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1
Shrestha, Alina. "Fatigue Testing and Data Analysis of Welded Steel Cruciform Joints." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1670.
Full textAbstract:
In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate the S-N data well. The equivalent structural stress parameter is introduced to investigate the fatigue behavior of welded joints using the traction based structural stress approach on finite element models of specimens, and representing the data as a single Master S-N curve.
2
Feng, Ran, and 馮然. "Design of cold-formed stainless steel tubular joints." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41290628.
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3
Schrauben, Corey S. "Behavior of full-scale bolted beam-to-column T-stub and clip angle connections under cyclic loading." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20013.
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4
Smallidge, Jeffrey M. "Behavior of bolted beam-to-column T-stub connections under cyclic loading." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19534.
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5
Jiao, Hui 1963. "The behaviour of very high strength (VHS) members and welded connections." Monash University, Dept. of Civil Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/9417.
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6
Derrick, Nathan Lynn. "Shear and Bending Strength of Cold-Formed Steel Solid Wall Panels Using Corrugated Steel Sheets for Mobile Shelters." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062814/.
Full textAbstract:
The objective of this thesis is to determine if the single sided resistance spot weld (RSW) can be used as a feasible connection method for cold formed steel (CFS) shear walls subject to lateral force of either seismic or wind loads on mobile shelters. The research consisted of three phases which include: a design as a 3D BIM model, connection tests of the resistance spot weld, and full-scale testing of the designed solid wall panels. The shear wall testing was conducted on specimens with both resistance spot weld and self-drilling screws and the results from tests gave a direct comparison of these connections when the solid wall panel was subjected to in-plane shear forces. The full-scale tests also included 4-point bending tests which was designed to investigate the wall panel's resistance to the lateral loads applied perpendicularly to the surface. The research discovered that the singled sided resistance spot weld achieved similar performance as the self-drilling screws in the applications of CFS wall panels for mobile shelters. The proposed single sided resistance spot weld has advantages of low cost, no added weight, fast fabrication, and it is a feasible connection method for CFS wall panels.
7
Kahle, Matthew Gilbert. "Partially restrained composite connections : design and analysis of a prototype structure." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/20830.
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8
Vora, Hitesh. "Shear Wall Tests and Finite Element Analysis of Cold-Formed Steel Structural Members." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9726/.
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The research was focused on the three major structural elements of a typical cold-formed steel building - shear wall, floor joist, and column. Part 1 of the thesis explored wider options in the steel sheet sheathing for shear walls. An experimental research was conducted on 0.030 in and 0.033 in. (2:1 and 4:1 aspect ratios) and 0.027 in. (2:1 aspect ratio) steel sheet shear walls and the results provided nominal shear strengths for the American Iron and Steel Institute Lateral Design Standard. Part 2 of this thesis optimized the web hole profile for a new generation C-joist, and the web crippling strength was analyzed by finite element analysis. The results indicated an average 43% increase of web crippling strength for the new C-joist compared to the normal C-joist without web hole. To improve the structural efficiency of a cold-formed steel column, a new generation sigma (NGS) shaped column section was developed in Part 3 of this thesis. The geometry of NGS was optimized by the elastic and inelastic analysis using finite strip and finite element analysis. The results showed an average increment in axial compression strength for a single NGS section over a C-section was 117% for a 2 ft. long section and 135% for an 8 ft. long section; and for a double NGS section over a C-section was 75% for a 2 ft. long section and 103% for an 8 ft. long section.
9
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.
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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.
10
Elflah, Mohamed A. Hussaen. "Structural behaviour of stainless steel bolted beam to column joints." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8545/.
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Initially, two experimental programmes studying the structural behaviour of stainless steel beam-to-open column joints and beam-to-tubular column joints under static loads are reported in detail. The joint configurations tested include flush and extended end plate connections, top and seat cleat connections and top, seat and web cleat connections. The full moment-rotation characteristics are reported in detail. It is observed that the connections displayed excellent ductility, superior than that of equivalent carbon steel connections, and attained loads much higher than the ones predicted by design standards for carbon steel joints. Nonlinear FE models have been developed and validated against the experimental results. The FE models are shown to accurately replicate the experimentally determined, initial stiffness, ultimate resistance, overall moment-rotation response and observed failure modes. In addition, a comprehensive parametric study is conducted. The design rules for stainless steel connections, which are based on the specifications of EN 1993-1-8 for carbon steel joints, are reviewed and are found to be overly conservative in terms of strength and inaccurate in terms of stiffness thus necessitating the development of novel design guidance in line with the observed structural response. Hence, simplified mechanical models in line with the observed response are developed.
11
Alemdar, Bulent Nedim. "Distributed plasticity analysis of steel building structural systems." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/22220.
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Tavrou, Chrysostomos Kyriacou, and stavrou@swin edu au. "Evaluation of adhesively bonded steel sheets using ultrasonic techniques." Swinburne University of Technology, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20060306.085412.
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Adhesives have presently reached a stage where they have become part of everyday
life both in a professional sense as well as for household applications. They offer
advantages that in many respects surpass other joining processes such as bonding
of large areas, joining a wide range and dissimilar materials; and without the need for
special tooling or operator training, that is often required by many other joining
processes. They are of course not a panacea to all fastening applications, but they
can easily be described as the most versatile and most widely used joining method at
present.
Engineering applications have also benefited from the advantages offered by
adhesives, but they are not as liberally used due to the severe consequences that
may result from bond failure. Although adhesives can demonstrate their ability to
fulfil the joining strength requirements under laboratory conditions, their application in
industry proved to be not as reliable as expected. A number of parameters that can
easily be controlled under laboratory conditions such as temperature, humidity,
surface preparation and uniform adhesive application are not as easily observed in
industry. Quality assurance during manufacturing can achieve excellent results;
however even in these cases the probability of having adhesive bond defects is still
present. Therefore, there is a need for post process inspection of adhesive bonds
where risk levels require higher reliability than what is offered though process quality
control.
Adhesive bond inspection is a well researched area with respectable outcomes. Non
destructive inspection techniques such as x-ray, thermal, and ultrasonic are well
utilised in the inspection of adhesive bonds. However, despite all the effort in this
area for more than forty years, there is still no singular technique that can achieve the
confidence level required in some engineering applications. Therefore, the need for
continuing research in the area of non-destructive evaluation of adhesive bonds is as
necessary today as it�s ever been. The research presented in this thesis, continues
in the same endeavour as many other researchers; that of achieving the ultimate
technique in adhesive bond inspection, capable of reaching the confidence level
required for all engineering applications.
The research in the thesis commenced with coverage of adhesives used for
engineering applications and a study of the adhesion science that was considered
necessary to enable an informed approach to the problem. Adhesive bond failure is
also analysed through a literature survey as well as experimental tests on standard
specimens. At the completion of the literature survey and preliminary tests, a
decision was taken to follow the ultrasonic path of non-destructive testing of adhesive
bonds. The reasons for this, are clearly outlined in the main body of this thesis but in
summary, the literature has shown that ultrasonic evaluation is the most widely used
technique by industry. Therefore, improvements on data analysis using existing
techniques that exploit ultrasonic inspection have the potential to reach the widest
spectrum of industrial applications.
Ultrasonic inspection equipment was sourced that was capable of achieving
experimental results to the accuracy level required in this research. A precision test
rig was designed and constructed that was subsequently calibrated using computer
based statistical techniques to ensure the validity of all results. Other ancillary
equipment, such as a portable tensile testing device were also designed and
constructed during the research as it became necessary.
Research concentrated on techniques found to be inadequately researched in this
domain. The first technique evaluated was to measure bond quality through the
stress distribution in adherent and adhesive. Computer based Finite Element
Analysis showed that the ability to detect variation in stress distribution at the
adhesion interface is capable of revealing the local bond strength. Having found that
there is no technique available at present that can measure the stress distribution at
the interface, a different direction was taken that showed potential in achieving
excellent quantitative results in the analysis of ultrasonic signals from adhesive
bonds. This technique was rigorously evaluated and the results are systematically
reported in this work.
13
Clubley, Simon. "Computational structural analysis and testing of Bi-Steel plate." Thesis, University of Southampton, 2001. https://eprints.soton.ac.uk/340969/.
Full textAbstract:
Bi-Steel panels are a new composite construction system developed by Corus formerly British Steel Plc. The comprise of steel plates permanently coupled by a matrix of transverse friction welded rods with a concrete in-fill. Numerical modelling using finite element analysis has been conducted on Bi-Steel plates with and without in-filled concrete. The results of non-linear analysis are compared with new and existing experimental data. Both material and geometrical non-linearity were considered in the computer analysis. The shear strength and deformation capacity of the Bi-Steel unit subject to push-out load is discussed. The steel and concrete interface is considered extensively in a series of contact studies. A range of element types is used to examine the effect of modelling the interface as a smeared or discrete contact. Mathematical modelling is used in conjunction with experimental data to validate solution accuracy. The inclusion of a smeared cracking and crushing mechanism has allowed the accurate modelling of concrete. A new method of differential smeared element reinforcement is proposed to maximise accuracy and numerical stability. The failure of a panel subject to an applied bending force is analysed to determine the combined effect of flexure and shear. Finally, a design model has been suggested to calculate the shear strength and deformation capacity of any section size. This research has indicated that Bi-Steel bars and plates have significant shear strength. The shear strength is affected by several important parameters. These include plate spacing, bar spacing and bar diameter. From load-deformation relationships it can be seen that Bi-Steel plates have high ductility and deformation capacity. For very thick plates (>12mm), the failure can be brittle if bar numbers are small. The failure will be initiated by shear failure at the weld interface.
14
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.
Full textAbstract:
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.
15
Collette, Kristin A. "Comparisons of structural designs in fire." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-050307-182832/.
Full textAbstract:
Thesis (M.S.) -- Worcester Polytechnic Institute.<br>Keywords: Office buildings; Steel beams; Lumped parameter method; Cardington Tests; Design fire curves . Includes bibliographical references (leaves 144-146).
16
Avery, P. "Advanced analysis of steel frame structures comprising non-compact sections." Thesis, Queensland University of Technology, 1998. https://eprints.qut.edu.au/36071/1/36071_Digitised_Thesis.pdf.
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During the past decade, a significant amount of research has been conducted internationally with the aim of developing, implementing, and verifying "advanced analysis" methods suitable for non-linear analysis and design of steel frame structures.
Application of these methods permits comprehensive assessment of the actual failure modes and ultimate strengths of structural systems in practical design situations, without resort to simplified elastic methods of analysis and semi-empirical specification equations. Advanced analysis has the potential to extend the creativity of structural engineers and simplify the design process, while ensuring greater economy and more uniform safety with respect to the ultimate limit state.
The application of advanced analysis methods has previously been restricted to steel frames comprising only members with compact cross-sections that are not subject to the effects of local buckling. This precluded the use of advanced analysis from the design of steel frames comprising a significant proportion of the most commonly used Australian sections, which are non-compact and subject to the effects of local buckling. This thesis contains a detailed description of research conducted over the past three years in an attempt to extend the scope of advanced analysis by developing methods that include the effects of local buckling in a non-linear analysis formulation, suitable for practical design of steel frames comprising non-compact sections.
Two alternative concentrated plasticity formulations are presented in this thesis: the refined plastic hinge method and the pseudo plastic zone method. Both methods implicitly account for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. The accuracy and precision of the methods for the analysis of steel frames comprising non-compact sections has been established by comparison with a comprehensive range of analytical benchmark frame solutions. Both the refined plastic hinge and pseudo plastic zone methods are more accurate and precise than the conventional individual member design methods based on elastic analysis and specification equations. For example, the pseudo plastic zone method predicts the ultimate strength of the analytical benchmark frames with an average conservative error of less than one percent, and has an acceptable maximum unconservati_ve error of less than five percent. The pseudo plastic zone model can allow the design capacity to be increased by up to 30 percent for simple frames, mainly due to the consideration of inelastic redistribution. The benefits may be even more significant for complex frames with significant redundancy, which provides greater scope for inelastic redistribution.
The analytical benchmark frame solutions were obtained using a distributed plasticity shell finite element model. A detailed description of this model and the results of all the 120 benchmark analyses are provided. The model explicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. Its accuracy was verified by comparison with a variety of analytical solutions and the results of three large-scale experimental tests of steel frames comprising non-compact sections. A description of the experimental method and test results is also provided.
17
LIMA, LUCIANO RODRIGUES ORNELAS DE. "BEHAVIOUR OF STRUCTURAL STEEL ENDPLATE JOINTS SUBJECTED TO BENDING MOMENT AND AXIAL FORCE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4165@1.
Full textAbstract:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>Tradicionalmente, o projeto de pórticos em estruturas de
aço assume que as ligações viga-coluna são rígidas ou
flexíveis. As ligações rígidas, onde não ocorre nenhuma
rotação entre os membros conectados, transferem não só
momento fletor, mas também força cortante e força normal.
Por outro lado, as ligações flexíveis são caracterizadas
pela liberdade de rotação entre os membros conectados
impedindo a transmissão de momento fletor.
Desconsiderando-
se estes fatos, sabe-se que a grande maioria das
ligações não possuem este comportamento idealizado. De
fato, a maioria das ligações transfere algum momento
fletor
com um nível de rotação associado. Estas ligações são
chamadas semi-rígidas e seu dimensionamento deve ser
executado de acordo com este comportamento estrutural
real.
Porém, algumas ligações viga-coluna estão sujeitas a uma
combinação de momento fletor e esforço axial. O nível de
esforço axial pode ser significativo, principalmente em
ligações de pórticos metálicos com vigas inclinadas, em
pórticos não-contraventados ou em pórticos com pavimentos
incompletos. As normas atuais de dimensionamento de
ligações estruturais em aço não consideram a presença de
esforço axial (tração e/ou compressão) nas ligações.
Uma limitação empírica de 5 por cento da resistência plástica da
viga é a única condição imposta no Eurocode 3. O objetivo
deste trabalho é descrever alguns resultados
experimentais
e numéricos para estender a filosofia do método das
componentes para ligações com ações combinadas de momento
fletor e esforço axial. Para se cumprir este objetivo,
quinze ensaios foram realizados e um modelo mecânico é
apresentado para ser usado na avaliação das propriedades
da
ligação: resistência à flexão, rigidez inicial e
capacidade
de rotação.<br>Traditionally, the steel portal frame design assumes that beam-to-column
joints are rigid or pinned. Rigid joints, where no relative rotations occur between
the connected members, transfer not only substantial bending moments, but also
shear and axial forces. On the other extreme, pinned joints, are characterised by
almost free rotation movement between the connected elements that prevents
the transmission of bending moments.
Despite these facts, it is largely recognised that the great majority of joints
does not exhibit such idealised behaviour. In fact, many joints transfer some
bending moments associated with rotations. These joints are called semi-rigid,
and their design should be performed according to their real structural behaviour.
However, some steel beam-to-column joints are often subjected to a
combination of bending and axial forces. The level of axial forces in the joint may
be significant, typical of pitched-roof portal frames, sway frames or frames with
incomplete floors. Current standard for steel joints do not take into account the
presence of axial forces (tension and/or compression) in the joints. A single
empirical limitation of 5 percent of the beam s plastic axial capacity is the only enforced
provision in Annex J of Eurocode 3. The objective of the present work is to
describe some experimental and numerical results to extend the philosophy of
the component method to deal with the combined action of bending and axial
forces. To fulfil this objective a set of sixteen specimens were performed and a
mechanical model was developed to be used in the evaluation of the joint
properties: bending moment resistance, initial stiffness and rotation capacity.
18
Holsgrove, Stephen Clive. "Large deformation, large roation elasto-plastic shell analysis with particular application to tubular members and joints." Thesis, Kingston University, 1987. http://eprints.kingston.ac.uk/20511/.
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The ultimate strength assessment of steel tubular members is of the utmost importance to the design and maintenance of many structures including large offshore platforms. Ultimate strength assessments I using numerical solutions must model both nonlinear material and geometric behaviour. The latter must consider large displacements, very often large rotations, and possibly even large strains. These numerical solutions must be computationally efficient and be capable of running on generally available computer hardware, i.e. minicomputers. To achieve this efficiency, attention must be paid to programming considerations, and a new suite of data management modules has been developed and is described in this thesis, which minimise disk storage and speed program development. In addition, the structural modelling was carried out almost exclusively using the Semiiaaf thin shell element. The work described in this thesis considers most of the components which contribute to the numerical ultimate strength analysis of steel tubular members. Theoretically, attention has been focused in two areas, namely the geometric nonlinearity and the automatic solution of the resulting nonlinear equations. A detailed study has been carried out to understand fully the main methods of accounting for geometric nonlinearity from fundamentals of continuum mechanics. The study has considered both the Green-Lagrange and Logarithmic strain measures with a Total Lagrangian, Updated Lagrangian and Eulerian description of motion. These formulations have been included in the Semiiaaf shell element, firstly using a continuum mechanics based approach, and secondly using the more orthodox stress resultant approach. At all stages within the thesis attention is drawn to the effects of the approximations which have been made and their resulting limitations in the respective formulations. The solution of the nonlinear equations is also covered in detail using Newton-type algorithms coupled with line searches. The solution algorithms have been derived for a constrained environment where a modified version of the generalised arc-length constraint has been used. The inclusion of material nonlinearity has been well developed previously but has been included for completeness. To demonstrate the performance and limitations of the theory presented, several carefully chosen numerical examples have been included which include the analysis of tubular steel T and X joints connections and residual strength assessment of a dented pipeline riser. Where possible, results have been compared with experimental tests. The thesis concludes that for general engineering structures, the Total Lagrangian approach based on the stress resultant model gives good engineering results, even in the presence of moderately large rotations. Of the alternative formulations the Updated Lagrangian layered approach is probably the most effective for large rotations and small to moderate strains.
19
Filiatrault, André. "Performance evaluation of friction damped braced steel frames under simulated earthquake loads." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25091.
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This thesis presents the results obtained from qualification tests of a new friction damping system, which has been proposed in order to improve the response of Moment Resisting Frames and Braced Moment Resisting Frames during severe earthquakes. The system basically consists of a special inexpensive mechanism containing friction brake lining pads introduced at the intersection of frame cross-braces. The main objective is to study the performance of a 3 storey Friction Damped Braced Frame model under simulated
earthquake loads.
The main members of the test frame were chosen from available hot-rolled sections and the mass selected to provide the expected fundamental frequency of a three storey Moment Resisting Frame. The seismic testing was performed on an earthquake simulator table. The experimental results are compared with the findings of an inelastic time-history dynamic analysis. Two different computer models were used for this purpose. The first one is based on an equivalent hysteretic model and is only approximate,
since it does not take into account the complete behaviour of the friction devices. A more refined computer model was then developed and the results from the two models are compared. It is found that the simpler approximate model overestimates the energy dissipated by the devices, but the inaccuracy is relatively small (10-20% in resulting member forces).
To quantify the performance of the Friction Damped Braced Frame relative
to conventional aseismic systems, an equivalent viscous damping study is made. Viscous damping is added to the Moment Resisting Frame and the Braced Moment Resisting Frame until their responses become similar to the response of the Friction Damped Braced Frame. The results show that for this purpose 38% of critical damping must be added to the Moment Resisting Frame and 12% to the Braced Moment Resisting Frame. The new system becomes more efficient as the intensity of the earthquake increases.
The economical potential of the new damping system is investigated by designing a reduced size Friction Damped Braced Frame having response characteristics which are similar to those of conventional structural systems with heavier members. For the model frames studied, the results show that if the effects of wind, live and torsion loads are neglected, it is possible to reduce the members sizes of the Friction Damped Braced Frame by 47% and still achieve a superior performance under strong earthquake, in comparison to the seismic response of the two other conventional frames with their original, heavier members.
The results, both analytical and experimental, clearly indicate the superior performance of the friction damped braced frame compared to conventional building systems. Even an earthquake record with a peak acceleration of 0.9 g causes no damage to the Friction Damped Braced Frame, while the Moment Resisting Frame and the Braced Moment Resisting frame undergo large inelastic deformations.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
20
Tahir, Mahmood Md. "Structural and economic aspects of the use of semi-rigid joints in steel frames." Thesis, University of Warwick, 1997. http://wrap.warwick.ac.uk/4192/.
Full textAbstract:
This thesis reports on five main areas as follows: 1. Braced steel frames designed for semi-continuous construction were studied to determine savings in both cost and weight. Various frame parameters such as the number of bays, use of grade S355 steel, beam spans, types of connection, and selection of beam size were investigated. The investigation confirmed that semicontinuous construction contributes to worthwhile percentage savings on both cost and weight. 2. Analysis and design of steel unbraced frames bending on both axes were performed with emphasis on stability and deflection checks. Rules are proposed to improve the stability and stiffness. For connections to the minor axis, a proposed joint detail is presented. The performance of the frames was checked for collapse load level at ULS; deflection limits at SLS were also checked; in both cases using first and second order analysis. The investigation demonstrated that the frames should be restricted to less than four storeys. 3. A study on minor axis joints was carried out for flush end plate connections connected to the column web. Previous experimental results of moment and stiffness were compared with predicted values. Moment values were predicted using Gomes' formulae. The stiffness due to the column web was predicted using finite element analysis. The results showed good agreement between experimental and predicted values. The study on the connections was extended to their suitability in steel frames bending about the minor axis; the investigation confirmed that the connections were not suitable for unbraced wind-moment frames. An equation for prediction of initial stiffness was nevertheless established for the connection. 4. Steel frames with composite beams designed for minimum wind combined with maximum gravity load were studied for their performance, taking into account cracking along the beams. The investigation showed that the frames meet the requirements of deflection and sustain a load level of 1.0 for ULS. For frames studied for maximum wind combined with minimum gravity load, the moment capacity of the joints governed the design which resulted in a deeper beam section. 5. Seven tests were carried out for a new type of shear connector system installed by compressed air. The aim of the tests was to study the shear capacity and ductility of the studs. The tests showed that the pins fail due to fracture and the stud systems needs some improvements to increase the key structural properties.
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Stewart, Lauren K. "Testing and analysis of structural steel columns subjected to blast loads." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3404594.
Full textAbstract:
Thesis (Ph. D.)--University of California, San Diego, 2010.<br>Title from first page of PDF file (viewed June 11, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (leaves 442-445).
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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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Sheerah, Ibraheem Yu Cheng. "Cold-formed steel bolted connections without washers on oversized and slotted holes." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/permalink/meta-dc-10983.
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Kabche, Jean Paul. "Structural Testing and Analysis of Hybrrid Composite/Metal Joints for High-Speed Marine Structures." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/kabchejp2006.pdf.
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Muniasamy, D. "Behaviour of semi-rigid composite connections for steel framed buildings." Thesis, Engineering systems department, 2009. http://hdl.handle.net/1826/3974.
Full textAbstract:
During propped construction the steel-concrete composite action resists dead as well as
imposed loads. Conversely, the steel section alone resists the floor self-weight in unpropped
beams. The major difference between propped and unpropped composite beams lies in the
ductility requirements rather than in the strength requirements. Relatively few studies have
been carried out to assess the rotation requirements for unpropped semi-continuous
composite beams. The outstanding critical factor in the case of unpropped construction is the
dead load stress that must be carried by the steel beam alone prior to hardening of the
concrete.
This research overcomes the difficulties involved in modelling the composite and noncomposite
stages by using a numerical integration technique developed from the basic
principles of structural mechanics. The method incorporates the fully non-linear material
properties and requires very little assumption. The technique was initially validated using the
experimental results from plain steel beam bending tests. The subsequent comparison
between the model predictions and the results from the large-scale frame test carried out for
this research purpose, showed that the method is capable of predicting non-elastic load vs.
end rotation behaviour within a high degree of accuracy. Thus the model can be used with
confidence in order to predict the connection rotation requirements for a wider range of
loading configurations than is practically possible from experimental testing alone.
A parametric study is carried out using the numerical integration technique developed for the
semi-continuous composite beam on a total of 2160 different beam configurations, utilising
different steel grades and loading conditions. In this study the influence of dead load stress on
the connection rotation requirement has been thoroughly evaluated along with several other
factors including span to depth ratio, location within the building frame, ratio between the support (connection) moment capacity and span (beam) moment capacity, loading type, steel
grade and percentage of the beam strength utilised during design. The connection rotation
capacity requirements resulting from this study are assessed to establish the scope for
extending the use of composite connections to unpropped beams.
The large-scale experiment that has been carried out provided an opportunity to investigate
the behaviour of a modified form of composite connection detail for use at perimeter
columns (single-sided composite connections) with improved rebar anchorage.
Additionally, another extensive parametric study is carried out using the numerical
integration technique developed for the steel beam to establish the influence of strainhardening
on elastic-plastic frame instability design.
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Halley, William G. "Fracture path transitions in peels tests of medium carbon steel spot welds." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07282008-135105/.
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Lebeck, Matthew Victor. "Predictive methods applied to the vibratory response of machining structural steel and weldments." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16021.
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Green, Travis P. "Behavior of full-scale partially-restrained beam-to-column T-stubn and shear tab connections under cyclic loading." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20720.
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Buchanan, Craig. "Testing and design of conventional and novel stainless steel hollow structural sections." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/49208.
Full textAbstract:
The topic of this thesis is the testing and design of conventionally formed and additive manufactured stainless steel hollow structural sections. Although design codes currently exist for stainless steel hollow structural elements, the provisions are based on limited structural data and therefore require further evaluation for their suitability, and are not intended to apply to additive manufactured elements. Focussing on conventionally formed circular hollow sections (CHS), the existing design provisions have been carefully reappraised based on a dataset of tests and finite element results generated in this study and existing tests collected from the literature. In total, 37 concentrically loaded column tests, 26 beam-column tests and 10 stub column tests have been undertaken on austenitic, duplex and ferritic stainless steel CHS. The experimental data has been supplemented with over 2400 finite element case studies. The reappraisal highlighted that there is additional capacity to be sought at the cross-section level for pure compression, bending and combined loading, and at the member level for beam-columns, but the current CHS flexural buckling provisions were found to be unconservative for certain global slenderness values. Based on these observations, revised design rules have been proposed. Additive manufactured sections, not currently covered by structural design standards, have also been investigated. An experimental programme consisting of 28 tensile coupon tests, 14 compressive coupon tests and 5 square hollow section (SHS) stub column tests has been undertaken. The initial results indicate general applicability of existing design standards to these new novel sections.
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Alsaket, Yahya. "Benchmark solutions for advanced analysis of steel frames." Thesis, Queensland University of Technology, 1999. https://eprints.qut.edu.au/36105/1/36105_Alsaket_1999.pdf.
Full textAbstract:
During the past ten years, considerable research has been conducted with the aim of
developing, implementing and verifying "advanced analysis" techniques suitable for the
non-linear analysis and design of steel framed structures. With the use of one of these
methods, the simplified concentrated methods, comprehensive assessment of the actual
failure modes and ultimate strengths of framing systems is now possible in practical
design situations, without resort to conventional elastic methods of analysis and semiempirical
specification equations. This research has the potential to extend the
creativity of the structural engineer and simplify the design process, while ensuring
greater economy and more uniform safety in certain design situations. However, the
application of concentrated plasticity methods is currently restricted to two
dimensional steel frame structures that are fully laterally restrained and constructed
from compact sections (i.e. sections not subject to local and/or lateral buckling
effects). Unfortunately this precludes the use of advanced analysis from the design of
frames consisting of cold-formed sections and a significant proportion of hot-rolled
universal beam sections. Therefore research is currently under way to develop
concentrated plasticity methods of analysis for steel frame structures subject to local
and/or lateral buckling effects. This thesis was aimed at developing appropriate
benchmark solutions that are needed to validate these simplified methods of analysis.
Finite element analyses and five large scale experiments were conducted in order to
study the ultimate strength behaviour of two-dimensional single bay single storey steel
frames subjected to local and/or lateral buckling effects. The frames comprised of
cold-formed rectangular hollow sections and hot-rolled I-sections. A good agreement
between the results from finite element analyses and experiments validated the
accuracy of the finite element model used. The finite element model was then used to
develop benchmark solutions for two-dimensional single storey, single bay steel frames
comprising cold-formed rectangular hollow sections and hot-rolled I-sections subjected
to local and/or lateral buckling effects. This thesis presents the details of finite element analyses and large scale experiments
and their results, and a series of analytical benchmark solutions that can be used for the
verification of simplified concentrated plasticity methods of analysis.
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Yousof, Mohamad. "Analytical Model for Lateral Deflection in Cold-formed Steel Framed Shear Walls with Steel Sheathing." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc700013/.
Full textAbstract:
An analytical model for lateral deflection in cold-formed steel shear walls sheathed with steel is developed in this research. The model is based on the four factors: fastener displacement, steel sheet deformation, and hold-down deformation, which are from the effective strip concept and a complexity factor, which accounts for the additional influential factors not considered in the previous three terms. The model uses design equations based on the actual material and mechanical properties of the shear wall. Furthermore, the model accounts for aggressive and conservative designers by predicting deflection at different shear strength degrees.
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Sarma, Abhijit. "High strain properties of advanced high strength spot welded steels." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5997.
Full textAbstract:
Thesis (M.S.)--University of Missouri-Columbia, 2007.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 14, 2008) Includes bibliographical references.
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Osman, Mahmoud Yassin. "Analysis of rectangular composite plates under static lateral loading." Thesis, Lancaster University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305779.
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Koen, Damien Joseph. "Structural Capacity of Light Gauge Steel Storage Rack Uprights." University of Sydney, 2008. http://hdl.handle.net/2123/3880.
Full textAbstract:
Master of Engineering (Research)<br>This report investigates the down-aisle buckling load capacity of steel storage rack uprights. The effects of discrete torsional restraints provided by the frame bracing in the cross-aisle direction is considered in this report. Since current theoretical methods used to predict the buckling capacity of rack uprights appear to be over-conservative and complex, this research may provide engineers an alternative method of design using detailed finite element analysis. In this study, the results from experimental testing of upright frames with K-bracing are compared to finite element predictions of displacements and maximum axial loads. The finite element analysis is then used to determine the buckling loads on braced and un-braced uprights of various lengths. The upright capacities can then be compared with standard design methods which generally do not accurately take into account the torsional resistance that the cross-aisle frame bracing provides to the upright. The information contained in this report would be beneficial to engineers or manufacturers who are involved in the design of rack uprights or other discretely braced complex light gauge steel members subject to axial loads.
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Radhakrishnan, Perumal. "Post-buckled performance of partially restrained and intermediately supported steel angles." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3609.
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The post-buckled performance of cross-braced single angles was experimentally determined. The results of this study will be used by the Bonneville Power Administration for the analysis of member performance in transmission towers.
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Lan, Xing. "Seismic Performance Evaluation of Novel Cold-Formed Steel Framed Shear Walls Sheathed with Corrugated Steel Sheets." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011859/.
Full textAbstract:
This thesis presents experiments and numerical analysis of a novel cold-formed steel framed shear wall sheathed with corrugated steel sheets. The objective of this newly designed shear wall is to meet the growing demand of mid-rise buildings and the combustibility requirement in the International Building Code. The strength of the novel shear wall is higher than currently code certified shear wall in AISI S400-15 so that it could be more favorable for mid-rise building in areas that are prone to earthquakes and hurricanes. Full-scale monotonic and cyclic tests were conducted on bearing walls and shear walls under combined lateral and gravity loads. Though the gravity loads had negative effects on the strength and stiffness of the shear wall due to the buckling of the chord framing members, it still shows promise to be used in mid-rise buildings. The objective of numerical analysis is to quantify the seismic performance factors of the newly design shear wall lateral-force resisting system by using the recommended methodology in FEMA P695. Two groups of building archetypes, story varied from two to five, were simulated in OpenSees program. Nonlinear static and dynamic analysis were performed in both horizontal directions of each building archetype. Finally, the results of the performance evaluation verified the seismic performance factors(R=Cd=6.5 and Ω =3.0) were appropriate for the novel shear wall system.
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Myers, Andrew T. "Testing and probabilistic simulation of ductile fracture initiation in structural steel components and weldments /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Chen, Yujie. "Nominal Shear Strength and Seismic Detailing of Cold-formed Steel Shear Walls using Steel Sheet Sheathing." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc30444/.
Full textAbstract:
In this research, monotonic and cyclic tests on cold-formed steel shear walls sheathed with steel sheets on one side were conducted to (1) verify the published nominal shear strength for 18-mil and 27-mil steel sheets; and (2) investigate the behavior of 6-ft. wide shear walls with multiple steel sheets. In objective 1: this research confirms the discrepancy existed in the published nominal strength of 27-mil sheets discovered by the previous project and verified the published nominal strength of 18 mil sheet for the wind design in AISI S213. The project also finds disagreement on the nominal strength of 18-mil sheets for seismic design, which is 29.0% higher than the published values. The research investigated 6-ft. wide shear wall with four framing and sheathing configurations. Configuration C, which used detailing, could provide the highest shear strength, compared to Configurations A and B. Meanwhile, the shear strength and stiffness of 2-ft. wide and 4-ft. wide wall can be improved by using the seismic detailing.
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Dara, Martin Luther. "Direct Strength Method for Web Crippling of Cold-formed Steel C and Z Sections Subjected to Interior One Flange Loading and End One Flange Loading." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822839/.
Full textAbstract:
The main objective of this research is to extend the “Direct strength method” for determining the web crippling strength of cold-formed steel C and Z sections subjected to End one flange loading and Interior one flange loading conditions. Direct strength method is applied for designing the columns and beams earlier. The existing specifications equation for calculating the web crippling strength of cold-formed steels designed by American Institute of Iron and Steel is very old method and it is based on the extensive experimental investigations conducted at different universities. Calculating the web crippling strength of cold-formed steels using direct strength method is a new technique. In the present research the web crippling strength of cold-formed steels were calculated using Direct Strength Method. The experimental data is collected from the tests that were conducted at different universities. The critical buckling strength of the members were calculated using Abaqus. Microsoft excel is used to generate the equations. The safety and resistance factors for the designed equations were calculated using “Load and resistance factor design” and “Allowable strength design” from North American Cold-Formed Steel Specification, 2012 edition book.
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Pine, T. "Weight reduction in automotive structural components : an investigation into the torsional properties of steel box sections and T-joints." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638535.
Full textAbstract:
Weight reduction of the automotive structure can be enhanced by using continuous joining techniques as a means of assembly. Continuous joints increase structural rigidity and thereby overcome the loss in stiffness associated with the higher strength but thinner steels proposed for use by the automotive industry. The comparison of continuously joined structures with conventionally joined (spot welded) structures will help to determine the potential weight reduction of the automotive structure. The effects of joining technique, sheet thickness, steel strength, section area, section design and level of end constraint on the torsional properties of box sections were determined experimentally using factorial design techniques. The joining techniques investigated included adhesive bonding, weldbonding, laser welding and spot welding. Finite element models were developed using ANSYS and ABAQUS and were used to extend the scope of the test programme. T-joints, comprised of two box sections jointed at right angles, were tested experimentally using factorial design techniques, and were also analysed numerically. Joining technique, sheet thickness and section area had the most influence on box section torsional stiffness. A 44% and 10% weight reduction was estimated through downgauging and area reduction, respectively, in conjunction with the substitution of spot welding with adhesive bonding. Joint eccentricity was also identified as a factor which influenced the torsional stiffness of box sections and could also be related to weight reduction. The effect of joint eccentricity at the connection of T-joints was shown to have a major effect on the torsional stiffness and strength of T-joints. A numerical comparison between a T shaped component from a BIW with a regular T-joint was conducted. The results confirmed the validity of using simplified test pieces to represent more complex components.
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De, Villiers Pieter Jacobus. "Imposed loads for inaccessible roofs of light industrial steel buildings." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53460.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2003.<br>Some digitised pages may appear illegible due to the condition of the original hard copy.<br>ENGLISH ABSTRACT: A critical evaluation of provisions for imposed loads in the South African Loading
Code for design of structures, SABS 0160-1989 (SABS), by comparison with other
codes was performed earlier. The evaluation revealed the SABS loading code to be
generally non-conservative in its provisions for imposed loads for a range of general
and specialist occupancy classes. The SABS provision for imposed loads for
inaccessible roofs was found to be substantially non-conservative in comparison with
the other codes. An investigation into the imposed load for inaccessible roofs is
subsequently performed in order to establish a scientific rationale through which the
codified design values may be measured effectively. Due to the lack of information
and the large uncertainties involved in the imposed roof load, stochastic treatment of
the loads is implemented. This is in line with the stochastic modelling of loads as
implemented in general.
The approach applied is to select a type of building that can be regarded as a generic
example of buildings to which these loads apply, and to discretisize the load into the
various sub-mechanisms that translate into the imposed roof load. The probabilistic
models for the load mechanisms are then quantified, either through physical load
surveys, or through conducting an expert survey for those variables which are not
observable. The use of expert opinion as a resource for information is not readily
accessible in terms of yielding scientifically defendable results. Therefore, the expert
survey is performed as a calibrated experiment whereby weights were calculated for
the individual experts' opinions and their opinions combined accordingly.
The probabilistic models for the load mechanisms are then translated into load effects
by taking into account the physical process resulting in the load effects. By applying
these mechanisms in such a way as to maximise the said load effects, equivalent
uniformly distributed loads (EUDL's) were calculated for each mechanism. The
probabilistic models obtained in terms of the EUDL's pose an easily accessible
format through which existing load models and codified provisions can be evaluated.
These load models are then utilised to evaluate the SABS provisions in terms of the
level of reliability catered for by SABS ultimate limit-state design criteria. It is
concluded that the SABS conservatively provides for maintenance loads on the roof,
while the reliability for construction loads is non-conservative for large tributary areas
and highly non-conservative for small areas. The load models so obtained can
further be applied for structural reliability assessment.<br>AFRIKAANSE OPSOMMING: "n Kritiese evaluasie van die voorskrifte vir opgelegde belastings in die Suid-
Afrikaanse Selastingskode vir die ontwerp van strukture, SASS 0160-1989 (SASS)
deur 'n vergelyking met ander kodes is vroeër uitgevoer. Die evaluasie het getoon
dat die SASS in die algemeen onkonserwatief is in sy voorsiening vir opgelegde
belastings oor 'n bereik van algemene en spesialis okkupasie tipes. Die SASS
voorskrif vir opgelegde belastings vir ontoeganklike dakke is hoogs onkonserwatief in
vergelyking met die ander kodes. 'n Ondersoek na die opgelegde belasting vir
ontoeganklike dakke word gevolglik uitgevoer met die doelom 'n wetenskaplike
rasionaal daar te stel waardeur die gekodifiseerde voorskrifte effektief gemeet kan
word. As gevolg van die gebrek aan inligting en groot onsekerhede betrokke by die
opgelegde dakbelasting word stogastiese modellering geimplimenteer.
Die aanslag wat gevolg is, is om 'n tipe gebou te selekteer wat beskou kan word as
verteenwoordigend van die geboue waarvoor hierdie belastings van toepassing is, en
om die belasting te diskretiseer in die verskeie lasmeganismes wat die opgelegde
dakbelasting voortbring. Die waarskynlikheidsmodelle vir die lasmeganismes word
dan gekwantifiseer, óf deur fisiese opnames, óf deur die uitvoering van 'n ekspertopname
vir daardie veranderlikes wat nie waarneembaar is nie. Die gebruik van
ekspert opinie as "n bron van inligting is nie maklik toeganklik in terme daarvan om
wetenskaplik verdedigbare resultate te lewer nie. Daarom is die ekspert-opname
uitgevoer soos 'n gekalibreerde eksperiment waardeur relatiewe gewigte bereken
word vir die individuele eksperts en hulopinies daarvolgens gekombineer word.
Die waarskynlikheidsmodelle vir die lasmeganismes word dan omgeskakel in laseffekte
deur in agneming van die fisiese proses wat die las-effek voortbring. Deur die
lasmeganismes op só 'n manier toe te pas dat die betrokke las-effekte gemaksimeer
word, word ekwivalent uniforme belastings (EUS's) bepaal. Die waarskynlikheidsmodelle
in terme van EUS's bied "n maklik toeganklike formaat waardeur bestaande
lasmodelle en gekodifiseerde voorskrifte evalueer kan word. Die lasmodelle word
gevolglik gebruik om die SASS voorskrifte te evalueer in terme van die vlak van
betroubaarheid wat gehandhaaf word deur SASS limiet-staat ontwerp kriteria. Dit is
bepaal dat die SASS konserwatief voorsiening maak vir onderhoudslaste op die dak,
maar onkonserwatief tot hoogs-onkonserwatief is vir konstruksie laste. Die bepaalde
lasmodelle kan verder toegepas word in strukturele betroubaarheids analise.
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Darcy, Greg. "Structural behaviour of an innovative cold-formed steel building system." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16589/1/Greg_Darcy_Thesis.pdf.
Full textAbstract:
Cold-formed steel structures have been in service for many years and are used as shelters for both domestic and industrial purposes. To produce an economical product, manufacturers have typically based their designs on the simple portal frame concept. As there is almost a direct relationship between overall cost and the weight of steel in a portal frame structure, it is of great importance to provide a structure with the minimum amount of steel whilst providing structural adequacy.
Portal frame sheds have been refined continuously for many years, with only minimal amounts of savings in steel. Therefore, to provide even greater savings in steel, an innovative building system is required. Modern Garages Australia (MGA) is one of the leading cold-formed steel shed manufacturers in Queensland. MGA has recently developed such an innovative building system that has significant economic savings when compared with portal frame structures.
The MGA building system has two key differences to that of the conventional portal frame system. These differences are that the MGA system has no conventional frames or framing system, and it has no purlins or girts. This results in the MGA system being completely fabricated from thin cladding, which significantly reduces the quantity of steel. However, the key problem with this building system is that the load paths and structural behaviour are unknown, and therefore the structure cannot be analysed using conventional methods. Therefore, the objectives of this research were to first investigate the structural behaviour of this new building system and its adequacy for an ultimate design wind speed of 41 m/s using full scale testing. The next objectives were to use finite element analysis to optimise the original MGA building system so that it is adequate for an ultimate design wind speed of 41 m/s, and to develop a new improved cold-formed steel building system that has greater structural efficiency than the original MGA building system.
This thesis presents the details of the innovative MGA building system, full scale test setup, testing program, finite element analysis of the MGA building system and the results. Details and results from the optimisation of the MGA building system, and the development of a new improved cold-formed steel building system are also presented. The full scale experimental investigation considered the required loadings of cross wind, longitudinal wind and live load test cases and simulated them on the test structure accurately using an innovative load simulation system. The wind loads were calculated for a 41 m/s ultimate design wind speed. Full scale test program included both non-destructive and destructive tests.
The finite element analyses contained in this thesis have considered cross wind, longitudinal wind and live load cases, as well as the destructive load case of the MGA building system. A number of different model types were created and their results were compared with the experimental results. In general, two main model types were created. The first type consisted of a 'strip' of the MGA building system (Strip model) and the second modelled the full structure (Full model). Both of these model types were further divided into models which contained no contact surfaces and those which contained contact surfaces to simulate the interfaces between the various components such as the brackets and cladding.
The experimental test results showed that the MGA test structure is not suitable for an ultimate design wind speed of 41 m/s. This conclusion is a result of a number of observed failures that occurred during the extensive testing program. These failures included local buckling, crushing failures, and distortional buckling of the cladding panels. Extremely large deflections were also observed. It was calculated that for the MGA building system to be adequate for the design wind speed of 41 m/s, a cladding thickness of 0.8 mm was required. This also agreed well with the finite element analysis results which concluded that a cladding thickness of 0.8 mm was required.
In order to avoid the increased use of steel in the building system, a new improved cold-formed steel building system was developed and its details are provided in this thesis. A finite element model of this new improved cold-formed steel building system was created and the results showed that the new building system was able to achieve a load step equivalent to an ultimate design wind speed of 50.4 m/s and was approximately 250% stiffer than the original MGA building system, without any increase in the overall weight of the building system. It is recommended that this new improved cold-formed steel building system be further developed with the aid of finite element modelling and be tested using a similar full scale testing program that was used for the original MGA building system.
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Darcy, Greg. "Structural behaviour of an innovative cold-formed steel building system." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16589/.
Full textAbstract:
Cold-formed steel structures have been in service for many years and are used as shelters for both domestic and industrial purposes. To produce an economical product, manufacturers have typically based their designs on the simple portal frame concept. As there is almost a direct relationship between overall cost and the weight of steel in a portal frame structure, it is of great importance to provide a structure with the minimum amount of steel whilst providing structural adequacy. Portal frame sheds have been refined continuously for many years, with only minimal amounts of savings in steel. Therefore, to provide even greater savings in steel, an innovative building system is required. Modern Garages Australia (MGA) is one of the leading cold-formed steel shed manufacturers in Queensland. MGA has recently developed such an innovative building system that has significant economic savings when compared with portal frame structures. The MGA building system has two key differences to that of the conventional portal frame system. These differences are that the MGA system has no conventional frames or framing system, and it has no purlins or girts. This results in the MGA system being completely fabricated from thin cladding, which significantly reduces the quantity of steel. However, the key problem with this building system is that the load paths and structural behaviour are unknown, and therefore the structure cannot be analysed using conventional methods. Therefore, the objectives of this research were to first investigate the structural behaviour of this new building system and its adequacy for an ultimate design wind speed of 41 m/s using full scale testing. The next objectives were to use finite element analysis to optimise the original MGA building system so that it is adequate for an ultimate design wind speed of 41 m/s, and to develop a new improved cold-formed steel building system that has greater structural efficiency than the original MGA building system. This thesis presents the details of the innovative MGA building system, full scale test setup, testing program, finite element analysis of the MGA building system and the results. Details and results from the optimisation of the MGA building system, and the development of a new improved cold-formed steel building system are also presented. The full scale experimental investigation considered the required loadings of cross wind, longitudinal wind and live load test cases and simulated them on the test structure accurately using an innovative load simulation system. The wind loads were calculated for a 41 m/s ultimate design wind speed. Full scale test program included both non-destructive and destructive tests. The finite element analyses contained in this thesis have considered cross wind, longitudinal wind and live load cases, as well as the destructive load case of the MGA building system. A number of different model types were created and their results were compared with the experimental results. In general, two main model types were created. The first type consisted of a 'strip' of the MGA building system (Strip model) and the second modelled the full structure (Full model). Both of these model types were further divided into models which contained no contact surfaces and those which contained contact surfaces to simulate the interfaces between the various components such as the brackets and cladding. The experimental test results showed that the MGA test structure is not suitable for an ultimate design wind speed of 41 m/s. This conclusion is a result of a number of observed failures that occurred during the extensive testing program. These failures included local buckling, crushing failures, and distortional buckling of the cladding panels. Extremely large deflections were also observed. It was calculated that for the MGA building system to be adequate for the design wind speed of 41 m/s, a cladding thickness of 0.8 mm was required. This also agreed well with the finite element analysis results which concluded that a cladding thickness of 0.8 mm was required. In order to avoid the increased use of steel in the building system, a new improved cold-formed steel building system was developed and its details are provided in this thesis. A finite element model of this new improved cold-formed steel building system was created and the results showed that the new building system was able to achieve a load step equivalent to an ultimate design wind speed of 50.4 m/s and was approximately 250% stiffer than the original MGA building system, without any increase in the overall weight of the building system. It is recommended that this new improved cold-formed steel building system be further developed with the aid of finite element modelling and be tested using a similar full scale testing program that was used for the original MGA building system.
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Pircher, M. "The effects of weld-induced imperfections on the stability of axially loaded steel silos /." View thesis View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030506.145720/index.html.
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Walker, Simon Valentin. "Characterization of fatigue damage in A36 steel specimens using nonlinear Rayleigh surface waves." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42753.
Full textAbstract:
A36 steel is a commonly used material in civil engineering structures where fatigue damage can lead to catastrophic failure. In this research, nonlinear Rayleigh surface waves are used to characterize damage in A36 steel specimens caused by monotonic tension and low cycle fatigue. Fatigue damage produces the increased acoustic nonlinearity that leads to the generation of measurable higher harmonics in an initially monochromatic Rayleigh wave signal. One specimen is subjected to static tension and four specimens are used for low cycle fatigue tests in the tension-tension mode with a constant stress amplitude. The fatigue tests are interrupted at
different numbers of cycles for the nonlinear ultrasonic measurements. Tone burst Rayleigh wave signals are generated and detected using a pair of oil coupled wedge transducers. The amplitudes of the first and second harmonic are measured at varying propagation distances to obtain the nonlinearity parameter for a given damage state.
The experimental results show an increase of acoustic nonlinearity in the early stages of fatigue life. Furthermore, a close relationship between plastic deformation and the acoustic nonlinearity is found, which indicates that the acoustic nonlinearity is indeed a measure of microplasticity in this material.
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Cross, Benjamin Thomas. "Analysis of the AASHTO fatigue design provisions for welded steel bridge details using reliability theory." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 101 p, 2007. http://proquest.umi.com/pqdweb?did=1338919111&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Narang, Vikas A. "Heat Transfer Analysis In Steel Structures." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050405-133533/.
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Braun, Moritz [Verfasser]. "Assessment of fatigue strength of welded steel joints at sub-zero temperatures based on the micro-structural support effect hypothesis / Moritz Braun." Hamburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2021. http://nbn-resolving.de/urn:nbn:de:gbv:830-882.0145720.
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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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Dias, Hanwellage Yomal Viduranga. "Structural and fire behaviour of gypsum plasterboard and steel sheathed LSF walls." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134411/1/Hanwellage_Dias_Thesis.pdf.
Full textAbstract:
This study investigated the structural and fire behaviour of steel stud framed walls lined with gypsum plasterboard and steel sheathing. An improved wall stud with greater structural efficiency was developed. Through analytical, numerical and experimental studies, the behaviour of steel sheathed LSF walls built using these improved studs, both under normal service conditions and in fire, was investigated. The findings of this study facilitate the development of structurally and economically superior LSF walls.