Achegas do movemento polo decrecemento no contexto da crise enerxética e do cambio climático

[Resumo] O crecemento continuado, sen límites e exponencial, é a formulación dominante no último medio século nun planeta con límites, finito. Trátase dun proxecto de desenvolvemento inxusto e imposible de estender a toda a poboación, por iso é imprescindible introducir a noción do límite nos ámbitos político e educativo á vez, tarefa que non vai ser nin doada nin agradable. O movemento social polo decrecemento promove un proceso de transformación radical porque cómpre cambiar as institucións, as mentalidades e as formas de vida colectiva.[Abstract] The exponential increased, continuous and unlimited growth within the last half century give us the definition of a limited, finite planet. It is an unbalance development project and not possible to extend to the whole population. Therefore it is inevitable to introduce limits on the political and education levels, a tough and difficult task. The social movement for the decreasing economy promotes a radical transformation process due to necessity in changing institutions, mentalities and collective life styles

In Situ and Laboratory Tests for the Evaluation of Dynamic Geotechnical Properties of a Cohesive Deposit in Florence

In order to determine dynamic parameters to use for seismic microzoning purposes in a new development area near Florence, the dynamic behavior of the alluvial silty clays situated in the upper 60 m of the deposit was experimentally investigated using geophysical surveys and cyclic laboratory tests. Previous studies on the geotechnical properties of the clays of Florence revealed that, in spite of some similarities in a comparison with other coeval clays described in the literature this soil exhibits a few anomalies, as e.g. higher variations between field and laboratory shear waves velocities and remarkable differences in the coefficients of the empirical relations that link the shear modulus to other geotechnical parameters. Moreover, many current correlations from CPT and DMT tests resulted not valid. This peculiar behavior cannot be explained in terms of cementation, because the carbonatic contents values, even if scattered, are practically normal. The objectives of the test program herein described were, therefore, as much to deepen our knowledge of the dynamic behavior of the soil both in situ and in laboratory, at low and high strain level, as to find out the reasons for this different behavior, by examining the possible influence of sample disturbance and of long-term effects, as well as of different geophysical survey techniques. The results of crosshole tests (CH), of spectral analysis of superficial waves surveys (SASW), of resonant column tests (RC) and of triaxial tests with measurement of shear and longitudinal wave velocities (Vt1), as well as the empirical relationships obtained between geotechnical parameters are analyzed and discussed

A Case History: Seismic Analysis of the Retaining Wall of the Sacro Convento in Assisi (Italy)

The aim of the present work is to analyse the seismic behaviour of the retaining wall of the square in front of the Basilica di San Francesco at Assisi that during a long seismic crisis occurred in September 1997 suffered some damage. Static, pseudo-static and dynamic analyses have been carried out on four significant sections of the wall. The data for the analysis derive from the geometric survey of the structures, the survey of the state of the damage, the measurement of the rotation movements of the wall, the collection of stratigraphic and geotechnical data, as well as the accelerometric recordings of the seismic events using instruments that had been in operation on the structures of the “Sacro Convento” since 1995. Built during the first half of the 16th century, the wall is made of stone masonry, is about 93 m long, 4 m thick, and supports an embankment, the height of which varies between 9.0 m and 12.5 m. The wall is approximately 18 m high, and is under the ground also in the front part; it has a rectangular transversal section in the lower part and a T-shaped section in the upper part. It is built on calcareous rock, and supports a covered portico that is about 3 5 m high. In practice, the recorded accelerometric history coincides with the one at the base of the wall. Numerous seismic events were recorded from 4/9/1997 to 6/10/1997, three of which had a PGA exceeding 0.15g. The most evident movement suffered by the wall was a rigid rotation that caused a movement at the top of the wall greater than 20 cm

Seismic microzonation: an essential tool for urban planning in seismic areas

Dramatic images of heaps of rubble produced in Italy by destructive earthquakes show the extreme vulnerability of urban systems and territory and the need for urgent measures to protect citizens, buildings, artistic heritage and landscape. According to this study, the reduction of vulnerability must go through ordinary city planning tools, prepared in time of seismic silence. They must be a strong reference point also for reconstruction. Therefore, a correct planning in seismic areas must be based on a deep knowledge of the territory, of its physical, historical and cultural characters. In this context, the studies of seismic microzonation have a central role in providing information about amplification phenomena linked to the interactions between seismic waves and soils and they are indispensable to manage an extraordinary event with ordinary urban planning instruments, as might be wished in an advanced nation

Seismic microzonation: an essential tool for urban planning in seismic areas

Dramatic images of heaps of rubble produced in Italy by destructive earthquakes show the extreme vulnerability of urban systems and territory and the need for urgent measures to protect citizens, buildings, artistic heritage and landscape. According to this study, the reduction of vulnerability must go through ordinary city planning tools, prepared in time of seismic silence. They must be a strong reference point also for reconstruction. Therefore, a correct planning in seismic areas must be based on a deep knowledge of the territory, of its physical, historical and cultural characters. In this context, the studies of seismic microzonation have a central role in providing information about amplification phenomena linked to the interactions between seismic waves and soils and they are indispensable to manage an extraordinary event with ordinary urban planning instruments, as might be wished in an advanced nation

Seismic microzonation: an essential tool for urban planning in seismic areas

Dramatic images of heaps of rubble produced in Italy by destructive earthquakes show the extreme vulnerability of urban systems and territory and the need for urgent measures to protect citizens, buildings, artistic heritage and landscape.According to this study, the reduction of vulnerability must go through ordinary city planning tools, prepared in time of seismic silence. They must be a strong reference point also for reconstruction.Therefore, a correct planning in seismic areas must be based on a deep knowledge of the territory, of its physical, historical and cultural characters.In this context, the studies of seismic microzonation have a central role in providing information about amplification phenomena linked to the interactions between seismic waves and soils and they are indispensable to manage an extraordinary event with ordinary urban planning instruments, as might be wished in an advanced nation

On the stability of fissured slopes subject to seismic action

A set of analytical solutions achieved by the upper bound theorem of limit analysis and the pseudo-static approach is presented for the assessment of the stability of homogeneous c, ϕ slopes manifesting vertical cracks and subject to seismic action. Rotational failure mechanisms are considered for slopes with cracks of either known or unknown depth and location. A validation exercise was carried out based on numerical limit analyses and displacement-based finite-element analyses with strength reduction technique. Charts providing the stability factor for fissured slopes subject to both horizontal and vertical accelerations for any combination of c, ϕ and slope inclination are provided. The effect of the direction of the vertical acceleration on slope stability is specifically analysed. Yield seismic coefficients are also provided. When the presence of cracks within the slope can be ascertained with reasonable confidence, maps showing the zones within the slope where they have no destabilising effect are provided. Finally, Newmark's method was employed to assess the effect of cracks on earthquake induced displacements. To this end, displacement coefficients are provided in chart form as a function of the slope characteristics. Two examples of slopes subjected to known earthquakes are illustrated

Earthquake Geotechnical Engineering Aspects of the 2012 Emilia-Romagna Earthquake (Italy)

On May 20, 2012 an earthquake of magnitude ML=5.9 struck the Emilia Romagna Region of Italy and a little portion of Lombardia Region. Successive earthquakes occurred on May 29, 2012 with ML=5.8 and ML=5.3. The earthquakes caused 27 deaths, of which 13 on industrial buildings. The damage was considerable. 12,000 buildings were severely damaged; big damages occurred also to monuments and cultural heritage of Italy, causing the collapse of 147 campaniles. The damage is estimated in about 5-6 billions of euro. To the damage caused to people and buildings, must be summed the indirect damage due to loss of industrial production and to the impossibility to operate for several months. The indirect damage could be bigger than the direct damage caused by the earthquake. The resilience of the damaged cities to the damage to the industrial buildings and the lifelines was good enough, because some industries built a smart campus to start again to operate in less of one month and structural and geotechnical guidelines were edited to start with the recovering the damage industrial buildings. In the paper a damage survey is presented and linked with the ground effects. Among these, soil amplification and liquefaction phenomena are analyzed, basing on the soil properties evaluation by field and laboratory tests. Particular emphasis is devoted to the damaged suffered by the industrial buildings and to the aspects of the remedial work linked with the shallow foundation inadequacy and to the liquefaction mitigation effects