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Articles 121 - 150 of 231

Full-Text Articles in Civil Engineering

The Strength Of Cement Bentonite In Containment Structures, Liong Tin So Dec 1991

The Strength Of Cement Bentonite In Containment Structures, Liong Tin So

Theses

In recent years the use of cutoff or slurry walls has increased in the containment of hazardous waste. Several materials have been utilized for backfill in slurry walls. Two important properties of the material are shear strength and permeability. Previously, sodium bentonite had been used. However, it was discovered that variable pH would cause an increase in permeability. Studies have shown calcium bentonite have a constant permeability with varied pH (Oweis and Khera, 1990). This study was undertaken to determine strength of calcium bentonite as affected by cement and slag.

Triaxial shear tests and unconfined compression tests were done on …


A Study Of The Potential Funding Mechanism For Surface Transportation In The New York Metropolitan Region, Krishnaveni Venkataswami Dec 1991

A Study Of The Potential Funding Mechanism For Surface Transportation In The New York Metropolitan Region, Krishnaveni Venkataswami

Theses

The present network of highways, soaring bridges, airports, seaports, and transit systems that serve the New York Metropolitan region are part of this region's inheritance from the generation of Americans who built them before us. These massive and sometimes daring achievements supported the economic growth of the region. Now that inheritance is in danger. The quality of the region's transportation infrastructure is barely adequate to fulfill current requirements, and insufficient to meet the demands of future economic growth and development. We are spending our inheritance.

A major problem is financial. Overall investment in transportation has slowed down in the last …


Load-Deformation Behavior Of Reinforced Fibrous Concrete Beams, Rujun He May 1991

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 …


Automated Determination Of Air Content In Hardened Concrete, Anita R. Navalurkar May 1991

Automated Determination Of Air Content In Hardened Concrete, Anita R. Navalurkar

Theses

An automated system was developed for the microscopic determination of air content and the related parameters in hardened concrete using the principles of Image Analysis and Computer Technology. Slices taken from the concrete specimen were viewed through a microscope with 40X magnification. The magnified image of the concrete slice is digitized by an Image Analyzing Software. Methodologies were developed for analysis of the digitized image and determination of air content and the required parameters. The automated system included a motorized positioner which translated microscope stage in a frame by frame sequence so that the whole image is digitized. Several tests …


Evaluation Of Cracking Mechanism In Fiber Reinforced Concrete Subjected To Impulsive Loading, Rajendra K. Navalurkar May 1991

Evaluation Of Cracking Mechanism In Fiber Reinforced Concrete Subjected To Impulsive Loading, Rajendra K. Navalurkar

Theses

This thesis presents an experimental evaluation of J-Integral for plain and fiber reinforced concrete subjected to impact loading. A computer assisted instrumented Charpy test system was employed in applying the impact loads. Twenty two three point bend specimens with two different notch lengths were tested under impact velocity of 43.29 in/sec. Development and testing of a new fiber optic sensor, for the determination of internal Crack Tip Opening Displacements (CTOD) in concrete is described.

Evaluation of JIC values from experimental results of this study indicate that JIC can be characterized as a material constant. The Dynamic value of …


Influence Of Fly Ash Characteristics On Compressive Strength Of Mortar, Poorna Rajeswari Ratnaweera May 1991

Influence Of Fly Ash Characteristics On Compressive Strength Of Mortar, Poorna Rajeswari Ratnaweera

Theses

Fly ash-cement mortar, constituting of fly ash, cement and sand, vary in strength characteristics from conventional cement sand mortar. Out of many parameters effecting the compressive strength characteristics of fly ash-cement mortar, four were investigated in this study. They are particle size and its distribution, weathering of fly ash, moisture content & water/cementitious ratio and mix proportioning.

Class F fly ashes from three different sources were used in this study. The particle size distribution and moisture content of fly ashes were investigated by standard ASTM methods. The unconfined compressive strength of mortar was obtained by testing 2"x2"x2" test cubes conforming …


Water Treatment Plant Sludge As Sanitary Landfill Liner, Sinnadurai Sockanathan May 1991

Water Treatment Plant Sludge As Sanitary Landfill Liner, Sinnadurai Sockanathan

Theses

This study was performed to explore the possibility of using the sludge waste from the water treatment plant at Boonton New Jersey as a containment material for the sanitary landfills or as a fill material. At present natural clay is being used as a containment liner for the landfills and by using this sludge, recycling of a waste product will be achieved in an economical manner.

As a first part of this studies, efforts were made to utilize the liquid sludge having a solid content of about 3%. Attempts to dewater the liquid sludge to a workable mix by adding …


Determination Of Water-Cement Ratio In Cement Paste By Atomic Absorption Spectrometry, Jiong Zhao May 1991

Determination Of Water-Cement Ratio In Cement Paste By Atomic Absorption Spectrometry, Jiong Zhao

Theses

As one of the important characteristics of concrete, water-cement ratio controls porosity and thus strength and corrosion resistance of hardened concrete.

This paper presents a laboratory observation for determination of water-cement ratio of fresh concrete for quality control and quality assurance. The atomic absorption spectrophotometer and the flouresence spectrophtometer were used to determine the calcium concentration in cement solution of various water-cement ratio. The level of water-cement ratio investigated ranged from 0.4 to 0.55 which covers the most range of water-cement ratios in present practice. The result of lab experiments shows an immediate relation between the water-cement ratio and the …


A Pc Based Computer Model With A Postprocessor For The Movement Of Groundwater, Joseph Byra Dec 1990

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 …


A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo Aug 1990

A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo

Theses

It could be difficult to understand electricity problems without knowing its history; how a combine of legal, administration, and financial means effects electricity in the development. The recent public law on energy-related issues traceable by this study is the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989.

In short, cogeneration was proposed to utility (as public property) from industry (as private property) under PURPA (of which National Energy Act is the legislative history). Thus, it should be clear that the problems of cogeneration is not pro or contra issues. It is a national issue. Then, a cogeneration planner …


Study Of Essential Factors Affecting The Efficiency Of Sludge Digestion, I-Chang Tsao May 1990

Study Of Essential Factors Affecting The Efficiency Of Sludge Digestion, I-Chang Tsao

Theses

The sludge produced by wastewater treatment plant has some major characteristics such as high COD ( 52093 mg/1 - 79683 mg/1) and VS ( 19247 mg/1 - 44178 mg/1). The present laboratory investigation has indicated that successful treatment and purification of the subject of sludge is possible using multiple-stage anaerobic digestion system.

The multiple-stage system is capable of degrading 40-55% of COD and 50 to 60% of VS. The conventional digestion system degrades 30-45% of COD and 40-50% of VS. After treated by conventional system and multiple-stage system, the concentration of COD and VS are still high (21200 mg/1 - …


Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu May 1990

Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu

Theses

A total of four slender high strength steel fiber ( 20 vol. hooked ends 1 in and 2 in ) reinforced concrete columns were casted, cured and tested to failure under biaxially eccentric load us—KT MTS testing system. The experimental load-deflection behavior exhibits not only the ascending branch but also the descending branch of the load and deformation curves.

The experimental ultimate load capacity was analyzed by the equation of Failure Surface Method developed by Hsu. recently, the result shows that the analysis method is able to predict the ultimate load value for biaxially loaded slender concrete columns.

For biaxially …


Construction Cost Estimating In Project Management, Kalpit N. Patel May 1990

Construction Cost Estimating In Project Management, Kalpit N. Patel

Theses

The primary objective of Cost Estimating is to support the timely generation of bid or alternative estimates. Cost Estimating also supports management analysis of estimate accuracy, reasonableness and project risk through the generation of summary reports and analysis. Estimates also provide a base of information during construction for such items as scope changes to the contract, variations in costs of the project cost, total project cost, feedback for scheduling etc.

Contruction cost estimating is the process of identifying and compiling the many items of cost that will enter into a construction project. This is a procedure that requires very detailed …


Investigation Of Mixed-Made Fracture In Concrete, Stylianos C. Aniftos May 1990

Investigation Of Mixed-Made Fracture In Concrete, Stylianos C. Aniftos

Theses

This study is aimed at evaluating the failure characteristics of concrete in the notched beam configuration. In general, for Mode I failure tension is commonly encountered. However, in the area of high shear stress, it remains to be a question whether shear or Mode II failure exists. Researches carried out in the past decade confirmed the existance of both Mode I and Mode II failure. It is the objective of this investigation to clarify this failure characteristics using FRANC an interactive fracture mechanics software.

The investigation carried out in this study used the experimental results of Bazant and Pfeiffer (3) …


Experimental Evaluation Of Process Zone Deformation In Concrete, Cherng-Maou Meng May 1990

Experimental Evaluation Of Process Zone Deformation In Concrete, Cherng-Maou Meng

Theses

Concrete structures are often subjected to a variety of loading conditions. Under ultimate load design, concrete structures can resist these loads without evident deformation. However, under service, tension cracks will develop and depending on their location, they may impair load carrying capacity.

It is generally believed that microcrack development is preceeded by formation of a relatively long microcracked region. A large number of studies have indicated that due to formation of this process zone (microcracked zone), Linear Elastic Fracture Mechanics (LEFM) principles are not applicable to concrete. However, a number of nonlinear models can be developed if the length of …


Shear Behavior Of Steel Fiber Reinforced Concrete Beams Under Monotonic And Cyclic Loads, June Suh May 1990

Shear Behavior Of Steel Fiber Reinforced Concrete Beams Under Monotonic And Cyclic Loads, June Suh

Theses

Up to now relatively few tests have been reported on shear behavior in fiber reinforced concrete beams. Even less experiments have been carried out under fatigue loading. In the present experiment, the reinforced concrete beams with 1 percent and 2 percent steel fiber volume fraction are investigated. Conventional stirrups are included in number of beams at certain intervals. Beams are loaded under monotonic and cyclic loads. The strength of beams are determined and the behavior of beams under each loading are observed in order to determine some advantages of adding steel fibers to reinforced concrete beams.

It has been found …


Calcium Bentonite In Containment Structures, Ramnarayan K. Tirumala May 1990

Calcium Bentonite In Containment Structures, Ramnarayan K. Tirumala

Theses

Experiments were conducted on calcium bentonite from different sources to determine its suitability as a material for slurry wall. The emphasis was placed on cement-bentonite types of materials. A few tests were conducted on specimens consisting of soil-bentonite materials. Permeability, swelling potential, and immersion tests were conducted. Specimens were initially permeated with water to determine which variety of bentonite was most suitable and later with chemicals. In cement bentonite specimens, the effect of addition of blast furnace slag, fly ash, and sand were also studied. Addition of slag cement lowered the permeability value by an order of magnitude, and with …


Behavior Of Slender High Strength Reinforced Columns Under Biaxially Eccentric Loading, Pei-Shiun Wu May 1990

Behavior Of Slender High Strength Reinforced Columns Under Biaxially Eccentric Loading, Pei-Shiun Wu

Theses

The advantage of using high strength concrete is to reduce column sizes and to increase stiffness. At present there are not any available design aids and the code provisions that provide adequate guidelines for the design of slender columns in high strength concrete.

A total of four 3 in. by 3 in. dimension, 4 ft. length high strength concrete specimens were casted, cured and tested till failures in a vertical pinned-ended configuration.The experimental results were compared with the analysis using Hsu failure surface equation.

Moment, curvature and load deflection cures were obtained successfully from the present experimental tests. These curves …


Effects Of Fly Ash And Kiln Dust On The Compressive Strength Of Cement Mortar, Yitao Yu May 1990

Effects Of Fly Ash And Kiln Dust On The Compressive Strength Of Cement Mortar, Yitao Yu

Theses

Fly ash generated from coal-burning power plants has been an increasing problem to the utility company in terms of storage and disposal in compliance with the environmental regulations. Presently, fly ash has been widely used in the concrete mix. Research shows that fly ash can improve many properties of fresh and harden concrete. Landfill is another significant usage of fly ash. Usually, fly ash is stored in dry and weathered conditions. The properties of fly ashes from different sources and in different storage conditions are different.

In this research, the compressive strength of mortar containing cement replacement of Deep Hollow, …


Prestressed Concrete Columns Under Bending And Axial Load, Ajit Chiplunkar May 1990

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 …


Desiccation And Permeability Of Backfill Materials In Soil-Bentonite Walls, Hemendra J. Moradia Jan 1990

Desiccation And Permeability Of Backfill Materials In Soil-Bentonite Walls, Hemendra J. Moradia

Theses

Soil-Bentonite Walls offer a cost effective solution to many groundwater problems in new and remedial work projects such as hydraulic barriers in dams, dewatering large soil cuts, and as part of pollution control systems around hazardous waste landfills. However, the performance of soil-bentonite walls in environments other then fresh water types is still a matter of great controversy. In recent years, some data on soil-bentonite backfill have became available. The data indicate change in properties of these walls with time of exposure and concentration of chemicals found in leachates. However, no research work is available in the literature on the …


Equation Of Interaction Diagrams For Prestressed Concrete Columns, Angamuthu Palaniappan Sep 1989

Equation Of Interaction Diagrams For Prestressed Concrete Columns, Angamuthu Palaniappan

Theses

A general analysis and design equation for prestressed concrete column is proposed. This equation represents the strength interaction diagrams of prestressed concrete columns under bending about one axis and combined with axial load. The equation proposed is a modification of the one developed by Dr. Hsu, C.T. Thomas for reinforced concrete columns published in the ACI structural journal in 1988. The analytical results were compared with the results of tests on 30 eccentrically loaded prestressed columns reported by H.R. Brown and A.S. Hall. The results were in good agreement with the static analysis and the above mentioned test reports. The …


Experimental Study Of Rectangular And Square Concrete Member Under Combined Biaxial Bending And Tension, Ming-Hua Shiau Sep 1989

Experimental Study Of Rectangular And Square Concrete Member Under Combined Biaxial Bending And Tension, Ming-Hua Shiau

Theses

The proposed research is based on an equation developed by Dr. Hsu, which represents the strength interaction diagrams and failure surface for reinforced concrete rectangular and square columns under combined biaxial bending and axial load. In this research, two rectangular columns and two square columns subject to biaxial bending and tension were tested and compared with the proposed failure surface equation. This study shows that the experimental test results achieve more strengths then those calculated by the equation of failure surface.


Optimal Design Of Prestressed Concrete Members Using Numerical Techniques, Nasseruddin Syed May 1989

Optimal Design Of Prestressed Concrete Members Using Numerical Techniques, Nasseruddin Syed

Theses

This research consists of the application of nonlinear optimization techniques for the economical design of prestressed concrete members. A computer program using Lattice and Matrix methods of optimization is employed for least weight design of I-shaped prestressed concrete girders. The program calculates the most optimum values of the cross-sectional dimensions.It has the freedom to impose any constraints on any of the design variables, including sectional dimensions, eccentricities, concrete cover and limiting stresses.

Comparison of results obtained in this thesis with other analytical methods indicate that with the advent of computers, the numerical methods have a definite advantage over other analytical …


Competitive Bidding Strategy In The Construction Industry : A Game Theoretic Approach, Hongbin Chen May 1989

Competitive Bidding Strategy In The Construction Industry : A Game Theoretic Approach, Hongbin Chen

Theses

A game theoretic approach is applied to analyze competitive bidding in the construction industry because previous models do not consider the conflict of interest that exists among competitors. The game theoretic model improves corporate performance when compared to previous Bayesian analyses.

The game theoretic model is discussed in conjunction with construction contracting practice. Competitive bidding is formulated as a game theoretic model in which a contractor optimizes his bid price to maximize his utility or corporate performance. Using available historical data, order statistics are employed to access the distribution of estimated costs among bidders for a project. The winner's curse …


Adsorption And Desorption Of Chromium On Clayey Soils, Ker-Shu Tan May 1989

Adsorption And Desorption Of Chromium On Clayey Soils, Ker-Shu Tan

Theses

Chromium residue waste was produced during sixties in the chromium production process. It was used as construction fill. Problems associated with chromium waste sites include structure distress and surface and groundwater contamination.

The purpose of this study was to investigate the adsorption and desorption of chromium on soil. In order to achieve this purpose, experiments were conducted to study the effect of pH, type of chromium compound, and type of soil on adsorption and desorption.

Experiments were performed on kaolinite, bentonite and sand. In our study, it was found that sand had almost no adsorption for chromium. Kaolinite had less …


Slurry Wall Backfill Integrity And Desiccation, Mahendraratnam Thilliyar May 1989

Slurry Wall Backfill Integrity And Desiccation, Mahendraratnam Thilliyar

Theses

The upper reaches of slurry wall, in a waste containment structure may under go cycles of wetting and drying, because of seasonal ground water level fluctuations. This may result in desiccation and cracking of back fill material. Experiments were conducted to study these effects with water, aniline, phenol, hydrochloric acid solutions on soils containing different proportions of bentonite, kaolinite, and sand. The largest crack was formed with phenol and the smallest with water. With hydrochloric acid no crack was formed. With increase kaolinite content, the width and density of crack decreased. Hydraulic conductivity tests on cracked specimens indicated high hydraulic …


Thermal Desorption Of Phenol Contaminated Clay Soils, Chia-Ling Ting May 1989

Thermal Desorption Of Phenol Contaminated Clay Soils, Chia-Ling Ting

Theses

Clay mineral/organic reactions have been studied extensively by a numerous physicochemical methods. There also has been extensive research done in the areas of adsorption, Lewis acid-base reactions, desorption, adduct formation. Many of these studies explain the role and dehydration of silicates.

Studies have shown through extraction, thermal analysis, and gas chromatography. That there is more than one type of bonding, weak and strong, taking place between the clay mineral and the organic waste.

In order to determine the practicality of the containment technology, this research has been investigated by using more powerful tools, such as thermogravimetric analysis, differential scanning calorimetry …


Sediment Transport/Sand Bypassing Analysis At Manasquan, Nj, Christopher Clemens Obropta May 1989

Sediment Transport/Sand Bypassing Analysis At Manasquan, Nj, Christopher Clemens Obropta

Theses

An experiment to determine the longshore sediment transport rate using a fluorescent dyed sand tracer was conducted during the summer of 1987 to help determine the feasibility of sand bypassing at the Manasquan Inlet in New Jersey. After the fluorescent sand tracer was introduced to the longshore transport system, the Spatial Integration Method was used to sample the surf zone. The Spatial Integration Method allowed the tracer cloud to be monitored in both time and space. The tracer experiment provided a constant to be used in the calculation of the longshore sediment transport rate. This constant is specific to the …


Laboratory Model Studies Of Pneumatic Fracturing Of Soils To Remove Volatile Organic Compounds, Panayiotis Papanicolaou May 1989

Laboratory Model Studies Of Pneumatic Fracturing Of Soils To Remove Volatile Organic Compounds, Panayiotis Papanicolaou

Theses

Bench-scale laboratory studies were conducted from January 1988 to October 1988 to demonstrate the feasibility of using Pneumatic Fracturing* to enhance the removal of Volatile Organic Compounds from the vadose soil zone. Experiments were conducted to investigate: 1) The effect of pneumatic fracturing on the rate of contaminant removal; and 2) the injection pressures required to initiate soil fracturing.

Contaminated soil was placed and compacted in three identical 15 inch square by 30 inch high plexiglass tanks. The first tank was equipped with a vapor extraction system consisting of vacuum and/or positive air injection. The second tank was equipped with …