A computer vision-based approach for structural displacement measurement
Journal:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010
Author:
Yunfeng Ji
Paper Abstract:
Along with the incessant advancement in optics, electronics and computer technologies during the last three decades, commercial digital video cameras have experienced a remarkable evolution, and can now be employed to measure complex motions of objects with sufficient accuracy, which render great assistance to structural displacement measurement in civil engineering. This paper proposes a computer vision-based approach for dynamic measurement of structures. One digital camera is used to capture image sequences of planar targets mounted on vibrating structures. The mathematical relationship between image plane and real space is established based on computer vision theory. Then, the structural dynamic displacement at the target locations can be quantified using point reconstruction rules. Compared with other tradition displacement measurement methods using sensors, such as accelerometers, linear-variable-differential-transducers (LVDTs) and global position system (GPS), the proposed approach gives the main advantages of great flexibility, a non-contact working mode and ease of increasing measurement points. To validate, four tests of sinusoidal motion of a point, free vibration of a cantilever beam, wind tunnel test of a cross-section bridge model, and field test of bridge displacement measurement, are performed. Results show that the proposed approach can attain excellent accuracy compared with the analytical ones or the measurements using conventional transducers, and proves to deliver an innovative and low cost solution to structural displacement measurement.
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Author: HORIKOSHI K; RANDOLPH M F | Size: 1,2 MB | Format:PDF | Quality:Scanner | Publisher: Journal of the Japanese Geotechnical Society of Soils and Foundations | Year: 1999 | pages: 59-68 | ISBN: 1341-7452
Estimation of overall(or average) settlement and differential settlement are the two most critical issues in the design of moderate to large sized raft and piled foundations. Recent studies have shown that a central pile group can largely eliminate differential settlements, but it is still necessary to estimate the average settlement of the combined pile group and raft foundation. This paper presents a simple method of estimating the overall stiffness of piled rafts in a non-homogeneous soil with finite depth, based on the method of Clancy and Randolph(1996). Although the method enables the estimation of the piled raft's stiffness even when piles are installed beneath the full raft area, particular emphasis is placed on the situation where the pile support is limited to the central region of the raft. The method combines the so called 'equivalent pier method'(Poulos and Davis, 1980) and the 'flexibility matrix method'(Randolph, 1983). In the presented method, a piled raft is replaced by a 'capped pier'. Firstly, a simple method of estimating the overall stiffness of stubby piers in a homogeneous or a non-homogeneous soil is presented. The estimated stiffnesses are compared with those calculated by a finite difference approach(FLAC, Itasca Corporation, Version 3.22). The comparison shows that the simple method gives approximate overall stiffness of piers with a wide range of slenderness ratios(length/radius) and pile-soil stiffness ratios. Secondly, the applicability of the equivalent pier method to pile group analysis is examined for homogeneous soil conditions. The calculated stiffnesses are compared with those obtained by FLAC, and the so called 'hybrid' method(HyPR: Clancy, 1993) where the existence of individual piles is considered. The applicability of the 'capped pier' method to piled raft analysis is then examined.
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Author: Peter Barrett, Catherine A. Stanley | Size: 64 MB | Format:PDF | Quality:Unspecified | Publisher: Wiley-Blackwell | Year: 1999 | pages: 152 | ISBN: 9780632051021
Very few buildings finish on time or at the right price, and clients often criticise the fact that the finished building is not what they expected. Poor communication between the parties at one or more stages of the construction process seems to be the cause, and improved briefing practice has long been recognised as one important area where such communication could be improved.
This book examines the briefing process to understand its strengths and weaknesses and the problems involved, draws on the experience of other disciplines and industries, and identifies best practice and purpose innovations in the briefing process. It is strongly industry oriented while drawing on sound research.
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With a wide range of contributions from America, Australia, Europe as well as the UK, Creating Sustainable Transport sums up many of the lessons learned and how they can be applied in improved planning. Non-motorized transport planning depends on combining improvements to infrastructure with education. The book examines both national strategies and local initiatives in cities around the world, including such topics as changes to existing road infrastructure and the integration of cycling and walking with public transport. The contributors consider topics such as developing healthier travel habits and ways of promoting cycling and walking as alternatives to the car.
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The only modern guide to interpreting and writing real property descriptions for surveyors
Technical land information is no longer the exclusive domain of professional surveyors. The Internet now houses a multitude of resources that nontechnical professionals—such as attorneys and realtors—access and implement on a daily basis. However, these professionals are trained in aspects of law and commerce that do not provide the proper education and experience to interpret and evaluate their land boundary information discoveries correctly. As a result, their analysis is often erroneous and the data misapplied—ultimately leading to confusion and costly litigation.
Professional Surveyors and Real Property Descriptions attempts to bridge the ever-widening gap between the users of land boundary information and the land surveyors who produce it. An expert team of authors integrates the historic and legal background of real property interests with fundamental concepts of the surveying profession in a manner accessible for average readers. These provide the basics for both properly comprehending older descriptions and competently constructing complete and modern real property descriptions that foster better communication. Highlights in this book include:
An in-depth exploration of historic descriptions and how to read them
Coverage of the widely accepted ALTA/ACSM Land Boundary Survey standards and associated property descriptions
A diverse collection of examples and practice scenarios
An overview of the latest issues related to the use of GPS and GIS
Written in easy-to-understand language, this practical resource assists nontechnical professionals in understanding exactly what a surveyor does and does not do, and serves as a valuable tool for obtaining the most satisfactory, accurate, and complete real property descriptions.
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As mankind continues to push back the boundaries and begins to explore other worlds and the ocean depths, a thorough understanding of how structures behave when subjected to extremes in temperature, pressure, and high loading rates will be essential. This symposium provided the perfect forum for presenting research into structures subjected to such extreme loads. There were a large number of papers presented under topics of impact, blast and shock loading, indicating a strong research interest in high rates of loading. Similarly new topics have been added to the traditional symposium list such as fire loading, earthquake loading, and fatigue and connection failures. It is clear now that fundamental knowledge of plastic deformation of structures to various extreme loads is coming of age. Each full paper was peer reviewed by at least two experts in the field.
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Author: Charles Walker, Adrian Smith | Size: 7.3 MB | Format:PDF | Quality:Original preprint | Publisher: Thomas Telford Publishing | Year: 1995 | pages: 304 | ISBN: 0727720538, 9780727720535
The worldwide championing of the privatization concept has led many governments to look for new ways of identifying and funding their infrastructure needs. The Build Operate/Own Transfer arrangement for infrastructure procurement has subsequently evolved, which, it is said, provides a 'win-win' scenario for all involved.
Privatized infrastructure: The BOT approach explains how, where and why the BOT concept evolved and to highlight the possible pitfalls as well as the potential windfalls.
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SCI P363 Steel building design - design data - blue book (amended may 2011)
Author: The Steel Construction Institute | Size: 4.97 MB | Format:PDF | Quality:Original preprint | Publisher: The Steel Construction Institute | Year: 2011 | pages: 591 | ISBN: 978-1-85942-186-4
This publication presents design data derived in accordance with the following Parts of Eurocode 3
and their National Annexes:
BS EN 1993-1-1:2005: Design of steel structures. Part 1-1: General rules and rules for
buildings.
BS EN 1993-1-5:2006: Design of steel structures. Part 1-5: Plated structural elements.
BS EN 1993-1-8:2005: Design of steel structures. Part 1-8: Design of joints.
Where these Parts do not give all the necessary expressions for the evaluation of data, reference is
made to other published sources.
The resistances in this publication have been calculated using the partial factors for resistance
given in the UK National Annexes for the Eurocodes (NA to BS EN 1993-1-1:2005 as published in
December 2008, NA to BS EN 1993-1-5:2006 aspublished in May 2008 and NA to BS EN 1993-1-8:2005 as published in November 2008). The partial factors are listed in Section 5.1. The other
parameters given in the National Annex that have been used when calculating member resistances
are given in the relevant section of this publication.
The following structural sections are covered in this publication:
Universal beams, universal columns, joists, bearing piles, parallel flange channels and
structural tees cut from universal beams and universal columns to BS 4-1
Universal beams and universal columns produced by Tata Steel* but not included in BS 4-1
Asymmetric Slimflor® beams (ASB) produced by Tata Steel*
Equal and unequal angles to BS EN 10056-1
Hot-finished structural hollow sections to BS EN 10210-2
Cold-formed structural hollow sections to BS EN 10219-2
Section ranges listed cover sections that are readily available at the time of printing.
Reprint - May 2011
Several corrections have been made, including clarification in the explanatory notes. Ratios used
for the classification of tees and cold formed sections have been corrected. The only changes to
tabulated member resistances are the shear resistances of parallel flange channels. A few minor
formatting errors have been corrected in the design tables.
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