Digital Commons Network^™

Behavior Of Square And L-Shaped Slender Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Wen Hu Tsao

Dissertations

A numerical analysis was developed to evaluate the complete load-deflection and moment-curvature relationships for square and L-shaped slender reinforced concrete columns subjected to biaxial bending and axial load. This computer model can be used for any cross section geometry and material properties of normal concrete. The analysis was based on a deformation control and both the ascending and descending branches of curves can be studied. The finite difference method was introduced to calculate the deflections which satisfy the compatibility equations. Six square slender columns and eight L-shaped slender columns were tested to compare their experimental load-deformation results with the analytical …

Bridge Deterioration Models, Christopher R.H. Howard

Theses

The deteriorated condition of America's bridges raises the need for a proper and optimal method of bridge management, from the conceptual stage through the construction stage, and throughout the useful life of our bridges. State agencies need to expand their data collection process so as to include additional information pertinent to the formulation of a credible system. This is critical in order to accommodate increased research efforts to investigate the behavioral pattern/s of the nations bridges and to eventually optimize bridge management systems. This thesis looks at the bridge deterioration model as a vital tool in realizing more effective bridge …

Response Characteristics Of Inelastic Single Degree Of Freedom Systems Subjected To Intraplate Earthquakes, Linda C. Jones

Theses

Within recorded, although not recent, history, there have been several large magnitude earthquakes in the Eastern and Central United States and the need to provide measures to protect from potential damage is recognized by the engineering community. Since there are inherent differences between earthquakes that occur along tectonic plate boundaries, interplate, and those that occur within the plate boundaries, intraplate, it is important to understand how these differences impact structural design. A parametric study of single degree of freedom systems subjected to various recorded and artificial ground motions was performed to identify the variations in response characteristics.

It was found …

Stability And Durability Of Large Aggregate Asphalt Concrete, Rais A. Khan

Theses

There are many factors which affect the properties of asphalt concrete and one of these is a maximum aggregate size used in the mix. In this study of the effect of maximum aggregate size on Marshall stability, flow and durability of asphalt aggregate mixtures is investigated.

Two different mixes having gradations with maximum aggregate sizes of 3/4 and 1-1/2 inches were considered. The optimum asphalt content for mix having 3/4 inch maximum aggregate size, was determined by the standard Marshall procedure. The optimum asphalt content for the mix having 1-1/2 inch maximum aggregate size, was estimated based on thickness of …

Frictional Resistance Of Geotextiles, Md. Khairul Alam

Theses

The pullout resistance of geotextiles was examined using pullout tests. A suitable wooden box with large (2 ft x 2 ft x 4 ft) dimensions was used to avoid the effect of boundary and to simulate field conditions. Two types of failure patterns were observed. For shallow embedment (<3 ft), geotextile produced a movement of the surrounding mass of sand in the shape of an inverted cone due to interlocking friction between geotextile and sand particles. The cone angle decreases with increase in depth of embedment. For embedment equal to or greater than 3 ft., no sand cone developed and the failure occurred along the interface of geotextile and sand. For 1 ft. surcharge, the increase in the pullout resistance due to combined horizontal and vertical embedment was about 30 %.

Influence Of Heavy Metal Concentration On Rotating Biological Contrator Performance, Huei-Sheng Cheng

Theses

Seven heavy metals ( Fe⁺², Mn⁺², Zn⁺², Ag⁺, Pb⁺², Cu⁺², Cd⁺² ) at various concentrations were investigated in a Rotating Biological Contactor (RBC) system. The experimental data indicated that the degree of heavy metal toxicity in the biological system mainly depended on the ratio of inflow heavy metal concentration to organic loading. The optimal ratio of heavy metal to organic loading was determined on the basis of the maximum removal of chemical oxygen demand (COD) under different operating conditions. In addition, the effect of heavy metal on …

Stochastic Hydrologic Modeling In Real Time Using A Deterministic Model (Streamflow Synthesis And Reservoir Regulation Model), Time Series Model, And Kalman Filter, Philip Kwok Fan Tang

Dissertations and Theses

The basic concepts of hydrologic forecasting using the Streamflow Synthesis And Reservoir Regulation Model of the U.S. Army Corps of Engineers, auto-regressive-moving-average time series models (including Greens' functions, inverse functions, auto covariance Functions, and model estimation algorithm), and the Kalman filter (including state space modeling, system uncertainty, and filter algorithm), were explored. A computational experiment was conducted in which the Kalman filter was applied to update Mehama local basin model (Mehama is a 227 sq. miles watershed located on the North Santiam River near Salem, Oregon.), a typical SSARR basin model, to streamflow measurements as they became available in simulated …

Disc Size Scale-Up In Rotating Biological Contactor System, Chi-Sheng Chang

Theses

Disc size scale-up of prototype and small-scale RBC plants are successfully developed by applying the 114 data sets obtained from 12 RBC plants to the evaluation of percent sBOD remaining. These data analyses are performed by the least square method, therefore, the scale-up factors of the prototype and the small-scale are determined at different hydraulic loading. Furthermore, the relationship between scale-up factor and the disc diameter are established under the given flow rate, the number of stages, and the number of discs. A group of Curves are obtained and can be utilized for the full-scale RBC plant preliminary design. The …

Stability Of Hot Mix Asphalt With Petroleum Contaminated Soils, De-Rong Lobo Huang

Theses

One of the most effective ways of reducing petroleum contaminated soil is to use it in the production of hot mix asphalt. Both asphalt cement and petroleum contaminates have similar chemical properties. Therefore, The contaminates will be locked within the asphalt matrix without potential leaching.

The six different petroleum contaminate soil samples from New Jersey were used in this research. Since those samples have different physical properties (such as moisture content, specific gravity, plastic limit, liquid limit, grain size distribution) and chemical properties( such as concentration of the contaminate, and type of contaminates) the maximum amount of petroleum contaminated soil …

Parallel-Vector Design Sensitivity Analysis In Structural Dynamics, Yongxing Zhang

Civil & Environmental Engineering Theses & Dissertations

In this study, the design sensitivity analysis is for the purpose of providing constraint derivative information for structural optimization under dynamic loads. Various existing formulations are reviewed, and the direct differentiation method is justified as the best one for design sensitivity analysis in structural dynamics. An alternative formulation for design sensitivity analysis with direct differentiation method is developed. The alternative formulation works efficiently with the reduced system of dynamic equations, and it eliminates the need for expensive and complicated eigenvector derivatives, which is required in the existing reduced system formulation. The relationship of the alternative formulation and the existing reduced …

Parallel-Vector Computation For Geometrically Nonlinear Frame Structural Analysis And Design Sensitivity Analysis, Majdi A. Baddourah

Civil & Environmental Engineering Theses & Dissertations

Parallel-vector algorithms are presented for solving the geometrically nonlinear structural problems and obtaining design sensitivity information. A new algorithm is also presented for parallel generation and assembly of the finite element stiffness and mass matrices. The presented assembly algorithm is based on a node-by-node approach rather than the more conventional element-by-element approach. Three different methods, Newton Raphson, Modified Newton Raphson, and the BFGS, are used in the analysis of the nonlinear structural problems. A study is made to determine the performance of each of the mentioned methods in a parallel-vector computer environment. Medium to large-scale, practical problems are solved to …

Evaluating The Role Of Geogrids In The Rehabilitation Of Cracked Dams Via Numerical Techniques, Kelly Dean Uhacz

Dissertations and Theses

Collapse and cracking of debris earth embankment dams is a serious problem in areas of the arid Western United States. The use of geogrids is evaluated in this thesis as a possible solution to prevent or reduce the amount of damage to the structures from collapse and cracking.

An apparatus was designed, constructed, and instrumented to electronically acquire data to evaluate the behavior of geogrids during pullout tests under various normal stresses. The pullout tests were also modelled using numerical techniques to correlate physical test data with numerical test data. Understanding the behavior of the geogrid, in both the physical …

Load-Deformation Behavior Of Reinforced Fibrous Concrete Beams, Rujun He

Theses

This study deals with the load-deformation behavior of steel fiber reinforced concrete beams.

Theoretical development of moment-curvature and load-deformation relationships is presented in this paper. It is based on the assumption that the failure at a section occurs either when the force equilibrium equation is violated or when the concrete elements start to get crushed in the member. The complete stress-strain relationship of plain fibrous concrete in reference [2] was used in this study.

A special computer program is presented herein to carry out the theoretical studies of load-deformation behavior of simply supported beam under two-point loading. The validity of …

Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang

Theses

There are between 2 to 3.5 million Underground Storage Tanks (UST) located through this nation. Most of these tanks store gasoline and fuel oil. Many tanks in fact are or will soon be leaking, thus making them one of the major sources of groundwater contamination in USA. The fate and transport of chemicals from the leaking USTs is estimated from mathematical models. A major difficulty in these modeling efforts has been a crucial lack of information concerning the constitutive relationships governing multiphase contaminant movement.

Centrifugal modeling is an alternative to mathematical modeling, which may give an insight to the problem …

An Analysis Of Reinforced Concrete Composites Utilizing Recycled Polyethylene Terephthalate Thermoplastic, Jaroslav V. Vaverka

Dissertations and Theses @ UNI

Removing plastic from landfills does not solve the solid waste problem entirely. Plastic products are difficult to recycle because, unlike aluminum or glass, the plastics used in food packaging cannot be reused for the same purpose. Among the commonly used plastic resins, polyethylene terephthalate (PET) has been widely adopted by the packaging industry. This research study was concerned with recycling of PET thermoplastic in concrete as a way to reduce the volume of solid waste.

Current surveys of recycling efforts reveal that existing PET recycling approaches have become inadequate. Solid waste management is stressing the eminent need for new recycling …

Limits Of Limit Equilibrium And Finite Element Techniques Applied To Cracked Debris Dams On Collapsing Foundations, Stanley Soliday Jr.

Dissertations and Theses

Limits of slope stability, limit equilibrium methods, and of the finite element code FEADAM are reached in the application of these methods to the problem of cracked dams constructed on collapsing soils.

Continuum Modeling Methodology For Dynamic Behavior Of Towers, Khaled A. Obeid

Civil & Environmental Engineering Theses & Dissertations

A very common problem in Civil Engineering is the analysis and design of lattice structures. These types of structures generally consist of repetitive sections and have been utilized in the erection of transmission and communication towers, space roof trusses, solar energy collectors, and space platforms. Since lattice structures consist of a significantly large number of members and subsequently a large number of nodes, the classical discrete technique of analysis can be very expensive even on today's modern computers. This study applies a rational approach which capitalizes on the repetitive nature of towers to develop the equivalent continuum model for the …

Micromechanics Of Granular Materials And Its Relation To Wave Velocity, Tarun K. Agarwal

Civil & Environmental Engineering Theses & Dissertations

The macro characters of the granular materials depend upon micromechanical parameters such as the void ratio, particle shape, contact force distribution, and initial state of the fabric of the assembly. Since it is difficult to evaluate these internal parameters from laboratory experiments, a macro measure is desired which depends directly on these internal parameters. One such measure has been shown to be dynamic shear modulus but it was incomplete in predicting directional changes in the internal parameters. Therefore, it is hypothesized here that the complete elastic moduli matrix will have more direct information about the internal parameters, especially the dynamic …