scholarly journals Assessment and Fragility of Byzantine Unreinforced Masonry Towers

2021 ◽  
Vol 6 (3) ◽  
pp. 40
Author(s):  
Emmanouil-Georgios Kouris ◽  
Leonidas-Alexandros S. Kouris ◽  
Avraam A. Konstantinidis ◽  
Chris G. Karayannis ◽  
Elias C. Aifantis
Keyword(s):  
Cultural Heritage ◽  
Seismic Vulnerability ◽  
Seismic Intensity ◽  
Elastic Behavior ◽  
Masonry Structures ◽  
Damage Classification ◽  
Plane Failure ◽  
Capacity Curves ◽  
Collapse Mechanisms ◽  
Recent Earthquakes

The seismic response of five cultural heritage towers erected between the 9th and 10th century AD are investigated herein. Firstly, their architectural and modal characteristics were studied in the light of seismic events that hit the monuments. There exist several historical reports of strong earthquakes, as well as damaged structures and collapses. The limit analysis is adopted to examine the post-elastic behavior of the towers up to collapse due to out-of-plane failure. Recurrent damage modes were collected from recent earthquakes and a classification of four possible collapse mechanisms in towers and slender masonry structures is here proposed: overturning, separation of perpendicular walls, diagonal cracking, and dislocation of the belfry. A thorough examination of the towers under investigation verified the proposed damage classification. The capacity curves were derived combining the capacity curves of each of the collapse mechanisms. Damage thresholds were defined on these curves in correspondence with damage states. The studied group of structures is representative of a wider typology. A statistical approach was adopted to describe damage with seismic intensity, and vulnerability curves were generated. The results of this study will improve the understanding of the performance and the collapse mechanisms of slender masonry structures under seismic loading and provide a characterization of seismic vulnerability for the studied cultural heritage types of towers.

scholarly journals Stochastic Vulnerability Assessment of Masonry Structures: Concepts, Modeling and Restoration Aspects

2019 ◽  
Vol 9 (2) ◽  
pp. 243 ◽  
Author(s):  
Panagiotis G. Asteris ◽  
Antonia Moropoulou ◽  
Athanasia D. Skentou ◽  
Maria Apostolopoulou ◽  
Amin Mohebkhah ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Methodological Approach ◽  
Seismic Action ◽  
Masonry Structures ◽  
Structural System ◽  
Brittle Behavior ◽  
Masonry Material ◽  
Probabilistic Nature

A methodology aiming to predict the vulnerability of masonry structures under seismic action is presented herein. Masonry structures, among which many are cultural heritage assets, present high vulnerability under earthquake. Reliable simulations of their response to seismic stresses are exceedingly difficult because of the complexity of the structural system and the anisotropic and brittle behavior of the masonry materials. Furthermore, the majority of the parameters involved in the problem such as the masonry material mechanical characteristics and earthquake loading characteristics have a stochastic-probabilistic nature. Within this framework, a detailed analytical methodological approach for assessing the seismic vulnerability of masonry historical and monumental structures is presented, taking into account the probabilistic nature of the input parameters by means of analytically determining fragility curves. The emerged methodology is presented in detail through application on theoretical and built cultural heritage real masonry structures.

Shake Table Tests on a Masonry Structure Retrofitted with Composite Reinforced Mortar

2019 ◽  
Vol 817 ◽  
pp. 342-349
Author(s):  
Stefano de Santis ◽  
Gianmarco de Felice ◽  
Garis Lorenzo Di Noia ◽  
Pietro Meriggi ◽  
Marika Volpe
Keyword(s):  
Seismic Vulnerability ◽  
Masonry Structure ◽  
Shake Table ◽  
Masonry Structures ◽  
Shake Table Tests ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Recent Earthquakes

Recent earthquakes have dramatically shown the seismic vulnerability of existing masonry structures and highlighted the urgent need of developing suitable strengthening solutions. In order to gain an improved understanding of the seismic response of masonry constructions and of the most appropriate technologies for their retrofitting, a shake table test was performed on a full-scale U-shaped tuff masonry structure, provided with an asymmetric plan with openings and with an inclined roof. The specimen was tested unreinforced and then repaired and retrofitted with composite reinforced mortar (CRM), comprised of a glass fibre reinforced polymer mesh applied with a lime mortar. Natural accelerograms were applied with increasing scale factor to collapse. Results provided information on the dynamic behaviour of masonry structures strengthened with CRM and on the enhancement of seismic performance provided by the retrofitting work.

scholarly journals Stochastic Dynamic Analysis of Cultural Heritage Towers up to Collapse

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 296
Author(s):  
Emmanouil-Georgios S. Kouris ◽  
Leonidas-Alexandros S. Kouris ◽  
Avraam A. Konstantinidis ◽  
Stavros K. Kourkoulis ◽  
Chris G. Karayannis ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Seismic Response ◽  
Seismic Vulnerability ◽  
Limit State ◽  
Collapse Mechanism ◽  
Ultimate Limit State ◽  
Stochastic Dynamic ◽  
Damage State ◽  
Limit States ◽  
Capacity Curves

This paper deals with the seismic vulnerability of monumental unreinforced masonry (URM) towers, the fragility of which has not yet been sufficiently studied. Thus, the present paper fills this gap by developing models to investigate the seismic response of URM towers up to collapse. On mount Athos, Greece, there exist more than a hundred medieval towers, having served mainly as campaniles or fortifications. Eight representative towers were selected for a thorough investigation to estimate their seismic response characteristics. Their history and architectural features are initially discussed and a two-step analysis follows: (i) limit analysis is performed to estimate the collapse mechanism and the locations of critical cracks, (ii) non-linear explicit dynamic analyses are then carried out, developing finite element (FE) simulations, with cracks modelled as interfacial surfaces to derive the capacity curves. A meaningful definition of the damage states is proposed based on the characteristics of their capacity curves, with the ultimate limit state related to collapse. The onset of slight damage-state is characterised by the formation and development of cracks responsible for the collapse mechanism of the structure. Apart from these two, another two additional limit states are also specified: the moderate damage-state and the extensive one. Fragility and vulnerability curves are finally generated which can help the assessment and preservation of cultural heritage URM towers.

scholarly journals Developed approach to determine the seismic vulnerability of reinforced concrete structures

2018 ◽  
Vol 149 ◽  
pp. 02078
Author(s):  
Serraye Mahmoud ◽  
Amri Salima
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Response Spectra ◽  
Seismic Intensity ◽  
Point Of View ◽  
Damage State ◽  
Capacity Curves ◽  
Performance Point ◽  
Materials Used

Several evaluation methods of the seismic vulnerability have been developed around the world. Which are very use ful from humanitarian and socioeconomic point of view. Generally these methods use knowledge obtained from previous earthquakes and they are basing on seismic intensity scales and on buildings direct observation. But the macroseismic intensity expresses the consequences of the seism, and not its physical characteristics of the structures. Contrary to this type of methods, an approach based on a nonlinear analysis (Push-Over method) is proposed in this work. It consists in modeling the excitation of the earthquake by a response spectrum and building's behavior by capacity curves. These capacity curves are obtained from numerical modeling performed by Opensees software. The superposition of the two curves, response spectra and capacity curve, makes it possible to determine the performance point and consequently to deduce the state of expected damage. To estimate the probability of damage of a building at a given level of solicitation (defined by Sd), we excites a group of buildings characterized by different parameters related to the geometry of the building and those are related to the materials used (concrete, steel) by seismic solicitation (Response spectrum - RPA 99). The performance point for each building is determined by a procedure defined in FEMA 440. We classifies the buildings according to the position of performance point on their curve which defines a damage state of ds (Mild, Moderate, Important or Ruin) according to the damage levels of Risk-UE. A statistical analysis is then made for each class to build the fragility curves.

scholarly journals Pozzolanic Mortars for Restoration of Sacred Tuff Masonry Structures

2019 ◽  
Vol 2 (3) ◽  
pp. 160
Author(s):  
Mariateresa Guadagnuolo ◽  
Giorgio Frunzio ◽  
Michelina Monaco ◽  
Anna Tafuro
Keyword(s):  
Seismic Vulnerability ◽  
Mechanical Characteristics ◽  
Middle Age ◽  
Mechanical Test ◽  
Masonry Structures ◽  
Architectural Heritage ◽  
Technical Requirements ◽  
Recent Earthquakes

Recent earthquakes have shown the seismic vulnerability of the Italian Architectural heritage and the need of interventions. The restoration design should take into account not only assessment and rehabilitation, but also the need of fruition of the cultural assets. These aspects have been considered in the last Italian seismic codes, a performance-based set of technical requirements to be addressed in the design process. In this framework, the requirements that the materials, meant to repair or replace historic ones, should fulfill are a key issue. In particular, for tuff masonry structures, the evaluation of the mechanical characteristics of the mortar is essential. Tests performed directly on samples withdrawn on site are perhaps the most reliable tools to determine the strength characteristics of a mortar to be used for restoration. Unfortunately, the possible dimensions of the samples are not compatible with the minimum required for a reliable mechanical test, so that the characterization of the old mortars and their historic context can be made obtaining information by the treatises of the time: components and their proportions, together with curing operations are often reported in the manuals. In particular, in the Middle Age the Roman knowledge about pozzolanic mortars was somewhat lost, and the results can be seen in the durability problems of several monuments of the period. These last considerations are the motivations of this paper, in which a study of the pozzolanic mortars in tuff masonry structures is provided. As a case study, the tuff masonry structures of the Paleocristian Basilica in Cimitile are considered and examined.

scholarly journals Seismic Vulnerability Assessment of Slender Masonry Structures

2015 ◽  
pp. 313-330
Author(s):  
Manjip Shakya ◽  
Humberto Varum ◽  
Romeu Vicente ◽  
Aníbal Costa
Keyword(s):  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Evaluation Method ◽  
Fragility Curves ◽  
Vulnerability Index ◽  
Seismic Intensity ◽  
Masonry Structures ◽  
Physical Damage ◽  
Engineering Research ◽  
Index Evaluation

Existing slender masonry structures, such as Pagoda temples, towers, minarets and chimneys, exist all over the world and constitute a relevant part of the architectural and cultural heritage of humanity. Their protection against earthquakes is a topic of great concern among the earthquake engineering research community. This concern mainly arises from the strong damage or complete loss suffered by these types of structures when subjected to earthquake and also from the need and interest to preserve them. This chapter firstly presents a methodology for assessing the seismic vulnerability of slender masonry structures based on vulnerability index evaluation method. Secondly, presents the correlation between vulnerability index and Macroseismic method to estimate the physical damage in relationship with seismic intensity. Finally, presents implementation of the methodology to construct vulnerability curves, fragility curves and estimate losses.

Seismic Vulnerability Analysis of FRP Retrofitting Industrial Buildings

2015 ◽  
Vol 724 ◽  
pp. 353-357
Author(s):  
Jian Zhu ◽  
Ping Tan ◽  
Pei Ju Chang
Keyword(s):  
Seismic Vulnerability ◽  
Response Spectrum ◽  
Time History ◽  
Seismic Intensity ◽  
Fiber Reinforced Polymers ◽  
Infill Wall ◽  
Intensity Index ◽  
Industrial Buildings ◽  
Dynamic Time ◽  
Masonry Infill Wall

This study focus on derivation of such vulnerability curves using Fiber Reinforced Polymers technologies retrofitted conventional RC industrial frames with masonry infill wall. A set of stochastic earthquake waves which compatible with the response spectrum of China seismic code are created. Dynamic time history analysis is used to compute the random sample of structures. Stochastic damage scatter diagrams based different seismic intensity index are obtained. Seismic vulnerability of FRP-reinforced RC industrial frames is lower than unreinforced frames obviously, and seismic capability of frames using FRP technologies is enhanced especially under major earthquake.

Seismic Vulnerability of Existing RC Buildings and Influence of the Decoupling of the Effective Masonry Panels from the Structural Frames

2012 ◽  
Vol 268-270 ◽  
pp. 646-655
Author(s):  
Fabio de Angelis ◽  
Donato Cancellara
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Effective Interaction ◽  
Collapse Mechanism ◽  
Limit States ◽  
Capacity Curves ◽  
Masonry Infills ◽  
N2 Method ◽  
Structural Frame

In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

scholarly journals SEISMIC VULNERABILITY OF REINFORCED CONCRETE BRIDGES IN PAKISTAN

2022 ◽  
Vol 28 (2) ◽  
pp. 93-105
Author(s):  
Muhammad Khalid Hafiz ◽  
Qaiser-uz-Zaman Khan ◽  
Sohaib Ahmad
Keyword(s):  
Seismic Hazard ◽  
Seismic Vulnerability ◽  
Seismic Hazard Assessment ◽  
Highway Bridges ◽  
Concrete Bridges ◽  
Seismic Retrofitting ◽  
Seismic Zone ◽  
Code Of Practice ◽  
Recent Earthquakes ◽  
Existing Bridges

Different researchers have performed seismic hazard assessment studies for Pakistan using faults sources which differ from Building Code of Pakistan (BCP 2007) with diverse standard deviations. The results of seismic hazard studies indicate that BCP requires gross revision considering micro and macro level investigations. The recent earthquakes in Pakistan also damaged bridge structures and some studies have been conducted by different researchers to investigate capacity of existing bridges. The most of bridge stock in Pakistan has been designed assuming seismic loads as 2%, 4% and 6% of dead loads following West Pakistan Code of Practice for Highway Bridges. The capacity of eight selected real bridges, two from each seismic zone 2A, 2B, 3 & 4 is checked against BCP demands. Static and dynamic analyses were performed and the piers were checked for elastic limits. It is established that piers are on lower side in capacity and the bridges in zone 2A are generally less vulnerable. Whereas the bridges in zone 2B, 3 and 4 are vulnerable from medium to very high level. Hence, an in-depth analytical vulnerability study of bridge stock particularly in high-risk zone needs to be conducted on priority and appropriate seismic retrofitting schemes need to be proposed.

Seismic Vulnerability Assessment of Masonry Building from Ottoman Period in Bosnia and Herzegovina

2015 ◽  
pp. 734-764
Author(s):  
Mustafa Hrasnica ◽  
Amir Čaušević ◽  
Nerman Rustempašić
Keyword(s):  
Bosnia And Herzegovina ◽  
Seismic Vulnerability ◽  
Stone Masonry ◽  
Masonry Building ◽  
Masonry Structures ◽  
Historical Buildings ◽  
Traditional Art ◽  
South East Europe ◽  
Structural Engineers ◽  
Scale Design

Traditional art of building in Bosnia and Herzegovina comprises brick or stone masonry structures. Most historical buildings belonging to national cultural heritage were made of stone-masonry. The country is situated in seismic active region of South-East Europe. In the case of strong earthquake motion such buildings could suffer heavy damages. Some structural elements of historical buildings, as domes and arches, cracked already by moderate earthquake but without the loss of stability. Substantial damages were caused by recent war disaster. Damages could be accumulated through the history as well. Generally, stone-masonry buildings in Bosnia and Herzegovina can be classified in vulnerability classes between A and C according to European Macroseismic Scale. Design and construction procedures for rehabilitation are presented here with examples of repair and strengthening of mosques, which present historical stone masonry structures dating from the Ottoman period in Bosnia and Herzegovina. Traditional and contemporary materials were used for their rehabilitation. It is important to preserve original forms, especially those of damaged elements. The challenge for structural engineers and architects was to find equilibrium between aesthetical and structural demands.

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