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An earthquake, which principally struck the Provinces of Reggio Emilia and Modena in Emilia-Romagna Region, Italy, occurred at 11:56 on October 15th 1996 and hit with a magnitudo of 4.8 Richter and VII MCS (Mercalli-Cancani-Sieberg). A significant number of damaged structures was observed, expecially concentrated in the cultural and historical heri...
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Presented in this paper are the main features and results of studies performed by ENEA for improving stability, in particular seismic protection, of cultural heritage. These studies are being carried out in the framework of the ISTECH project, funded by the European Commission. They concern the evaluation of the benefits related to the use of shape...
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... Research has been conducted to explore its application in civil engineering structures. Forni et al. (1997), Castellano et al. (1999) and Indirli et al. (2001) applied superelastic NiTi SMA into the rehabilitation of a church bell tower in Italy. Four vertical prestressing steel-SMA strands were installed in the tower structure, and SMA strands were put in series with unbonded prestressing bars. ...
In this article, an application of superelastic shape memory alloy strands for improving the seismic performance of unbonded prestressed reinforced concrete bridge column is proposed. In the reinforced concrete column with unbonded prestressing steel-shape memory alloy strands, superelastic shape memory alloy strands are put in series with unbonded steel strands, and the loading plateau of shape memory alloy is exploited to limit the increase in the axial load of column under an earthquake. Quasi-static analysis and seismic analysis were conducted to compare the seismic performance of conventional reinforced concrete column, reinforced concrete column with unbonded prestressing steel strands, and the proposed reinforced concrete column with unbonded prestressing steel-shape memory alloy strands. Result shows that reinforced concrete column with unbonded prestressing steel-shape memory alloy strands has larger ultimate displacement capacity than reinforced concrete column with unbonded prestressing steel strands in the quasi-static analysis. In the seismic analysis, reinforced concrete column with unbonded prestressing steel-shape memory alloy strands suffers from smaller earthquake residual displacement than reinforced concrete column and reinforced concrete column with unbonded prestressing steel strands. Furthermore, parametric analysis was carried out to investigate the effects of unbonded steel strand ratio, prestressing force ratio, bonded longitudinal reinforcement ratio, and maximum tensile force ratio (area of shape memory alloy strands) on the ultimate displacement and quasi-static residual displacement of reinforced concrete column with unbonded prestressing steel-shape memory alloy strands. Results show that increasing the prestressing force ratio and the maximum tensile force ratio within certain ranges can improve the self-centering capability of column. Increasing the area of bonded longitudinal reinforcement and unbonded steel strand ratio results in larger residual displacement.
... A significant number of damaged structures was observed, especially concentrated in the cultural and historical heritage. Also in this case, immediately after the seismic event, ENEA placed some personnel to investigate the performance of the structures, operating in some towns, but principally in the Municipality of S. Martino in Rio (Reggio Emilia, Italy), located inside the more affected area Forni et al., 1997). During the reconstruction phase, ENEA carried out some studies for improving seismic protection of cultural heritage, in the framework of the ISTECH Project ("Development of Innovative Techniques for the Improvement of Stability of Cultural Heritage in Particular Seismic Protection", funded by the European Commission), leading to the rehabilitation intervention of the San Giorgio in Trignano Church Bell-Tower (San Martino in Rio). ...
The 2012 seismic sequence which hit the Po Valley (Districts of Ferrara, Modena, Reggio Emilia, Bologna, Emilia-Romagna Region; Mantova, Lombardia Region; Rovigo, Veneto Region) caused 27 deaths, some hundreds of injured people, thousands of homeless, widespread failure of strategic and residential buildings, factories and infrastructures. Immediately after the first event, it was also evident that several cultural heritage constructions (churches, bell-towers, castles, and palaces) suffered collapse or severe damage, putting in danger a vast structural and mobile patrimony. This earthquake evidenced that the Po Valley is always prone to seismic risk, although the area has been included in the Italian seismic zonation only after 2003. This paper summarises the historic information, available in various catalogues and documents, about effects of past earthquakes on historic centres located in the affected area, providing highlighting examples as the Veronese 1117 catastrophe, and focussing on seismic events occurred in the Emilia-Romagna plain in the centuries. Moreover, the paper gives a description of the damage/collapse mechanisms observed in some heritage buildings located in various affected towns of Emilia-Romagna, surveyed by ENEA expert teams, supporting the Italian Civil Protection Department and the Regional Directorate for Cultural Heritage and Landscape of Emilia-Romagna. In particular, some results are shown about buildings investigated by using the prompt survey forms Chiese and Palazzi, providing a consistent amount of data useful to suggestions for future strengthening interventions.
... The main expected advantage is the control of the force imposed by the bar to the masonry walls; actually, with a SMAD proper design, the force transmitted to the tower shouldn't be higher than the "upper plateau" of the SMA elements used in the device (Fig. 5). The St. Giorgio in Trignano Bell-Tower (San Martino in Rio), which had been cut into two pieces -luckily remaining superposed -by the 1996 Reggio Emilia and Modena earthquake [2], was selected as the ISTECH demo-intervention; its rehabilitation was completed in 1999, under the supervision of ENEA and based on its analyses and support to the design and restoration works, a few months after that of the Basilica of St. Francis at Assisi, only because restoring the latter was more urgent [11][12]. This structure had been proposed by ENEA, based on its experience achieved by participating to the emergency management activities (in support to the Regional Civil Defense Department) after the 1996 earthquake. ...
... The Bell-Tower was identified by ENEA after examining other structures of possible interest, like the Church of San Vito in Caposele, Avellino District (damaged by the 1980 Campano -Lucano earthquake) and the Civic Bell-Tower of San Martino in Rio (also severely damaged by the 1996 earthquake, restored, with the cooperation of ENEA, in a conventional way, because the use of SMADs was found to be ineffective). Numerical analyses (DEM, Discrete Element Method [13], FEM, Finite Element Method [11][12]) and "in situ" dynamic characterizations of the Trignano Bell-Tower were performed [14]. It is noted that the Trignano Bell-Tower did not suffer any damage at all during the new earthquake, which struck again the Reggio Emilia and Modena Districts in June 2000 (contrary to other structures which had been restored with conventional techniques). ...
Particular attention has been devoted by ENEA for several years to the development, validation and application of innovative techniques applicable to the seismic protection of cultural heritage, in the framework of European and national projects.
In particular, ENEA actively participated in the REEDS and ISTECH Project, funded by the European Commission (EC), which allowed the development of devices capable of improving the stability of such structures, in particular their seismic protection. In ISTECH, Shape Memory Alloy (SMA) Devices (SMADs) were developed and employed in the demo-application foreseen by the project itself, which was the restoration of the Bell-Tower of the San Giorgio in Trignano Church at San Martino in Rio (Reggio Emilia, Italy), which had been severely damaged by the 1996 Modena and Reggio Emilia earthquake. It is worthwhile stressing that, contrary to other structures which had been restored in a conventional way, the Trignano Bell-Tower did not suffer any damage during the earthquake which struck again the Reggio Emilia and Modena Districts in June 2000. Moreover, in the framework of ISTECH exploitation, two further pilot applications of SMADs were completed during the restoring intervention: to the transept tympana of the St Francis at Assisi and to the San Feliciano Cathedral facade at Foligno (Perugia, Italy), both heavily damaged by the 1997 Marche and Umbria earthquake.
At present, further research projects, heavily involving ENEA, are in progress or have been proposed for the development and pilot application of innovative techniques for the seismic protection of cultural heritage; in particular:
- the PROSEESM Project of the PARNASO Program, approved by the Italian Ministry of University and Research (MURST); two possible pilot applications of SI (coupled to other techniques) for the restoration of damaged cultural heritage structures have already been identified (the San Giovanni Battista Church at Apagni, Sellano, and the Santa Lucia Church at Aggi, Nocera Umbra (Perugia District), both severely damaged by the 1997 Marche and Umbria earthquake, with the agreement of the Superintendent for cultural heritage of Umbria Region. Further structures, for pilot applications of techniques also different from SI will be soon identified, contacting the Superintendent for cultural heritage of Marche Region;
- a feasibility study for the reconstruction, with seismic isolation (SI) in the original site and with the original materials, of Mevale di Visso, Macerata, Italy (a village destroyed by the 1997 Marche and Umbria earthquake), entrusted to ENEA by the Technical and Scientific Committee of Marche Region
In this paper, other promising innovative antiseismic techniques (with realized and possible applications) are also reported.
... The main expected advantage is the control of the force imposed by the bar to the masonry walls; actually, with a SMAD proper design, the force transmitted to the tower shouldn't be higher than the "upper plateau" of the SMA elements used in the device (Fig. 5). The St. Giorgio in Trignano Bell-Tower (San Martino in Rio), which had been cut into two piecesluckily remaining superposed -by the 1996 Reggio Emilia and Modena earthquake [2], was selected as the ISTECH demo-intervention; its rehabilitation was completed in 1999, under the supervision of ENEA and based on its analyses and support to the design and restoration works, a few months after that of the Basilica of St. Francis at Assisi, only because restoring the latter was more urgent [11][12]. This structure had been proposed by ENEA, based on its experience achieved by participating to the emergency management activities (in support to the Regional Civil Defense Department) after the 1996 earthquake. ...
... The Bell-Tower was identified by ENEA after examining other structures of possible interest, like the Church of San Vito in Caposele, Avellino District (damaged by the 1980 Campano -Lucano earthquake) and the Civic Bell-Tower of San Martino in Rio (also severely damaged by the 1996 earthquake, restored, with the cooperation of ENEA, in a conventional way, because the use of SMADs was found to be ineffective). Numerical analyses (DEM, Discrete Element Method [13], FEM, Finite Element Method [11][12]) and "in situ" dynamic characterizations of the Trignano Bell-Tower were performed [14]. It is noted that the Trignano Bell-Tower did not suffer any damage at all during the new earthquake, which struck again the Reggio Emilia and Modena Districts in June 2000 (contrary to other structures which had been restored with conventional techniques). ...
Particular attention has been devoted by ENEA for several years to the development, validation and application of innovative techniques applicable to the seismic protection of cultural heritage, in the framework of European and national projects. ENEA actively participated in the REEDS and ISTECH Project, funded by the European Commission (EC), which allowed the development of devices capable of improving the stability of such structures, in particular their seismic protection. In ISTECH, Shape Memory Alloy (SMA) Devices (SMADs) were developed and employed in the demo-application foreseen by the project itself, which was the restoration of the Bell-Tower of the San Giorgio in Trignano Church at San Martino in Rio (Reggio Emilia, Italy), which had been severely damaged by the 1996 Modena and Reggio Emilia earthquake. It is worthwhile stressing that, contrary to other structures which had been restored in a conventional way, the Trignano Bell-Tower did not suffer any damage during the earthquake which struck again the Reggio Emilia and Modena Districts in June 2000. Moreover, in the framework of ISTECH exploitation, two further pilot applications of SMADs were completed during the restoring intervention: to the transept tympana of the St Francis at Assisi and to the San Feliciano Cathedral facade at Foligno (Perugia, Italy), both heavily damaged by the 1997 Marche and Umbria earthquake. At present, further research projects, heavily involving ENEA, are in progress or have been proposed for the development and pilot application of innovative techniques for the seismic protection of cultural heritage; in particular:
- the PROSEESM Project of the PARNASO Program, approved by the Italian Ministry of University and Research (MURST); two possible pilot applications of SI (coupled to other techniques) for the restoration of damaged cultural heritage structures have already been identified (the San Giovanni Battista Church at Apagni, Sellano, and the Santa Lucia Church at Aggi, Nocera Umbra (Perugia District), both severely damaged by the 1997 Marche and Umbria earthquake, with the agreement of the Superintendent for cultural heritage of Umbria Region. Further structures, for pilot applications of techniques also different from SI will be soon identified, contacting the Superintendent for cultural heritage of Marche Region;
- a feasibility study for the reconstruction, with seismic isolation (SI) in the original site and with the original materials, of Mevale di Visso, Macerata, Italy (a village destroyed by the 1997 Marche and Umbria earthquake), entrusted to ENEA by the Marche Region Technical and Scientific Committee;
- the 3d isolation of the roman archaeological ship, in the framework of a collaboration between Archaeological Superintendent of Pompei-Ercolano, Istituto Centrale del Restauro and ENEA.
In this paper, other promising innovative antiseismic techniques (with realized and possible applications) are also reported.
... 4b shows the cracks at the windows level, caused by a rotation of about 3 cm of the upper part of the structure. Also this tower was monitored and the first frequency measured (2.7 Hz), by recording both ambient and vibrations and aftershocks (Forni et al., 1997a). Moreover, it was subjected to four aftershocks which were recorded and used in the numerical analyses. ...
Presented in this paper are the main features and first results of studies performed by ENEA, with the cooperation of the University of Bologna, for improving stability, in particular seismic protection, of cultural heritage. These studies are being carried out in the framework of the ISTECH project, funded by the European Commission. They concern the evaluation of the benefits related to the use of shape memory alloy devices for the seismic rehabilitation of the aforesaid structures. The use of such materials across gaps or fissures has not only a strengthening function, by making the structure capable of absorbing deformations due to creep and settlements, but also may add considerable energy dissipation if the structure deformation is sufficiently large. The great interest for cultural heritage is related to the limited encumbrance. Until now, considered have been a church damaged by the 1980 Campano-Lucano (Irpinia) earthquake and more recently, bell towers damaged by the 1996 Modena & Reggio Emilia (Novellara) earthquake.
... Some case studies corresponding to real structures were also analysed and their seismic vulnerability assessed. Among the analysed case studies are the Lisbon aqueduct, that survived the 1755 Lisbon earthquake and the S. Giorgio in Trignano bell tower in S. Martino del Rio, Italy, which was seriously damaged during the October 1996 earthquake [8]. Figure 4 displays the possible longitudinal collapse mode for the Lisbon aqueduct, for which a very large acceleration would be necessary. ...
SUMMARY This paper focuses on a methodology for modelling the seismic behaviour of masonry structures. A special emphasis is given to structures of typical monuments built either with brick or stone blocks. The discrete element method is shown to adequately simulate the behaviour of the blocky structures. The simulation of collapse patterns is analysed for some structural elements. Case studies related to the seismic behaviour of real monumental structures are also presented.
A diagonal steel-shape memory alloy bracing device is proposed for seismic retrofitting of vulnerable building frame structure. Superelastic shape memory alloy bar is put in series with steel bars in the bracing. The device makes use of the loading plateau of superelastic shape memory alloy to limit the tensile force of diagonal bracing. A precast soft-storey building frame in Australia was selected for a case study. A numerical model of the frame was developed and validated with the results from full-scale pull-down field tests. Nonlinear time history analysis was then conducted to evaluate the seismic performance of the frame with different retrofitting strategies. The result shows that the diagonal steel-shape memory alloy bracing can reduce the displacement demand on the soft-storey frame. Meanwhile, the level of tensile force of steel-shape memory alloy bracing can be controlled by the force plateau of the shape memory alloy bar, which is recommended to be 20% of the yielding force of the steel bar. The lower tensile force demand could alleviate the force demand at the associated support connections.
Si descrive il restauro del Campanile della Chiesa di S. Giorgio in Trignano (S. Martino in Rio,
Reggio Emilia), gravemente danneggiato dal terremoto del 15 Ottobre 1996 e scelto come obiettivo
dell'applicazione pilota di Tecniche Innovative Antisismiche (TIA) prevista dal Progetto
Comunitario ISTECH.
Il lavoro di ripristino convenzionale ha riguardato il consolidamento complessivo della muratura, la
ricucitura delle lesioni provocate dal sisma, il rifacimento dei solai, la rimozione e il restauro del
sistema campanario. L’intervento innovativo ha visto l’inserimento di quattro tiranti verticali di
acciaio (post-tensionati e ancorati ai livelli di fondazione e copertura) negli angoli interni del
campanile, e l'installazione, in serie con essi, di quattro dispositivi antisismici innovativi in Leghe a
Memoria di Forma (LMF) o in inglese Shape Memory Alloy (SMA), realizzati utilizzando i risultati
ottenuti da analisi numeriche sofisticate e prove sperimentali (sia in laboratorio sia “in situ”)
previste dal Progetto ISTECH. L’intervento sul Campanile di Trignano, e quello quasi
contemporaneo sui timpani laterali della Basilica Superiore di San Francesco di Assisi,
rappresentano le prime applicazioni al mondo con Dispositivi SMA (SMAD).
Main results of the European Commission (EC) funded ISTECH Project are here presented. This project aims to develop innovative techniques for the restoration of cultural heritage structures, especially masonry buildings. Said structures are especially vulnerable to earthquake ground motion owing to reduced resistance and ductility as demonstrated by the vast amount of destruction visited by earthquakes in the past. Sometimes, traditional restoration techniques are inadequate in avoiding collapses. Furthermore, they are often too invasive.
The use of devices based on superelastic shape memory alloys has proved very effective in improving the seismic resistance of masonry structures. Different such types of devices have been investigated to fulfil different structural needs. For example, Shape Memory Alloys Devices (SMADs) can be used to prestress masonry but at the same time avoid the risk of overstressing owing to the force limitation offered by the alloys’ superelastic “plateau”. Other types of SMADs can be applied without transmitting static loads to the masonry structures, only becoming active under dynamic actions. The latter SMAD types can be used as horizontal restraints to enhance the out-of-plane seismic strength of outside masonry walls like those of church façades. SMADs can be custom designed, taking into account each monument's unique characteristics.
The development of said innovative restoration techniques and devices included theoretical and numerical studies as well as intensive testing of material specimens, devices and structural models. Numerical modelling of different structural elements and actual structures was performed using both finite as well as discrete element methods; the latter take into account the blocky nature of masonry structures. Both the numerical studies and the experimental results show that the SMADs can substantially increase the stability of masonry structures exposed to an earthquake. For example, out-of-plane shaking table tests on masonry mock-ups show that the structure protected with SMAD ties can remain unharmed after an earthquake of at least 50 % higher intensity than the earthquake causing the collapse of a structure reinforced with traditional steel ties. Pseudo-dynamic tests on other masonry mock-ups subjected to in-plane seismic excitations also show significant increase in the seismic resistance of the models protected with SMADs (in series with steel ties applying prestress forces).
The successful results of the research project led to two restoration applications now under way in Italy: the Bell-Tower of the S.Giorgio in Trignano Church in S.Martino in Rio, damaged during the October 1996 earthquake, and the transept tympana of the Basilica of S. Francesco in Assisi, damaged during the September 1997 earthquake.
Within the framework of the European Commission-funded ISTECH Project [FIP et al., 1995], a series of experimental campaign has been carried out, in order to evaluate the benefits induced by the application of superelastic Shape Memory Alloy (SMA) Devices (SMADs), an innovative technique for the restoration of a Cultural Heritage Structure (CUHES), especially masonry buildings. Said structures are greatly vulnerable to earthquake ground motion and traditional interventions are sometimes inadequate and often too invasive.
The experimental campaigns have been the following ones: 1) shaking table tests on masonry wall mock-ups (focused in this paper), simulating a portion of a CUHES, with the aim to evaluate the effectiveness of SMADs for the prevention of the out-of-plane collapse due to dynamic forces acting orthogonally; 2) large-scale tests on masonry walls [Bono et al., 1998], with the aim to increase, by the use of SMADs, resistance and stability against the forces induced by an earthquake in the plane of the model; 3) furthermore, long period tests, regarding creep evaluation in a masonry wall sample and compression of two little brick columns, pre-stressed respectively by a SMAD and a conventional device, in order to measure the static vertical load during the time.
The use of SMADs has proved very effective in improving the seismic resistance of the aforesaid structures. The successful results of the research led to two restoration applications now under way in Italy: the Bell-Tower of the S. Giorgio in Trignano Church in S. Martino in Rio, damaged during the October 1996 earthquake [Forni et al., 1997], and the transept tympana of the Basilica of S. Francesco in Assisi, damaged during the September 1997 earthquake [Croci 1998, a-c].
