THESIS - Design of walls with linear elastic finite element methods
Author: Marc Romans | Size: 3.94 MB | Format:PDF | Publisher: Delft University of Technology | Year: 2010 | pages: 123 | ISBN: none
Abstract
This thesis focuses on the design of reinforced concrete walls with the use of linear elastic finite element methods. Since the introduction of Eurocode EN1992, the set of design standards in which design requirements related to concrete structures are committed to paper, it is allowed to derive the required amount of reinforcement directly from the membrane forces which follow from a linear elastic finite element analysis. This method deviates however at some points considerably from common design methods. Compared to the common design methods the moment diagram is for example no longer shifted over a specific distance during the design of beams to prevent failure due to the development of inclined bending cracks. In addition, the assumed linear elastic isotropic material behavior in the finite element analyses results in the computation of load transfer mechanisms which deviate considerably from mechanisms which are expected to develop in practice. These deviations gave rise to analyze this recently approved design method in further detail, indicated by the term linear elastic finite element method (LE-FEM) henceforth.
The linear elastic finite element method is verified by considering a large number of single- and several two-span beams. The required reinforcement of these beams is determined with LE-FEM by taking all relevant provisions of the Eurocodes into account. In a subsequent step the structural behavior of the considered beams was analyzed by means of a non-linear finite element analysis, in which a similar level of reliability was taken into account as during the design process. These nonlinear analyses, which are performed in ATENA, are capable to predict the actual behavior of concrete.
Structural analyses of the considered specimen led to the following main conclusions:
· Assuming linear elastic material behavior of concrete for reinforcement design with LE-FEM of structures does not approximate concrete behavior in an accurate way.
· No direct relation is found between the limited amount of longitudinal reinforcement which reaches the supports and the observed failure mode. Concrete crushing in the compressive zone, caused by flexural deformations, turned out to be the normative failure mode.
· Reinforcement designs according to LE-FEM of the considered beams do not meet requirement related to crack control in the serviceability limit state. It is not possible to determine the stresses in the required distributed reinforcement without the application of advanced (non-linear) methods, since there is no direct relation between the applied load and stress development in individual reinforcement bars.
· Design of structures with LE-FEM which are loaded by a compressive force and contain symmetrical reinforcement, such as columns, results in an overestimation of the concrete compressive strength since eccentricities and second order effects are left out of consideration.
· Redistribution of considered two-span beams in case differential support settlements appear is insufficient to withstand settlements which are allowed by the codes.
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This European Standard defines terms, which are used in the production and application of screed material and floor screeds. The terms are valid for all standards prepared by TC 303.
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Verifying the correctness of structural engineering calculations
Author: Douglas William Brown | Size: 1,7 MB | Format:PDF | Publisher: University of Surrey - UK | Year: 2006 | pages: 542 | ISBN: Thesis - No ISBN
Approximately 50% of calculations submitted to building control departments for approval are now produced by computer. Engineers say that due to the pressure of work in the design office, checking is not as thorough as they would like. From the starting position that the data has been checked, this research develops an extensive set of models which are self checking and have each been verified with sets of automatically generated data providing extensive coverage for each model. All systems are described in sufficient detail such that they may be used by others.
The systems developed for verifying the correctness of structural engineering calculations, based on:
• the inclusion of an automatic self-check in every structural model
• the development of a parameter specification table permitting
• the automatic generation of engineered sets of test data for each model
• the automatic running of the sets of test data for a thousand runs for each model
• the automatic reporting of the results giving a statistical summary are all new to the field of structural engineering.
Verifying the correctness of structural engineering calculations considers calculations for both the structural analysis of frameworks and the structural design of components such as beams, slabs & columns, and develops a unified approach for the development of Verified Models for both types of calculation. In this thesis, verifying means establishing the truth or correctness of software models by examination or demonstration.
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My note: As a title said, it's a beginning book - very basic - Useful for students introductory to basis machines dynamics.
At Commtest we know that vibration monitoring can be an easy and painless task – not a mysterious art. We have written Beginner’s Guide to Machine Vibration to give you the key information you need to increase your profits using a vb vibration monitoring instrument.
Engineers, technicians, machine operators, and accountants will be able to quickly grasp the concepts presented in this book. The Author have avoided complicated mathematics and physics formulas, focusing on just the principle concepts necessary for performing basic vibration monitoring. The text is interspersed with simple diagrams, and care has been taken to use everyday language wherever possible.
We are confident that once you are armed with a vb vibration monitoring instrument and after a few readings of Beginner’s Guide to Machine Vibration, you will be able to perform basic vibration monitoring.
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Author: JOHN L.CLARKE (Editor) | Size: 2.7 MB | Format:PDF | Publisher: Blackie Academic & Professional, an imprint of Chapman & Hall | Year: 1993 | pages: 161 | ISBN: 0203795903; 0751400068
Lightweight aggregate concrete is covered, briefly, in most structural design codes but reference is generally made to specialist documents for more detailed information. This book aims to bring together all aspects of the material, considering the manufacture of the aggregates, mix design and construction, design requirements and specific applications in buildings, bridges and other structures. Information has been included not only from the UK but also from the rest of Europe, the USA and Japan. The authors of the various chapters all have extensive experience of lightweight aggregate concrete and are drawn from all branches of the industry.
This book is intended for all those who may be concerned with lightweight aggregate concrete, be they specifiers, materials suppliers, designers, contractors or the eventual owners of the building or structure. It is hoped that, by dealing with all the aspects, this book will help lightweight aggregate concrete to achieve its rightful place in construction.
This edition published in the Taylor & Francis e-Library, 2005.
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The first objective of this introductory text is to familiarize students who have been exposed to only one course on fluids with the basic elements of fluid mechanics so that, in the event that their future work relies on occasional numerical solutions, they will be familiar with the jargon of the discipline and the expected results. At the same time, this book can serve as a long-term reference text, contrary to the oversimplified approach occasionally used for such introductory courses. The second objective is to provide a comprehensive foundation for more advanced courses in fluid mechanics (within disciplines such as mechanical or aerospace engineering). In order to avoid confusing the students, the governing equations are introduced early, and the assumptions leading to the various models are clearly presented. This provides a logical hierarchy and explains the interconnectivity between the various models. Supporting examples demonstrate the principles and provide engineering analysis tools for many engineering calculations.
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Construction Business Development: Meeting New Challenges, Seeking Opportunities
Author: Christopher Preece, Krisen Moodley and Paul Smith. | Size: 1,43 MB | Format:PDF | Publisher: Butterworth-Heinemann | Year: 2003 | pages: 216 | ISBN: 0750651091
Construction Business Development is the first book to provide an insight into business development strategies, tools and techniques in construction. This edited text combines academic research with the broad industrial experience of construction business development professionals and marketing consultants. It uses illustrations and case studies in addressing current and future challenges and opportunities in a highly competitive business environment.
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Economic Design and Construction with
Light Weight Aggregate Concrete (Full set of reports under EuroLightCon project)
The following reports have been published under the EuroLightCon-project:
R1 Definitions and International Consensus Report. April 1998
R2 LWAC Material Properties State-of-the-Art. December 1998
R3 Chloride penetration into concrete with lightweight aggregates. March 1999
R4 Methods for testing fresh lightweight aggregate concrete, December 1999
R5 A rational mix design method for LWAC using typical UK materials, January 2000
R6 Properties of Lytag-based concrete mixtures strength class B15-B55, January 2000
R7 Grading and composition of the aggregate, March 2000
R8 Properties of lightweight concretes containing Lytag and Liapor, March 2000
R9 Technical and economic mixture optimisation of high strength LWAC, March 2000
R10 Paste optimisation based on flow properties and compressive strength, March 2000
R11 Pumping of LWAC based on expanded clay in Europe, March 2000
R12 Applicability of the particle-matrix model to LWAC, March 2000
R13 Large-scale chloride penetration test on LWAC-beams exposed to thermal and hygral cycles, March 2000
R14 Structural LWAC. Specification and guideline for materials and production, May 2000
R15 Light Weight Aggregates, May 2000
R16 In-situ tests on existing lightweight aggregate concrete structures, May 2000
R17 Properties of LWAC made with natural lightweight aggregates, May 2000
R18 Durability of LWAC made with natural lightweight aggregates, May 2000
R19 Evaluation of the early age cracking of LWAC, May 2000
R20 The effect of the moisture history on the water absorption of LWA, May 2000
R21 Stability and pumpability of LWAC. Test Methods, May 2000
R22 The economic potential of LWAC in c.i.p. concrete bridges, May 2000
R23 Mechanical properties of LWAC, May 2000
R24 Prefabricated bridges, May 2000
R25 Chemical stability, wear resistance and freeze-thaw resistance of LWAC, May 2000
R26 Recycling lightweight aggregate concrete, May 2000
R27 Mechanical properties of LWAC compared with both NWC and HSC, May 2000
R28 Prestressed beams loaded with shear force and/or torsional moment, May 2000 (not available for download)
R29 A prestressed steel-LWAconcrete bridge system under fatigue loading
R30 Creep properties of LWAC, May 2000
R31 Long-term effects in LWAC: Strength under sustained loading; Shrinkage of High Strength LWAC, May 2000
R32 Tensile strength as design parameter, May 2000
R33 Structural and economical comparison of bridges made of inverted T-beams with topping, May 2000
R34 Fatigue of normal density concrete and lightweight concrete, May 2000
R35 Composite models for short- and long-term strength and deformation properties of LWAC, May 2000
R36 High strength LWAC in construction elements, May 2000
R37 Comparison of bridges made of NWC and LWAC. Part 1: Structural comparison of steel concrete composite bridges, May 2000
R38 Comparing HSLWAC and HSC with the aid of a computer model, May 2000
R39 Proposal for a Recommendation on design rules for high strength LWAC, May 2000
R40 Comparison of bridges. Part 2: Structural and economic comparison of bridges made of box beams post-tensioned in transversal direction, May 2000
R41 LWA concrete under fatigue loading. Literature survey and fatigue tests, May 2000
R42 Shear capacity of prestressed beams, May 2000
R42a Appendix
R43 Prestressed steel-LWAC bridge system under fatigue loading, May 2000
Description:
EuroLightCon project is funded by the European Union under the Industrial & Materials Technologies Programme (Brite-EuRam III) Contract BRPR-CT97-0381, Project BE96-3942.
Established in 1997, EuroLightCon is a three-year project that involves close cooperation between Norwegian, Dutch, German, British, Spanish and Icelandic companies, universities, research institutes and government agencies. The project aims to further develop lightweight concrete technology by testing new aggregates that utilize waste products, by identifying new areas of use for LWA concrete, and by drawing up rules for the dimensioning of reliable structures.
It is the objective of the EuroLightCon-project to develop a reliable and cost effective design and construction methodology for structural concrete with LWA. The proj ect addresses LWA manufactured from geological sources (clay, pumice etc.) as well as from waste/secondary materials (fly-ash etc.). The methodology shall enable the European concrete and construction industry to enhance its capabilities in terms of cost-effective and environmentally friendly construction, combining the building of lightweight structures with the utilisation of secondary aggregate sources.
The major research tasks are:
1. Lightweight aggregates: The identification and evaluation of new and unexploited sources specifically addressing the environmental issue by utilising alternative materials from waste. Further the development of more generally applicable classification and quality assurance systems for aggregates and aggregate production.
2. Lightweight aggregate concrete production: The development of a mix design methodology to account for all relevant materials and concrete production and in-use properties. This will include assessment of test methods and quality assurance for production.
3. Lightweight aggregate concrete properties: The establishing of basic materials relations, the influence of materials characteristics on mechanical properties and durability.
4. Lightweight aggregate concrete structures: The development of design criteria and rules with special emphasis on high performance structures. The identification of new areas for application.
At the time the project is being performed, a Working Group under the international concrete association FIB (the former CEB and FIP) is preparing an addendum to the CEB-FIP Model Code 1990, to make the Model Code applicable for LWAC. Basis for this work is a state-of-the-art report referring mainly to European and North-American Standards and Codes. Partners in the project are also active in the FIB Working Group.
Download links:
The reports can be dowloaded separately as PDFs here:
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Author: Timothy A. Davis | Size: 10.5 MB | Format:PDF | Publisher: Society for Industrial and Applied Mathematic | Year: 2006 | pages: 217 | ISBN: 0898716136
This book presents the fundamentals of sparse matrix algorithms, from theory to algorithms and data structures to working code. The focus is on direct methods for solving systems of linear equations; iterative methods and solvers for eigenvalue problems are beyond the scope of this book. The goal is to impart a working knowledge of the underlying theory and practice of sparse matrix algorithms, so that you will have the foundation to understand more complex (but faster) algorithms. Methods that operate on dense sub matrices of a larger sparse matrix ( multifrontal and supermodel methods) are much faster, but a complete sparse matrix package based on these methods can be tens of thousands of lines long. The sparse LU, Cholesky, and QR factorization codes in MATLAB®, for example, total about 100,000 lines of code. Trying to understand the sparse matrix technique by starting with such huge codes is a daunting task. To overcome this obstacle, a sparse matrix package, CSparse,1 has been written specifically for this book.2 It can solve Ax = b when A is unsymmetric, symmetric positive definite, or rectangular, using about 2,200 lines of code. Although simple and concise, it is based on recently developed methods and theory. All of CSparse is printed in this book. Take your time to read and understand these codes; do not gloss over them. You will find them much easier to comprehend and learn from than their larger (yet faster) cousins. The larger packages you may use in practice are based on much of the theory and some of the algorithms presented more concisely and simply in CSparse. For example, the MATLAB statement x=A\b relies on the theory and algorithms from almost every section of this book. Parallel sparse matrix algorithms are excluded, yet they too rely on the theory discussed here.
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