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1
Fu, Tuan-Chun. "Development of Effective Approaches to the Large-Scale Aerodynamic Testing of Low-Rise Building." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/986.
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Low-rise buildings are often subjected to high wind loads during hurricanes that lead to severe damage and cause water intrusion. It is therefore important to estimate accurate wind pressures for design purposes to reduce losses. Wind loads on low-rise buildings can differ significantly depending upon the laboratory in which they were measured. The differences are due in large part to inadequate simulations of the low-frequency content of atmospheric velocity fluctuations in the laboratory and to the small scale of the models used for the measurements. A new partial turbulence simulation methodology was developed for simulating the effect of low-frequency flow fluctuations on low-rise buildings more effectively from the point of view of testing accuracy and repeatability than is currently the case. The methodology was validated by comparing aerodynamic pressure data for building models obtained in the open-jet 12-Fan Wall of Wind (WOW) facility against their counterparts in a boundary-layer wind tunnel. Field measurements of pressures on Texas Tech University building and Silsoe building were also used for validation purposes. The tests in partial simulation are freed of integral length scale constraints, meaning that model length scales in such testing are only limited by blockage considerations. Thus the partial simulation methodology can be used to produce aerodynamic data for low-rise buildings by using large-scale models in wind tunnels and WOW-like facilities. This is a major advantage, because large-scale models allow for accurate modeling of architectural details, testing at higher Reynolds number, using greater spatial resolution of the pressure taps in high pressure zones, and assessing the performance of aerodynamic devices to reduce wind effects. The technique eliminates a major cause of discrepancies among measurements conducted in different laboratories and can help to standardize flow simulations for testing residential homes as well as significantly improving testing accuracy and repeatability. Partial turbulence simulation was used in the WOW to determine the performance of discontinuous perforated parapets in mitigating roof pressures. The comparisons of pressures with and without parapets showed significant reductions in pressure coefficients in the zones with high suctions. This demonstrated the potential of such aerodynamic add-on devices to reduce uplift forces.
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Asghari, Mooneghi Maryam. "Experimental and Analytical Methodologies for Predicting Peak Loads on Building Envelopes and Roofing Systems." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1846.
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The performance of building envelopes and roofing systems significantly depends on accurate knowledge of wind loads and the response of envelope components under realistic wind conditions. Wind tunnel testing is a well-established practice to determine wind loads on structures. For small structures much larger model scales are needed than for large structures, to maintain modeling accuracy and minimize Reynolds number effects. In these circumstances the ability to obtain a large enough turbulence integral scale is usually compromised by the limited dimensions of the wind tunnel meaning that it is not possible to simulate the low frequency end of the turbulence spectrum. Such flows are called flows with Partial Turbulence Simulation.
In this dissertation, the test procedure and scaling requirements for tests in partial turbulence simulation are discussed. A theoretical method is proposed for including the effects of low-frequency turbulences in the post-test analysis. In this theory the turbulence spectrum is divided into two distinct statistical processes, one at high frequencies which can be simulated in the wind tunnel, and one at low frequencies which can be treated in a quasi-steady manner. The joint probability of load resulting from the two processes is derived from which full-scale equivalent peak pressure coefficients can be obtained. The efficacy of the method is proved by comparing predicted data derived from tests on large-scale models of the Silsoe Cube and Texas-Tech University buildings in Wall of Wind facility at Florida International University with the available full-scale data.
For multi-layer building envelopes such as rain-screen walls, roof pavers, and vented energy efficient walls not only peak wind loads but also their spatial gradients are important. Wind permeable roof claddings like roof pavers are not well dealt with in many existing building codes and standards. Large-scale experiments were carried out to investigate the wind loading on concrete pavers including wind blow-off tests and pressure measurements. Simplified guidelines were developed for design of loose-laid roof pavers against wind uplift. The guidelines are formatted so that use can be made of the existing information in codes and standards such as ASCE 7-10 on pressure coefficients on components and cladding.
3
Nassiri, Esmail. "Modelling nonlinear behaviour of two-dimensional steel structures subjected to cyclic loading." Thesis, Queensland University of Technology, 1998.
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4
Moravej, Mohammadtaghi. "Investigating Scale Effects on Analytical Methods of Predicting Peak Wind Loads on Buildings." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3799.
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Large-scale testing of low-rise buildings or components of tall buildings is essential as it provides more representative information about the realistic wind effects than the typical small scale studies, but as the model size increases, relatively less large-scale turbulence in the upcoming flow can be generated. This results in a turbulence power spectrum lacking low-frequency turbulence content. This deficiency is known to have significant effects on the estimated peak wind loads.
To overcome these limitations, the method of Partial Turbulence Simulation (PTS) has been developed recently in the FIU Wall of Wind lab to analytically compensate for the effects of the missing low-frequency content of the spectrum. This method requires post-test analysis procedures and is based on the quasi-steady assumptions. The current study was an effort to enhance that technique by investigating the effect of scaling and the range of applicability of the method by considering the limitations risen from the underlying theory, and to simplify the 2DPTS (includes both in-plane components of the turbulence) by proposing a weighted average method. Investigating the effect of Reynolds number on peak aerodynamic pressures was another objective of the study.
The results from five tested building models show as the model size was increased, PTS results showed a better agreement with the available field data from TTU building. Although for the smaller models (i.e., 1:100,1:50) almost a full range of turbulence spectrum was present, the highest peaks observed at full-scale were not reproduced, which apparently was because of the Reynolds number effect. The most accurate results were obtained when the PTS was used in the case with highest Reynolds number, which was the1:6 scale model with a less than 5% blockage and a xLum/bm ratio of 0.78. Besides that, the results showed that the weighted average PTS method can be used in lieu of the 2DPTS approach. So to achieve the most accurate results, a large-scale test followed by a PTS peak estimation method deemed to be the desirable approach which also allows the xLum/bm values much smaller than the ASCE recommended numbers.
5
Mundell, Chris. "Large scale testing of drystone retaining structures." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518299.
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Drystone walls have been used extensively around the world as earth retaining structures wherever suitable stone is found. Commonly about 0.6m thick (irrespective of height), there are about 9000km of drystone retaining walls on the UK road network alone, mostly built in the 19th and early 20th centuries, with an estimated replacement value in excess of £1 billion[1]. Drystone wall design is traditionally empirical, based on local knowledge of what has worked in the past. Methods vary from region to region, driven by both custom and the nature of the materials available. Design is not necessarily optimised, and includes unknown margins of safety. There is a recognised need for guidance on the assessment and maintenance of dry stone retaining walls, as no suchdocumentscurrentlyexist. Thisthesisdocumentstheconstructionofaseriesoffull-scaletestsdesignedto provide sufficient information to validate current theoretical and numerical analysis techniques. The development of a unique test rig is detailed, in addition to the testing regime and results from a programme of five 2.5m high drystone retaining walls. The walls were subjected to localised surcharging and foundation movements, recreating the conditions that many in-situ walls are subject to. Movements such as toppling, bulging and sliding were observed, and recorded using a broad range of instrumentation. This has provided high quality, quantitative data relating to the factors which influence these mechanisms, and their affect on wall stability. Also documented are the associated laboratory tests which have been conducted to determine the mechanical properties of backfill and the walls themselves, as well as the manner in which they interact together. To assist in the analysis of these full-scale tests, a limit equilibrium program has been developed. This package allows the rapid generation of a wall of any size and constructed with any materials. The limit equilibrium program has then been used in conjunction with the data from the full-scale and laboratory tests to analyse observed drystone wall behaviour. These include the phenomena of toppling, bulging, bursting, sliding and individual block rotation. In each case, the underlying causes of such movements have been determined, and the critical parametersidentified.
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Yao, Zhao-Cheng. "Reliability of structures with load history-dependent strength and an application to wood members." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26753.
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Because of an interaction between the load history and the material's properties a reduction in the serviceability of safety of a structure may be seen as the result of a random process of damage accumulation with time.
A damage model is proposed and verified to deal with this type of problem in general, and specifically with duration-of-load effects in timber structures.
Through comparisons with and discussion of other damage accumulation models, the proposed model is found to be both suitable to represent experimental results and relatively easy to use.
A reliability analysis for a single structural member with a service life of 30 years is studied for different snow loading conditions of three Canadian cities,using the damage model in combination with Rackwitz-Fissler's algorithm.
A simplified analysis method is proposed and compared with a large-scale Monte-Carlo simulation. The results of the reliability analysis are found to be satisfactory.
Finally, the implementation of the reliability analysis in a simple design guideline for load duration effects is discussed.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
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Johansson, Fredrik. "Stabilitly analysis of large structures founded on rock : an introductory study." Licentiate thesis, KTH, Civil and Architectural Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-583.
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<p>Previous investigations of Swedish and international dams have shown difficultiesto assess the safety against failure in rock foundations. The problem was alsogiven additional interest in connection to the recent construction of the newbridge at Traneberg in Stockholm. This project was created in order to increasethe knowledge in the subject of stability analysis of large structures founded onrock, and how they should be performed in order to describe the safety in areliable way.</p><p>This thesis covers the first half of this project. The objectives of the thesis were todescribe the knowledge and current state of practice in the subject with a literaturestudy, and with a case study of the arch dam at Krokströmmen show the problemsfor stability analyses where foundation and structure interact. The objective wasalso to produce a foundation for future work.</p><p>At Krokströmmen arch dam, previous three dimensional finite element analyseshave been performed (Johansson and Palmgren 1996). In these analyses, thestiffness of the foundation was not considered. Based on the results from theseanalyses, stability was analytically analyzed for each monolith by Stille et al.(2002). The results indicated low factors of safety for the central monoliths. As aconsequence, a reinforcement slab was constructed to increase stability.</p><p>In order to show how varying stiffness and non-linear resistance of the foundationaffects stability, a quasi three dimensional finite element analyses were carriedout. In these analyses, five of the central monoliths were first analyzed separately.Thereafter, the reaction forces were adjusted to fit the results from the analyses byJohansson and Palmgren (1996). The monoliths were thereafter coupled togetherwith assumptions of equal deformations and constant total reaction forces for thefive monoliths. Through an iterative procedure, constant deformation and newredistributed reaction forces were obtained. These forces were used to discuss thestability for one of the monoliths in detail.</p><p>This thesis shows that the problem is more complex than described in the Swedishdam safety guidelines, RIDAS (Svensk Energi 2002), and the Swedish bridgedesign code, BRO 2004 (Vägverket 2004). An accurate analysis of the stability ina rock foundation under large structures demands a more refined approach, whichconsiders the specific features associated with rock mechanical problems. Thecase study showed that the interaction between foundation and structure can beconsiderable; deformations and reaction forces acting on the foundation wereredistributed when the stiffness of the foundation was considered. Furthermore,the resistance is a function of deformation. These aspects are necessaryconsidering if stability should be determined with high confidence.</p><p>An additional question which was identified and brought up for discussion wasthe possibility of time-dependent deformation in the foundation at Krokströmmendue to creep and cyclic loading, which in turn can affect the long term stability.</p>
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Mastbergen, Daniel Blair. "Simulation and Testing of Resin Infusion Manufacturing Processes for Large Composite Structures." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/mastbergen/MastbergenD0805.pdf.
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The use of composite materials in large primary structures such as wind turbine blades and boat hulls has dramatically increased in recent years. As these structures get larger, new manufacturing processes are required to make them possible. Larger parts also require more expensive tooling, and a higher cost for scrapped parts. This may prohibit the trial and error approach that has been used for many years. The need for accurate process modeling in the design of tooling is becoming essential. Unfortunately, as the processes become more complex so do the models. Although there are several potential processes capable of producing very large parts (10 m - 50 m), they all have one common feature. In order to alleviate the problem of forcing the resin to flow large distances though the fabric, they use a distribution system to spread the resin over the surface of the part. The resin then flows a substantially shorter distance between the channels or through the thickness. The goal of this work was to develop a modeling technique that could accurately model these processes, yet not so complex as to loose its utility. In this study, the flows through the different regions of the mold are examined individually. These regions include the injection system, the distribution channel, and the fabric. The governing equations for each region are then combined to form a comprehensive model that accounts for the flow through each region simultaneously. A series of tests were conducted to verify the models of the individual components, as well as the comprehensive model. The rate limiting step through the fabric was also examined in detail. The model correlated well with the experiments performed, and revealed critical information about these types of processes. A major conclusion is that an accurate and straightforward model can be created for large scale processes, using the small scale bench tests performed in this study. Also, the governing equations developed here from Darcy flow and Stokes flow aid in understanding how the scaling of key parameters affects the process as a whole. Variations in the geometry of the channel, the fabric thickness and fabric properties such as permeability and compressibility can be accounted for in the model.
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Hesabi, Somayeh. "3D modeling of large elongated structures for non-destructive testing and inspection." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27640.
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Selon un rapport de l’Agence centrale de renseignement (CIA) ¹, présenté dans un journal NDT ², il y avait un total de 3.3 millions km de pipelines dans 120 pays du monde en 2014. Cela signifie que les pipelines ont un rôle important à jouer dans l’infrastructure de l’énergie pour le transport de liquides ou du gaz naturel. Bien que les pipelines représentent le plus efficace et le plus fiable pour transporter divers liquides allant de l’eau à l’huile, ils sont vulnérables aux défauts externes et internes. Heureusement, une inspection périodique des pipelines peut augmenter leur sécurité et leur fonctionnalité et réduire les catastrophes environnementales ainsi que les pertes économiques causées par les potentielles explosions ou autres dysfonctionnements. Considérant les avantages des capteurs 3D qui permettent de créer une réplique numérique précise de la surface des objets réels en plus des avantages de la technologie d’Evaluation Non Destructive (END) qui fournit un suivi des défauts sous la surface, la présente recherche propose une solution visant à construire un modèle 3D d’un pipeline ou d’autres structures allongées pour suivre leur état. Dans ce but, nous mesurons d’abord la géométrie du pipeline avec des capteurs 3D portables et construisons le modèle 3D de la structure. Ensuite, les informations des défauts sous la surface qui sont estimées efficacement par des approches développées par d’autres membres de l’équipe en utilisant la thermographie infrarouge sont intégrées au modèle 3D reconstruit. Le manuscrit étudie différents défis liés à la modélisation 3D précise de grandes structures allongées et la répétabilité de l’approche de modélisation à des fins de contrôle de qualité et d’entretien à long terme. 1. The World Factbook, updated 18 May 2015. 2. Materials Evaluation (M.E.), vol. 73, no. 7, July 2015<br>According to a Central Intelligence Agency (CIA) report ¹ presented in a flagship NDT journal ², there were a total of 3.3 million km of pipelines present in 120 countries in the world in 2014. This means that pipelines play an important role in the energy infrastructure in order to safely transport liquid or natural gas. Although pipelines are the most efficient and reliable way to carry various liquids ranging from water to oil, they are vulnerable to external and internal damages. Fortunately, a periodic inspection of pipelines can increase their functionality and decrease the environmental disasters as well as economic losses caused by potential spills, explosions or other malfunctions. In this context of the exploitation of pipelines and other similar elongated structures and considering the benefits of 3D sensors which allow us to create an accurate digital replica of the surface of physical objects in addition to the advantages of Non-Destructive Testing (NDT) technology which provides the ability of under-surface monitoring, our research proposes a solution to build a 3D model of pipeline or other elongated structures to monitor their status. For this purpose, we first measure the geometry of the pipeline by handheld 3D scanners and construct the 3D model of the structure. Then, the information of subsurface defects that is estimated efficiently by approaches developed by other team members using infrared thermography is integrated to the reconstructed 3D model. The manuscript investigates different challenges related to the 3D modeling of large elongated structures with high accuracy and repeatability for quality control purposes as well as for long-term maintenance. 1. The World Factbook, updated 18 May 2015. 2. Materials Evaluation (M.E.), vol. 73, no. 7, July 2015
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Shearer, Murray J. "Analysis of large-scale gas explosion tests and assessment of potential impact on structures." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/844451/.
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This document provides a framework for the assessment of gas explosion impact on structures. It shows how the probability of a structure achieving a predefined level of success in withstanding a defined gas explosion scenario may be calculated. The thesis opens with a general introduction to the need for assessing the impact of gas explosions in offshore installations. In the second chapter relevant literature regarding the existing theory and approaches used in assessment of gas explosions is reviewed. In particular, limitations of existing techniques are highlighted. The experimental data that is available to the author is also discussed. In the third chapter a set of objectives is defined. Meeting these objectives would allow many of the outstanding issues in gas explosion assessment, highlighted in chapter two, to be addressed. These objectives essentially define the need for assessment of explosions to relate to the impact upon the structure they engulf and that the impact is dependent not only upon the explosion but upon the structure so effected. The fourth chapter extends an existing technique of applying time-averaging windows to pressure-time histories from explosions. In this chapter, the importance of an approach to analysing explosions that relates directly to structural response is first established. An improved understanding of the effect of explosion parameters upon explosion magnitude is also made. The fifth chapter makes use of conventional signal analysis techniques to address weaknesses of time-averaging approach. These techniques allow a better relationship between identified structural response frequency and quantification of loading to be reached. These techniques also allow analysis of the explosion time history to be made in the frequency domain. Our understanding of the explosion parameters on explosion magnitude is again advanced. Whereas the fifth chapter allows analysis to be made in the frequency pressure domain, the sixth chapter shows how analysis can be made in the frequency-loading domain. This is achieved by assessing the impact of pressure-time histories on a simple oscillating structure, a single degree of freedom object. Of all the techniques developed, this is believed to be the most appropriate. In the seventh chapter we begin to apply the techniques developed by assessing, among other things, the inherent repeatability of an explosion and our ability to accurately predict the magnitude of the explosion. We start to generate a body of statistical data relating to accidental gas explosions. Chapter eight shows how the knowledge gained in previous chapters might be applied within a framework that is relevant to current practices in risk assessment. The framework selected is known as the limit state approach. It is shown how performance criteria for the structure undergoing gas explosions might be set and how the probability of the structure meeting these conditions might be assessed.
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Smith, John P. "Effective and efficient non-destructive testing of large and complex shaped aircraft structures." Thesis, University of Central Lancashire, 2004. http://clok.uclan.ac.uk/7646/.
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The main aim of the research described within this thesis is to develop methodologies that enhance the defect detection capabilities of nondestructive testing (NDT) for the aircraft industry. Modem aircraft non-destructive testing requires the detection of small defects in large complex shaped components. Research has therefore focused on the limitations of ultrasonic, radioscopic and shearographic methods and the complimentary aspects associated with each method. The work has identified many parameters that have significant effect on successful defect detection and has developed methods for assessing NDT systems capabilities by noise analysis, excitation performance and error contributions attributed to the positioning of sensors. The work has resulted in 1. The demonstration that positional accuracy when ultrasonic testing has a significant effect on defect detection and a method to measure positional accuracy by evaluating the compensation required in a ten axis scanning system has revealed limitsio the achievable defect detection when using complex geometry scanning systems. 2. A method to reliably detect 15 micron voids in a diffusion bonded joint at ultrasonic frequencies of 20 MHz and above by optimising transducer excitation, focussing and normalisation. 3. A method of determining the minimum detectable ultrasonic attenuation variation by plotting the measuring error when calibrating the alignment of a ten axis scanning system. 4. A new formula for the calculation of the optimum magnification for digital radiography. The formula is applicable for focal spot sizes less than 0.1 mm. 5. A practical method of measuring the detection capabilities of a digital radiographic system by calculating the modulation transfer function and the noise power spectrum from a reference image. 6. The practical application of digital radiography to the inspection of super plastically formed ditThsion bonded titanium (SPFDB) and carbon fibre composite structure has been demonstrated but has also been supported by quantitative measurement of the imaging systems capabilities. 7. A method of integrating all the modules of the shearography system that provides significant improvement in the minimum defect detection capability for which a patent has been granted. 8. The matching of the applied stress to the data capture and processing during a shearographic inspection which again contributes significantly to the defect detection capability. 9. The testing and validation of the Parker and Salter [1999] temporal unwrapping and laser illumination work has led to the realisation that producing a pressure drop that would result in a linear change in surface deformation over time is difficult to achieve. 10. The defect detection capabilities achievable by thermal stressing during a shearographic inspection have been discovered by applying the pressure drop algorithms to a thermally stressed part. 11. The minimum surface displacement measurable by a shearography system and therefore the defect detection capabilities can be determined by analysing the signal to noise ratio of a transition from a black (poor reflecting surface) to white (good reflecting surface). The quantisation range for the signal to noise ratio is then used in the Hung [1982] formula to calculate the minimum displacement. Many of the research aspects contained within this thesis are cuffently being implemented within the production inspection process at BAE Samlesbury.
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Abayakoon, Sarath Bandara Samarasinghe. "Large deflection elastic-plastic analysis of plate structures by the finite strip method." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26946.
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A solution procedure based on the finite strip method is presented herein, for the analysis of plate systems exhibiting geometric and material non-linearities. Special emphasis is given to the particular problem of rectangular plates with stiffeners running in a direction parallel to one side of the plate. The finite strip method is selected for the analysis as the geometry of the problem is well suited for the application of this method and also as the problem is too complicated to solve analytically.
Large deflection effects are included in the present study, by taking first, order non-linearities in strain-displacement relations into account. Material non-linearities are handled by following von-Mises yield criterion and associated flow rule. A bi-linear stress-strain relationship is assumed for the plate material, if tested under uniaxial conditions. Numerical integration of virtual work equations is performed by employing Gauss quadrature. The number of integration points required in a given direction is determined either by observing the individual terms to be integrated or by previous experience. The final set of non-linear equations is solved via a Newton-Raphson iterative scheme, starting with the linear solution.
Numerical investigations are carried out by applying the finite strip computer programme
to analyse uniformly loaded rectangular and I beams with both simply supported and clamped ends. Displacements, stresses and moments along the beam are compared with analytical solutions in linear analyses and with finite element solutions in non-linear analyses. Investigations are also extended to determine the response of laterally loaded square plates with simply supported and clamped boundaries. Finally, a uniformly loaded stiffened panel is analysed and the results are compared with finite element results. It was revealed that a single mode in the strip direction was sufficient to yield engineering accuracy for design purposes, with most problems.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
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Corcoran, Joseph Michael. "Output-Only Experimental Modal Testing of Large Residential Structures and Acoustic Cavities Using Sonic Booms." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31329.
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In this thesis, an output-only experimental modal testing and analysis technique known as the Natural Excitation Technique (NExT) is examined for use with large residential structures and interior cavities. The technique which assumes a random, stationary input causing the response data is reviewed and extended for the first time to include the assumption of an impulse input. This technique is examined with respect to the experimental modal analysis of single and two room residential structures. Each structure is first tested using conventional modal testing methods. Then, NExT is applied using each structureâ s response to a simulated sonic boom, an impulsive input. The results of these analyses along with the results obtained from a finite element model are compared. Then, the interior cavities enclosed by the residential structures are examined using NExT. Therefore, this thesis also demonstrates the successful use of NExT on acoustic systems for the first time. Three configurations of the interconnected cavities enclosed by the two room structure are considered to study physical phenomena. Both interior pressure response to random, stationary inputs and the sonic boom response are used with NExT to determine modal properties. The results of these analyses are compared to a theoretical analysis. Advantages to using NExT with both the response to a random, stationary input and an impulsive input are demonstrated for structural and acoustic systems.<br>Master of Science
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Facchini, Mauro. "Optical techniques applied to the study of building materials and to the inspection of civil structures." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/27863.
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Where the evaluation of the mechanical properties and behaviour of building materials is concerned, there is still not a universally accepted solution for making such measurements. Optical diagnostic techniques are particularly attractive for a non-destructive evaluation of a surface's state and the detection of incipient damage. Non-contact, high precision measurements and full-field of observation are features that can bring enormous advantages in experimental tests.
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Moor, Constantin. "Three dimensional analysis of steel portal frame buildings." Thesis, Queensland University of Technology, 1997. https://eprints.qut.edu.au/36010/1/36010_Moor_1997.pdf.
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The true strength and deflection behaviour of industrial and commercial
steel portal frame buildings is understood better if the effects of stiffness of
end frames and profiled steel claddings are included. The conventional
designs ignore these effects and are very much based on an idealised twodimensional
frame behaviour. This thesis describes an investigation into the
three-dimensional behaviour of steel portal frame buildings using computer
modelling and full scale tests.
The full scale tests of a 12 m x 12 m clad and unclad steel portal frame
building with true pinned and standard (normal) bases were conducted
under a range of design load cases which indicated that the observed
deflections and bending moments in the portal frames were considerably
different to those obtained from a two-dimensional analysis of frames
ignoring the effects of cladding and end frame rigidity. Three dimensional
analyses of the same building including these effects using the "equivalent
truss member'' theory were carried out and the results agreed well with full
scale test results. The cladding flexibility coefficient required for this
computer analysis was obtained from shear tests of 6 m x 6 m crest-fixed
trapezoidal steel claddings.
In both full scale tests and computer modelling, the stiffness of cladding and
end frames had a significant influence on moments and deflections of the
portal frames when Cross Wind load was considered. For the tested frame
these effects were equivalent to stiffening the column bases from pinned to
fixed conditions. However, for Longitudinal Wind and Live Loads, the results
showed that buildings with a flat roof slope (in this case 5° ) will not gain
from the presence of claddings and the differences in maximum moment and
deflections are insignificant when cladding action and rigidity of end frame
are considered. In the design of the common industrial and commercial buildings, Cross
Wind load is the governing load case. Therefore it is important that the
significant effects observed due to the presence of cladding and end frame
rigidity be taken into account in the analysis and design of these buildings.
There was a noticeable load transfer from the central frame to the gable
frame when claddings and end frame bracing were added to the building
considered in the full scale tests and three-dimensional computer analysis.
This increased the moments on the end gable frame, but decreased the
higher moments on the central frame, leading to a more balanced moment
and deflection distribution among these frames. It is expected that such a
three dimensional analysis and design method will lead to lighter steel
frames as the maximum moments are reduced. Therefore this method which
is based on the true building behaviour is recommended for Cross Wind
loads.
This design method as well as recent advances in the use of higher strength
materials, can lead to buildings with more slender members, larger spans
and thus larger deflections. As a result, unlike in the past, deflection criteria
may become more critical than strength and increasing the member sizes is
not always the best solution for limiting such problems. For this purpose the
use of appropriate deflection limits and a better understanding of the true
deflection behaviour of the buildings are important. This investigation has
shown that choosing the location of the points where the deflection is to be
limited is more important than limiting maximum deflections for the whole
building. Serviceability problems usually do not appear in members such as
columns or rafters, instead they appear in panels such as walls, partitions,
ceilings and claddings. In order to eliminate serviceability problems in the
buildings it is then necessary to consider the "Characteristic panel" concept
developed by the author of this thesis. As a result, it is important from a
serviceability point of view not to limit the maximum horizontal and vertical
deflections in portal frames buildings, but to consider appropriate
characteristic panels in the buildings and analysing their relative deflections
to limit their specific deformations.
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Zhang, Zhi, and Zhi Zhang. "Analytical Investigation of Inertial Force-Limiting Floor Anchorage System for Seismic Resistant Building Structures." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625385.
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This dissertation describes the analytical research as part of a comprehensive research program to develop a new floor anchorage system for seismic resistant design, termed the Inertial Force-limiting Floor Anchorage System (IFAS).
The IFAS intends to reduce damage in seismic resistant building structures by limiting the inertial force that develops in the building during earthquakes. The development of the IFAS is being conducted through a large research project involving both experimental and analytical research. This dissertation work focuses on analytical component of this research, which involves stand-alone computational simulation as well as analytical simulation in support of the experimental research (structural and shake table testing).
The analytical research covered in this dissertation includes four major parts:
(1) Examination of the fundamental dynamic behavior of structures possessing the IFAS (termed herein IFAS structures) by evaluation of simple two-degree of freedom systems (2DOF). The 2DOF system is based on a prototype structure, and simplified to represent only its fundamental mode response. Equations of motions are derived for the 2DOF system and used to find the optimum design space of the 2DOF system. The optimum design space is validated by transient analysis using earthquakes.
(2) Evaluation of the effectiveness of IFAS designs for different design parameters through earthquake simulations of two-dimensional (2D) nonlinear numerical models of an evaluation structure. The models are based on a IFAS prototype developed by a fellow researcher on the project at Lehigh University.
(3) Development and calibration of three-dimensional nonlinear numerical models of the shake table test specimen used in the experimental research. This model was used for predicting and designing the shake table testing program.
(4) Analytical parameter studies of the calibrated shake table test model. These studies include: relating the shake table test performance to the previous evaluation structure analytical response, performing extended parametric analyses, and investigating and explaining certain unexpected shake table test responses.
This dissertation describes the concept and scope of the analytical research, the analytical results, the conclusions, and suggests future work. The conclusions include analytical results that verify the IFAS effectiveness, show the potential of the IFAS in reducing building seismic demands, and provide an optimum design space of the IFAS.
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Alghrir, Yassin [Verfasser]. "New Concept for a Non-Welding Connection in Steel Structures and Steel-Concrete Composite Structures to Accommodate Large Building Tolerances Using Grout / Yassin Alghrir." Düren : Shaker, 2020. http://d-nb.info/1210389797/34.
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Xu, Guoqing. "Assessment of risk of disproportionate collapse of steel building structures exposed to multiple hazards." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41079.
Full textAbstract:
Vulnerability of buildings to disproportionate (or progressive) collapse has
become an increasingly important performance issue following the collapses of the
Alfred P. Murrah Federal Building in Oklahoma City in 1995 and the World Trade
Center in 2001. Although considerable research has been conducted on this topic, there are still numerous unresolved research issues. This dissertation is aimed at developing structural models and analysis procedures for robustness assessment of steel building structures typical of construction practices in the United States, and assessing the performance of these typical structures.
Beam-column connections are usually the most vulnerable elements in steel buildings structures suffering local damage. Models of three typical frame connections for use in robustness assessment have been developed with different techniques, depending on the experimental data available to support such models. A probabilistic model of a pre-Northridge moment-resisting connection was developed through finite element simulations, in which the uncertainties in the initial flaw size, beam yield strength and fracture toughness of the weld were considered. A macro-model for a bolted T-stub connections was developed by considering the behavior of each connection element individually (i.e. T-stub, shear tab and panel zone) and assembling the elements to form a complete connection model, which was subsequently calibrated to experimental data. For modeling riveted connections in older steel buildings that might be candidates for rehabilitation, a new method was proposed to take advantage of available experimental data from tests of earthquake-resistant connections and to take into account the effects of the unequal compressive and tensile stiffnesses of top and bottom parts in a connection and catenary action.
These connection models were integrated into nonlinear finite element models of structural systems to allow the effect of catenary and other large-deformation action on the behavior of the frames and their connections following initial local structural damage to be assessed. The performance of pre-Northridge moment-resisting frames was assessed with both mean-centered deterministic and probabilistic assessment procedures; the significance of uncertainties in collapse assessment was examined by comparing the results from both procedures. A deterministic assessment of frames with full and partial-strength bolted T-stub connections was conducted considering three typical beam spans in both directions. The vulnerability of an older steel building with riveted connections was also analyzed deterministically. The contributions from unreinforced masonry infill panels and reinforced concrete slabs on the behavior of the building were investigated.
To meet the need for a relatively simple procedure for preliminary vulnerability assessment, an energy-based nonlinear static pushdown analysis procedure was developed. This procedure provides an alternative method of static analysis of disproportionate collapse vulnerability that can be used as an assessment tool for regular building frames subjected to local damage. Through modal analysis, dominant vibration modes of a damaged frame were first identified. The structure was divided into two parts, each of which had different vibration characteristics and was modeled by a single degree-of-freedom (SDOF) system separately. The predictions were found to be sufficiently close to the results of a nonlinear dynamic time history analysis (NTHA) that the method would be useful for collapse-resistant design of buildings with regular steel framing systems.
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Bellander, Rickard. "Testing large samples of PCM in water calorimeter and PCM used in room applications by night-air cooling." Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-495.
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Coy, Bradly B. "Buckling-Restrained Braced Frame Connection Design and Testing." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2030.pdf.
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Baheru, Thomas. "Development of Test-Based Wind-Driven Rain Intrusion Model for Hurricane-Induced Building Interior and Contents Damage." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1127.
Full textAbstract:
Major portion of hurricane-induced economic loss originates from damages to building structures. The damages on building structures are typically grouped into three main categories: exterior, interior, and contents damage. Although the latter two types of damages, in most cases, cause more than 50% of the total loss, little has been done to investigate the physical damage process and unveil the interdependence of interior damage parameters. Building interior and contents damages are mainly due to wind-driven rain (WDR) intrusion through building envelope defects, breaches, and other functional openings. The limitation of research works and subsequent knowledge gaps, are in most part due to the complexity of damage phenomena during hurricanes and lack of established measurement methodologies to quantify rainwater intrusion. This dissertation focuses on devising methodologies for large-scale experimental simulation of tropical cyclone WDR and measurements of rainwater intrusion to acquire benchmark test-based data for the development of hurricane-induced building interior and contents damage model. Target WDR parameters derived from tropical cyclone rainfall data were used to simulate the WDR characteristics at the Wall of Wind (WOW) facility. The proposed WDR simulation methodology presents detailed procedures for selection of type and number of nozzles formulated based on tropical cyclone WDR study. The simulated WDR was later used to experimentally investigate the mechanisms of rainwater deposition/intrusion in buildings. Test-based dataset of two rainwater intrusion parameters that quantify the distribution of direct impinging raindrops and surface runoff rainwater over building surface — rain admittance factor (RAF) and surface runoff coefficient (SRC), respectively — were developed using common shapes of low-rise buildings. The dataset was applied to a newly formulated WDR estimation model to predict the volume of rainwater ingress through envelope openings such as wall and roof deck breaches and window sill cracks. The validation of the new model using experimental data indicated reasonable estimation of rainwater ingress through envelope defects and breaches during tropical cyclones. The WDR estimation model and experimental dataset of WDR parameters developed in this dissertation work can be used to enhance the prediction capabilities of existing interior damage models such as the Florida Public Hurricane Loss Model (FPHLM).
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Covi, Patrick. "Multi-hazard analysis of steel structures subjected to fire following earthquake." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/313383.
Full textAbstract:
Fires following earthquake (FFE) have historically produced enormous post-earthquake damage and losses in terms of lives, buildings and economic costs, like the San Francisco earthquake (1906), the Kobe earthquake (1995), the Turkey earthquake (2011), the Tohoku earthquake (2011) and the Christchurch earthquakes (2011). The structural fire performance can worsen significantly because the fire acts on a structure damaged by the seismic event. On these premises, the purpose of this work is the investigation of the experimental and numerical response of structural and non-structural components of steel structures subjected to fire following earthquake (FFE) to increase the knowledge and provide a robust framework for hybrid fire testing and hybrid fire following earthquake testing. A partitioned algorithm to test a real case study with substructuring techniques was developed. The framework is developed in MATLAB and it is also based on the implementation of nonlinear finite elements to model the effects of earthquake forces and post-earthquake effects such as fire and thermal loads on structures. These elements should be able to capture geometrical and mechanical non-linearities to deal with large displacements. Two numerical validation procedures of the partitioned algorithm simulating two virtual hybrid fire testing and one virtual hybrid seismic testing were carried out. Two sets of experimental tests in two different laboratories were performed to provide valuable data for the calibration and comparison of numerical finite element case studies reproducing the conditions used in the tests. Another goal of this thesis is to develop a fire following earthquake numerical framework based on a modified version of the OpenSees software and several scripts developed in MATLAB to perform probabilistic analyses of structures subjected to FFE. A new material class, namely SteelFFEThermal, was implemented to simulate the steel behaviour subjected to FFE events.
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Covi, Patrick. "Multi-hazard analysis of steel structures subjected to fire following earthquake." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/313383.
Full textAbstract:
Fires following earthquake (FFE) have historically produced enormous post-earthquake damage and losses in terms of lives, buildings and economic costs, like the San Francisco earthquake (1906), the Kobe earthquake (1995), the Turkey earthquake (2011), the Tohoku earthquake (2011) and the Christchurch earthquakes (2011). The structural fire performance can worsen significantly because the fire acts on a structure damaged by the seismic event. On these premises, the purpose of this work is the investigation of the experimental and numerical response of structural and non-structural components of steel structures subjected to fire following earthquake (FFE) to increase the knowledge and provide a robust framework for hybrid fire testing and hybrid fire following earthquake testing. A partitioned algorithm to test a real case study with substructuring techniques was developed. The framework is developed in MATLAB and it is also based on the implementation of nonlinear finite elements to model the effects of earthquake forces and post-earthquake effects such as fire and thermal loads on structures. These elements should be able to capture geometrical and mechanical non-linearities to deal with large displacements. Two numerical validation procedures of the partitioned algorithm simulating two virtual hybrid fire testing and one virtual hybrid seismic testing were carried out. Two sets of experimental tests in two different laboratories were performed to provide valuable data for the calibration and comparison of numerical finite element case studies reproducing the conditions used in the tests. Another goal of this thesis is to develop a fire following earthquake numerical framework based on a modified version of the OpenSees software and several scripts developed in MATLAB to perform probabilistic analyses of structures subjected to FFE. A new material class, namely SteelFFEThermal, was implemented to simulate the steel behaviour subjected to FFE events.
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Pőssl, Petr. "Komplexní diagnostika železobetonového objektu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226969.
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The thesis summarizes methods used to finding material characteristics of reinforced concrete structures, treatment plan of diagnostic survey on the basis of visual inspection of the bridge, documentation of diagnosticated defects and condition assessment of the bridge.
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Snyder, Nicholas B. "DESIGN, VALIDATION, AND VERIFICATION OF THE CAL POLY EDUCATIONAL CUBESAT KIT STRUCTURE." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2148.
Full textAbstract:
In this thesis, the development of a structure for use in an educational CubeSat kit is explored. The potential uses of this kit include augmenting existing curricula with aspects of hands on learning, developing new ways of training students on proper space systems engineering practices, and overall contributing to academic capacity building at Cal Poly and its collaborators. The design improves on existing CubeSat kit structures by increasing accessibility to internal components by implementing a modular backplane system, as well as adding the ability to be environmentally tested. Manufacturing of the structure is completed with both additive (Fused Deposition Modeling with ABS polymer and Selective Laser Melting with AlSi10Mg metal) and subtractive (milling with Al-6061) technologies. Modal, harmonic, and random vibration analyses and tests are done to ensure the structure passes vibration testing qualification loads, as outlined by the National Aeronautics and Space Administration’s General Environmental Standards. Successful testing of the structure, defined as deforming less than 0.5 millimeters and maintaining a factor of safety above 2, is achieved with all materials of interest. Thus, the structure becomes the first publicly available CubeSat kit designed to survive environmental testing. Achieving this goal with a structure made of the cheap, widely available material ABS showcases the potential usability of 3D-printed polymers in CubeSat structures.
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Elshesheny, Ahmed. "Dynamic soil-structure interaction of reinforced concrete buried structures under the effect of dynamic loads using soil reinforcement new technologies. Soil-structure interaction of buried rigid and flexible pipes under geogrid-reinforced soil subjected to cyclic loads." Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18312.
Full textAbstract:
Recent developments in constructions have heightened the need for protecting existing buried infrastructure. New roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Additionally applied loads over water mains led to catastrophic damage, which result in severe damage to the infrastructure surrounding these mains. Therefore, providing protection to these existing buried infrastructure against increased loads due to new constructions is important and necessary.
In this research, a solution was proposed and assessed, where the protection concept would be achieved through the inclusion process of geogrid-reinforcing layers in the soil cover above the buried infrastructure. The controlling parameters for the inclusion of geogrid-reinforcing layers was assessed experimentally and numerically. Twenty-three laboratory tests were conducted on buried flexible and rigid pipes under unreinforced and geogrid-reinforced sand beds. All the investigated systems were subjected to incrementally increasing cyclic loading, where the contribution of varying the burial depth of the pipe and the number of the geogrid-reinforcing layers on the overall behaviour of the systems was investigated. To further investigate the contribution of the controlling parameters in the pipe-soil systems performance, thirty-five numerical models were performed using Abaqus software. The contribution of increasing the amplitude of the applied cyclic loading, the number of the geogrid-reinforcing layers, the burial depth of the pipe and the unit-weight of the backfill soil was investigated numerically.
The inclusion of the geogrid-reinforcing layers in the investigated pipe-soil systems had a significant influence on decreasing the transferred pressure to the crown of the pipe, generated strains along its crown, invert and spring-line, and its deformation, where reinforcing-layers sustained tensile strains. Concerning rigid pipes, the inclusion of the reinforcing-layers controlled the rebound that occurred in their invert deformation. With respect to the numerical investigation, increasing the number of the reinforcing-layers, the burial depth of the pipe and the unit-weight of the backfill soil had positive effect in decreasing the generated deformations, stresses and strains in the system, until reaching an optimum value for each parameter. Increasing the amplitude of the applied loading profile resulted in remarkable increase in the deformations, stresses and strains generated in the system. Moreover, the location of the maximum tensile strain generated in the soil was varied, as well as the reinforcing-layer, which suffered the maximum tensile strain.<br>Government of Egypt
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Sheng, Risheng. "Application de l’approche de simulation des grandes échelles à l’évaluation des charges de vent sur les structures." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0030/document.
Full textAbstract:
Des bâtiments de grande hauteur sont construits avec un poids et un amortissement structurel de plus en plus faibles en lien avec l'évolution des techniques de construction et des matériaux. La connaissance des charges de vent dynamiques est un enjeu important pour la conception des grands bâtiments afin de garantir leur sécurité structurelle. L'objectif de cette thèse est d’évaluer la capacité de la simulation numérique des grandes échelles (LES) à prédire les charges de vent sur les structures et d’étudier l'influence des conditions d’entrée d’une simulation LES sur ces charges. Des expériences ont été menées à échelle réduite dans la soufflerie atmosphérique NSA du CSTB afin de documenter l’écoulement atmosphérique modélisé, de caractériser son interaction avec un bâtiment et les charges de vent statiques et dynamiques résultantes. Le sillage du bâtiment a été caractérisé grâce à des mesures PIV. Les efforts globaux et les pressions locales ont été mesurés par une balance et des prises de pression à haute fréquence. Ces expériences en soufflerie ont permis de développer un générateur de conditions amont (GCA) pour la simulation LES, visant à reproduire les principales caractéristiques de la turbulence dans la couche limite. La base de données constituée a également permis de qualifier les résultats des simulations LES réalisées avec le code OpenFOAM dans la configuration de l’expérience. L’utilisation du nouveau GCA et d’un générateur dégradé qui ne respecte pas toutes les caractéristiques de l'écoulement a permis de montrer la nécessité de bien reproduire les caractéristiques du vent incident pour accéder aux charges dynamiques sur le bâtiment<br>High-rise buildings are built with increasingly low weight and structural damping in relation to the evolution of construction techniques and materials. The understanding of dynamic wind loads is an important issue for the design of high-rise buildings in order to guarantee their structural safety. The objective of the present work is to assess the ability of large eddy simulation (LES) to predict wind loads on structures and to investigate the influence of the inflow boundary conditions of a LES simulation on these loads. Experiments were carried out at a small scale in the NSA atmospheric wind tunnel of CSTB to document the modeled atmospheric boundary layer, to characterize its interaction with a building and the resulting static and dynamic wind loads. The wake flow around the building has been characterized by PIV measurements. Global and local wind loads were measured by a high frequency force balance and high frequency pressure taps. These wind tunnel experiments allowed for the development of an inflow turbulence generator for the LES simulation,which was aimed at reproducing the main characteristics of turbulence in the boundary layer. The database also made it possible to assess the quality of the results of the LES simulations carried out with the OpenFOAM code in the same configuration as the experiment. The use of both the new turbulence generator and a degraded one that does not account for all the characteristics of the flow has made it possible to show the necessity to reproduce the characteristics of the upstream wind flow in order to access the dynamic wind loads on the building
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Jedlička, Lukáš. "Diagnostika vybrané mostní konstrukce." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409954.
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This thesis deals with building survey of bridge register number 43-011 located near Česká. The part of thesis is literary reaserch dealing with system of management and cotrol of road bridges, precast bridge contructions made with DS-C type girgers and about general diagnostical methods. The practical section contains of in situ diagnostical survey and bridge inspection, laboratory evaluation and comparision, load bearing capacity calculation and suggestion of potencional technical precautions.
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Pokorný, Jan. "Bytový dům Prostějov, stavebně technologická příprava stavby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409939.
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In my diploma thesis, I focus on a building technology project of an apartment house in Prostějov. My work aims to design an optimal construction process. The thesis consists of a technical report, coordination drawing, project of the building site, building machines and mechanisms, time schedule and financial plan, description of technological process of the ventilated facade and of the monolithic reinforced concrete vertical structures including quality controls and testing plans. The process of making ventilated facade in comparison with the ETICS system is presented in more detail. Because the construction works take place in a city centre, the study of noise on the construction site is included as well.
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Cruz, Cháidez Servio Tulio de la. "Contribution to the assessment of the efficiency of friction dissipators for seismic protection of buildings." Doctoral thesis, Universitat Politècnica de Catalunya, 2003. http://hdl.handle.net/10803/6229.
Full textAbstract:
Esta Tesis trata de la simulación numérica y experimental de estructuras de edificios equipadas con disipadores de energía de fricción, sujetos a cargas de sismo. La Tesis pretende contribuir a la evaluación de la eficacia de los disipadores de fricción para reducir la respuesta lateral de los edificios sujetos a sismos. Así, el objetivo global es la evaluación de la utilidad de los disipadores de fricción frente a las cargas sísmicas.<br/><br/>La Tesis está organizada de tal manera que sea fácil su seguimiento. Por esta razón, los capítulos se han escrito siguiendo una secuencia lógica. Una breve descripción de los capítulos se presenta a continuación.<br/><br/>El primer capítulo trata de los aspectos generales del Control Estructural con un especial énfasis en los disipadores de fricción, los cuales se incluyen en el llamado enfoque de 'Control Pasivo'.<br/>El Capítulo 2 proporciona un repaso general al estado del conocimiento relativo a los principios de la fricción seca y a la investigación y aplicación de los dispositivos disipadores de fricción, así como a sus simulaciones numéricas.<br/><br/>Un procedimiento numérico ha sido desarrollado (programa ALMA) en los Capítulos 3 (edificios de una sola planta) y 4 (edificios de varias plantas) para llevar a cabo simulaciones numéricas de edificios equipados con disipadores de fricción y los resultados obtenidos fueron comparados a los que se obtuvieron con el programa comercial ADINA. La similitud entre los resultados de ambos programas es aceptable.<br/><br/>El Capítulo 5 describe los ensayos sobre una mesa vibratoria que se hicieron en dos modelos de edificios: uno de una sola planta y otro de dos plantas; ambos equipados con disipadores de fricción. Los resultados obtenidos se compararon a los resultados conseguidos con ALMA. Los resultados coinciden aceptablemente.<br/><br/>Luego de probar la validez del programa ALMA, éste se usó para hacer un estudio numérico preliminar para obtener la llamada 'carga óptima de deslizamiento' de los disipadores de fricción en el Capítulo 5. Las curvas que se pueden dibujar a partir de los resultados obtenidos con este estudio, pueden ser aplicadas para determinar las cargas óptimas de deslizamiento de edificios de una y varias plantas.<br/><br/>Finalmente, el Capítulo 7 contiene las conclusiones de esta Tesis y algunas propuestas para las futuras líneas de investigación.<br/><br/>Además, se han incluido cinco apéndices. El Apéndice A contiene los principios básicos del Análisis del Contacto. El Apéndice B trata de la solución numérica de las ecuaciones de movimiento para sistemas de uno y varios grados de libertada. Este apéndice está muy relacionado con el contenido de los Capítulos 3 y 4 de esta Tesis. El Apéndice C describe la solución de las ecuaciones de movimiento usando multiplicadores de Lagrange. El Apéndice D describe el equipo de laboratorio y la instrumentación usada en los ensayos. Los resultados de éstos, y la comparación entre éstos y los resultados numéricos (programa ALMA), son presentados en el Apéndice E.
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Лясковець, Дмитро Михайлович, та Dmytro Liaskovets. "Проект стенду для випробування великогабаритних будівельних конструкцій". Master's thesis, 2020. http://elartu.tntu.edu.ua/handle/lib/33666.
Full textAbstract:
Робота містить всі передбаченні завданням і нормативними документами структурні
елементи. Розроблено проект стенду для випробування великогабаритних будівельних матеріалів.
Виконано огляд випробувальних стендів інших проектних рішень. Проаналізовано їхні недоліки та
запропоновано варіанти вирішення в дані конструкції. Підібрано спеціальне електронне та
механічне обладнання під попередньо закладені характеристики. Зроблені розрахунки навантажень
силових установок та каркасних з’єднань. Досліджено фактори негативного впливу та створено
інструкції з охорони праці<br>The work contains all the structural elements provided by the task and regulations. A
project of a stand for testing large construction materials has been developed. A review of test benches of
other design solutions was performed. Their shortcomings are analyzed and solutions to these designs are
proposed. Special electronic and mechanical equipment is selected for the pre-set characteristics. Load
calculations of testing machines and frame connections are made. Factors of negative influence are
investigated and instructions on labor protection are created<br>Вступ
Розділ 1. Архітектурно-будівельний
1.1 Приклади великогабаритних конструкцій
1.2 Конструкційні рішення для випробування залізобетонних виробів
1.3 Загальна характеристика сучасних випробувальних комплексів
1.4 Випробувальні стенди для проведення випробувань на міцність при
стиску та розтягу
Розділ 2. Розрахунково-конструктивний
2.1 Основні вимоги до проведення механічних випробувань
2.2 Вимоги до стендів для великогабаритних будівельних матеріалів та
конструкцій
2.2.1 Пристрої вимірювання
2.2.2 Визначення прогинів, лінійних деформацій механічними засобами
2.2.3 Електроні засоби для визначення прогинів, деформацій. Конструктивні
схеми засобів
2.3 Конструктивні схеми випробувального стенду
Розділ 3. Науково дослідний
3.1 Види з’єднань металевих конструкцій
3.2 Класифікація зварних швів
3.3 Класифікація видів зварок
3.4 Болтові з’єднання
3.5 Робота та розрахунок болтів, що працюють на розтяг
3.6 Робота та розрахунок болтів на дію зсувних сил
3.7 Робота і розрахунок з’єднань на високоміцних болтах
3.8 Розрахунок з’єднань на болтах під дією різних силових факторів
Розділ 4. Охорона праці
4.1 Оціночна характеристика
4.2 Аналіз травматизмів
4.3 Профілактика травматизму і професійних захворювань
4.4 Гігієнічна оцінка умов праці
4.5 Загальні вимоги до технічного обладнання та процесів
4.6 Виробнича санітарія
4.6.1 Освітлення
4.6.2 Вентиляція та опалення
4.7 Пожежна безпека
4.8 Інструктажі з техніки безпеки
4.8.1 Інструкція з пожежної безпеки
4.8.2 Інструкція з охорони праці при роботі з випробувальним стендом
Бібліографія
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Chang, En-Tzu, and 張恩慈. "Deterioration Evaluation of RC Building Structures Using Material Testing Data Base." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/8krar5.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>河海工程學系<br>103<br>This study was aimed to investigate the material factors affecting the degree of deterioration of reinforced concrete structures. Durability indicators were divided into two categories: the status of concrete and reinforcement. The status of concrete includes compressive strength, resistance coefficient, concrete cracks, honeycomb and spalling; reinforcement status includes corrosion potential, corrosion current, chloride ion content, neutralization depth and protective layer thickness. Durability indicators were determined through the findings on the durability of concrete structure and the evaluation of projects related to materials testing and evaluation standards.
A reinforced concrete durability comprehensive assessment system and durability indicators were established. Case studies were also presented to illustrate the methodology of assessment system.
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Tu, Tsung-Hun, and 杜宗翰. "The investigation of UAV with Thermal Camera for the non-destructive testing of building structures." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/92s76s.
Full textAbstract:
碩士<br>正修科技大學<br>營建工程研究所<br>106<br>In this study, visible light and thermal imaging cameras are mounted on the unmanned aerial vehicle (UAV) for non-destructive testing of structures. For this, three types of different structures are selected for this study, including 10 monuments in Tainan City, exterior walls of the campus buildings and one solar power plant. In the testing process, visible light photos and thermal images of the structures are first obtained, and then interpretative analysis is performed to identify the positions where the temperature is abnormal, and after that site verification is conducted for the abnormal positions, so as to obtain effectiveness of infrared thermal imaging camera in non-destructive testing of the structures.
Theresults of abnormal temperature distribution are obtained from the 4 roofs of the monuments, exterior walls of 2 buildings and roof-mounted solar panel of the solar power plant.Afterthesite inspection, water leakage, ageing, voids, adhesion failure of wall tiles or equipment failure were not identified in the areas at normal temperature. The problems were identified at the areas at abnormal temperature. The results showedthat the non-destructive testing method can detect defective structures and help reinforce, maintain and manage the structures.
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Giri, Paritosh. "Integrated approaches for non-destructive testing of construction materials and structures." Thesis, 2019. http://hdl.handle.net/1959.7/uws:51404.
Full textAbstract:
Civil infrastructures include structures which are inherently large in dimension, geometrically complex with different elements and joints, and composed of different materials. Due to the diverse material properties, geometrical shapes and varied damages in these structures, the selection of a non-destructive testing technique is a challenging task. This thesis aims to highlight the need for utilising multiple standalone techniques or integrated approaches for non-destructive testing of diverse construction materials and structures. This way, the benefits of different sensor techniques can be utilised to develop a system which can overcome the limitations of conventional non-destructive testing techniques. For this, systems based on three major techniques, namely, laser displacement technique, microwave sensing technique and piezoelectric sensing technique is developed. The displacement measuring property of laser displacement sensors is utilised to generate one-dimensional, two-dimensional and three-dimensional surface profiles and images of different specimens. The microwave imaging technique is developed for the non-destructive testing of planar and tilted construction materials in civil infrastructures. A piezoelectric based sensor technique is developed for the detection of gap and debonding in concrete based composite structure. The development of these standalone and integrated systems highlights the need of different non-destructive testing techniques for applications in demand. The integrated approaches not only enable monitoring of diverse materials and structures but also assure accurate and reliable information from these structures. Therefore, the integrated non-destructive testing approach is a key to overcome the limitations of current methods in monitoring the integrity of in-service structures on a continuous real-time basis.
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Dhanvijay, Sonal Suryabhan. "Structural dynamic testing for seismic response simulation and time variant reliability estimation." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4754.
Full textAbstract:
The research work reported in this thesis addresses a few problems which arise in the context of experimental dynamic testing of engineering structures under earthquake loads. Firstly, we consider the problem of characterizing and controlling errors that occur during hybrid simulation based pseudo-dynamic testing with substructuring. The study notes the complex interaction between the errors, that originate due to the approximations involved in the numerical modelling, and the experimental errors associated with actuation and measurements. This interaction involves a nonlinear dynamic response simulation of the test structure, and the error of simulation is noted to be system state dependent. The study proposes an adaptive time stepping strategy which is based on the solution of an associated linearized variational equation of motion of the test structure. The proposed method is illustrated on systems displaying geometric nonlinearity and contact nonlinearity due to pounding. The test protocol is implemented on a reaction wall based multiple servo-hydraulic actuation-based test system. The study is followed by an investigation into experimental estimation of time variant reliability of engineering structures subjected to earthquake loads modelled as a set of random processes. Specifically, the study has developed an experimental protocol which employs a combination of Markov Chain splitting methods and surrogate modelling tools, to arrive at a sampling variance reduced estimator for the probability of failure. It is shown that the implementation of the experimental protocol does not require explicit knowledge of a valid mathematical model of the test structure. The procedure developed has been shown to be applicable to tackle the problems of time variant component and system reliability estimation, and the procedure can handle both linear and nonlinear vibrating systems. The proposed test protocol has been implemented not only on the reaction wall based multiple servo-hydraulic actuation-based test system, but also on a multi-actuator earthquake shaking table
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Kim, Hyunjin 1974 Jan 21. "Progressive collapse behavior of reinforced concrete structures with deficient details." 2006. http://hdl.handle.net/2152/12986.
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Govender, Stanton Wesley. "Parametric studies on the temperature dependent behaviour of steel structures within a fire context." Thesis, 2012. http://hdl.handle.net/10413/9120.
Full textAbstract:
The mechanical and material properties of structural steel at elevated temperatures play
an important role in structural fire design. The South African 350W and S355 structural
steels are common in building structures with S355 slowly replacing the older 350W. The
cost and feasibility of full scale fire tests are some of the causes for the lack of
experimental data on the behaviour of steel structures when exposed to fire. Therefore
excessively conservative design codes based on isolated laboratory experiments are used
in practice which leads to increased material costs. Another area of concern with respect
to building safety is the reusability of structural steels post fire exposure, which is not
effectively addressed within these codes.
This study aims to establish greater insight into structural fire design and simulation on
which further research can be built. Experimental programs on the temperature
dependent behaviour of these steel members loaded axially are conducted and compared
with theory and the Eurocode 3 standard [1]. The reusability of steel exposed to fire and
after being cooled down is investigated and compared to the findings by Outinen [2].
Further testing on material to determine the relationship between remaining life and
hardness degradation after cooling down was conducted.
Experimental data from various external studies are used to develop novel computer
models using the finite element analysis software, SimXpert [3]. These are verified against
the original data and compared to existing design codes. A parametric approach is used
with these models to demonstrate the advantages of computer simulations in structural
fire design. Different cross sections and slenderness ratios are evaluated for their
susceptibility to buckling at elevated temperatures.
The results of this study show that as temperature and exposure time increase the
integrity of steel members decrease. The current design codes accurately predict the
behaviour of isolated specimens but lack data on real situations where the specimen is
part of a complex structure. It was found that steel members can be reused if their
exposure temperature does not exceed 700°C, after which their strength can reduce to
90%. This temperature dependant behaviour was successfully modelled using basic
computer simulations and then demonstrated the ease in which they can be used in place
of experimental regimes. The parametric advantages of these simulations were
demonstrated by predicting the effects of slenderness ratios and geometry cross sections
on the buckling behaviour.<br>Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2012.
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Kiwombojjo, Michael. "The role of capacity building in community home based care for AIDS patients: an exploratory study of Taso : Sseeta-Nazigo Community Aids Initiative." Diss., 2002. http://hdl.handle.net/10500/748.
Full textAbstract:
The focused of this study is the role of capacity building in Community Home Based Care (CHBC) for HIV/AIDS patients. The study forms part of my Master's in Development Administration programme, undertaken through UNISA. The dissertation was accomplished by studying the
TASO community initiative in Sseeta-Nazigo, Mukono District, Uganda. It explores the concept of capacity building and its applicability to CHBC.
The primacy data was gathered by conducting Key Infonnant Interviews (KIIs) and Focus Group Discussions (FGD). The secondary data was gathered by reviewing literature to augment the primary data. In addition, data was gathered through observations within the community.
The fmdings have identified seven critical components of capacity building: community mobilisation, skills development, Information, Education and Communication (IEC) Voluntary Counselling and Testing (VCT), networking and collaboration, support and supervision, Monitoring and Evaluation (M&E). The study observed that capacity built in the above areas resulted in three outcomes: skills development, improvement in procedures, and institutional development. Informed recommendations were subsequently made related to the seven componentsof capacity building in CHBC<br>Development Studies<br>M. A. (Development Studies)