scholarly journals Seismic performance of strengthened masonry structures: actual behaviour of buildings in Norcia and Campi Alto during the 2016 Central Italy seismic sequence

Author(s):  
Romina Sisti ◽  
Marco Di Ludovico ◽  
Antonio Borri ◽  
Andrea Prota

AbstractThe structural response of unreinforced masonry buildings designed for gravity load only or with reference to obsolete seismic provisions is widely studied in the literature in order to define proper strengthening strategies and solution to mitigate the seismic risk. However, the critical analysis of the effectiveness of past used strengthening solution is still lacking. To fill such gap, the present study deals with the evaluation of the seismic performances of buildings in Campi Alto struck by the 2016 central Italy seismic sequence. The behaviour of buildings in Campi Alto is compared with that of buildings in Norcia. A large part of the buildings in these two towns was strengthened between 1980 and 2000 during the reconstruction processes following previous earthquakes which occurred in 1979 and 1997. However, the strengthened buildings in Norcia reported limited damage while a significant and widespread level of damage was detected on several strengthened buildings in the hamlet of Campi Alto. This study focuses on the buildings in Campi Alto with the aim of investigating on the reasons of their unsatisfactory behaviour. Thus, the seismic action experienced by buildings in Norcia and Campi Alto is initially compared and the main vulnerabilities of these buildings are also evaluated. Then, 20 projects of strengthening interventions submitted to the Civil Engineering Department of the Umbria Region between 1984 and 2012 have been herein analysed and discussed in order to focus on the effectiveness of the strengthening solution adopted in the past. The analyses of such projects and of the empirical damage detected after the 2016 seismic sequence is a unique opportunity to derive useful information for future applications.

2021 ◽  
Author(s):  
Romina Sisti ◽  
Marco Di Ludovico ◽  
Antonio Borri ◽  
Andrea Prota

Abstract The structural response of unreinforced masonry buildings designed for gravity load only or with reference to obsolete seismic provisions is widely studied in the literature in order to define proper strengthening strategies and solution to mitigate the seismic risk. However, the critical analysis of the effectiveness of past used strengthening solution is still lacking. To fill such gap, the present study deals with the evaluation of the seismic performances of buildings in the historical centre of Norcia and Campi Alto struck by the 2016 central Italy seismic sequence. A large part of these buildings was strengthened between 1980 and 2000 during the reconstruction processes following previous earthquakes occurred in 1979 and 1997. The strengthened buildings in Norcia reported limited damage while a significant and widespread level of damage was detected on several strengthened buildings in the hamlet of Campi Alto. The study focuses on such latter aspect with the aim of investigating on the reasons of such unsatisfactory behaviour. Thus, a comparison between seismic action experienced by buildings in Norcia and Campi Alto is initially analysed along with the evaluation of the main vulnerabilities of these buildings. Then, 20 projects of strengthening interventions submitted to the Civil Engineering Department of the Umbria Region between 1984 and 2012 have been herein analysed and discussed in order to focus on the effectiveness of the strengthening solution adopted in the past. The analyses of such projects and of the empirical damage detected after the 2016 seismic sequence is a unique opportunity to derive useful information for future applications.


2013 ◽  
Vol 405-408 ◽  
pp. 2020-2024
Author(s):  
Li Ming Wu

Taking the typical reinforced concrete stiffening truss suspension bridge as example, finite element analysis model under seismic action is established. Dynamic response analysis is done on this suspension bridge using finite element software ANSYS and contrast is done between this analysis result and structural response under gravity load effect. Contrast result shows that structural response under seismic action is obviously higher than that under gravity load effect in which internal force response is greater than displacement. The function of dynamic load should be taken into account in the design of bridge structure in order to provide reference for the structural design of long-span flexible bridge.


Moreana ◽  
2009 ◽  
Vol 46 (Number 176) (1) ◽  
pp. 175-190
Author(s):  
Bernard Bourdin

The legacy from Christianity unquestionably lies at the root of Europe, even if not exclusively. It has taken many aspects from the Middle Ages to modern times. If the Christian heritage is diversely understood and accepted within the European Union, the reason is essentially due to its political and religious significance. However, its impact in politics and religion has often been far from negative, if we will consider what secular societies have derived from Christianity: human rights, for example, and a religious affiliation which has been part and parcel of national identity. The Christian legacy has to be acknowledged through a critical analysis which does not deny the truth of the past but should support a European project built around common values.


Author(s):  
حنان ساري ◽  
محمد أبو الليث الخيرآبادي

انتشرت لفظة الحداثة في عصرنا الحالي انتشاراً واسعاً، وأخذت مفهومات متعددة، ونحن لا نراها أكثر من أنها امتداد طبيعي للقلق الأوروبي.وسعى التيار الحداثي لتقديم مشاريع تعتمد كلية على مناهج وآليات غربية في دراستها وتعاملها مع القرآن الكريم والسنة، ولعل أهم الذين تقدموا بتلك المشاريع؛ محمد أركون، عبد المجيد الشرفي التونسي، محمد عابد الجابري، حسن حنفي، نصر حامد أبوزيد، الطيب التيزني السوري، محمد شحرور، جمال البنا وغيرهم، وطالبوا بإعادة قراءة القرآن الكريم على ضوء المناهج النقدية الغربية في عملية التقليد الأعمى، ومن ثم نقلوا التجربة الأوروبية بكل آثارها الفوضوية إلى ساحة الفكر الإسلامي. وإن مدعي تجديد الدين من هؤلاء، ليس لهم صلة بالدين أو علومه، بقدر ما تشبعت أفكارهم بمناهج علمانية، فالمراد من جهودهم ليس الدين، وإنما غرس الحداثة بدل الدين، فهي خطَّةٌ تقوم على التَّغيير من داخل البيت الإسلاميِّ من خلال العبث بالنُّصوص الشَّرعيَّة بتحريفها وتفريغها من محتواها الحقيقيِّ، ووضع المحتوى الذي يريدون؛ فهم يَطرحون أفكارَهم وآراءَهم على أنَّها رؤى إسلاميَّة ناشئة عن الاجتهاد في فهم الدِّين. وقد حَمَلَ هذا الاتجاهُ شعار (التَّحديث والعصرنة للإسلام)؛ فهم يريدون منَّا تركَ ما أَجْمَعَتْ عليه الأُمَّةُ من معاني القرآن والسُّنَّة، لفهم جديد مغاير لفهم السَّلَف الصَّالح يكون متناسبًا مع هذا العصر الذي نعيش فيه. الكلمات المفتاحيّة: الحداثة، أوهام، الحداثيون، قراءة معاصرة، العصرنة للإسلام. Abstract In modern times, the word Modernity has spread widely and has become widely understood, and we see it as a natural extension of European concern and confusion. The Modernist Movement strived to present the ideas that rely completely on Western methodologies and approaches in their study and dealing with Qur’an and Sunnah. The most important scholars that have presented these ideas are; Mohammad Arkoun, ‘Abd Al-Majid Sharafi al-Tunisi, Mohammed ‘Abed al-Jabri, Hassan Hanafi, Nasr Hamid Abu Zayd, Tayyeb Tizini, Muhammad Shahrour, Jamal Al-Banna, and others, they called for a re-reading and reinterpret the Qur’an in the light of Western critical approaches. Then, conveyed and brought the European experience and practice with all its chaotic effects to Islamic thought. The slogan of “Renewal of Religion” from these people has no relation to religion (Islam) or its sources, but instead saturated their ideas with secular methods. They tried to instill modernity rather than religion, and misinterpreted the Islamic sources by distorting it and evacuating it from the true context and setting it with their own understanding. They claim their ideas and opinions as the effort to understand religion and carried the slogan of “Modernization and Modernization of Islam”; they want us to leave the consensus of the Muslim scholars on religious issues (Ijmaa’ al-Ummah) especially relating to the meaning of the Qur’an and Sunnah and bring us to a new views and understanding on religious issues which are contradictory to the views of the past Muslim scholars (al-salaf al-soleh) to fulfill their opinions. Keywords: Modernity, Misunderstanding, Modernists, Contemporary Reading, Modernization of Islam.


Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 58 ◽  
Author(s):  
Francesco Clementi

This paper presents a detailed study of the damages and collapses suffered by various masonry churches in the aftermath of the seismic sequence of Central Italy in 2016. The damages will first be analyzed and then compared with the numerical data obtained through 3D simulations with eigenfrequency and then nonlinear static analyses (i.e., pushover). The main purposes of this study are: (i) to create an adequately consistent sensitivity study on several definite case studies to obtain an insight into the role played by geometry—which is always unique when referred to churches—and by irregularities; (ii) validate or address the applicability limits of the more widespread nonlinear approach, widely recommended by the Italian Technical Regulations. Pushover analyses are conducted assuming that the masonry behaves as a nonlinear material with different tensile and compressive strengths. The consistent number of case studies investigated will show how conventional static approaches can identify, albeit in a qualitative way, the most critical macro-elements that usually trigger both global and local collapses, underlining once again how the phenomena are affected by the geometry of stones and bricks, the texture of the wall face, and irregularities in the plan and elevation and in addition to hypotheses made on the continuity between orthogonal walls.


Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 322
Author(s):  
Evelina Volpe ◽  
Luca Ciabatta ◽  
Diana Salciarini ◽  
Stefania Camici ◽  
Elisabetta Cattoni ◽  
...  

The development of forecasting models for the evaluation of potential slope instability after rainfall events represents an important issue for the scientific community. This topic has received considerable impetus due to the climate change effect on territories, as several studies demonstrate that an increase in global warming can significantly influence the landslide activity and stability conditions of natural and artificial slopes. A consolidated approach in evaluating rainfall-induced landslide hazard is based on the integration of rainfall forecasts and physically based (PB) predictive models through deterministic laws. However, considering the complex nature of the processes and the high variability of the random quantities involved, probabilistic approaches are recommended in order to obtain reliable predictions. A crucial aspect of the stochastic approach is represented by the definition of appropriate probability density functions (pdfs) to model the uncertainty of the input variables as this may have an important effect on the evaluation of the probability of failure (PoF). The role of the pdf definition on reliability analysis is discussed through a comparison of PoF maps generated using Monte Carlo (MC) simulations performed over a study area located in the Umbria region of central Italy. The study revealed that the use of uniform pdfs for the random input variables, often considered when a detailed geotechnical characterization for the soil is not available, could be inappropriate.


Author(s):  
Iunio Iervolino ◽  
Pasquale Cito ◽  
Chiara Felicetta ◽  
Giovanni Lanzano ◽  
Antonio Vitale

AbstractShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.


1998 ◽  
Vol 26 (2) ◽  
pp. 89-110 ◽  
Author(s):  
R. A. W. Mines

The paper describes a final-year undergraduate course that has been taught at the University of Liverpool for the past three years. The main aims of the course are to introduce the student to the design of structures using multi-component (composite) materials and to the performance of such structures under impact loading. Given the complexity of generalized composite behaviour and of structural crashworthiness, a simple structural case is considered, namely, a beam subject to three-point bending. A feature of the course is that not only is linear structural response considered but also non-linear (progressive) structural collapse is covered. The course is split into four parts, namely: (i) analysis of composite laminae, (ii) analysis of laminated beams, (iii) local and global effects in sandwich beams, and (iv) post-failure and progressive collapse of sandwich beams. Static and impact loadings are considered. Comments are made on how the theories are simplified and communicated to the undergraduate students.


2015 ◽  
Vol 203 (1) ◽  
pp. 399-415 ◽  
Author(s):  
G. Calderoni ◽  
A. Rovelli ◽  
Y. Ben-Zion ◽  
R. Di Giovambattista

1982 ◽  
Vol 18 ◽  
pp. 243-260
Author(s):  
Diana M. Webb

In his excellent study of medieval Italian society, Hyde makes a thought-provoking comparison of ‘the Italians of the age of Dante’ with the humanists of a later generation. The former he sees as distinguished by ‘a sense of continuity with the past and with other parts of the Catholic world’ from the humanists who ‘concentrated on what was close at hand, digging deep rather than spreading wide, so that their world revolved around central Italy.’ It is not my intention here to dispute this assertion, but to use it to stimulate reflection on the nature of Italian self-awareness in the early renaissance period, in the light of a further contrast between Hyde’s two ages which he does not himself emphasise.


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