Feasibility Investigation of Superelastic Effect Devices for Seismic Isolation Applications
Author: G. Attanasi, F. Auricchio, and G.L. Fenves | Size: 0.84 MB | Format:PDF | Quality:Unspecified | Year: 2008 | pages: 09
The objective of this work is to investigate the feasibility of a new seismic isolation device concept, in which
the restoring force is given by the superelastic effect of shape memory alloys. Seismic isolation is an option
for passive protection of structure when an earthquake occurs, because it modifies the structural global
response and improves performance. Dynamic responses of proposed innovative SMA isolation system and
of traditional bearing device are compared through dynamic time history analyses. Results show that the
SMA system is effective in reducing force and displacement demands, dissipating the input seismic energy
and limiting the residual displacements.
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Author: George C. Lee and Zach Liang Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo, State University of New York USA | Size: 0.62 MB | Format:PDF | Quality:Unspecified | Year: 37
In earthquake resistance design of structures, two general concepts have been used. The first is to increase the capacity of the structures to resist the earthquake load effects (mostly horizontal forces) or to increase the dynamic stiffness such as the seismic energy dissipation ability by adding damping systems (both devices and/or structural fuses). The second concept includes seismic isolation systems to reduce the input load effects on structures. Obviously, both concepts can be integrated to achieve an optimal design of earthquake resilient structures. This chapter is focused on the principles of seismic isolation. It should be pointed out that from the perspective of the structural response control community, earthquake protective systems are generally classified as passive, active and semi-active systems. The passive control area consists of many different categories such as energy dissipation systems, toned-mass systems and vibration isolation systems. This chapter addresses only the passive, seismic isolation systems [Soong and Dargush, 1997; Takewaki, 2009; Liang et al, 2011] Using seismic isolation devices/systems to control earthquake induced vibration of bridges and buildings is considered to be a relatively matured technology and such devices have been installed in many structures world-wide in recent decades. Design guidelines have been established and they are periodically improved as new information based on research and/or field observations become available during the past 20-30 years [ATC 1995; SEAONC 1986; FEMA 1997; IBC 2000; ECS 2000; AASHTO 2010, ASCE 2007, 2010]. Besides the United States, base isolation technologies are also used in Japan, Italy, New Zealand, China, as well as many other countries and regions. [Naiem and Kelly, 1999; Komodromos, 2000; Christopoulos, C. and Filiatrault 2006] Affiliated with the increased use of seismic isolation systems, there is an increased demand of various isolation devices manufactured by different vendors. This growth of installing seismic isolation devices in earthquake engineering has been following the typical pattern experienced in structural engineering development, which begins from a “statics” platform by gradually modifying the design approach to include the seismic effects based on structural dynamics principles as they develop and new field observations on the responses of real-world structures. The process is typically slow because most studies and laboratory observations have been concentrated on the performances of the devices with scaled-down experiments. Results could not be readily scaled-up for design purposes. At the same time,
there were very limited field data on the actual performances of seismically isolated
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This is drawings of a "Billet Storage" building of "Medium Section Rolling Mill Plant".
I Uploaded Drawings and Analysis files, unfortunately calculation notes is in Persian language thus I did not uploaded it, if you think it is useful I`ll upload it.
Please review and share with others your comments.
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Ensuring reservoir safety into the future. Thomas Telford, London, 2008 Nonlinear seismic assessment of lightly reinforced concrete intake towers
Author: R. SABATINO, Lloyd’s Register, London, UK (formerly KBR Ltd) A.J. CREWE, University of Bristol, UK W.E. DANIELL, University of Bristol, UK C.A. TAYLOR, University of Bristol, UK | Size: 1.8 MB | Format:PDF | Quality:Unspecified | Year: | pages: 14
Published guidance on the seismic analys is of reinforced concrete intake/outlet towers is limited, especiall
y for their nonlinear response, due to limited knowledge on the nonlinear characteristics ofexisting and new towers. Proving the integrity of existing towers is an international problem for dam owners, and an industrial need exists for arational, cost-effective and validated method for their assessment.This paper describes a series of tests aimed at investigating the seismic performance of typically reinforced, non-seismically designed towers.Monotonic and cyclic push-over tests were performed on 1/6th scaled models. The results from the physical tests were used to validate a 3D nonlinear finite element model of the towers, using embedded steel reinforcement and a smeared crack model to simulate crack properties of the concrete material. The dynamic performance of the structures was investigated by developing a simplified single degree of freedom model and performing a number of simulations to obtain fragility curves of the system. This simplified model was capable of simulating the degrading, hysteretic properties of the towers and was used to perform no nlinear time history analyses using a range of parameters. A probabilist ic approach was selected as the basis of the performance evaluation process using fragility analyses as a tool for modelling the uncertainty associated with the parameter selection. Based on the experimental and analytical results, a three-staged assessment procedure for the seismic performance assessment of the towers was proposed.
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NUMERICAL MODELS FOR THE SEISMIC ASSESSMENT OF AN OLD MASONRY TOWER
Author: Paulo B. Lourenço;Fernando Peña ;Daniel V. Oliveira; | Size: 1.8 MB | Format:PDF | Quality:Unspecified | Publisher: SEISMIC ASSESSMENT OF AN OLD MASONRY TOWER F. Peña, P.B. Lourenço, N. Mendes & D.V. Oliveira | Year: | pages: 20
The present paper describes the seismic assessment of the Qutb Minar in Delhi, India. Three models with different levels of complexity and simplifications were developed. The use of these models allows to overcome the complexity on the study of the seismic behavior of ancient masonry structures; by combining the results of the different models it is possible to obtain a better and more comprehensive interpretation of the seismic behavior. The models were used for non-linear static (pushover) and non-linear dynamic analyses. The static and dynamic analyses give different behaviors, indicating that push-over analysis should be used carefully in the seismic assessment of masonry structures. For the static analysis, the base of the tower is the most vulnerable part; while according to the dynamic analysis, it is the upper part of the tower. This last behavior is according to the historical damage suffered by the tower due to earthquakes. The different behaviors can be explained by the influence of the higher modes of vibration.
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Author: Prof. Davide Bigoni | Size: 17.1 MB | Format:PDF | Quality:Unspecified | Publisher: UNIVERSITY OF TRENTO Modeling, Preservation and Control of Materials and Structures Ph. D. | Year: 08/04/2011 | pages: 172
This study is dedicated to simplified vulnerability assessment of
masonry towers, in particular to the definition of collapse mechanism geometry.
After a preliminary analysis on damages and collapse mechanisms
caused to towers by the earthquakes and a review of analysis
methods in literature, a model to determine the plane of fracture that defines the kinematic blocks of an overturning mechanism was proposed, based on simple equilibrium conditions.
According to the Italian codes, in fact, tower structures are classified as one of the churches macroelements, characterized by peculiar collapse mechanisms; respect to other macroelements, for towers a slight variation in mechanism geometry implies relevant variation in collapse multiplier values; this is mainly due to the importance of mass and height in these structures. Hence a correct definition of kinematism geometry results very important.
The proposed method was applied also including a limit on masonry compressive strength, despite traditional limit analysis method that usually assumes as infinite masonry compressive strength.
For the use in common practice, the curve of fracture was evaluated through parametric analyses for different geometrical configurations, to which many existing towers can be assimilated. Finally, besides a comparison with real collapse mechanisms surveyed on towers after earthquakes, the proposed method was applied also in the vulnerability assessment of a medieval masonry tower, the Ghirlandina in Modena.
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Seismic vulnerability assessment to slight damage based on experimental modal parameters
Author: Clotaire Michel , Philippe Gueguen , Matthieu Causse | Size: 1 MB | Format:PDF | Quality:Unspecified | pages: 50
The aim of this paper is to adjust behaviour models for each class of structure for vulnerability assessment by using ambient vibration. A simple model based on frequencies, mode shapes and damping, taken from ambient vibrations, allows computation of the response of the structures and comparison of inter-storey drifts with the limits found in the literature for the slight damage grade, considered here as the limit of elastic behaviour. Two complete methodologies for building fragility curves are proposed: (1) using a multi-degree of freedom system including higher modes and full seismic ground motion, (2) using a single-degree of freedom model considering the fundamental mode f0 of the structure and ground motion displacement response spectra SD(f0). These two methods were applied to the city of Grenoble, where 60 buildings were studied. Fragility curves for slight damage were derived for the various masonry and reinforced concrete classes of buildings.
A site-specific earthquake scenario, taking into account local site conditions, was considered, corresponding to an ML=5.5 earthquake at a distance of 15km. The results show the benefits of using experimental models to reduce variability of the slight damage fragility curve. Moreover, by introducing the experimental modal model of the buildings, it is possible to improve seismic risk assessment at an overall scale (the city) or a local scale (the building) for the first damage grade (slight damage). This level of damage, of great interest for moderate seismic prone
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American Petroleum Institute API RP 2A- WSD Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms—Working Stress Design 2000
Author: American Petroleum Institute | Size: 1 MB | Format:PDF | Quality:Unspecified | Publisher: American Petroleum Institute | Year: 2000 | pages: 243
This Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platforms containsengineering design principles and good practices that have evolved during the development of offshore oilresources. Good practice is based on good engineering; therefore, this recommended practice consists essentiallyof good engineering recommendations. In no case is any specific recommendation included which could not beaccomplished by presently available techniques and equipment. Consideration is given in all cases to the safety ofpersonnel, compliance with existing regulations, and antipollution of water bodies.
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Author: William D. Callister, Jr. | Size: 31.3 MB | Format:PDF | Quality:Unspecified | Publisher: John Wiley & Sons, Inc | Year: 2007 | pages: 975 | ISBN: 978-0-471-73696-7
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Posted by: amiboyz - 11-18-2013, 08:43 AM - Forum: Archive
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ACCEPTANCE CRITERIA FOR CONCRETE AND REINFORCED AND UNREINFORCED MASONRY STRENGTHENING USING FIBER-REINFORCED, COMPOSITE SYSTEMS
Size: 72 KB | Format:PDF | Quality:Unspecified | Publisher: International Conference of Building Officials | Year: 1997 | pages: 8
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Evaluation reports issued by the ICBO Evaluation Service, Inc. (ICBO ES), are based upon performance features of the
Uniform Building Code, ICBO Uniform Mechanical Codeand related codes.
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