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Articles 931 - 960 of 1043

Full-Text Articles in Civil and Environmental Engineering

A Probabilistic Approach For Modeling And Real-Time Filtering Of Freeway Detector Data, Shourie Kondagari Jan 2006

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 …

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Spectral Analysis Of Total Suspended Solids Mixtures For Solids Composition Determination, Curtis W. Sutherland Jan 2006

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 …

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Improvements In Groundwater Flow Modeling Through The Integration Of Resistivity Logs And Hydraulic Conductivity And The Use Of Variogram Uncertainty, Asheka Rahman Jan 2005

Improvements In Groundwater Flow Modeling Through The Integration Of Resistivity Logs And Hydraulic Conductivity And The Use Of Variogram Uncertainty, Asheka Rahman

LSU Doctoral Dissertations

This study developed a coregionalized model to estimate hydraulic conductivity using spatial cross correlation between hydraulic conductivity and borehole geophysical data (a transform of the formation factor). An experimental pseudocross variogram is used instead of a cross variogram because data are not collocated. Experimental variogram uncertainty is investigated using confidence intervals for the experimental variogram calculated assuming variogram sills are lognormally distributed. These intervals are used for sensitivity modeling using kriging, cokriging, simulation and cosimulation. The hydraulic conductivity fields generated by kriging, cokriging, simulation, and cosimulation are then used in a high-resolution groundwater model created using telescopic mesh refinement (TMR) …

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Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed Jan 2005

Physically Based Multiscale-Viscoplastic Model For Metals And Steel Alloys: Theory And Computation, Farid H. Abed

LSU Doctoral Dissertations

The main requirement of large deformation problems such as high-speed machining, impact, and various primarily metal forming, is to develop constitutive relations which are widely applicable and capable of accounting for complex paths of deformation. Achieving such desirable goals for material like metals and steel alloys involves a comprehensive study of their microstructures and experimental observations under different loading conditions. In general, metal structures display a strong rate- and temperature-dependence when deformed non-uniformly into the inelastic range. This effect has important implications for an increasing number of applications in structural and engineering mechanics. The mechanical behavior of these applications cannot …

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Speciation, Equilibria And Kinetics For Rainfall-Runoff Metals In Adsorptive-Filtration Unit Operations And Processes, Tianpeng Guo Jan 2005

Speciation, Equilibria And Kinetics For Rainfall-Runoff Metals In Adsorptive-Filtration Unit Operations And Processes, Tianpeng Guo

LSU Doctoral Dissertations

Populations transferred by rainfall runoff can have many adverse effects livings and people. Treatment of rainfall-runoff continues to pose unique challenges due to the unsteady nature of processes including mobilization, partitioning and transport of heavy metals as well as other constituent loads. BMPs that incorporate heavy metal removal are generating more attention as the nature of stormwater is better understood. This dissertation focused on metal partitioning and speciation in rainfall-runoff through the in-situ Partial Exfiltration Reactor (PER) and exposed to various redox circumstances, and metal removal by sorptive engineered manganese oxides coated media. Adsorption capacity of three manganese oxides coated …

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Speciation, Equilibrium Distribution And Kinetics Of Rainfall-Runoff Phosphorus In Adsorptive-Filtration Unit Operations And Processes, Jia Ma Jan 2005

Speciation, Equilibrium Distribution And Kinetics Of Rainfall-Runoff Phosphorus In Adsorptive-Filtration Unit Operations And Processes, Jia Ma

LSU Doctoral Dissertations

This study examined the influence of hydrology on rainfall runoff phosphorus partitioning between aqueous and particulate-bound phase, and dissolved phosphorus speciation at the upper end of a Cementitious Porous Pavement (CPP) small urban watershed. This study also investigated particulate bound phosphorus temporal distribution during storm event and phosphorus equilibrium distribution on a wide gradation of solids captured by hydrodynamic separator after the storm completed. Results indicate that EMC of urban rainfall runoff phosphorus exceeds EPA water quality criteria, with majority of particulate-bound phosphorus while rainfall by itself contains non-comparable low concentration of phosphorus. Dissolved phosphorus was mainly H2PO4- and HPO4-2 …

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Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang Jan 2005

Cementitious Permeable Pavement As A Passive Unit Operation And Process For Stormwater Quality And Quantity Control, Xuheng Kuang

LSU Doctoral Dissertations

With respect to the problems caused by impervious pavements, cementitous permeable pavement (CPP) functions as a passive unit operation and process for stormwater quality and quantity control through infiltration, evaporation, filtration, absorption and reaction mechanisms. CPP pore characteristics were examined through pore connectivity analysis using X-Ray Tomography (XRT). Image resolution influence on image analysis results was evaluated. Relationships between parameters of pore characteristics were evaluated. Factors that significantly influence fluid flow in CPP media include effective porosity, pore connectivity and pore size distribution. A modified Kozeny-Carman model in which effective porosity, specific surface area based on effective pores (SSA)pe, and …

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Experimental Sloshing Studies In Sway And Heave Base Excited Square Tanks, Wei Peng Jan 2005

Experimental Sloshing Studies In Sway And Heave Base Excited Square Tanks, Wei Peng

LSU Master's Theses

In this thesis, free-surface water waves are experimentally investigated with a focus on sloshing in tanks. The sloshing problem is selected for its relatively simple geometry, yet it captures the features of nonlinearities including wave breaking. Free-surface motions are monitored in a square tank with base dimensions of 1 x 1 m2. Sloshing motions have been studied both off- and at resonance in shallow to deep water to investigate nonlinear free surface effects. The tank has been prescribed to move in sway and / or heave excitation. Interesting hysteresis behavior at the surface is captured at and near resonance. Faraday …

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Water Quality Modeling For Unconventional Bod, Trieu Van Le Jan 2005

Water Quality Modeling For Unconventional Bod, Trieu Van Le

LSU Master's Theses

Predictions of the dissolved oxygen (DO) concentration in a stream are sensitive to the choice of Biochemical Oxygen Demand (BOD) reaction model which frequently is assumed to be first order, although published BOD data sets from analyses of samples from rivers show that many are described best by second order or three-halves order BOD reaction. Two DO models for a stream are developed, one with a second order and the other with a three-halves order BOD reaction. The DO equations are solved using Laplace transform method which simplifies the mathematical solution of the model equations by avoiding difficult to evaluate …

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Two Dimensional Sediment Transport Model Using Parallel Computers, Vikas Singh Jan 2005

Two Dimensional Sediment Transport Model Using Parallel Computers, Vikas Singh

LSU Master's Theses

Management and development of water bodies is vital for meeting domestic, agricultural, energy and industrial needs. To that end, dams, artificial channels, lakes and other water structures have been constructed. Management and development of these structures encounter problems of land erosion, reservoir silting, and degradation and aggradation of channel beds, which need to be addressed. Fundamental to these problems are sediment transport, erosion and deposition. Numerical modeling of sediment transport is the best tool to simulate sediment transport in a water body. This study develops a vertically integrated two-dimensional numerical sediment transport model. Sediment transport is simulated in two parts …

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Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma Jan 2005

Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma

LSU Master's Theses

The heat straightening method of repair for damaged steel structures has been employed for many years. The method was based on the experience of practitioners. Recent research has given an engineering background for the technique and established certain procedures and guidelines to be followed while using heat straightening. Although a scientific basis has now been established, there still exist some major gaps in the data. Misuse of the heat straightening technique has produced fractures in the steel during repair.There are two parameters that may be keys to limiting fracture sensitivity: degree of damage and application of jacking force stress during …

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Sediment Tmdl Calculations For Amite River, Pradeep Kumar Mishra Jan 2005

Sediment Tmdl Calculations For Amite River, Pradeep Kumar Mishra

LSU Master's Theses

The Amite River is recognized as one of the 15 water bodies impaired by sediments in Louisiana. A sediment TMDL calculation for the Amite River is required by the EPA. Based on EPA’s Protocol sediment TMDL calculations for the Upper Amite River are conducted in this thesis. The sediment TMDL calculations are composed of four parts: (1) Development of a new sediment transport and dispersion model for the Amite River, (2) Estimation of sediment loads (sources) produced by watershed erosion, (3) Flow computation, and (4) Determination of sediment TMDL for the Amite River. Using the mass conservation principle and Reynolds …

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Comparative Study Of The Physical And Mechanistic Properties Of Hma Mixture: Field Vs Laboratory, Chenggang Zhang Jan 2005

Comparative Study Of The Physical And Mechanistic Properties Of Hma Mixture: Field Vs Laboratory, Chenggang Zhang

LSU Master's Theses

The objectives of this study were to investigate the variability in the physical and mechanistic properties of HMA due to production, characterize and compare the mechanistic properties of roadway cores and laboratory compacted samples, develop the relationship between modulus from in situ NDT and those obtained from laboratory tests on roadway cores, and compare air voids measurements between laboratory and field test methods. Six ongoing rehabilitation projects in Louisiana were selected, in each of which several test sections were tested. Comparative analyses were conducted on density measurements between two laboratory (AASHTO T-166 and ASTM D6752-02, or Vacuum sealing) and one …

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Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda Jan 2005

Modeling The Fate And Transport Of Chlorinated Benzenes In Baton Rouge Bayou, Sudheer Nimmagadda

LSU Master's Theses

Knowledge of the fate and transport of chlorinated benzenes is necessary at certain sites for effective remediation of contaminated soils using plants. Current research is examining the capability of wetland plants to catalyze degradation or attenuate migration, but again requires knowledge of the uptake of contaminants from an aqueous environment. A two stage model was used to estimate the rate of uptake of contaminants from sediments. The first stage of the model predicts pollutant leaching rates from sediments to the overlying water, which would then be fed into the plant or bioreactor model systems. In this study the flux from …

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Assimilation And Removal Of Phosphorus Within The Marshland Upwelling System, Derek A. Evans Jan 2005

Assimilation And Removal Of Phosphorus Within The Marshland Upwelling System, Derek A. Evans

LSU Master's Theses

The marshland upwelling system (MUS) is an alternative onsite wastewater system that was developed to treat domestic wastewater derived from coastal communities. Previous studies have researched the systems ability to treat fecal coliforms and nitrogen. The objectives of this research were to (1) assess the treatment efficiency of the MUS for removing both total phosphorus and orthophosphate, (2) provide preliminary design and operational guidelines for phosphorus removal, and (3) develop a parameter to project longevity of the MUS for treating phosphorus. Performance efficiency was compared for a system which operated for 23 months located in Bayou Segnette State Park and …

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Modeling Destination Choice In Hurricane Evacuation With An Intervening Opportunity Model, Bin Chen Jan 2005

Modeling Destination Choice In Hurricane Evacuation With An Intervening Opportunity Model, Bin Chen

LSU Master's Theses

In this study, a trip distribution model for hurricane evacuation using the intervening opportunity method was developed. Post Hurricane Floyd survey data was used for model calibration and comparison. To model the behavior that people tend to evacuate away from the path of the hurricane, a new concept of equal destination attractiveness was introduced and an extended intervening opportunity model was built on this basis and implemented in TransCAD. The gravity model, intervening opportunity model and its extended version were compared using several statistical measures. This study demonstrates that it is possible to use the intervening opportunity theory to model …

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Modeling Destination Choice And Measuring The Transferability Of Hurricane Evacuation Patterns, Naveen Kumar Modali Jan 2005

Modeling Destination Choice And Measuring The Transferability Of Hurricane Evacuation Patterns, Naveen Kumar Modali

LSU Master's Theses

In this study a gravity model was used to model destination choice during a hurricane evacuation. Hurricane Floyd data was used to calibrate and apply the gravity model. Two different models were generated for different destination types; home of friends/relative and hotels and motels are the two different destination types for which the models were generated. The performance of the gravity model was tested by comparing the observed and estimated OD matrices using the chi-squared test. The results have indicated that gravity model developed in this study can successfully reproduce the observed trip destinations during a hurricane evacuation The Floyd …

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Pah And Pcb Distribution In Sediment Fractions And Sorptive Phases, Trudy J. Estes Jan 2005

Pah And Pcb Distribution In Sediment Fractions And Sorptive Phases, Trudy J. Estes

LSU Doctoral Dissertations

Contaminant distribution is integral to environmental evaluations of contaminated sediment on every level. The technical and economic feasibility of treatment or beneficial use is a function of the accessibility or separability of the contaminants within the sediment. The magnitude of release to the environment during dredging and disposal is dependent upon the partitioning behavior of the contaminants. Yet, little attention has been paid to contaminant distribution in the fine sediment fractions. Further, conventional distribution coefficients provide little information regarding the relative contaminant loading of each of the sorptive phases. Bioavailability of contaminants in oil and grease, soot and organic carbon, …

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Spatial And Temporal Estimation Of Pumping And Recharge In Groundwater System Analysis, Sherly Hartono Jan 2005

Spatial And Temporal Estimation Of Pumping And Recharge In Groundwater System Analysis, Sherly Hartono

LSU Doctoral Dissertations

In many parts of the U.S., groundwater is used as the primary or secondary source of water for the public supply, agricultural, and industrial sectors. In southwestern Louisiana, a majority of the water demand is supplied by the Chicot aquifer. Numerical flow models are useful for managing and optimizing groundwater systems. However, many important model parameters are difficult to quantify, exhibit a certain degree of uncertainty, and may vary both spatially and temporally. Two of the most important and sensitive parameters for a regional groundwater model of the Chicot aquifer are pumping rates and recharge. The use of GIS-based methods …

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Distributed Airlift Systems Design With Application To Recirculating Soft Shell Crawfish Shedding Systems, Sripavani Gudipati Jan 2005

Distributed Airlift Systems Design With Application To Recirculating Soft Shell Crawfish Shedding Systems, Sripavani Gudipati

LSU Master's Theses

Soft shell crawfish, a seafood delicacy, has a potential market for growth in the aquaculture industry. Since the industry's collapse in the 1990's, the advent of new technologies like eyestalk ablation, automated hydraulic separation and distributed airlift systems has elevated the hope for restoration. In a distributed airlift system, airlifts and distribution pipes supply water to holding trays. Airlifts are simple devices used to pump water by injecting air at the bottom of an open pipe. The combination of airlifts and distribution pipes has potential economic benefits for low head applications in recirculating aquaculture systems. This thesis focuses on guidelines …

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Development Of An Alternative Approach To Estimate Vehicle Miles Traveled Using A Classification Procedure, Srividya Vadlamani Jan 2005

Development Of An Alternative Approach To Estimate Vehicle Miles Traveled Using A Classification Procedure, Srividya Vadlamani

LSU Master's Theses

In this study a Classification and Regression Tree (CART) classification system method was developed as an alternative to the HPMS conventional method of VMT estimation. Louisiana Highway Performance Monitoring System (HPMS) data from Federal Highway Administration (FHWA) and Louisiana highway network data from Louisiana Department of Transportation (LADOTD) were used to carry out the analysis. The CART classification was derived based on link attributes that effectively distinguished the homogeneous traffic volume sections. VMT estimation on individual links as well for the different systems was calculated using the CART classification system and the values were assigned on each link. The default …

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Computational Model For Elasto-Plastic And Damage Analysis Of Plates And Shells, Pawel Benedykt Woelke Jan 2005

Computational Model For Elasto-Plastic And Damage Analysis Of Plates And Shells, Pawel Benedykt Woelke

LSU Doctoral Dissertations

Shells and plates are very important for various engineering applications. Analysis and design of these structures is therefore continuously of interest to the scientific and engineering community. Accurate and conservative assessments of the maximum load carried by the structure, as well as the equilibrium path in both elastic and inelastic range are of paramount importance. Elastic behaviour of shells has been very closely investigated, mostly by means of the finite element method. Inelastic analysis on the other hand, especially accounting for damage effects, has received much less attention from the researchers. A computational model for finite element, elasto-plastic and damage …

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Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang Jan 2005

Multivariate Hydrological Frequency Analysis And Risk Mapping, Lan Zhang

LSU Doctoral Dissertations

In hydrological frequency analysis, it is difficult to apply standard statistical methods to derive multivariate probability distributions of the characteristics of hydrologic or hydraulic variables except under the following restrictive assumptions: (1) variables are assumed independent, (2) variables are assumed to have the same marginal distributions, and (3) variables are assumed to follow or are transformed to normal distribution. Relaxing these assumptions when deriving multivariate distributions of the characteristics of correlated hydrologic and hydraulic variables. The copula methodology is applied to perform multivariate frequency analysis of rainfall, flood, low-flow, water quality, and channel flow, using data from the Amite river …

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Biofiltration For Treatment Of Gas-Phase Voc Mixtures, Bing Qi Jan 2005

Biofiltration For Treatment Of Gas-Phase Voc Mixtures, Bing Qi

LSU Doctoral Dissertations

Biological processes are increasingly used for treatment of air streams contaminated by biodegradable volatile organic compounds (VOCs). The research described in this dissertation involves systematic investigation of various facets of applying biological processes dominated by fungi to remove mixtures of VOCs representative of emissions from paint application and manufacturing. Screening studies were first conducted to assess the ability of multiple fungal species to degrade various industrially important VOCs. In the following phases of the research, studies were conducted to evaluate performance of laboratory-scale bioreactors inoculated with fungi for treatment of mixtures of VOCs representative of emissions from paint spray booths …

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Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel Jan 2005

Experimental Investigation Of Stick-Slip Behavior In Granular Materials, Lynne E. Roussel

LSU Master's Theses

The mechanical behavior of granular materials is highly dependent on the arrangement of particles, particle groups, and associated pore spaces. Changes in the internal structure due to large deformation may cause changes in the mechanical behavior. The changes include: particle sliding, rolling, and interaction; shear band formation; and fabric anisotropy. During those changes, stick-slip behavior may take place between the granular particles. The objective of the thesis is to study the factors that influence the stick-slip behavior of granular materials. The influence of particle size, uniformity, confining pressure, density, and strain rate are investigated in this thesis. A series of …

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Experimental Quantification And Dem Simulation Of Micro-Macro Behaviors Of Granular Materials Using X-Ray Tomography Imaging, Yanrong Fu Jan 2005

Experimental Quantification And Dem Simulation Of Micro-Macro Behaviors Of Granular Materials Using X-Ray Tomography Imaging, Yanrong Fu

LSU Doctoral Dissertations

A non-invasive experimental method and a clustering DEM model were developed in this study to investigate micro-macro behaviors of real granular materials with irregular particle shape configurations. The investigated behaviors include global deformations, failure strengths and residual strengths, stress and strain distributions, local coordination number, local void ratio, particle kinematics, and fabric orientation distributions. The experimental method includes an approach to automatically identify and recognize multiple particles using x-ray computed tomography imaging (XCT) and an enhanced approach to digitally represent microstructures of granular materials. The digitally represented microstructure can be directly employed for numerical simulation setup. A compression test and …

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Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano Jan 2005

Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano

LSU Master's Theses

The Marshland Upwelling System (MUS) is an alternative onsite wastewater treatment technology designed to utilize the natural ecology of saltwater marshes to remove human-borne contaminants. Over the past twelve years, MUSs have been installed in Port Fourchon, Louisiana, Moss Point, Mississippi, and Bayou Segnette, Louisiana. The purpose of this study was to investigate the nitrogen reduction capabilities of the Bayou Segnette system. The objectives of this research were to: 1) determine the first-order removal constants necessary for the development of nitrogen transport equations, 2) explore the spatial dependencies of nitrogen concentrations within the Bayou Segnette system, and 3) determine the …

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Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu Jan 2005

Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu

LSU Master's Theses

In the USA alone, about 27% of the bridges are classified as structurally deficient or functionally obsolete. Bridge owners are continually investigating methods to effectively retrofit existing bridges, or to economically replace them with new ones. Modern composite materials for structural applications, at one time only in the domain of aerospace engineering, are increasingly making their way into civil engineering applications. In addition to retrofitting current concrete and steel structures using FRP sheets or plates, a great deal of work is being conducted to develop versatile, fully-composite structural bridge systems. To reduce the self-weight and also achieve the necessary stiffness, …

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Assessing The Needs For Intermediate Diaphragms In Prestressed Concrete Girder Bridges, Anand Kumar Chandolu Jan 2005

Assessing The Needs For Intermediate Diaphragms In Prestressed Concrete Girder Bridges, Anand Kumar Chandolu

LSU Master's Theses

Reinforced concrete Intermediate Diaphragms (IDs) are still being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed and also use of IDs increases the cost and time of construction. There is no consistency in the practice of providing IDs among various states and codes of practice and overall there is a lack of clarity on the effectiveness of IDs and their needs in prestressed concrete bridges. The objectives of this research are to assess the need of reinforced concrete (RC) IDs in PC girder bridges and to determine their effectiveness and …

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Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin Jan 2005

Damage Mechanics Of Composite Materials Using Fabric Tensors, Ziad N. Taqieddin

LSU Master's Theses

The major objective of this work is to relate continuum damage mechanics introduced through the concept of fabric tensors to composite materials within the framework of classical elasticity theory. A model of directional data-damage mechanics for composite materials is formulated using fabric tensors. In addition, a general hypothesis for damage mechanics is postulated. It is seen that the two available hypotheses of elastic strain equivalence and elastic energy equivalence may be obtained as special cases of the postulated general hypothesis. This general hypothesis is then used to derive the sought relationship between the damage tensor for composite materials and the …

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