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Modeling The Monotonic And Cyclic Viscoplastic Soil Behavior, Ronaldo I. Borja

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

We describe a class of viscoplastic constitutive models capable of simulating the monotonic and cyclic rate-dependent soil behavior. These models are developed by enriching their inviscid counterparts with a viscous character to model the irreversible deformation that develops with time. The viscoplastic strain rate is of the Duvaut-Lions type whose magnitude increases with the distance of the stress point from its projection onto the inviscid solution. With appropriate choice of an inviscid elasto-plastic soil model, one can generate quasipreconsolidation effects during creep and account for the influence of frequency on the shape and width of hysteresis loops formed during cyclic …

Modelling The Deformation Of Sand During Cyclic Rotation Of Principal Stress Directions, Marte Gutierrez, Kenji Ishihara, Ikuo Towhata

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper presents an elastoplastic constitutive model for the deformation of sand during cyclic rotation of principal stress directions. The model employs a plastic potential theory that allows for the dependency of flow on the stress increment direction and a stress-dilatancy relation incorporating the effects of noncoaxiality. The continuous plastic deformation of sand during principal stress rotation at constant shear stress level is allowed for in the model by using a small elastic area in the stress space. The effects of cyclic stress history is modelled by using discrete surfaces of equal hardening modulus which are allowed to move with …

Presentation Of The Porewater Pressure Buildup Using Moroto's And State Parameter, Predrag Kvasnička, Tomislav Lvšić

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In this paper it is attempted to generate the rise of pore water pressures in undrained strain controlled cyclic triaxial tests for various densities (void ratios), confining pressures and strain amplitudes. The results of cyclic triaxial tests on one type of standard Yugoslav sand are presented. Introducing the Moroto's parameter based on cumulative shear work normalized with confining pressure (Moroto, 1976) and a state parameter defined as a distance between initial void ratio and the steady state line (Been and Jefferies, 1985) the band of the results is narrowed and a single curve for representing the pore water pressure buildup …

General Report Session 1: Static And Dynamic Soil Parameters And Constitutive Relations Of Soils, Peter M. Byrne, Li Yan

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The soil parameters that are commonly of interest in dealing with earthquake and soil dynamics problems are:

1) The maximum shear modulus G₀, or the shear wave velocity, V_s.

2) The variation of secant shear modulus with shear strain level, G/G₀ vs γ.

3) Equivalent viscous damping as a function of strain.

4) Other parameters such as, dilatometer modulus, normalized SPT or CPT value, state parameters, formation factor.

In terms of constitutive relations the following models have been used:

1) Linear elastic (total stress) - appropriate at very small strains < 10^-3%.

2) Equivalent linear …

Centrifugal Modeling Of A Pile Under Vertical Random Excitation, Lary R. Lenke, Hon-Kim Ko, Ronald Y. S. Pak

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Data from the experimental modeling of a pile in a geotechnical centrifuge are compared with analytical results. The model pile was subjected to vertical random excitation with subsequent determination of the compliance function in the frequency domain. This compliance function was found to be consistent with theory. An absorbing boundary was used to minimize reflected wave energy from the centrifuge container boundaries.

Session 2: Closing Remarks, C. K. Shen

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

Analysis Of Liquefiable Sand Deposits Using Gravel Drains, Zhi-Ying Xu

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In this paper, based on the simplified assumption about seismic pore water pressure a partial differential equation of 3-D axi-symmetrical problem which takes into account of the generation, diffusion and dissipation of seismic pore water pressure is presented. This equation is then solved by the method of separation of variables and 5-function and a mathematical formula for residual pore water pressure is obtained. The formula can be used in the calculation and design of the gravel drains installed in the sand layer prone to liquefy. The computed results by this formula are presented in a series of charts which can …

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 …

Design Curves For The Reuse Of Stormwater, Gregory Miller Harper

Retrospective Theses and Dissertations

The reuse of stormwater runoff is becoming an increasingly popular addition to stormwater management systems. The advantages include a reduction in pollution and volume discharges to surface waters, the return of runoff to the ground, and savings in the cost of using potable water. This research, by developing a relationship between the reuse volume (temporary storage volume), the rate at which stormwater is reused, and the percentage of annual surface runoff that is reused, provides a procedure in which to design stormwater reuse systems. The traditional design of pond temporary storage volume has been based on the consideration of water …

Knowledge-Based Support For Management Of Concurrent, Multidisciplinary Design, Raymond E. Levitt, Yan Jin, Clive L. Dym

All HMC Faculty Publications and Research

Artificial intelligence (AI) applications to design have tended to focus on modeling and automating aspects of single discipline design tasks. Relatively little attention has thus far been devoted to representing the kinds of design 'metaknowledge' needed to manage the important interface issues that arise in concurrent design, that is, multidisciplinary design decision-making. This paper provides a view of the process and management of concurrent design and evaluates the potential of two AI approaches—blackboard architectures and co-operative distributed problem-solving (CDPS)—to model and support the concurrent design of complex artifacts. A discussion of the process of multidisciplinary design highlights elements of both …

Calibration Of A Parametric-Stochastic Model, Zhida Song, L. Douglas James

Reports

Conceptually, stochastic parametric modeling offers a powerful tool to select a scale for expressing catchment variability for hydrologic simulation and relating model parameters to catchment characteristics. Practically, success depends on having an efficient method for model calibration. The calibration of a stochastic model is much more difficult than a deterministic one because simulation shifts from using fixed parameters to simulate of flows as deterministic values to taking multiple combinations of paramter values randomly from distributions to simulate flows as stochastic variables. The proposed method calibrates the first two moments of each parameter distribution to represent the average and the variability …

Studies Related To Nutrients Entering Groundwater From The Heber Valley Sewer Farm And Dairies, Roland W. Jeppson, Joan Mclean, Calvin G. Clyde, Scott Korom

Reports

Foreword: This report includes the results from a two year study in the Heber Valley to determine amounts of nutrients that are entering the groundwaters of the Heber Valley, and might ultimately enter Deer Creek Reservoir. Since Deer Creek Reservoir in Heber Valley, Utah supplies approximately 65 percent of the water distributed to Salt Lake County, the maintenance of its quality is of considerable importance. To maintain the quality of this reservoir and limit its eutrophication "best management" practices for surface water have been implemented gradually during the past decade in Heber Valley. These practices have significantly improved the qualities …

Sectar: Model For Economically Optimal Sustained Groundwater Yield Planning, Richard C. Peralta, K. Asghari, R. N. Shulstad

Civil and Environmental Engineering Faculty Publications

This paper presents an approach for computing economically optimal sustained yield ground-water extract ion strategies and supportable irrigated crop acreages. Computed regional strategies maximize the present value of net economic return_ They are useful for long-term agricultural planning because they are sustainable even beyond the planning period considered within the economic optimization. The hybrid approach uses only steady-state flow equations and iterative simulation/optimization to reduce optimization memory requirements below that required by conventional models utilizing both steady and unsteady equations. SECTAR, a quadratic optimization planning model assumes heads will evolve toward optimal steady-state but does initially not know the nonlinear …

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 …

User Guide For Pc-Stabl3d, Gennady Moshkovich

JTRP Technical Reports

PC-STABL3D is the program for IBM PC compatible computers, developed to handle general stability analysis of three-dimensional slopes. Random generation routines are invoked to create trial failure surfaces, which are analyzed using the limiting equilibrium approach. The current version of PC-STABL3D is enhanced by a graphical pre/postprocessor, which facilitates creation and edition 0 data files, examination of problem geometry, and analyzing of the obtained failure surfaces. After the failure surfaces are generated and their factors of safety are computed, the program performs statistical analysis of received factors of safety, and calculates minimum statistical factor of safety. The information about minimum …

A Pc Based Computer Model With A Postprocessor For The Movement Of Groundwater, Joseph Byra

Theses

Currently available computer programs that model groundwater flow are inherently limited in their capabilities, in one way or another. Additionally, many of these computer programs are relatively inaccessible to the general user because they operate off of mainframe computers and sophisticated plotters. As a result, a simple to use computer program called 2DFLOW has been modified so it can be run on a personal IBM compatible computer. It models steady-state fluid flow through saturated porous media. In addition, a postprocessor called 2DPLOT has been developed. The postprocessor generates the equipotential contours and the flux vectors that describe the physics of …

The Dewaterability Of Anaerobically-Digested Sludges, Hui-Ching Lee

Theses

Vacuum filtration is the most common method used for sludge dewatering. Filtering or dewatering was operated to reduce the moisture content of the sludge after anaerobic digestion treatment.

The main purpose of this study is to determine the effect of the operating conditions of anaerobic digestion system on specific resistance in sludge filtration. The anaerobic sludges used for the present study were produced from the conventional single stage system and the multiple-stage system. From the experimental results, presently obtained that it is possible to compare the advantage and disadvantage of the two different digestion systems.

In addition, the effectiveness of …

Temperature Scale-Up On Rotating Biological Contactor Nitrification System, Kuanchun Lee

Theses

The relationship between RBC scale-up factor (SUF) and wastewater temperature is successfully developed by using Dr. Wu's mathematical model as a basis and 114 sets of data from the operation of 8 full-scale and 5 pilot-scale RBC plants served for NH3-N removal. The SUF obtained from this study is put into practice to present the scale-up of hydraulic loading for basic full-scale RBC plant design when the pilot study results are known and the design efficiency is fixed. An additional study is made to investigate two different RBC products manufactured by Autotrol Inc. and Lyco Inc. in terms of the …

Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration

Publications (WR)

The Lake Mead Fertilization Project is a research program designed to investigate the potential for using large-scale artificial fertilization to enhance the game fisheries of this reservoir through an increase in the population of threadfin shad, the system's primary forage species. A substantial decline in the population of largemouth bass, together with poor condition of adult striped bass, are the two major issues affecting the Lake Mead game fisheries. Both issues have been hypothesized to be a result of an inadequate amount of forage in the reservoir. Previous studies have in turn suggested that a major factor limiting the shad …

Kentucky's Future Economic Growth Policy: A Legislative Perspective, John A. "Eck" Rose

Kentucky's Annual Forum on Transportation

No abstract provided.

Safety Indexes For Shear-Bond Failure Of Composite Slabs, Laurence A. Mccuaig, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

A Simple Semi-Analytical, Semi-Numerical Approach To Thin-Walled Structures Stability Problems, J. Rhodes, P. W. Khong

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

A Numerical Model For Fire-Exposed Composite Steel/Concrete Slabs, Ralph Hamerlinck, Leen Twilt, Jan W. B. Stark

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Gis Address-Matching And Transportation Analysis, James D. Orrell

Dissertations and Theses

Geographic Information System (GIS) address-matching combined with other GIS processing offers new analytical opportunities in the area of transportation planning and analysis. Address-matching, an automated method for generating geographically-referenced (geocoded) point locations on a map from common tabular databases, can facilitate transportation analysis by providing a planning tool based on individual rather than aggregated spatial distributions more common to transportation issues.

This thesis presents a case study in which GIS address-matching was I applied to a transportation problem at Oregon Health Sciences University (OHSU) in Portland, Oregon. The transportation problem at OHSU is common to major employment centers in urban …

Load And Resistance Factor Design Of Cold-Formed Steel Reliability Based Criteria For Cold-Formed Steel Members, Ling-En Hsiao, Wei-Wen Yu, Theodore V. Galambos

CCFSS Library (1939 - present)

In the design of steel buildings, the "Allowable Stress Design (ASD)" method has long been used for cold-formed steel structural members in the United States and other countries. In this approach, member forces, or moments, determined on the basis of working loads should not exceed the allowable values. The allowable value is used to prevent the possible structural failure by using an appropriate factor of safety selected primarily on the basis of engineering judgment and long-time experience. Recently, in the United States, the concepts of risk and reliability analysis have been successfully applied to the Load and Resistance Factor Design …

Research Project Summaries (July 1989-December 1990), Utah Water Research Laboratory

Reports

From every side we hear of new threats to our water supply. Carcinogens, droughts, dam failures, global warming, hazardous wastes, deforestation, overpopulation, liability, and an aging infrastructure become household fears; this list grows longer and more foreboding to the average citizen. Some of these threats are real, while others are imaginary. Some we know how to overcome and others we can find ways to overcome, yet, for some, we are still helpless. The strength of a university lies in its success in stimulating inquisitive minds in critical examination of the problems of the world. People sense hope as experts find …

Effects Of Alternative Furrow Irrigation Parameters On Pesticide Movement In Cropped Areas In Utah, Antonio Maria Requena, Ahmad Yar Ranjha, Richard C. Peralta, Howard M. Deer, Majid Ehteshami, Robert W. Hill

Civil and Environmental Engineering Faculty Publications

Production of adequate supplies of food and fiber currently requires that pesticides be used to limit crop losses caused by insects, pathogens, weeds and other pests. Although pesticides are necessary in today' s agriculture, they can be a serious problem if they reach and contaminate ground water, especially where drinking water needs are met by ground water. The relative reduction of potential ground-water contamination due to agricultural use of pesticides was analyzed for particular sites in Utah. The potential reduction of pesticides in ground water was considered by utilizing alternative irrigation systems, water management practices and pesticides. A one-dimensional simulation …

Prestressed Concrete Columns Under Bending And Axial Load, Ajit Chiplunkar

Theses

A general analysis and design equation for slender and nonslender prestressed concrete columns subjected to uniaxial or biaxial moments combined with axial load is proposed. The proposed equation is an extension to the one developed by Hsu for reinforced concrete columns. The analytical results of the ultimate loads of eccentrically loaded slender prestressed columns are compared with the experimental results reported by Brown and Hall and Aroni respectively. The comparative study shows that the proposed equation of interaction diagram is in good agreement with the actual tests.

The ultimate loads of biaxially loaded short columns are also compared with the …

Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strengths Of Cold-Formed Steel Members Under Dynamic Loads, Maher Kassar, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION Since May 1988, the research project on automotive components sponsored by American Iron and Steel Institute (AISI) at University of Missouri-Rolla (UMR) has been concentrated on a study of the effect of strain rate on mechanical properties of sheet steels and the structural behavior and strength of cold-formed steel members subjected to impact loads. The results of the static and dynamic tensile mechanical properties of three selected sheet steels in the virgin condition as well as for the steels subjected to different amount of cold stretchings, were established in 1988 and early 1989. Details of the tension coupon tests …

Pesticide And Water Management Alternatives To Mitigate Potential Ground-Water Contamination For Selected Counties In Utah, Majid Ehteshami, Antonio M. Requena, Richard C. Peralta, Howard M. Deer, Robert W. Hill, Ahmad Yar Ranjha

Civil and Environmental Engineering Faculty Publications

Production of adequate supplies of food and fiber currently requires that pesticides be used to limit crop losses from insects, pathogens, weeds and other pests. Although pesticides are necessary in today's agriculture, they can be a serious problem if they reach and contaminate ground water, especially in places where drinking water needs are supplied from ground water. The relative reduction of potential ground-water contamination due to agricultural use of pesticides was analyzed for particular sites in Utah. The potential reduction of pesticides in ground water was considered by utilizing alternative irrigation systems, water management practices and pesticides. A one-dimensional simulation …