Engineering Commons^™

Optimum Design Of A Pultruded Frp Bridge Deck., Hyeong-Yeol Kim, Young-Min Choi, Yoon-Koog Hwang, Hyo-Nam Cho

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

In this paper, an optimum design of GFRP bridge deck having a pultruded cellular cross-section is presented. The optimization process utilizes a modified genetic algorithm with the index technique. Based on the optimum design, viable cross-sectional dimension, volumes of fibers and matrix, fiber orientation, and stacking sequence for GFRP decks suitable for the pultrusion process are proposed.

The Evolution Of Best Practices With High Performance Steel For Bridges, Edward P. Wasserman, W. Henry Pate, Tim Huff

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

High Performance Steel, grade 70 (HPS-70W) became available for use in early 1996 for fabrication and testing in bridges. Two (2) states, Nebraska and Tennessee agreed to be the first to implement usage. This paper provides a discussion of 3 Tennessee case histories in which high performance steel has been used to achieve weight and cost economies.

Variable Engagement Model For The Design Of Fibre Reinforced Concrete Structures, Jackie Yen Lei Voo, Stephen J. Foster

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

In this paper a model is developed to describe the behaviour of randomly orientated discontinuous fibres in reinforced composites subject to uniaxial tension. The model is built by integrating the behaviour of single, randomly oriented, fibres over 3D space and is capable of describing the peak and post-peak response of fibre-cement-based composites in tension. The model is used to form a constitutive law for use in finite element analysis of reactive powder concrete members with a prestressed reactive powder beam failing in shear analysed. A good correlation between the theoretical and experimental results attained.

The Effect Of Aggregate Particle Size On Formation Of Geopolymeric Gel, Christine Isabella , Grant C. Lukey, Hua Xu, Jannie S.J. Van Deventer

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

Due to enhanced mechanical and chemical properties, geopolymeric materials are a potential alternative to ordinary Portland cement and high-strength cement for the construction industry. The effects of aggregate particle size on the formation and the mechanical properties of geopolymeric materials are investigated in the current work. The addition of soluble silicates to the alkaline activator was found to increase the dissolution of silicate ions from the aggregate into the geopolymer binder phase. The results indicate that the surface area of aggregate influences the strength development of a geopolymer.

Histar High Performance Hot-Rolled Beams, Lucien Weber

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

The construction industry is continuously looking for superior building components. Innovative production processes are, in combination with tight quality control, the keys to structural steel grades with outstanding properties. Especially the thermomechanical treatment allows for combining material properties which were formerly thought to be incompatible: high yield strength for big material thicknesses, good toughness and excellent weldability.

This paper presents the Quenching and Self-Tempering (QST) process which allows for the production of heavy hot-rolled H-beams in high strength structural steel grades with excellent weldability characteristics. The new steel grades fully comply and even exceed the requirements of the European and …

High Performance Steel For Highway Bridges, Vasant C. Mistry

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

All steels possess a combination of properties that determines how well steel performs. Strength, weldability, toughness, ductility, corrosion resistance, and formability are all important to determine how well steel performs. High-performance steel (HPS) can be defined as having an optimized balance of these properties to give maximum performance in bridge structures while remaining cost-effective.

Seismic Evaluation Of R/C Buildings Using High Performance Materials, Dimitrios Konstantinidis, Andreas J. Kappos

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

The performance of reinforced concrete (R/C) buildings made of high performance materials (HPM) in seismic areas is evaluated through the parametric analysis of twenty-two buildings designed and detailed according to the current (prEN) version of Eurocode 8, for ductility classes (DC) ''Medium'' and ''High'', in combination with the current (prEN) version of Eurocode 2. Seismic assessment of the buildings is carried out by means of nonlinear static (pushover) analysis and nonlinear dynamic (time-history) analysis.

Interface Behaviour In Frp Plates Bonded To Concrete: Experimental Tests And Theoretical Analyses, Ciro Faella , Enzo Martinelli, Emidio Nigro

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

Simplified models for simulating FRP-to-concrete interface behavior are introduced and empirical relationships are utilized for their calibration. Moreover, the results of pull-out tests on FRP-to-concrete joints are presented. They are utilized in calibrating a bilinear shear-stress-to-interface-slip relationship by means of an inverse identification procedure.

Seismic Performance Of Precast Column-Foundation Connection Assembled By Post-Tensioning, Minehiro Nishiyama, Fumio Watanabe

Advanced Materials for Construction of Bridges, Buildings, and Other Structures III

In order to develop design recommendations for column-foundation connection assembled by post-tensioning in seismic regions, cyclic loading tests were carried out on 14 test units simulating such kind of connections under earthquake loading. The tests were consisted of two series: Series A was mainly for comparison between precast reinforced and precast prestressed concrete column-foundation connections, and Series B for investigating differences between test units with grouted and ungrouted tendons. The main experimental parameter other than the above was an axial load level.

Finite Element Modelling Of Moisture Movement In Concrete Floors, Niall Holmes, Roger West

Conference papers

Predictive methods for determining the point at which it is safe to apply floor coverings to concrete floors can save time and money for the client, contractor and the floor installer. The current standard states that impervious floor coverings should not be applied until the surface of the floor reaches a relative humidity (RH) of 75%, established using a surface hygrometer test. Tests at Trinity College Dublin on drying concrete slabs in natural and forced drying environments show that there is a large variation in the residue of moisture deep in the concrete when the floor covering is applied, particularly …

Aisi Manual Cold-Formed Steel Design 2002 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Specifications for the Design of Cold-Formed Steel Structural Members. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel design. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. With anticipated improvements in understanding of the behavior of cold-formed steel and the continuing development of new technology, this material may eventually become dated. It is anticipated that AISI will …

Cold-Formed Steel Design Manual, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by the American Iron and Steel Institute Committee on Specifications for the Design of Cold-Formed Steel Structural Members. The Committee has made a diligent effort to present accurate, reliable, and useful information on cold-formed steel design. The Committee acknowledges and is grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject.

With anticipated improvements in understanding of the behavior of cold-formed steel and the continuing development of new technology, this material may eventually become dated. It is anticipated that AISI will …

Acuta Enews September 2003, Vol. 32, No. 9

ACUTA Newsletters

In This Issue

32nd Annual Conference Highlights

ACUTA Members' Needs and Preferences................ Jeri Semer, CAE, Executive Director

ACUTA Board Report Carmine Piscopo, Providence College

Provisioning: lt Really Has Nothing To Do with Vitttes................. Kevin Tarzillo, Dux Public Relations

New Additions to Telecommunications Relay Services (2).................. Dave Ostrom, Washington State Univ

Winners, Winners, Winners!

DC Update................ Whitney Johnson, Retired, Northern Michigan Univ

ACUTA Member Sites to See

Welcome Mew Members

Ict Adoption And Impact On The Italian Logistics Service Providers’ Performance, Pietro Evangelista, Riccardo Mogre, Alessandro Perego, Antonino Raspagliesi, Edward Sweeney

Conference papers

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 20, Number 1, September 2003, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Achieving Airtight Ducts In Manufactured Housing, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

Data and findings presented here were gathered between 1996 and 2003 during 39 factory visits at 24 factories of six HUD Code home manufacturers interested in improving the energy efficiency their homes. Factory observations typically showed that building a tighter duct system was the most cost effective way to improve the product's energy efficiency.

Interval Arithmetic, Affine Arithmetic, Taylor Series Methods: Why, What Next?, Nedialko S. Nedialkov, Vladik Kreinovich, Scott A. Starks

Departmental Technical Reports (CS)

In interval computations, the range of each intermediate result r is described by an interval [r]. To decrease excess interval width, we can keep some information on how r depends on the input x=(x1,...,xn). There are several successful methods of approximating this dependence; in these methods, the dependence is approximated by linear functions (affine arithmetic) or by general polynomials (Taylor series methods). Why linear functions and polynomials? What other classes can we try? These questions are answered in this paper.

Moisture Re-Distribution In Concrete Under Impermeable Coverings, Niall Holmes

Conference papers

It is normally considered safe to apply an impermeable floor covering to concrete surfaces when the surface relative humidity reaches 75% as determined by a surface hygrometer. However, over time, defects can appear on the covering such as blistering of vinyl and rising of tiles from the surface. One cause is the on-going diffusion of the residual moisture deep within the slab to the surface. The covering traps this residual moisture, thus preventing evaporation to the ambient air and gradually generates a vapour pressure underneath the covering, which can result in damage.

Here, experimental results on the long-term influence of …

Finite-Temperature Anisotropy Of Ptco Magnets, Ralph Skomski, Arti Kashyap, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

The temperature dependence of the magnetocrystalline anisotropy of PtCo and its atomic origin are investigated by first-principle and model calculations. The Pt spin moment necessary to realize the leading 5d anisotropy contribution is due to neighboring Co atoms. At finite temperatures, Co spin disorder strongly reduces the Pt moment and the anisotropy. This is in contrast to the situation encountered in 3d and 3d–4f magnets, where the atomic magnetic moments remain largely conserved, even above the Curie temperature. A consequence of the L1₀ mechanism is that theK₁ (T) curve of exhibits a negative curvature, in contrast to the …

A Full Function-Based Calculus Of Directed And Undirected Intervals: Markov's Interval Arithmetic Revisited, Juergen Wolff Von Gudenberg, Vladik Kreinovich

Departmental Technical Reports (CS)

This paper proposes a new interpretation of intervals as classes of functions having the same domain. Interval operations are seen as operations on these classes. This approach allows to recover Markov's directed interval arithmetic by taking into account the monotonicity of the functions.

A Feasible Algorithm For Locating Concave And Convex Zones Of Interval Data And Its Use In Statistics-Based Clustering, Vladik Kreinovich, Eric J. Pauwels, Scott Ferson, Lev Ginzburg

Departmental Technical Reports (CS)

Often, we need to divide n objects into clusters based on the value of a certain quantity x. For example, we can classify insects in the cotton field into groups based on their size and other geometric characteristics. Within each cluster, we usually have a unimodal distribution of x, with a probability density d(x) that increases until a certain value x0 and then decreases. It is therefore natural, based on d(x), to determine a cluster as the interval between two local minima, i.e., as a union of adjacent increasing and decreasing segments. In this paper, we describe a feasible algorithm …

Impacts Of Columbia River Discharge On Salmonid Habitat: 2. Changes In Shallow-Water Habitat, David A. Jay, Tobias Kukulka

Civil and Environmental Engineering Faculty Publications and Presentations

This is the second part of an investigation that analyzes human alteration of shallow-water habitat (SWH) available to juvenile salmonids in the tidal Lower Columbia River. Part 2 develops a one-dimensional, subtidal river stage model that explains ~90% of the stage variance in the tidal river. This model and the tidal model developed in part 1 (Kukulka and Jay, 2003) uncouple the nonlinear interaction of river tides and river stage by referring both to external forcing by river discharge, ocean tides, and atmospheric pressure. Applying the two models, daily high-water levels were predicted for a reach from rkm-50 to rkm-90 …

The Estimation And Control Of A Laboratory Heating And Ventilation System, Robin P. Mooney

Masters in Advanced Engineering

This dissertation is concerned with the estimation and control of a laboratory heating and ventilation system (Instrutek VVS-400). The system is a 2x2 multi-input multi-output process (MIMO). It has been shown that simple techniques such as the ultimate cycle method do not provide adequate control of the process. The system was interfaced with a PC using Matlab/Simulink via a data acquisition package (Humusoft). Continuous time process identification techniques were applied to the flow and temperature processes. The alternative tangent and point method was used to model the processes, and their interaction, using a first order lag plus delay model. Models …

Identification And Pid Control Of Time-Delayed Processes, Tony Kealy

Masters

This research was conducted primarily to investigate a selection of known methods for the identification of a mathematical model for processes with an inherent time delay, and subsequently, use the parameters of the identified model to regulate the processes via the PI/PID control strategy. The research examines the level of difficulty in performing or sanctioning different system identification methods in order to re-tune the controller. The process model identification methods are carried out on both simulated and real processes in the first part of the research. The selected parametric identification methods are chosen because they encompass open- and closed- loop …

A Full-Wave Investigation Of The Use Of A 'Cancellation Factor' In Gw-Airglow Interaction Studies, Yonghui Yu

Master's Theses - Daytona Beach

Atmospheric gravity waves (GWs) perturb minor species involved in the chemical reactions of airglow emissions in the mesopause region of the earth's atmosphere. The so-called 'Cancellation Factor' (CF) is defined as a transfer function relating the amplitude of airglow brightness fluctuation to the amplitude of GW-induced fluctuation in temperature [Swenson and Gardner, 1998]. This transfer factor can be used to determine GW fluxes and the forcing effects of GWs on the mean state through airglow observations, because GW fluxes are proportional to the square of GW amplitude.

Numerical models [Walterscheid et al., 1987; Schubert et al., 1991] have previously shown …

Use Of Pulsed-Uv Processes To Destroy Ndma, Sun Liang, Joon H. Min, Marshall K. Davis, James F. Green, Donald S. Remer

All HMC Faculty Publications and Research

About five years ago, N-nitrosodimethylamine (NDMA) began to be detected in drinking water sources. Typically an oxidative degradation product of unsymmetrical dimethylhydrazine, NDMA is a component of rocket fuel and is also formed during numerous industrial manufacturing processes as a byproduct of reactions involving chemicals called alkylamines. The US Environmental Protection Agency has identified NDMA as a probable human carcinogen. However, because NDMA had not historically been considered a common drinking water contaminant, no federal or state drinking water standards were established for it until 1998 in California. In addition to its presence in drinking water, it has recently been …

Engineering Is Fun - Let's Celebrate, Jim Mcgovern

Articles

In this news article the author outlines why the Faculty of Engineering at DIT and all its professional engineering graduates have cause to celebrate 50 years of engineering at DIT from September 2003.

An Examination Of Eu Directive 98/76/Ec In Regards To The Irish Road Haulage Industry, Eoin Plant, Declan Allen, Edward Sweeney

Conference papers

The Irish economy experienced a tremendous increase in economic growth during the 1990s and early 21st Century (Celtic Tiger). This economic boom was export driven and the Irish Road Haulage Industry transported the majority of products produced at some stage, if not a number of stages in the logistics tunnel. In recent times there has been somewhat of a growing unease in the road haulage industry in relation to increasing costs, squeezing already tight profit margins. A report commissioned by the Department of Public Enterprise illustrated that 48% of hauliers identified themselves as needing training in the area of cost …

North American Design Guidelines For Concrete Reinforcement And Strengthening Using Frp: Principles, Applications And Unresolved Issues, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper reports on the North American state-of-the-art in the use of FRP composites in concrete structures. for new construction, FRP bars have been used as the internal reinforcement in concrete members to replace conventional steel rebars for a host of reasons. the principles for design and construction have been established and proposed to industry by the American Concrete Institute (ACI). for repair and upgrade, strengthening of concrete members with externally bonded FRP laminates or near surface mounted (NSM) bars has received remarkable attention. the design and construction principles for use in practice are being finalized by ACI. on the …

Enhanced Retention In The Passive-Avoidance Task By 5-Ht1a Receptor Blockade Is Not Associated With Increased Activity Of The Central Nucleus Of The Amygdala, Allen M. Schneider, Emily Wilkins , '01, Aaron Alexander Firestone , '01, E. Carr Everbach, J. C. Naylor, Peter E. Simson , '78

Psychology Faculty Works

The effect of blockade of S-HT1A receptors was investigated on (1) retention in a mildly aversive passive-avoidance task, and (2) spontaneous single-unit activity of central nucleus of the amygdala (CeA) neurons, a brain site implicated in modulation of retention. Systemic administration of the selective S-HT1A antagonist NAN-190 immediately after training markedly-and dose-dependently-facilitated retention in the passive-avoidance task; enhanced retention was time-dependent and was not attributable to variations in wattages of shock received by animals. Systemic administration of NAN-190 had mixed effects on spontaneous single-unit activity of CeA neurons recorded extracellularly in vivo; microiontophoretic application of S-HT, in contrast, consistently and …