Hybrid Frp-Concrete-Steel Double-Skin Tubes Subjected To Cyclic Axial Compression,
2014
Missouri University of Science and Technology
Behavior Of Hybrid Frp-Concrete-Steel Double-Skin Tubes Subjected To Cyclic Axial Compression, Omar I. Abdelkarim, Mohamed A. Elgawady
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper presents the results of an experimental study that was conducted to investigate the effects of key parameters on the compressive behavior of fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (FSDT). Hybrid FSDT columns have been introduced as a new form of hybrid columns. They consist of an outer tube made of FRP and inner tub made of steel, with sandwiched concrete between them. This paper investigated the effect of fiber angle and the ratio of steel tube diameter to its thickness (Di/ts) on the compressive behavior of FSDT columns. Six FSDT cylinders with different (Di/ts), in addition to two …
Effects Of Chemical Stabilizers On An Expansive Clay,
2014
Missouri University of Science and Technology
Effects Of Chemical Stabilizers On An Expansive Clay, Honghua Zhao, Louis Ge, Thomas M. Petry, Yi Zhen Sun
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Expansive clays exhibit a high potential for the volume change behavior when the soil moisture changes. The estimated annual cost of the damage to the facilities built on expansive clay in the United States exceeds 9 billion dollars. Because of the physicochemical nature of the expansive clay, the use of chemical agents to improve their engineering properties is common. This research investigated the effects of chemical agents on an expansive soil from Texas through a laboratory injection method. The agents used in this study included lime, potassium-based agents, and a group of ionic agents. Swelling tests, chemical tests, and soil …
A Simple Turbulence Model For Stably Stratified Wall-Bounded Flows,
2014
Missouri University of Science and Technology
A Simple Turbulence Model For Stably Stratified Wall-Bounded Flows, F. Karimpour, S. K. Venayagamoorthy
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this study, we present a simple zero-equation (algebraic) turbulence closure scheme as well as the standard k-Ïμ model for stably stratified wall-bounded flows. We do this by proposing a parameterization for the turbulent Prandtl number (Prt) for stably stratified flows under the influence of a smooth solid wall. The turbulent Prandtl number is the linking bridge between the turbulent momentum and scalar fluxes in the context of Reynolds-averaged Navier-Stokes (RANS) simulations. Therefore, it is important to use appropriate parameterizations for Prt in order to define the right level of momentum and scalar mixing in stably stratified flows. To date, …
Cyber-Physical Codesign Of Distributed Structural Health Monitoring With Wireless Sensor Networks,
2014
Missouri University of Science and Technology
Cyber-Physical Codesign Of Distributed Structural Health Monitoring With Wireless Sensor Networks, Gregory Hackmann, Weijun Guo, Guirong Yan, Zhuoxiong Sun, 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 Codesign 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, Multilevel Computing Architecture Specifically Designed to Leverage the Multiresolution Feature of the Flexibility-Based Approach. the Proposed Approach Has Been Implemented …
