Architecture Commons^™

Compressibility Characteristics Of Low-Plasticity Silt Before And After Liquefaction, Shuying Wang, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Low-plasticity silt is known to have a potential to liquefy during earthquakes. The compressibility characteristics could change before and after a dynamic event that produces liquefaction. This research investigates the liquefaction resistance and post liquefaction reconsolidation characteristics of Mississippi River Valley (MRV) silt using laboratory cyclic triaxial compression testing. The MRV silt experienced initial liquefaction under cyclic loading, and the results are presented as cyclic stress ratio versus loading cycle curve. After cyclic loading, the liquefied specimens were reconsolidated. Permeability did not change significantly as a result of liquefaction. The reconsolidation curves are more parallel to the compression line than …

Choice Of Thixotropic Index To Evaluate Formwork Pressure Characteristics Of Self-Consolidating Concrete, Ahmed F. Omran, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Formwork lateral pressure exerted by concrete is affected by mixture composition, placement conditions, and formwork characteristics. The mixture composition includes binder type and content, supplementary cementitious materials, fillers, water-to-cementitious ratio, content and characteristics of coarse aggregate, paste volume, chemical admixtures, concrete unit weight, concrete consistency, and temperature. Thixotropy of concrete expressed here in terms of structural build-up at rest is employed to collectively reflect the effect of combined mix design factors on formwork pressure. This research demonstrates relationships between 12 indices that can be used to evaluate the structural build-up at rest of concrete, determined using portable vane, inclined plane, …

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, 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 …

Linking Solid Particle Packing Of Eco-Scc To Material Performance, Florian V. Mueller, Olafur H. Wallevik, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The concept of Eco-SCC aims to achieve self-compacting concrete (SCC) design for intermediate compressive strength mixtures that are commonly used in the ready-mix concrete industry. Contrary to many other approaches, in which the reactive cement clinker is replaced by a less reactive component, Eco-SCC involves the reduction of the total powder content. In the approach presented in this paper, the lubricant volume is increased by using a non-reactive filler. An improved particle packing with an enhanced lattice effect can minimize the lubricant demand and enhance the stability of the concrete. The effect of particle-size distribution on stability and performance of …

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 …

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 …

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 …

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 …

Thermophysical And Mechanical Properties Of Hardened Cement Paste With Microencapsulated Phase Change Materials For Energy Storage, Hongzhi Cui, Wenyu Liao, Shazim Ali Memon, Biqin Dong, Waiching Tang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this research, structural-functional integrated cement-based materials were prepared by employing cement paste and a microencapsulated phase change material (MPCM) manufactured using urea-formaldehyde resin as the shell and paraffin as the core material. The encapsulation ratio of the MPCM could reach up to 91.21 wt%. Thermal energy storage cement pastes (TESCPs) incorporated with different MPCM contents (5%, 10%, 15%, 20% and 25% by weight of cement) were developed, and their thermal and mechanical properties were studied. The results showed that the total energy storage capacity of the hardened cement specimens with MPCM increased by up to 3.9-times compared with that …

Characterization Of Shear Wave Velocity And Its Anisotropy In Uniform Granular Materials, Xin Kang, Bate Bate, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Small strain stiffness of granular materials is important to many engineering applications, such as earthquake engineering, pavement, machine foundation, embankment subjected to tidal impacts, and foundations for structures under wind loads. Shear wave velocity, which is an indicator of stiffness, was measured with a newly developed bender element testing system. Test data supported that this testing system is effective in evaluating the shear wave velocity and its anisotropy of uniform spherical granular materials, including glass beads, uniform medium, and fine sands. Influencing factors on the Vs such as grain size and applied stress were studied. Two components of the soil …

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 …

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 …

Impact Of Organic Coatings On Frictional Strength Of Organically Modified Clay, B. Bate, Q. Zhao, S. E. Burns

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Organic matter is frequently encountered in both naturally occurring and engineered particulate media. Charged functional groups in the organic matter can lead to cation exchange within the clay interlayer, which results in the formation of an organic coating on the clay surfaces and alters the interfacial frictional regime in the soil mass. This study investigated the triaxial shear frictional behavior of montmorillonite particles coated with a controlled organic phase composed of quaternary ammonium cations. Through cation exchange, organic cations were loaded onto the clay's interlayer exchange sites, with control on the density of organic coverage and structure of the organic …

Preserving The Historic Garden Suburb: Case Studies From London And New York, Jeffrey A. Kroessler

Publications and Research

The garden city or garden suburb was a response to the social and environmental ills of cities at the turn of the twentieth century. Letchworth Garden City, Hampstead Garden Suburb, and Welwyn Garden City were built outside London in the early 1900s, and each remains a highly desirable place of residence today. From the start, each was tightly regulated, and remains so a century later. By protecting the appearance and enhancing property values, the strict application of historic preservation principles contribute to the long-term sustainability of each place. Similar garden suburbs were built in the borough of Queens in New …

Catalogue Of Hijazi Architecture In Jidda And Makkah C. 1850- 1920s: Selected Buildings, Hidaya Monir Abbas

Theses and Dissertations

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Architectural Jurisprudence: The Relationship Between The Four Sunni Schools Of Law And Mosque Architecture, Ahmed Hamdy Kamal

Theses and Dissertations

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Ottoman Kaftan Culture During 16th-18th Centuries, Bushra Tatari Chaabi

Theses and Dissertations

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Behavior Of I-Section Gfrp Beam Including Retrofitting For Damage Effects, Mamadou Konate, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents the outcome of a study of an I-section Glass Fiber Reinforced Polymer (GFRP) beam including retrofitting for damage effects. A total of three beam tests were conducted in the following sequence: GFRP beam with no retrofitting and a single mid-span web brace; the partially damaged (cracked) beam with GFRP plates used for retrofitting; and the retrofitted beam re-tested with the lateral brace at the top flange level. Both cracking and lateral-torsional buckling behavior is studied and experimental load-deflection relationships recorded. Using the mechanical properties of GFRP based on the experimental data, theoretical predictions are made for the …

Science-Fictional North Korea: A Defective History, Seo-Young J. Chu

Publications and Research

Kafkaesque, Orwellian, eerie, surreal, bizarre, grotesque, alien, wacky, fascinating, dystopian, illusive, theatrical, antic, haunting, apocalyptic: these are just a few of the vaguely science-fictional adjectives that are now associated with North Korea. At the same time, North Korea has become an oddly convenient trope for a certain aesthetic – an uncanny opacity; an ominous mystique – that many writers and artists have exploited to generate striking science-fictional effects in texts with little or no connection to North Korean reality. (The 2002 Bond film Die another Day, for example, draws from North Korea’s science-fictional aura to animate North Korean super-villains who …