Prestressed Composite Section Design

Prestressed Composite Section Design

The design of a composite section depends upon the type of composite section, the
stages of prestressing, the type of construction and the loads. The type of construction
refers to whether the precast member is propped or unpropped during the casting of
the CIP portion. If the precast member is supported by props along its length during the
casting, it is considered to be propped. Else, if the precast member is supported only at
the ends during the casting, it is considered to be unpropped.

The advantages of composite construction are as follows.
1) Savings in formwork
2) Fast-track construction

3) Easy to connect the members and achieve continuity.

The prestressing of composite sections can be done in stages. The precast member
can be first pre-tensioned or post-tensioned at the casting site. After the cast-in-place
(cast-in-situ) concrete achieves strength, the section is further post-tensioned.
The grades of concrete for the precast member and the cast-in-place portion may be
different. In such a case, a transformed section is used to analyse the composite

section.

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The Latest Methods of Construction Design

The Latest Methods of Construction Design

,Karel Petr, František Lopot
Martin Dub

Preference :

The book “The Latest Methods of Construction Design” has been created on the
basis of contributions of the 55th International Conference of Machine Design
Departments. This book is a follow-up to an earlier very successful book “Modern
Methods of Construction Design.”
This conference is one of the oldest central conferences, dealing with methods
and applications in the machine design. The main aim of the conference is to
provide an international forum where experts, researchers, engineers, and also
industrial practitioners, managers, and PhD students can meet, share their experiences,
and present the results of their efforts in the broad field of machine design
and related fields.
In the year 2014, the Department of Designing andMachine Components, Faculty
of Mechanical Engineering, Czech Technical University in Prague, whose members
deal above all with machine design, experimental methods and measuring, engineering
analyses, and products innovation, organized the 55th International Conference of
Machine Design Departments on the occasion of 150th anniversary of Faculty of
Mechanical Engineering (CTU in Prague). The mountain town of Beroun in Central
Bohemia was chosen for this celebratory event.
Since 1960, when the first conference was organized in Melnik by Brno University
of Technology, more than 50 years have passed. The main aim of the
conference was to providing an opportunity for professional experiences sharing
in the field of machine design, gears, and transmission mechanisms. The heads of
Mechanical Design Departments decided to organize these conferences annually
first at the national and later at the international level. The significance of the
conference has grown. Historically, the conferences were organized in different
places by different mechanical design departments of Czech and Slovak technical
universities:

The Latest Methods of Construction Design

Content :

• Machine Design
• Tribology
• Hydraulics – Fluid Mechanisms
• Engineering Analyses
• Modern Material and Technology
• Optimization and Design
• Product Innovation
• Experimental Methods and Measuring

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Mechanical Damage and Crack Growth in Concrete

Mechanical Damage and Crack Growth in Concrete

Alberto Carpinteri

Preference :

Fracture mechanics technology has received considerable attention in recent years and has advanced to the stage where it can be employed in engineering design to prevent against the brittle fracture of high-strength materials and highly constrained structures. While research continued in an attempt to
extend the basic concept to the lower strength and higher toughness materials, the technology advanced rapidly to establish material specifications, design rules, quality control and inspection standards, code requirements, and regulations for safe operation. Among these are the fracture toughness testing procedures of the American Society of Testing Materials (ASTM), the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Codes for the design of nuclear reactor components, etc.

Structural elements can fail in many different ways. The ultimate load condition may be reached by a combination of plastic flow, slow or fast crack propagation, depending on the material strength, ductility and toughness, and the size of the structural components. Highly constrained and/or
brittle materials may result in sudden crack formation and unstable crack propagation, whereas less constrained and/or more ductile materials are more likely to fail progressively by plastic yielding. In those situations, the presence of initial cracks do not play an important role in the failure process.
In many cases, however, the terminal condition is preceded by slow crack growth that continues even into the stage of global structure failure. There are other situations where slow crack growth may occur simultaneously with plastic flow and the final failure can still be catastrophic.
The current fracture mechanics literature contains a multitude of ideas, concepts, and criteria, that are not always consistent one with the other. Plastic Limit Analysis and Linear Elastic Fracture Mechanics are two theories that address failure of structural components with very ductile and very
brittle behavior, respectively. They are unable to account for the slow crack growth and the softening behavior in concrete structures aside from the effect of material heterogeneity that is connected with the brittleness of concrete.

Mechanical Damage and Crack Growth in Concrete

Content :

• Historical review: strength of materials and fracture mechanics
• Fracture of concrete and brittle materials
• Three-point bending of slab with edge crack
• Center cracked slab in tension
• Off-center compression of slab with edge crack
• Steel reinforced beam with crack in bending
• Panel with opening and diagonal cracks
• Fracture testing and design

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Air Conditioning Engineering

Air Conditioning Engineering

W.P. Jones

Preference :

Air conditioning (of which refrigeration is an inseparable part) has its origins in the
fundamental work on thermodynamics which was done by Boyle, Carnot and others in the
seventeenth and eighteenth centuries, but air conditioning as a science applied to practical
engineering owes much to the ideas and work of Carrier, in the United States of America,
at the beginning of this century. An important stepping stone in the path of progress which
has led to modern methods of air conditioning was the development of the psychrometric
chart, first by Carrier in 1906 and then by Mollier in 1923, and by others since.
The summer climate in North America has provided a stimulus in the evolution of air
conditioning and refrigeration which has put that semi-continent in a leading position
amongst the other countries in the world. Naturally enough, engineering enterprise in this
direction has produced a considerable literature on air conditioning and allied subjects.
The Guide and Data Book published by the American Society of Heating, Refrigeration
and Air Conditioning has, through the years, been a foremost work of reference but, not
least, the Guide to Current Practice of the Institution of Heating and Ventilation Engineers
has become of increasing value, particularly of course in this country. Unfortunately,
although there exists a wealth of technical literature in textbook form which is expressed
in American terminology and is most useful for application to American conditions, there
is an almost total absence of textbooks on air conditioning couched in terms of British
practice. It is hoped that this book will make good the dificiency.

Air Conditioning Engineering

Content :

• The Need for Air Conditioning 
• Fundamental Properties of Air and Water Vapour
• Mixtures
• The Psychrometry of Air Conditioning Processes
• Comfort and Inside Design Conditions
• Climate and Outside Design Conditions
• The Choice of Supply Design Conditions 
• Heat Gains from Solar and Other Sources
• Cooling Load 
• The Fundamentals of Vapour Compression
• Refrigeration
• Air Cooler Coils
• The Rejection of Heat from Condensers and Cooling
• Towers
• Refrigeration Plant 
• Automatic Controls
• Vapour Absorption Refrigeration 
• Airflow in Ducts and Fan Performance
• Ventilation and a Decay Equation 
• Filtration

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