286 research outputs found
Vulnerability assessment of the S. JoĂŁo de Loure Bridge: Vougaâs river
Steel bridges are particularly sensible to corrosion, which can put at risk the structural safety by affecting the joint elements. Having this in mind, the objective of this work was to evaluate the influence of the joint's stiffness in the structural response of the S. JoĂŁo de Loure steel bridge. An improved model was developed for the bridge on the structural analysis software SAP2000. Maximum deflection, axial forces and corresponding stresses, and natural frequencies, were analyzed. Numerical results allow concluding about the influence of the joint's stiffness in the structural response of the bridge
S. JoĂŁo de Loure Bridge: vulnerability assessment and study of a common strengthening solution
This paper presents a structural vulnerability assessment of the steel bridge S. JoĂŁo de Loure. A structural model of the bridge was created and the influence of the jointâs stiffness on its structural response was evaluated using the structural analysis software SAP2000. Natural frequencies, axial forces and corresponding stress, and maximum mid-span deflection, were analyzed. A common strengthening solution with prestressing cables was studied intending to reduce the bridgeâs mid-span deflection
Earthen construction: structural vulnerabilities and retrofit solutions for seismic actions
Earthen structures present very appealing characteristics regarding a more sustainable practice with the
preservation of our natural resources. However, when subjected to earthquake ground motions, this type of
construction may present a deficient performance, which may cause significant human losses and important
structural damage. The seismic response of earthen structures is typically characterized by fragile failures. There
are several examples of recent earthquakes that affected earthen buildings in a severe way, evidencing the
vulnerability of this type of construction, like the El Salvador earthquake, in 2001, the Bam, Iran earthquake, in
2003, the Pisco, Peru earthquake, in 2007 and the Maule, Chile earthquake, in 2010.
The construction of earth structures on earthquake-prone areas must be carefully studied and should include
seismic reinforcement solutions in order to improve their seismic performance.
In this paper, the performance of earthen structures in recent earthquakes will be examined, analyzing failure
modes inherent to these particular construction materials and associated construction techniques. Also, seismic
reinforcement approaches and techniques will be presented in a comprehensive manner. Examples of tests conducted for the assessment of retrofitting solutions efficiency will be presented, and the results obtained will be discussed
The effect of the number of response cycles on the behaviour of reinforced concrete elements subject to cyclic loading
The development of damage in reinforced concrete (RC) structures is a cumulative process. Some damage
indices used to quantify damage make use of the number of response cycles as an Engineering Demand
Parameter (EDP) relating with damage development. Other indices make use of deformation in terms of
displacement or chord rotation. These functions are generally a function of whether the response is monotonic or
cyclic, and are insensitive to the number of major deflection cycles leading to that state of damage. Many such
relations are derived from experimental data from low-cycle fatigue tests performed on RC elements. The
loading in such tests generally consists of either a monotonic increase in load or a gradually increasing cyclic
load. Since damage development is a cumulative process, and hence depends on the load history, the loading
pattern in low-cycle fatigue tests for assessment purposes should reflect the response of an earthquake. This
paper will discuss a procedure to determine a loading history for cyclic tests, based on earthquake demands. The
preliminary results of a campaign of low-cycle fatigue tests on RC elements to investigate the effect of using
different load histories are also discussed
Low cycle fatigue tests of reinforced concrete columns and joints built with ribbed reinforcement and plain stirrups
The majority of existing reinforced concrete (RC) buildings were built prior to the introduction of seismic codes.
As observed in various recent earthquakes, due to their lack of structural capacity and ductility such structures
are very vulnerable and have suffered considerable damage. The number of cyclic tests that have been carried
out to investigate the behaviour of RC components with detailing typical of these buildings is very limited. Such
tests are very relevant for seismic vulnerability assessment purposes. In this paper, a low-cycle fatigue testing
campaign on RC columns and connections specifically devised to investigate various physical parameters that
affect damage development, is presented. The campaign consists of 19 columns and 7 beam-column connections.
Some of the preliminary results and observations are presented and discussed
Experimental and numerical analysis of the cyclic behaviour of RC beam-column connections with plain reinforcing bars
The information available in the literature about the cyclic behaviour of reinforced concrete elements with plain reinforcing bars is scarce. As a consequence, the influence of bar slippage in elements with plain bars is not yet comprehensively understood. In this paper are presented and discussed the main results of the cyclic tests carried out on five full-scale reinforced concrete beam-column joints with plain bars and without specific detailing for seismic demands. An additional joint specimen with deformed bars was also tested for comparison. Furthermore, numerical models were built to simulate the response of two of the specimens. Particular attention was given to the influence of bar slippage. The results of the conducted analyses underline the importance of accounting for bond-slip in the numerical modelling of elements with plain bars and also highlight the need for specific models to simulate the effects of this mechanism in the presence of plain bars
Global consultancies: determinants of market entry and strategies for conquering clients in foreign locations
Reports in the general and specialist press as well as several official estimates (e.g.
UNCTAD, 1993, EU, 1989-1996) point at a rapid increase in the use and internationalisation
of management consultancies. However, the application of MNE definitions, measurements
and theories to this type of services is still in its infancy. Thus, this paper sets out to identify
first, the main determinants of market seeking investments of global consultancies, they
evolved over time, and its implications for the nature and scope of subsidiaries activities.
These are more like miniature replicas of their parent firms than specialised units in a world
wide service network. Secondly, the strategies they have used to tap successfully into foreign
markets, overcoming the problems facing service providers (e.g. Holmstrom, 1985, Dunning,
1989) and the liability of operating in a foreign location. It focus on the importance of trustcreating
mechanisms for the establishment of lasting relationships with clients and how they
were facilitated by shared social, cultural or educational proximity between consultants and
clients. It draws on in-depth interview based case studies of twelve global consultancies and
their operations in the Portuguese economy. Avenues for future research are pointed out
Materials and techniques of Art Nouveau architecture in Italy and Portugal: a first insight for an European route to consistent restoration
The results of the investigations on building materials and techniques of Casa Major Pessoa, a typical Art
Nouveau construction in Aveiro (Portugal), and two coeval Art Nouveau buildings in Bologna (Italy) are presented
as a methodological contribution to the restoration of this kind of buildings. This is the first step to
ascertain the existence of a common thread between local materials, technologies and architecture in European
countries at the same period. A holistic approach was adopted: materials were investigated along with
architectural, structural and technological features, in order to achieve a first insight into the Art Nouveau
architecture in Europe in particular for its consistent restoration without loss of historical memory
Searching for sectoral patterns of innovation in european manufacturing industry
The present paper is conducted under the research project âEnterprise of the Future:
Trends and Scenarios towards Competitivenessâ which attempts to disclosure
determinants of future enterprise competitiveness. Innovation is not only a must today
but also an imperative in future competitiveness scenarios. In modern evolutionary
economics it is argued that sector-specific factors are one of the key factors explaining
innovative behaviour and performance of firms. Several contributions have pointed that
industries largely differ in terms of knowledge base and technological sources,
opportunities and appropriation of innovative activities, technological trajectories and
firmsâ strategies. Using as background Pavittâs taxonomy, this paper explores the
nature, extent and sources of variety of innovation in the manufacturing industry,
aiming at identifying common patterns across industries, and sectoral patterns across
countries. This paper presents evidence based on the aggregated results of the last IV
Community Innovation Survey released by EUROSTAT (CIS4), for which data is
available for a number of industries and countries
Directions in entrepreneurship education in Europe
An extraordinary proliferation of entrepreneurship courses and programs was and still is underway
in colleges and universities worldwide. In Europe this phenomenon has been further stimulated
by the focus on Entrepreneurship as key objective for the implementation of the Europe2020
strategy (EC, 2010).
This paper provides a systematized overview of patterns and directions in EE in Europe in recent
years. We conduct a review of the published research of the theme with an European focus in an
attempt to organize the literature along precise lines. When possible we use empirical findings to
sustain our arguments. Systematizing the existing literature is a necessary step in developing the
field. For researchers, this overview will be constructive in providing an analysis of the directions
of published research and in setting up a research agenda for the future. It also raises awareness
with regard to entrepreneurship, and in particular, to its potential contribution to the individuals
and to the competitiveness of economies. The empirical analysis adds to our knowledge about the
current situation of EE in practice in Europe
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