Civil Engineering Commons^™

Fracture Of Cementitious Composites, Sira Tindukasiri

Theses

Studies in fracture mechanics of concrete use a testing setup which tends to include unacceptably large errors in deflection measurements. Recent work reported by Kim [3] has proposed a new testing setup to eliminate these errors and consequently produce better determinations of fracture parameters.

The error which occurs most frequently is in the measurement of the load-line deflection. Until recently, the way this measurement has been made, using a dial gauge or LVDT (Linear Variable Differential Transformer) to measure the deformation between the center of the specimen and the frame, includes the crushing of the concrete surface at the supports …

Behavior Of R/C Columns Under Nonproportional Variations In Axial And Lateral Loads, Kaniz Fatema Ahsan

Theses

The study on the behavior of reinforced concrete columns subjected to the motion of earthquake suggests that the structure may experience nonproportional variations in axial and lateral forces. In order to assess the capacity of a reinforced concrete structure under nonproportional loadings, an analytical model is developed using the fiber modeling technique.

The method is based on detailed analytical description of the geometry and material properties used in evaluating the behavior of the critical regions rather than a simplified and predefined set of hysteresis rules. The present study has two principal components of investigation. First, the analyses are done at …

Behavior Of High Strength Concrete And Slender Reinforced Concrete Columns With And Without Steel Fibers, Lin Showmay Hsu

Dissertations

A series of compression tests are conducted on 3 in. by 6 in. cylindrical specimens using a modified testing method that give the complete stress-strain behavior for both plain and fibrous high strength concretes with or without tie confinements. The volume fractions of fiber in the concrete are 0%, 0.5%, 0.75%, and 1.0%, respectively. Empirical equations are proposed herein to represent the complete stress-strain relationships of high strength and high strength fibrous concretes with compressive strength exceeding 10,000 psi. Various parameters are studied and their relationships are experimentally determined. The comparison between the experimental and analytical results shows to have …

The Influence Of Pore Fluids On Shear Strength And Stress-Strain Behavior Of Granular Soils, Prasanna Ratnaweera

Dissertations

When a dry granular soil is subjected to an external load, the stresses are transferred through mineral to mineral contacts. The shear strength of such a soil is governed by its contact properties. Presence of a thin layer of fluid between mineral to mineral contacts in a saturated soil will alter its contact properties. Therefore any change in the physical properties of pore fluid can logically be reasoned to influence the deformation characteristics of granular soils.

To investigate the influence of pore fluid viscosity on shear strength and stress-strain behavior of a soil, a series of consolidated drained triaxial tests …

The Collapse Of The Cypress Viaduct During The Loma Prieta Earthquake Of October 17, 1989, Mohamed M. Eid

Theses

The Loma Prieta earthquake of October 17, 1989 in California was one of the most disastrous earthquakes in U.S history. It caused damage to commercial, residential, and industrial structures, transportation and utilities.

This study includes investigations about the Cypress Viaduct collapse re?ported by:

1. California Governor's Board of Inquiry [4].
2. National Institute of Standards and Technology (NEL) W.
3. 3The Author.

Investigators in the first report concluded that the collapse was due to horizontal ground motion. In the second one, it was due to the vertical ground motion.

In the author's investigation, a detailed static and dynamic analyses are performed to determine …

Three-Dimensional Beam-Columns, Mohammad Hassan Shams

Theses

This thesis explores several special cases of three-dimensional beam-columns and suggests that the method of finite differences can be used when a solution of general case is required. The thesis begins with a review of the three-dimensional beam-column equations and then shows how these equations can be used to generate the member stiffness matrix for the nonlinear analysis of three-dimensional frames. Examples are included which discuss the differences between the analytical and numerical solutions.

A Modified Approach To Flood Prediction In Urban Watersheds, Joseph Ofungwu

Dissertations

The purpose of this dissertation was to develop a better method for dealing with the problems of flood prediction in Urban Watersheds. It has long been realized that urbanization activity such as increased imperviousness, drainage improvements, etc. increases runoff volumes. Therefore, traditional flood prediction methods using the Log Pearson III distribution underestimate flood frequencies when applied to urban watersheds without modification.

In attempt to compensate for the effects of urbanization on streamflow, previous workers usually employed regional analysis techniques involving a number of different watersheds at various degrees of urbanization. Results obtained by this approach leave room for improvement primarily …

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 …

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 %.

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 …

Strength And Fragility Of Concrete, Kang-Qun Shao

Theses

It is known that both strength and fragility are two of the most important properties in concrete. In this research, theories of Chemistry, Physical Chemistry of Surfaces, Thermodynamics and Fracture Mechanics are used to study the relationships between the macromechanical behavior of concrete and the microstructure in concrete. The objectives of this research are therefore to find some effective ways to explain theoretically why the concrete is so brittle (fragile) and how to increase its strength or to decrease its fragility. Based on the present studies, an equation is formulated to calculate the coefficient of the fragility (or brittleness) of …

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 …