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Articles 1 - 16 of 16
Full-Text Articles in Architectural Engineering
Strengthening Of Short Shear Span Reinforced Concrete T Joists With Fiber-Reinforced Plasic Composites, Francesco Micelli, Raghu H. Annaiah, Antonio Nanni
Strengthening Of Short Shear Span Reinforced Concrete T Joists With Fiber-Reinforced Plasic Composites, Francesco Micelli, Raghu H. Annaiah, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this work, the results of an experimental study conducted in a 1964-vintage building are presented. Twelve reinforced concrete (RC) T-joists strengthened with fiber-reinforced plastic (FRP) composites were loaded until failure in a short shear span configuration. Different strengthening schemes, including different FRP materials and a new FRP anchorage system, were adopted in order to compare the performance of the different installations. Carbon FRP and aramid FRP sheets in an epoxy matrix were bonded to the RC joists using the wet layup technique. All of the joists were loaded close to one end support and showed similar cracking patterns at …
Strengthening And Load Testing Of Three Bridges In Boone County, Missouri, S. Schiebel, R. Parretti, Antonio Nanni, M. Huck
Strengthening And Load Testing Of Three Bridges In Boone County, Missouri, S. Schiebel, R. Parretti, Antonio Nanni, M. Huck
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Three bridges in Boone County, Missouri - Brown School Road, Coats Lane, and Creasy Springs Bridges - were selected for strengthening with carbon-fiber-reinforced polymer laminates in both shear and flexure. The objective of the rehabilitation program was to remove the 15-ton load posting that had been imposed on each of the bridges. To verify the results of the upgrade, load tests were performed before and after strengthening on two of the bridges - Brown School Road and Coats Lane Bridges. This paper presents the procedures followed in the design, installation, and load testing of the bridges. A recommendation regarding the …
Comparison Of Radiated Power From Structurally Different Violins, Lily M. Wang, Courtney B. Burroughs
Comparison Of Radiated Power From Structurally Different Violins, Lily M. Wang, Courtney B. Burroughs
Durham School of Architectural Engineering and Construction: Faculty Publications
The acoustic power has been determined from intensity measurements on three structurally different violins: a Scherl and Roth student violin, Hutchins' SUS29S, and Hutchins' mezzo violin SUS 100. While each violin was bowed with an open-frame mechanical bowing machine, the intensity measurements were made by scanning each side of the bowing machine with an intensity probe. One-third octave band sound power levels of the acoustic radiation from each of the three instruments as each of the four open strings is bowed show that the structurally different mezzo violin produces greater power at low frequencies when the lowest (G) string is …
Review Of Stabilization Of Clays And Expansive Soils In Pavements And Lightly Loaded Structures - History, Practice, And Future, Thomas M. Petry, Dallas N. Little
Review Of Stabilization Of Clays And Expansive Soils In Pavements And Lightly Loaded Structures - History, Practice, And Future, Thomas M. Petry, Dallas N. Little
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Expansive clay soils-those that change significantly in volume with changes in water content-are the cause of distortions to structures that cost taxpayers several billion dollars annually in the United States. Much has been learned about their behavior over the past 60 years, and relatively successful methods have been developed to modify and stabilize them. This paper reviews some of the key advances developed over the past 60 years in improving our understanding of the nature and methods of modifying and stabilizing expansive clay soils. The state of the practice in stabilization is presented, and practical and research needs to help …
Evaluation And Carbon Fiber Reinforced Polymer Strengthening Of Existing Garage: Case Study, Milan Vatovec, Paul L. Kelley, Tarek Alkhrdaji, Antonio Nanni
Evaluation And Carbon Fiber Reinforced Polymer Strengthening Of Existing Garage: Case Study, Milan Vatovec, Paul L. Kelley, Tarek Alkhrdaji, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The concrete-repair fiber reinforced polymer technology emerged in the United States during the past 10 years. Since 1995, carbon fiber reinforced polymer (CFRP) has been applied to strengthen concrete decks of a troubled posttensioned garage in Atlanta. During the construction of the garage, design deficiencies were found. A remedial repair, involving heavily reinforced, 7.6 cm (3 in.) thick Gunite (Shotcrete) beams, applied to the underside of the slab between drop panels in the east-west (E-W) direction, was developed in 1984. Since then, delamination of Gunite beams and other structural problems repeatedly occurred. Epoxy injection and other limited repairs were done …
Strength And Modulus Degradation Of Carbon Fiber-Reinforced Polymer Laminates From Fiber Misalignment, Xinbao Yang, Antonio Nanni, Stephen B. Haug, Chung Leung Sun
Strength And Modulus Degradation Of Carbon Fiber-Reinforced Polymer Laminates From Fiber Misalignment, Xinbao Yang, Antonio Nanni, Stephen B. Haug, Chung Leung Sun
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Fiber-reinforced polymer (FRP) laminates are being used as external reinforcement for strengthening concrete members. The performance of unidirectional FRP laminates is highly dependent on fiber orientation with respect to applied load direction. In the case of fabrication by manual layup, it is possible to have fiber plies installed with improper orientation. In this project, the degradation of strength and modulus of carbon FRP laminates from fiber misalignment was investigated experimentally using tensile coupons. The specimens consisted of one and two plies of unidirectional carbon FRP impregnated with a two-component epoxy. The misalignment angles varied from 0 to 40° for the …
Formal Engineering Of Residential Buildings, Joseph E. Minor
Formal Engineering Of Residential Buildings, Joseph E. Minor
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The performance of residential buildings during hurricanes is as important as the performance of other buildings. Buildings where people live and where they are likely to be when a hurricane strike must survive. If this premise is accepted, it follows that residential buildings should be afforded a degree of engineering attention that is commensurate with that given to industrial and commercial buildings. Building code authorities have not been blind to this need. In new procedures adopted for hurricane zones in the United States, common sizes and geometric shapes of timber and masonry residential buildings are formally engineered, and associated construction …
Bending Strength Of Hybrid Cold-Formed Steel Beams, Chi Ling Pan, Wei Wen Yu
Bending Strength Of Hybrid Cold-Formed Steel Beams, Chi Ling Pan, Wei Wen Yu
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
For the purpose of determining the load-carrying capacity of cold-formed steel structural members, the effective width approach has been used. Since most studies were limited only to the structural members, which were assembled from the same material in a given section, this investigation was concentrated on a study of structural strength and behavior of hybrid cold-formed steel beams subjected dynamic loads. An investigation was also conducted to study the validity of effective design width formulas for the design of these specimens. The materials used in this study were 25 AK and 50 SK sheet steels. A total of 72 spot-welded …
Rehabilitation Of Rectangular Simply Supported Rc Beams With Shear Deficiencies Using Cfrp Composites, Ahmed Khalifa, Antonio Nanni
Rehabilitation Of Rectangular Simply Supported Rc Beams With Shear Deficiencies Using Cfrp Composites, Ahmed Khalifa, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The present study examines the shear performance and modes of failure of rectangular simply supported reinforced concrete (RC) beams designed with shear deficiencies. These members were strengthened with externally bonded carbon fiber reinforced polymer (CFRP) sheets and evaluated in the laboratory. The experimental program consisted of twelve full-scale RC beams tested to fail in shear. The variables investigated within this program included steel stirrups, and the shear span-to-effective depth ratio, as well as amount and distribution of CFRP. The experimental results indicated that the contribution of externally bonded CFRP to the shear capacity was significant. The shear capacity was also …
Effect Of Ph And Gas-Phase Ozone Concentration On The Decolorization Of Common Textile Dyes, Craig D. Adams, Steven Gorg
Effect Of Ph And Gas-Phase Ozone Concentration On The Decolorization Of Common Textile Dyes, Craig D. Adams, Steven Gorg
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper presents the results of a laboratory study on the effect of pH (2, 5, and 9) and gas-phase ozone concentration (1, 7, and 11 wt. %) on the decolorization efficiency via ozonation for seven common textile dyes. Higher gas-phase ozone concentrations resulted in higher decolorization rates due to more rapid ozone transfer. Higher gas-phase ozone concentration, however, was also observed to have a positive, neutral, or negative effect on ozone dose requirements for different dyes. In general, greater ozone utilization efficiency was achieved at lower pH levels where direct ozone reactions predominate. It was observed that because ozonation …
Removal Of Antibiotics From Surface And Distilled Water In Conventional Water Treatment Processes, Craig D. Adams, Yang Wang, K. Loftin, M. Meyer
Removal Of Antibiotics From Surface And Distilled Water In Conventional Water Treatment Processes, Craig D. Adams, Yang Wang, K. Loftin, M. Meyer
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and …
Optimal Placement Of Dampers And Actuators Based On Stochastic Approach, Franklin Y. Cheng, Hongping Jiang, Xiaozhe Zhang
Optimal Placement Of Dampers And Actuators Based On Stochastic Approach, Franklin Y. Cheng, Hongping Jiang, Xiaozhe Zhang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A general method is developed for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant structures. The study includes development of a statistical criterion, formulation of a general optimization problem and establishment of a solution procedure. Numerical analysis of the seismic response in time-history of controlled structures is used to verify the proposed method for optimal device application and to demonstrate the effectiveness of seismic response control with optimal device location. This study shows that the proposed method for the optimal device application is simple and general, and that the optimally applied dampers and actuators …
Biological Fixed Film Systems, Mark W. Fitch, Ellen England
Biological Fixed Film Systems, Mark W. Fitch, Ellen England
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
No abstract provided.
Behavior Of Screw Connections In Residential Construction, Roger A. Laboube, M. A. Sokol
Behavior Of Screw Connections In Residential Construction, Roger A. Laboube, M. A. Sokol
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Self-drilling screws are the primary means of fastening cold-formed steel members in residential construction. Because the fabrication of connections is the most labor-intensive aspect of the construction process, a better understanding of the behavior of screw connections could lead to more optimum connection design. Therefore, studies have been performed at the University of Missouri-Rolla aimed at developing a better understanding of the behavior of single-shear connections using self-drilling screws in cold-formed steel construction. The study's focus was on design parameters typically employed in residential construction. Fastener patterns, screw spacing, stripped screws, and the number of screws in a connection was …
Variable Speed Drive (Vsd) Applications In Dual-Duct Constant Volume Systems, Ik-Seong Joo, Mingsheng Liu, Kirk Conger, Gang Wang
Variable Speed Drive (Vsd) Applications In Dual-Duct Constant Volume Systems, Ik-Seong Joo, Mingsheng Liu, Kirk Conger, Gang Wang
Durham School of Architectural Engineering and Construction: Faculty Publications
Models have been developed for static pressure and potential supply fan energy savings by using variable speed drive (VSD) in dual-duct constant volume systems. Experiments have been performed using a full size dual-duct constant volume system installed in a 68,000 ft2 (6,317 m2) office and classroom building. The measured static pressure variations and the energy savings agree with the model projected values. The VSD saves the fan power by as much as 35%, reduces the total airflow by 15%, and decreases the excessive static pressure on the terminal box dampers. This paper presents the systems models, the …
Finite Element Assessment Of The Effects Of Seismic Loading Rate On Soil Liquefaction, Radu Popescu
Finite Element Assessment Of The Effects Of Seismic Loading Rate On Soil Liquefaction, Radu Popescu
Architectural Engineering
The influence of frequency content of seismic excitation on the extent and pattern of pore-water pressure build-up in saturated soil deposits is addressed. Seismic acceleration time histories are generated as uniformly modulated nonstationary stochastic processes, in accordance with prescribed response spectra and prescribed modulating functions. Based on numerical examples, it is shown that the interplay between the frequency content of seismic excitation and the dynamic characteristics of the soil system and their evolution during and after the earthquake have important implications on the dynamic response.Key words: seismic motion, frequency content, finite elements, soil dynamics.