Transfer and Development Length of Prestressing Tendons in Full-Scale AASHTO Prestressed Concrete Girders Using Self-Consolidating Concrete

Self-consolidating concrete (SCC) is a highly workable concrete that flows through densely reinforced or complex structural elements under its own weight. The benefits of using SCC include: a) Reducing labor costs by eliminating the need for mechanical vibration, b) Improving constructability, c) Providing a virtually flawless finish, d) Providing uniform and homogenous concrete, and e) Easily filling a complex shape formwork. Even though SCC is comparable to conventional concrete in terms of strength, the comparability of its bond to steel is less well-defined. This disparity of knowledge becomes more critical when using SCC in prestressed members due to the impact that bond strength has on the transfer and development lengths of prestressing tendons. The increasing interest among Illinois precasters in using SCC in bridge girders has motivated the Illinois Department of Transportation (IDOT) and the Illinois Center for Transportation (ICT) to sponsor this synthesis study, which reviews and combines information from literature discussing the impact of using SCC on the transfer and development lengths of prestressing tendons in AASHTO bridge girders. The primary objectives of this study include: (1) Utilizing the results of previous research to evaluate the effect of using SCC on the transfer and development lengths of prestressing tendons and evaluate how SCC compares with conventional concrete, (2) Investigating the feasibility of using SCC in AASHTO bridge girders without the need for changing current design provisions recommended by the ACI and AASHTO, and (3) Providing IDOT with recommendations regarding the application of SCC in prestressed bridge girders. 17. KeyICT-R27-36published or submitted for publicationis peer reviewe

Encountering design for development: An exploration of design value and ethics in practice

In recent years, there has been a turn to design practices with the promise of more human-centred outcomes. However, the value of this shift remains understudied in social change settings such as D/development. This thesis explores the distinct value of design for D/development from the standpoints of the actors closely intertwined in its projects. The discussion is grounded in understanding little-d development as ‘human flourishing’ based on the self-determined life that one would like to live. Whereas big-D Development is conceptualised as the Eurocentric post-WWII system to transition Global South countries into modernist, capitalist economies. Following a period of ‘prolonged crisis’ relating to its top-down power, outside-in knowledge flows, rigid working cultures, and questionable impact – some scholars consider Development as a ‘grand design gone sour’. Actors operating within this system are facing a challenge of reinvention. Given this backdrop, there is growing adoption of design practices in the search for, and transition toward alternatives. The discussion regarding the value of design in this thesis is grounded in understanding the act of ‘designing’ as an ontological, collaborative and social process of cultural exploration. Such acts of designing are deeply in-tune with the struggles and aspirations of human experience; and can drive the transformation of things, beings and Being. Yet, there remains limited empirical evidence regarding how encountering design is of value to actors involved in complex social change processes. Drawing on an ethnography of projects in Ghana and Kenya, as well as interviews with citizens/users, implementers, funders and designers; I argue that acts of designing can build trust, integrate knowledge, sustain ownership, enhance relevance, affirm agency, reduce risks, reorient accountability, strengthen capability, and challenge power dynamics. This makes the value of design relevant in the search for, and transition toward alternatives. However, this contribution is contingent on the navigation of a variety of ethical dilemmas. As such, this thesis elucidates how design is encountered, what kind of value it offers actors, and what is required for this value to be realised in social change settings such as Development projects

Blended Learning Is the Natural Evolution of Electronic Learning

The aim of this study was to structure a knowledge matrix, through in which to manifest the features of blended learning , its concept , success criteria, advantages and its application in university teaching , many studies have agreed that blended learning is the natural evolution of E-learning . it is perceived as a teaching – learning method which blends modern techniques and traditional methods together in specific time and place frames, within normal environmental classroom teaching circumstances, in which the teacher and the student interact, each one according to his role and the requirements of the teaching situation, with the least possible cost in order to reach the teaching outcomes with high com pretence and quality. It appeared that the process of blending between different teaching methods does not occur in a random or moody way, but in an organized homogeneous scientific method , which is governed by several criteria and controls related to the requirements of the teaching situation . Therefore , the blended learning success criteria in its excellent aims , teachers and students good performance, excellent instructional content ,perfect infers and technical stature , provision of financial potentials societal mobilization. The obstacles which hinder the application of blended learning are centered around the high financial cost of the inputs of such kind of learning, the low level of education experience and skill of some teachers and students in dealing seriously with information and communication technology and teaching technology. The study concluded by emphasizing the importance of reconsidering the inputs of the instructional process and the procedures of its implementation in order to cope with the concept of electronic and technological revolution employ its basics to achieve the requirements of current stage , pursue novelty , persuade individuals that change and development are a modern necessity. Keywords: blended learning, electronic learning, university teaching, technological revolutio

The Cyclic Loading of Normal Concrete in a Specific Stress Range

This research presents a study about the effect of static cyclic loading at compression on the properties of normal concrete, which are: the modulus of elasticity, the compressive strength and the ultimate strain. The static cyclic loading of concrete is achieved by loading-unloading-reloading at compression, for a short duration, in a specific stress range and for a few number of cycles. Experimental program includes tests for sixteen concrete specimens with maximum compressive strength 30 MPa. Twelve of the specimens are tested under a static cyclic loading, at the stress range (40 to 80) percent of the maximum compressive strength. The four remaining specimens are tested under uniaxial loading till failure. The cyclic loading is carried out for a few number of cycles, which is determined with (5, 10, 15, 20) cycles. Analytical part of this study is based on mathematical formulations for the stress-strain response, which are developed from the test results, in order to get the properties of concrete. A comparison between the properties of concrete in the two cases of loading (cyclic and uniaxial), is carried out. The results show an obvious improvement in the properties of concrete under cyclic loading, when achieved in the specific stress range (40 to 80) percent of the maximum strength, and for the number of cycles 15 or 20 cycles. The improvement in the properties of normal concrete under cyclic loading is the fundamental for the application of this kind of loading on High-Strength concrete. Hence, the cyclic loading causes an increase in the ultimate strain of normal concrete, so it may be of greater efficacy in High-Strength concrete

Design for development management

Due to the evolving role of development organisations over the years, critical questions are being asked of their accountability and performance throughout the development literature. The complexity of the challenges these organisations are facing are accelerating faster than can be addressed with traditional, analytically based management approaches. The design community has much to say on how it can play a more significant role in this context. Consolidating an in-depth literature review with applied, hands-on and in-the-field experience, we propose new perspectives on how more human-centred design approaches assist development organisations. Particularly, how these organisations may achieve greater social accountability by moving beyond quantitative measures in defining and delivering initiatives to address real human needs. In addition we extend Buchanan's 2001 seminal body of work which introduced the role of human centred design as affirming human dignity through the empowering of people and communities to engage in decisions that work for them rather than being recipients of external and sometimes misaligned "solutions" to them. Our work is relevant to a mixed audience comprised of designers, development managers, donor organisations, and other actors involved in the design of new futures for marginalised populations in developing countries

Wireless Energy Harvesting with Amplify-and-Forward Relaying and Link Adaptation under Imperfect Feedback Channel

Energy harvesting is an alternative approach to extend the lifetime of wireless communications and decrease energy consumption, which results in fewer carbon emissions from wireless networks. In this study, adaptive modulation with EH relay is proposed. A power splitting mechanism for EH relay is used. The relay harvests energy from the source and forwards the information to the destination. A genetic algorithm (GA) is applied for the optimisation of the power splitting ratio at the relays. Two scenarios are considered namely, perfect and imperfect feedback channels. Results show that the spectral efficiency (SE) degradation, which is due to an imperfect feedback channel, was approximately 14% for conventional relays. The use of energy harvesting results in a degradation in the performance of SE of approximately 19% in case of a perfect feedback channel. Finally, an increase in the number of energy harvesting relays enhances the SE by 22%

Social Communication Networks the Most Powerful Present at the Service of Education

This study aimed at building up a knowledge matrix in which the features of the pictures of social communication networks, their concept, most famous ones and their role in serving teaching are revealed. They are web sites and different and various software's which allow people to interact around an idea , a piece of information , a topic or a certain aim .Any educational institution , for example , can initiate blogs or electronic sites specific for them . They allow their students to have access to communication and writing in them about their affairs, interests and educational activities. Social networks have been designed as a new communication language for internet users in society in order to overcome the factors of both place and time cope with current novelties, strengthen social relationships between users to break the barrier of some individuals social isolation, create opportunities for knowledge interactivity and communication and keep up with the huge amount of information, in a way that has increased the desire for learning. Social communication networks are important information media which have recently spread and played political, economic, social and educational roles in the world as are the case in the USA and china. The role of social communication networks (new media) is no longer confined to communication with friends, exchange of social and political debates and spread of beliefs, but their role exceed them .Many companies started to use these sites for marketing their products for communicating with the target crowd. Governments used them for spreading data, information, news and receiving views and comments from people. However, some people disagree with the idea of using and incorporating some sites of social networks in education as this does not allow equal learning opportunities and makes the learns thinking mechanic and addict to the computer some government like Germany and china expressed their concern about the use of face book, twitter and you tube sites because it violates the private and public rights of students personal files. The study concluded the emphasis on the importance of informational revolution and benefit from their various sites and networks and their current and future effects, especially in educational and teaching fields by encouraging governments to pass legislations on those sites to protect their citizens from the risks and disadvantages of those social networks. People of businesses and companies also should think of solutions such as the use of-Search drives- more specialized Arabic social and scientific network to enrich users scientifically and socially. Keywords: Network, Social communication, Electronic sites, Blogs, Electronic learning

Lateral impact response for prestressed concrete girder bridges with intermediate diaphragms

Bridge engineers are concerned with the impact damage produced by an over-height vehicle striking the girders of a prestressed concrete (PC) girder bridge. When a bridge is struck by an over-height vehicle, usually the exterior and in some instances one or more of the remaining girders are damaged. The effect of intermediate diaphragms in providing damage protection to the PC girders is not clearly understood. This thesis discusses an analytical study that evaluates the degree of damage protection provided by intermediate diaphragms in PC girder bridges. Also, the study investigated whether a steel intermediate diaphragm would essentially provide the same degree of demage protection as that provided by a particular RC diaphragm. This investigation includes several tasks. The first task was a literature search and a survey of the states departments of transportation to determine the state-of-the-art in the use and design of intermediate diaphragms for resisting lateral impact loads. The second task was a finite-element calibration study that involved strains and displacements of previously documented experimental work and those results predicted by a finite-element analysis. The third task involved finite-element models that were developed for a non-skewed bridge and a skewed bridge. Each model was analyzed with either one RC or two different types of steel intermediate diaphragms. The bridge models were analyzed for a lateral impact load applied at different locations along the bottom flange of an exterior girder. A comparison was made between the induced strains and displacements in the girders for each diaphragm case. This study revealed that intermediate diaphragms have an effect on reducing girder damage in PC girder bridges. When a lateral impact load was applied at a diaphragm location, the RC diaphragm provided more damage protection for the girders than that provided by either of the two selected steel diaphragms. The three types of diaphragms studied essentially provided the same degree of damage protection when a lateral impact load was applied away from a diaphragm location

Exploring the influence of Design Thinking tools on the accountability of decision makers in aid projects

There is continued criticism regarding the over-reliance on rational, linear and quantitative management approaches by decision makers of aid projects within Non-Governmental Organisations (NGOs). Such approaches have led to accountability efforts being primarily directed to donors with limited participation from beneficiary populations. There is an increasing interest in Design Thinking by decision makers as an approach to support more beneficiary-centred accountability in projects. However, there is limited understanding about whether Design Thinking tools can influence the accountability of decision makers. Accountability can be conceptualised as `felt' accountability which privileges the internal motivations and virtue of decision makers; and as 'imposed' accountability which privileges formal, coercive and compliance-based mechanisms on decision makers. The objective of this thesis was to understand whether specific Design Thinking tools can influence the `felt' accountability of decision makers in aid projects. To achieve this, the thesis explored two case studies in Ghana and in UK/Lebanon. The research methods involved participatory action research during the projects, followed by semi-structured interviews with key decision makers after project completion. The analysis was conducted by a combination of manual processes and NVivo software. The analysis revealed decision makers perceived two specific tools, being personas and Journey maps, as having influenced their `felt' accountability. There are four emergent factors that suggest how the tools may be contributing to the `felt' accountability of decision makers: this is firstly by building a shared picture among diverse groups, secondly by humanising complex information, thirdly by grounding discussions in realities, and lastly by deepening empathy and connection between decision makers and beneficiaries. This is the first study to suggest that the inclusion of Design Thinking tools can influence, and even enhance the `felt' accountability of decision makers towards beneficiaries. However, more research is needed to test these suggestive findings