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Articles 1 - 22 of 22
Full-Text Articles in Engineering
Calibration Of Flexural Design Of Concrete Members Reinforced With Frp Bars, Sujata Nandkumar Kulkarni
Calibration Of Flexural Design Of Concrete Members Reinforced With Frp Bars, Sujata Nandkumar Kulkarni
LSU Master's Theses
Fiber Reinforced Polymer (FRP) composites have been increasingly accepted in the construction industry as a promising substitute for steel. Bridge deck deterioration is one of the most common deficiencies in a bridge system. The use of FRP bars as reinforcement for concrete bridge decks provides a potential for increased service life, economic, and environmental benefits. This research presents the development of resistance models for concrete members (beams and slabs) reinforced with FRP bars (FRP-RC), for carrying out reliability analysis. The scope of this model is limited to the flexural behavior only; i.e. the failures are not shear failure and debonding. …
A Plasticity-Damage Model For Plain Concrete, Umit Cicekli
A Plasticity-Damage Model For Plain Concrete, Umit Cicekli
LSU Doctoral Dissertations
A plastic-damage model for plain concrete is developed in this work. The model uses two different yield criteria: one for plasticity and one for damage. In order to account both for compression and tension loadings, the damage criterion is divided into two parts: one for compression and a second for tension. The superscripts (+) and (-) in this work are used to represent tension and compression cases, respectively. The total stress is decomposed into tension and compressions components. The total strain is decomposed into elastic and plastic parts. The strain equivalence concept is used such that the strains in the …
Refurbishment Of Louisiana State University Calibration Chamber, Ardita Dushi
Refurbishment Of Louisiana State University Calibration Chamber, Ardita Dushi
LSU Master's Theses
This thesis focuses on the refurbishment of Louisiana State University calibration chamber. The testing equipments were checked and connected together to complete the calibration chamber system. The data acquisition system was upgraded to National Instruments (NI) SCXI system. Therefore, a compatible computer program language in LabVIEW was developed. LabVIEW is a programming language developed by NI that reads the data from the instruments, displays the data in graphical form, calculates the desired parameters, commands the transducer to apply the required pressure to the specimen, and saves the data at the desired frequency. The Anisotropic Modified Cam Clay Model (AMCCM) following …
Acoustic Emission Monitoring And Quantitative Evaluation Of Damage In Reinforced Concrete Members And Bridges, Archana Nair
Acoustic Emission Monitoring And Quantitative Evaluation Of Damage In Reinforced Concrete Members And Bridges, Archana Nair
LSU Master's Theses
A considerable proportion of highway bridges in the US, are made of reinforced concrete. The vulnerability of these structures during their long service life is a cause of major concern for civil engineers. Since there is a need to detect and recuperate the condition of the bridge structures numerous innovative non-destructive testing (NDT) techniques have come into the forefront. Of the many available technologies, acoustic emission (AE) monitoring has been the most popular non-destructive technique used on highway bridges. Acoustic emission is a passive monitoring technique. Thus, it can be appropriately used for field bridge monitoring applications. Usually AE monitoring …
Development And Application Of Methods For Evaluation Of Hurricane Shelters, James P. Gregg
Development And Application Of Methods For Evaluation Of Hurricane Shelters, James P. Gregg
LSU Master's Theses
With the population of hurricane prone regions increasing, it has become more difficult to evacuate entire communities, increasing the need for hurricane shelters in coastal areas. Community officials generally use American Red Cross Standard ARC 4496 to evaluate the suitability of buildings for use as shelters.. ARC 4496 uses a least-risk process that evaluates many building and site characteristics. However, it does not address characteristics of the approaching storm and does not provide insight to the expected hazards and performance of the facility under different hurricane conditions. A new method for evaluating facilities for use as hurricane shelters is proposed. …
Partial Continuity In Prestressed Concrete Girder Bridges With Jointless Decks, Ram Naren Mothe
Partial Continuity In Prestressed Concrete Girder Bridges With Jointless Decks, Ram Naren Mothe
LSU Master's Theses
Jointless multi-simple span deck-girder (composite concrete deck with steel or prestressed concrete girders) bridge construction has been accepted as an alternative to jointed construction. Bridge deck joints add to the construction and maintenance costs of the bridge. Bridge support bearing pads deterioration is a common problem in bridges with jointed bridge decks. One of the methods used for building a jointless bridge is to provide a link slab that connects the decks of the adjacent spans. This study mainly focuses on the behavior of the link slab and its effect on the behavior of the bridge system as a whole. …
Use Of Polyhydroxyalkanoates For Denitrification In Recirculating Aquaculture Systems, Maria Teresa Gutierrez-Wing
Use Of Polyhydroxyalkanoates For Denitrification In Recirculating Aquaculture Systems, Maria Teresa Gutierrez-Wing
LSU Doctoral Dissertations
Increasing demand of aquacultural products is driving the industry toward more intensive culture practices. Aquacultural operations are constrained by limitations on the availability high quality waters and regulatory pressures on the discharges. Recirculating systems can address these issues by reducing the amount of water required in the operation. Closed systems are especially suited where biosecurity is important. In closed systems, nitrate accumulates, limiting the time the water can be reused. In marine inland systems, water reuse reduces the cost of salt for make up water. To increase the water reuse time, some form of nitrate removal process must be incorporated …
Structural Performance Of Approach Slab And Its Effect On Vehicle Induced Bridge Dynamic Response, Xiaomin Shi
Structural Performance Of Approach Slab And Its Effect On Vehicle Induced Bridge Dynamic Response, Xiaomin Shi
LSU Doctoral Dissertations
Differential settlement often occurs between the bridge abutment and the embankment soil. It causes the approach slab to lose its contacts and supports from the soil and the slab will bend in a concave manner. Meanwhile, loads on the slab will also redistribute to the slab ends, which may result in faulting (or "bump") at the slab ends. Once a bump forms, repeating traffic vehicles can deteriorate the expansion joint in turn. In this case, the vehicle receives an initial disturbance before it reaches the bridge. This excitation introduces an extra impact load on the bridge and affects its dynamic …
A Stochastic Mesoscopic Cell-Transmission Model For Operational Analysis Of Large-Scale Transportation Networks, Ciprian Danut Alecsandru
A Stochastic Mesoscopic Cell-Transmission Model For Operational Analysis Of Large-Scale Transportation Networks, Ciprian Danut Alecsandru
LSU Doctoral Dissertations
The cell transmission model (CTM), developed by Daganzo in 1994 was not fully exploited as an operations model for analysis of large-scale traffic networks. Because of its macroscopic / mesoscopic features, CTM offers calibration and computational advantages over microscopic models. This study presents a series of enhancements to the original form of CTM. These enhancements show potential to increase the model’s accuracy and realism of traffic flow representation. For example, topological enhancements and modifications to the flow advancing equation are introduced to allow variable cell lengths and non-discrete movements of vehicles between cells. In addition, implementation of lane-changing behavioral logics …
Design And Evaluation Of Automated, Continuous Culture Techniques For Brachionus Rotundiformis, Zhengzhong Zhang
Design And Evaluation Of Automated, Continuous Culture Techniques For Brachionus Rotundiformis, Zhengzhong Zhang
LSU Doctoral Dissertations
A 40-L recirculating rotifer turbidostat (RRT) pilot system consisting of a rotifer reactor, biofilter, foam fractionator, feed container, harvester, and two air-lift pumps was designed to produce B. rotundiformis, a small (S-type) rotifer, that is increasingly demanded for production of small-gape marine finfish larvae. The system’s automatic monitoring (turbidity, pH, conductivity and temperature) and controlling (turbidity, pH, feeding and harvesting) were performed by a Rugid™ computer. A 4 (temperature) x 3 (salinity) study indicated that a 30oC/15 ppt treatment is the most favorable to the growth of B. rotundiformis. Under these conditions, the effect of harvest rate on rotifer system …
Theoretical And Experimental Study On Cable Vibration Reduction With A Tmd-Mr Damper, Wenjie Wu
Theoretical And Experimental Study On Cable Vibration Reduction With A Tmd-Mr Damper, Wenjie Wu
LSU Doctoral Dissertations
Stay cables are vulnerable to dynamic excitations because of their low intrinsic damping. Excessive cable vibrations cause frequent maintenance and are detrimental to the safety of the entire bridge. Targeting the severe cable vibration problem, in addition to using the existing Magnetorheological (MR) damper, the current study proposes a new type of damper, called the Tuned Mass Damper-Magnetorheological (TMD-MR) damper. Theoretical and experimental investigations for the damper performance on the cable vibration reduction are conducted, which provides the necessary research support for practical implementation. Experiments on the individual MR damper are carried out first to gain some experience on the …
Fundamental Characterization Of Louisiana Hma Mixtures For The 2002 Mechanistic-Empirical Design Guide, Sandeep Obulareddy
Fundamental Characterization Of Louisiana Hma Mixtures For The 2002 Mechanistic-Empirical Design Guide, Sandeep Obulareddy
LSU Master's Theses
The main objective of this research was to develop a catalog for dynamic modulus values inputs in the 2002 Empirical and Mechanistic Guide for Design of New and Rehabilitated Pavement Structures (2002 M-E Design Guide) and to examine the permanent deformation characteristics of Louisiana hot mix asphalt (HMA) mixtures based on four laboratory tests, namely dynamic modulus |E*|, flow number, flow time and hamburg wheel tracker test. In addition, the sensitivity of rut prediction from the 2002 M-E Design Guide, using the dynamic modulus |E*| test results was evaluated and the Witczak and Hirsch models were also evaluated, for the …
A Nonlocal Model For Coupled Damage-Plasticity Incorporating Gradients Of Internal State Variables At Multiscales, Robert J. Dorgan
A Nonlocal Model For Coupled Damage-Plasticity Incorporating Gradients Of Internal State Variables At Multiscales, Robert J. Dorgan
LSU Doctoral Dissertations
The thermodynamically consistent formulation and the subsequent numerical implementation of a gradient enhanced continuum coupled damage-plasticity model as a constitutive framework to model ill-posed localization problems is presented. By the introduction of "nonlocal," gradient-enhanced measures in the plasticity potential function and yield criterion and in the damage potential function and damage criterion, the proposed model introduces microstructural characteristic material length scales which allows the size of localized zones to be predicted based on material constants, as opposed to local models where the loss of ellipticity causes the localized zones to be mesh dependent.
The gradient model proposed introduces non-linear functions …
A Comparative Analysis Of Hurricane Evacuation Traffic Conditions Using Static And Dynamic Traffic Assignments, Santosh Kumar Andem
A Comparative Analysis Of Hurricane Evacuation Traffic Conditions Using Static And Dynamic Traffic Assignments, Santosh Kumar Andem
LSU Master's Theses
This study compares link flows of evacuation traffic using Static Traffic Assignment (STA) with those obtained from Dynamic Traffic Assignment (DTA) and observed traffic counts. The analysis is conducted on a sample of households from South Carolina who evacuated in the face of hurricane Floyd in 1999. The results indicate that traditional static models have the potential to significantly underestimate congestion levels in the network, and DTA models account for nonuniform demand and traffic dynamics in hurricane evacuation much more realistically. From observed traffic counts, traffic volumes vary considerably during an evacuation and the DTA flow estimates generally reproduced these …
An Adaptive Multi-Scale Computational Method For Modeling Nonlinear Deformation In Nanoscale Materials, Wenming Wang
An Adaptive Multi-Scale Computational Method For Modeling Nonlinear Deformation In Nanoscale Materials, Wenming Wang
LSU Doctoral Dissertations
In this dissertation a coupled multi-scale computational model for simulating nonlinear deformation processes in crystalline metals at finite temperatures is developed. The computational model uses the finite element method to model the coarse scale response of the material. The constitutive response in the finite element will be modeled through interatomic potentials acting on the underlying homogeneous crystal lattice that characterizes its nanostructure. An adaptive remeshing technique is proposed to automatically delineate regions of severe deformation where homogeneity of the microstructure/deformation is violated. In these regions the finite element will be replaced by a set of deformed atoms which interact with …
Evaluation Of Media Influence And Practical Applications For The Use Of Static Low Density Media Filters In Domestic Wastewater Treatment, Steven Marty Bellelo
Evaluation Of Media Influence And Practical Applications For The Use Of Static Low Density Media Filters In Domestic Wastewater Treatment, Steven Marty Bellelo
LSU Master's Theses
Static Low Density Media filters have been used over the past two decades for nitrification and solids removal in high-density recirculating aquaculture systems. The SLDM filters are submerged biofilters which contain a plastic media with a density less than that of water. The media beds remain packed, or static, during operation except for periodic expansion of the bead bed during a backwash. More recently SLDM filters have been evaluated for secondary clarification of domestic wastewater where concurrent biological treatment and particulate removal occur within one unit. Recirculation is accomplished using airlifts which provide external aeration coupled with multiple pass removal …
Development Of A Mix Design Methodology For Asphalt Mixtures With Analytically Formulated Aggregate Structures, Khalid Salim Alshamsi
Development Of A Mix Design Methodology For Asphalt Mixtures With Analytically Formulated Aggregate Structures, Khalid Salim Alshamsi
LSU Doctoral Dissertations
This research documents an extensive study on the design and characterization of asphalt mixtures for use as road pavement material. Several aspects of asphalt mixtures were addressed using the state of the art laboratory test equipment and technical literature from different information sources. The research was divided into two phases. Phase one included the design and detailed analysis of compaction and performance characteristics of asphalt concrete mixtures with aggregate structures that were designed using an analytical method of aggregate blending. Three aggregate types were considered in this study: limestone, sandstone, and granite. All the aggregates were crushed aggregates. Three different …
Frictional Interaction Properties Between Geomaterials And Geosynthetics, Julian Javier Coronel
Frictional Interaction Properties Between Geomaterials And Geosynthetics, Julian Javier Coronel
LSU Master's Theses
Soil reinforcement interaction is a primary issue for designing reinforced soil structures. The soil to geosynthetic interaction parameters are influenced by a) Interaction mechanism between geomaterials and geosynthetics (pull-out or direct shear), b) Physical and mechanical properties of geomaterials (density, grain shape and size, grain size distribution, water content, and plasticity of clayey soils), and c) Mechanical properties (tensile peak strength), shape and geometry of geosynthetics. The soil to geogrid interface friction parameters (interface friction angle "δ" and adhesion "ca") for different plasticity indexes, moisture contents, and dry densities were investigated. For this purposes, a large scale direct …
Influence Of Typha Latifolia And Phragmites Communis Root Matter On Degredation Of Aged 1,2,3,4-Tetrachlorobenzene In Bayou Sediments, Elaiza Maria Alvarez
Influence Of Typha Latifolia And Phragmites Communis Root Matter On Degredation Of Aged 1,2,3,4-Tetrachlorobenzene In Bayou Sediments, Elaiza Maria Alvarez
LSU Master's Theses
The purpose of this study was to investigate the effects of Typha latifolia and Phragmites communis root matter in degradation of sediments contaminated with aged 1,2,3,4- Tetrachlorobenzene (1,2,3,4-TeCB). In the present study, complete reductive dechlorination of 1,2,3,4-TeCB was observed in root matter systems, contrasting sediment with no roots present. Microcosms amended with Phragmites communis roots achieved the greatest first-order reaction rate constant over a 4-week period (0.113 d-1, half-life time of 6.13 days). Typha latifolia roots also played an important role in reductive dehalogenation of 1,2,3,4-TeCB, although the first-order reaction rate constant observed within the same period of …
A Probabilistic Approach For Modeling And Real-Time Filtering Of Freeway Detector Data, Shourie Kondagari
A Probabilistic Approach For Modeling And Real-Time Filtering Of Freeway Detector Data, Shourie Kondagari
LSU Master's Theses
Traffic surveillance systems are a key component for providing information on traffic conditions and supporting traffic management functions. A large amount of data is currently collected from inductive loop detector systems in the form of three macroscopic traffic parameters (speed, volume and occupancy). Such information is vital to the successful implementation of transportation data warehouses and decision support systems. The quality of data is, however, affected by erroneous observations that result from malfunctioning or mis-calibration of detectors. The open literature shows that little effort has been made to establish procedures for screening traffic observations in real-time. This study presents a …
Effect Of Speed Limit Increase On Crash Rate On Rural Two-Lane Highways In Louisiana, Athira Swarna Jayadevan
Effect Of Speed Limit Increase On Crash Rate On Rural Two-Lane Highways In Louisiana, Athira Swarna Jayadevan
LSU Master's Theses
Though the rural two lane roads are the low volume-less traveled roads, the majority of the crashes occur on these roads and the high speed of motor vehicles on these roads is suspected to be one of the main causes for this. This study focused on the development of a methodology to study the impact of a speed limit increase on the crash rate on the rural two lane roads in Louisiana. The Louisiana crash database obtained from the Louisiana Department of Transportation (LADOTD) was used to carry out the analysis. The analysis consisted of the comparison of crash rates …
Spectral Analysis Of Total Suspended Solids Mixtures For Solids Composition Determination, Curtis W. Sutherland
Spectral Analysis Of Total Suspended Solids Mixtures For Solids Composition Determination, Curtis W. Sutherland
LSU Doctoral Dissertations
Total Suspended Solids (TSS) analysis provides an initial and very basic measure for study and characterization of water quality. The present tedious procedures used for the identification of different solids constituents present in TSS and for the classification or insight into the origins of those solids are time-consuming and expensive. The research reported herein investigates the use of instrumental analysis using reflectance spectra of TSS as an attractive alternative to sufficiently characterize and identify TSS in a more rapid and economical method that could be used to study TSS transport and to identity TSS points of origin. For this investigative …