Engineering Commons^™

Bond Strength And Transfer Length Of Pre-Tensioned Bridge Girders Cast With Self-Consolidating Concrete, Amgad F. Morgan Girgis, Christopher Y. Tuan

Civil Engineering Faculty Publications

Self-consolidating concrete (SCC) is becoming increasingly popular in the precast/prestressed concrete industry in the United States. However, there have been concerns regarding the bond strength, transfer length, and development length of prestressing strands and mild steel reinforcement with SCC. Further, there are no design guidelines for using SCC. In this study, a literature survey on the bond strength of SCC was conducted. Moustafa pullout tests were performed to determine the bond strength of 0.6 in. (15.2 mm) pretensioning strands with sec. The transfer lengths of three pretensioned concrete bridge girders were measured using Demec points. Pullout tests were also performed …

Evaluation Of The Use Of Lithium Compounds In Controlling Alkali-Silica Reactivity In Concrete Pavement, Christopher Y. Tuan, Michael T. Kelly, Mark E. Buss

Nebraska Department of Transportation: Research Reports

No abstract provided.

Evaluation Of Microwave Reflection Properties Of Cyclically Soaked Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, K. E. Kurtis, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Detection of chloride ingress and evaluation of its distribution and temporal movement in reinforced concrete structures is an important practical issue. Steel reinforcing bars embedded in good quality concrete are normally protected from corrosion. However, the presence of a sufficient concentration of free chloride ions in the region of the reinforcing steel can initiate the process of corrosion. Therefore, it is important to be able to detect ingress of chloride ions and their distribution in cement-based materials. Moreover, it is important to obtain this information nondestructively. In recent years, near-field microwave nondestructive evaluation methods, using open-ended rectangular waveguide probes, have …

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

Kurt A. Rosentrater

Malt production facilities are the producers of ingredients for our baking, beverage, and specialty food industries. To date, information about the unique design requirements of these facilities has been limited. In an effort to summarize state of the art design procedures for malting facilities constructed in North America, an overview of accepted standards and procedures has been assembled. With this paper engineers should become more familiar with specific design considerations for malting plants and develop appropriate references to expand their knowledge base. Educators may find this paper useful too.

Properties Of Concrete Mixtures Incorporating Magnetized Water, Mohamed Abdel Raouf Metwally

Archived Theses and Dissertations

Water is a vital constituent that controls much of concrete properties such as strength and workability. Water is added to concrete in the form of a liquid at ambient temperature. However, it is occasionally added in the form of hot water in freezing conditions or in the form of ice/chilled water in hot weathering conditions. Recently, work has been conducted to magnetize water to adequate level before being incorporated in concrete. Indications show that some improvements can occur to concrete made with magnetized water. However, there is scarcity of data as to how such magnetized water can influence the properties …

Nonlinear Model For Reinforced Concrete Under Cyclic Loading, Aly Said, M. Elmorsi, M. Nehdi

Civil and Environmental Engineering and Construction Faculty Research

Most of the available shear models for reinforced concrete rely on empirical formulations. In this study, a rational shear stress function is used to define the shear stress–strain envelope for reinforced concrete. Cyclic rules are proposed to define the loading, unloading and reloading relationships for reinforced concrete under shear stress reversals. A normal stress function describing the cyclic relationship of concrete under axial stress is also introduced. The proposed functions are verified using experimental data of reinforced concrete panels tested under monotonic and cyclic loading. Subsequently, the normal and shear stress functions along with their cyclic rules are integrated in …

Behavior Of Structural Concrete Members Strengthened By Composite Fabrics, Jian Chen

Dissertations

The new technique of using Fiber Reinforced Polymer (FRP) materials to repair and strengthen various concrete members is becoming more and more popular in structural retrofitting field. Among all the confining materials, Carbon Fiber Reinforced Polymer (CFRP) fabric jackets are identified as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. This study investigates the detailed structural behavior of confined concrete members using CFRP fabric jackets by both analytical and experimental approaches.

A series of CFRP wrapped concrete cylinder tests were conducted to study the compressive stress-strain behavior for CFRP confined …

Investigation Of Fibre Reinforcing The Cover Of Concrete Columns, Muhammad N. S Hadi, Denis Montgomery

Faculty of Engineering - Papers (Archive)

This paper explores the effects of adding synthetic reinforcing fibres to highstrength reinforced concrete columns and in particular only to the cover of the columns. An experimental program was conducted where seven circular reinforced concrete columns were tested with varying fibre content-one contained no fibres, two contained fibres throughout the cross-section and four contained fibres only in the outer concrete. The other column properties were kept the same for all the seven columns. All seven columns were tested by the application of a concentric, axial compression force. It was found that although only minor improvements were noticeable for a fibre …

Composite Action Of Structural Steel Beams And Precast Concrete Slabs, Brian Uy, M. A. Bradford

Faculty of Engineering - Papers (Archive)

The innovative composite behavior between structural steel beams and precast concrete slabs for multi-storey buildings is discussed. The issues that need to be resolved in order to establish composite behavior as well as suggestions for future course of action are highlighted.

Modelling Shearing Characteristics Of Reinforced Concrete, Hossein Jalalifar, Najdat I. Aziz, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

Numerical modeling represents the most versatile computational method for various engineering disciplines. Nowadays, numerical modelling is extensively used in civil and mining applications because of cost and risk problems associated with excessive field studies, particularly in ground control applications. In this study, the behaviour of shearing a fully grouted bolt with regard to assessing strata reinforcement (particularly in shearing) has been simulated. In addition, the effect of both different rock strength and different pretensioning levels with 3D numerical simulation are analysed. It was found that the strength of surrounding material contributed to the increased resistance of the installation and has …

Fibre Reinforcing Concrete Columns, Muhammad N. S Hadi, Denis Montgomery

Faculty of Engineering - Papers (Archive)

This paper explores the effects of adding steel fibres to high-strength reinforced concrete columns and in particular only to the cover of the columns. An experimental program was conducted where seven circular reinforced concrete columns were tested with varying fibre content - one contained no fibres, three contained fibres throughout the cross-section and three contained fibres only in the outer concrete. The other column properties were kept the same for all the seven columns. All seven columns were tested by the application of a concentric, axial compression force. It was found that although only minor improvements were noticeable fora fibre …

Composite Steel-Concrete Beams And Columns Fabricated With High Strength Steel (Hss) Plate, Brian Uy

Faculty of Engineering - Papers (Archive)

High strength quenched and tempered structural steel has seen widespread implementation in heavily loaded columns in multistorey building construction. However, many current international codes do not cater for the use o f high strength steel and thus much needed research is required to give structural engineers the confidence to use this new and innovative material in a safe and efficient manner in construction. Herein, experiments and analytical studies on composite steel-concrete composite beams and recommendations for modified . design procedures will be summarised. This paper will also provide a comprehensive summary of experimental results on the uses of high strength …

Strength Of Concrete-Filled Steel Box Columns With Local Buckling Effects, Qing Quan Liang, Brian Uy, J. Y. Richard Liew

Faculty of Engineering - Papers (Archive)

The key aspects and features of a nonlinear fiber element analysis method for predicting the strength and behavior of concrete-filled steel box columns with local buckling effects are discussed. The methods is quite useful in predicting the ultimate strengths and behavior of concrete slabs and can also be employed in the advanced analysis of composite frames.

The Effect Of Resin Thickness On Bolt-Grout-Concrete Interaction In Shear, Najdat I. Aziz, Jalalifar Hossein, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

Numerical modelling is extensively used in civil and mining engineering applications because of cost and risk problems associated with different experimental studies. In this study, the effect of resin thickness was evaluated in bolt-grout-concrete interaction and bending behaviour of a fully grouted bolt installed across joints in post failure region. Tests were conducted in 20 and 40 MPa concretes, and modelling simulations were made, using ANSYS version 8.1, to include both with and without different pretension loads. It was found that in all resin thickness, both the strength of the concrete and bolt pretension had major influences on the shear …

Structural Condition Assessment Of Prestressed Concrete Transit Guideways, Robert Zachary Shmerling

Electronic Theses and Dissertations

Objective condition assessment is essential to make better decisions for safety and serviceability of existing civil infrastructure systems. This study explores the condition of an existing transit guideway system that has been in service for thirty-five years. The structural system is composed of six-span continuous prestressed concrete bridge segments. The overall transit system incorporates a number of continuous bridges which share common design details, geometries, and loading conditions. The original analysis is based on certain simplifying assumptions such as rigid behavior over supports and simplified tendon/concrete/steel plate interaction. The current objective is to conduct a representative study for a more …

Effect Of Helical Pitch And Tensile Reinforcement Ratio On The Concrete Cover Spalling Off Load And Ductility Of Hsc Beams, Nuri M. Elbasha, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

[extract] In recent years a marked increase in the use of High Strength Concrete (HSC) has been evident in Australian building construction despite the fact that the current Australian design standard, AS3600 provides no design rules. HSC has been used extensively in civil construction projects world wide because it reduces the cross section and the weight for long construction members.

High strength concrete and high strength steel are used together to increase the load capacity and reduce the beams' cross section. Using these two materials to design over reinforced beams will lead to huge reduction of cost, which is a …