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Full-Text Articles in Engineering

A Pilot Study On The Effects Of Temperature On The Material Properties Of Prestressed Concrete And The Use Of Thermogravimetric Analysis In The Assessment Of Heat-Affected Concrete, Kacie Caple Dec 2007

A Pilot Study On The Effects Of Temperature On The Material Properties Of Prestressed Concrete And The Use Of Thermogravimetric Analysis In The Assessment Of Heat-Affected Concrete, Kacie Caple

All Theses

An understanding of the material property changes in building materials due to exposure to a fire is needed for accurate damage assessment of a structure. Discussion pertaining to material property changes and the bond between concrete and prestressing steel following elevated temperature exposures is presented. Evaluation of the use of thermogravimetric analysis (TGA) as a post-fire analysis tool to determine the maximum temperature exposure of concrete is also included.
Heated concrete cylinders were tested to determine the compressive strength and modulus of elasticity changes of concrete. Heated steel prestressing strands were tested in tension to determine changes in the ultimate …


Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton Dec 2007

Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton

Theses and Dissertations

Half-cell potential testing has been recommended as a non-destructive method for assessing the corrosion potential of reinforcing steel in concrete bridge decks. The technique is particularly useful because it can be utilized to evaluate the probability of corrosion before damage is evident at the surface of a bridge deck. The specific objective of this research was to quantify the effects of age, chloride concentration, concrete cover thickness, spatial position, temperature, and presence or condition of epoxy coating on half-cell potential measurements of concrete bridge decks typical of those in Utah. The laboratory testing associated with this research followed a full-factorial …


Design Considerations For The Construction And Operation Of Flour Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater Jun 2007

Design Considerations For The Construction And Operation Of Flour Milling Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Flour milling facilities have been the cornerstone of agricultural processing for centuries. Like most agri-industrial production facilities, flour milling facilities have a number of unique design requirements. Design information, to date, has been limited. In an effort to summarize state of the art design procedures for flour milling facilities constructed in the United States, an overview of accepted standards and procedures has been assembled and discussed. With this paper engineers should become more familiar with specific design considerations for flour milling production facilities and develop appropriate references to expand their knowledge base. Educators may find this paper useful too.


Biomass And Coal Fly Ash In Concrete: Strength, Durability, Microstructure, Quantitative Kinetics Of Pozzolanic Reaction And Alkali Silica Reaction Investigations., Shuangzhen Wang Apr 2007

Biomass And Coal Fly Ash In Concrete: Strength, Durability, Microstructure, Quantitative Kinetics Of Pozzolanic Reaction And Alkali Silica Reaction Investigations., Shuangzhen Wang

Theses and Dissertations

Biomass represents an important sustainable energy resource, with biomass-coal cofiring representing among the most effective and cost efficient CO2 reduction strategies. Fly ash generated during coal combustion represents a technically advantageous, inexpensive, and environmentally beneficial admixture in concrete production, partially replacing cement. However, strict interpretation of American Society of Testing and Materials (ASTM) and American Concrete Institute (ACI) standards prohibits use of fly ashes from any source other than coal in concrete production; therefore, fly ash from biomass coal cofiring is excluded from use in concrete. This dissertation discusses biomass impacts on concrete properties through experiments conducted on several combinations …


Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard Mar 2007

Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard

Theses and Dissertations

Construction of tunnels and small- to medium-span bridges is a $12 billion per year industry in the United States, with a significant portion going into buried arch structures. Notwithstanding such expenditure, modern arch design and construction, in many cases, is highly conservative. This is because the closed-form solutions used by most designers today do not correctly account for soil-structure interaction. In fact, soil-structure interaction makes a closed form solution impossible. With the advent of high power computers in recent years, some designers have turned to finite element (FE)modeling as the main vehicle of analysis. Such numerical procedures provide an accurate …


Assessment Of Drucker-Prager Type Plasticity Models For Predicting The Behaviour Of Frp-Confined Concrete, T Yu, J G. Teng, Y L. Wong, S L. Dong Jan 2007

Assessment Of Drucker-Prager Type Plasticity Models For Predicting The Behaviour Of Frp-Confined Concrete, T Yu, J G. Teng, Y L. Wong, S L. Dong

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a critical assessment of the ability of existing Drucker-Prager (D-P) type plasticity models to predict the behaviour of confined concrete using both experimental observations and a recent analytical model. This assessment shows that for a D-P plasticity model to succeed in predicting the behaviour of FRP-confined and other passively-confined concrete, it needs to possess the following three features: (a) a yield criterion which includes the third deviatoric stress invariant, (b) a hardening/softening rule which is dependent on the confining pressure; and (c) a flow rule which is dependent on both the confining pressure and the rate of …


Behaviour Of Frp Strengthened Concrete Columns Under Eccentric Compression Loading, Muhammad N. S Hadi Jan 2007

Behaviour Of Frp Strengthened Concrete Columns Under Eccentric Compression Loading, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

This paper presents results of testing eccentrically loaded columns externally wrapped with two types of materials. Six cylindrical (205 mm diameter and 925 mm height) plain columns were cast and tested. Half of the columns were wrapped with GFRP and the other half with CFRP. All columns were tested by applying an axial load at 50 mm eccentricity. In each group (GFRP or CFRP wrapped) of columns, one column did not have any vertical straps, one had vertical straps made of one layer of wrapping material and one column had vertical straps made of three layers of wrapping material. All …


Behaviour Of Frp Wrapped Circular Concrete Columns Under Eccentric Loading, Muhammad N. S Hadi Jan 2007

Behaviour Of Frp Wrapped Circular Concrete Columns Under Eccentric Loading, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

The use of steel reinforcement in concrete construction has proven to be very effective due to the excellent properties that the reinforcing steel has that compliment the concrete properties, for example increase in tensile strength and ductility. However, one of the drawbacks of steel is its long-term behaviour especially in areas where the humidity is high. In such areas, the steel usually suffers from rust and oxidation which eventually lead to the deterioration of the concrete structure. One method to reduce this effect is to protect the reinforcing bars, for example wrapping or using cathodic protection. This paper investigates the …


Use Of Recycled Tire Rubber In Concrete, Purdue Ect Team Jan 2007

Use Of Recycled Tire Rubber In Concrete, Purdue Ect Team

ECT Fact Sheets

More than 250 million scrap tires weighing more than 3 million tons are generated each year in the United States. This is considered as one of the major environmental challenges facing municipalities around the world because waste rubber is not easily biodegradable even after a long period of landfill treatment. One of the solutions suggested is the use of tire rubber particles as additives in cement-based materials. Experiments under the laboratory environments commonly presented that the use of rubber in the concrete cement mix reduced drying shrinkage, brittleness, and elastic modulus, which might improve the overall durability and serviceability of …


Modelling Of High Strength Concrete Reinforced With Helical Reinforcement, Muhammad N. S Hadi Jan 2007

Modelling Of High Strength Concrete Reinforced With Helical Reinforcement, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

This paper investigates the behaviour of high strength concrete beams reinforced with helical reinforcement in the compression zone. Using helical reinforcement increases the strength and ductility of high strength concrete. The finite element packages ANSYS and Strand7 have been used to model high strength concrete beams with helical pitches of 25, 50, 75, 100 and 150 mm. Three dimensional elements were used to model the concrete and bar elements to model the steel.Special care had to be taken when modelling the helices. The results of finite element analyses were compared with experimental results which showed a good correlation.


Continuous Unidirectional Carbon Fibre-Reinforced Concrete Beams, Manouch Salehi, Muhammad N. S Hadi Jan 2007

Continuous Unidirectional Carbon Fibre-Reinforced Concrete Beams, Manouch Salehi, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

This paper reports a set of experimental results for continuous unidirectional carbonfibre-reinforced concrete beams. The fibers are embedded at different layers in thetension side of the beam below the neutral axis. All together nine concrete beamswere constructed and tested, three of which contained no reinforcement. The carbonfibre-reinforced concrete beam load-deflection results are presented graphically forthree beams with one-layer, one with two-layers and two with four-layers ofcontinuous unidirectional fibres. The maximum deflections of the reinforced beamsare compared with those of plain concrete beams.


Evaluation Of Time Independent Rheological Models Applicable To Fresh Self-Compacting Concrete, Dimitri Feys, Ronny Verhoeven, Geert De Schutter Jan 2007

Evaluation Of Time Independent Rheological Models Applicable To Fresh Self-Compacting Concrete, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-Compacting Concrete is a New Type of Concrete Which is More Liquid Compared to Traditional Concrete and Which Does Not Need Any Form of External Compaction. as a Result, This Type of Concrete is Suitable for a New Placing Technique: Pumping SCC from the Bottom in the Formwork and Letting It Rise in the Formwork Due to the Applied Pressure. in Order to Understand the Phenomena Occurring during Pumping Operations, the Rheological Properties of SCC Must Be Investigated and Controlled. Tests Have Been Performed with Two Different Rheometers, Which Are Described in This Paper. for the Tattersall MIk-II Rheometer, a …


Long-Term Effects Of Super Heavy-Weight Vehicles On Bridges, Scott M. Wood, Necip Onder Akinci, Judy Liu, Mark D. Bowman Jan 2007

Long-Term Effects Of Super Heavy-Weight Vehicles On Bridges, Scott M. Wood, Necip Onder Akinci, Judy Liu, Mark D. Bowman

JTRP Technical Reports

A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel bridge were instrumented using more than 50 sensors each. Strains and deflections were measured during a live load test, and each bridge was monitored for more …