Abstract:
This study explores the seismic behavior of masonry buildings in close proximity to a fault rupture as compared to those located farther away. It takes into account the distinctive features of near-fault ground motions, such as forward directivity and the fling effect, which have the potential to cause significant earthquake-related damage. The study employs a dataset comprising 100 earthquake records, which represent both near-fault and far-fault ground motions, and conducts an analysis of nineteen masonry buildings with varying typologies. Analytical models for each of these buildings are constructed using experimental data concerning the quality of masonry materials. Nonlinear static and dynamic analyses are carried out to evaluate the buildings’ capacity to withstand seismic deformations and the extent of damage incurred. The findings indicate that near-fault ground motions exert a more significant influence on the dynamic response and result in greater damage to masonry structures when compared to far-fault ground motions.

wo earthquakes struck the NW region of Albanian territory on 21 September 2019 (M_w = 5.6) and on 26 November 2019 (M_w = 6.4). The epicenters of the seismic activity were located offshore NW Durrës, one of Albania’s most populated cities, located 30 km from the capital Tirana. Various aftershocks followed subsequently. While there were no reported injuries, a number of buildings sustained significant damage near the epicenter following the initial event. Subsequently, during the second event, there was loss of life and extensive damage to civilian structures, resulting in multiple collapses. This study focuses on the earthquake damages observed in residential and public buildings in the earthquake-affected region. The earthquakes predominantly affected low-rise masonry buildings, while the newly constructed RC structures built according to the latest seismic rules were almost unaffected. The commonly encountered building typologies in the region, together with photos showing the amount of destruction are presented here. As observed by the authors during the reconnaissance visit to the stricken area, examples of various damage patterns are presented, along with a technically substantiated description of the reasons for those damages. Although modern buildings during recent earthquakes in the region show acceptable performance, the detailed surveys from the Durrës Earthquakes showed that there is still an important level of deficiency in current masonry buildings built by conventional methods and materials. This problem may reoccur in future earthquakes that may hit other rural regions of Albania, which must be focused on systematically in the near future.

Basilicas constructed in the post-Byzantine time in Balkans cover a period of 400 years, from the 16th century to the 19th century. These masonry religious objects are of particular interest due to their different building typologies and historical value, so it is important that they be saved for future generations. This paper analyses the static and dynamic response of the Basilica of St. Sotiri near Gjirokaster (Albania). The static response and dynamic properties of the church have been assessed using FEM technique and the performance of the structure is investigated. As a result, important information is obtained to identify the critical regions of the structure and its seismic safety. The aim of this study is to point out that clear insight and information on interpreting the actual response of historical buildings can be obtained by numerical analysis methods. Authors believe that the approach and findings of this case study are useful to understand the load response of a wide range of monumental churches.

Data from past earthquakes is an important tool to reveal the impact of future earthquakes on engineering structures, especially in earthquake-prone regions. These data are important indicators for revealing the seismic loading effects that structures will be exposed to in future earthquakes. Five different earthquakes from six countries with high seismic risk were selected and were within the scope of this study. The measured peak ground acceleration (PGA) for each earthquake was compared with the suggested PGA for the respective region. Structural analyzes were performed for a reinforced-concrete (RC) building model with four different variables, including the number of storeys, local soil types, building importance class and concrete class. Target displacements specified in the Eurocode-8 were obtained for both the suggested and measured PGA values for each earthquake. The main goal of this study is to reveal whether the proposed and measured PGA values are adequately represented in different countries. We tried to reveal whether the seismic risk was taken into account at a sufficient level. In addition, target displacements have been obtained separately in order to demonstrate whether the measured and suggested PGA values for these countries are adequately represented in structural analysis and evaluations. It was concluded that both seismic risk and target displacements were adequately represented for some earthquakes, while not adequately represented for others. Comments were made about the existing building stock of the countries considering the obtained results.

Masonry structures began to be built with the existence of human beings and are an inspiration for today’s structures. Monumental historical buildings built according to people’s religious beliefs have special importance among such structures. Despite being exposed to many natural disasters over time, such structures that have survived till today are an indispensable part of the historical heritage. Within the scope of this study, structural analyses were carried out for the historical Ulu Mosque’s minaret in Bitlis (Turkey), located in the Van Lake basin, using both on-site measurements and finite element methods. Detailed historical and architectural features were given for the minaret and the mosque. In addition to four different earthquake ground motion levels of 2%, 10%, 50% and 68%, structural analyses were deployed separately for seven different geographical locations in the same seismic risk area. Moreover, time history analyses were conducted using the acceleration records of the Van earthquake that occurred in the region. The minaret performance levels were determined by using the displacement values obtained. The study examined the different probabilities of exceedance and the changes in the regions with the same seismic risk. As a result of each structural analysis, base shear forces, displacement, period and maximum stress values were obtained for the minaret. The displacement, base shear force, and stress values increased as the exceedance probability decreased. While the same seismic and structural analysis results were obtained for the selected settlements in the same earthquake zone in this study, remarkable differences were observed for these settlements using the geographical-location-specific design spectrum.

A prolonged earthquake series hit the regions of Albania on September 21 and November 26, 2019, causing loos of live and extensive damage to the civilian structures. The main aim of this study is to investigate the structural and earthquake response of a template design, commonly encountered in the region, which was seriously damaged by the 2019 Durres/Albania earthquake. A 3D mathematical model of the entire structure was prepared, implementing macro-modeling approach to simulate its response under seismic shakings. Inherent material properties of its constituents were determined experimentally and adopted for the analytical model. Initially, an eigenvalue analysis was deployed to identify the dominant vibrations modes of the structure. Then, pushover analyses were performed to assess the earthquake response of the template designed structure, and possible failure mechanisms were examined. Finally, the obtained results from the software were compared with the real-life damage experienced by the building. In the end, it was observed that the analytical model proved to accurately estimate the earthquake behavior exhibited by the structure during the seismic shaking.

Significant structural damages due to earthquakes reveal the importance of seismic design provisions. This paper presents a comparison between the seismic design provisions of Albania, Croatia, Iran, and Turkey for the design of mid-rise reinforced-concrete (RC) frames. Information on the historical development of the considered provisions is given. The code provisions are compared, illustrating the main differences in the minimum requirements for column and beam detailing and analysis for mid-rise RC frames. 4-story, 5-story, and 6-story buildings are designed according to each design code, and their performance is evaluated comparatively by using a displacement-based adaptive pushover procedure and eigenvalue analysis. It is observed that the recent Turkish code has the highest and the Albanian code has the lowest level of requirements in terms of member size and reinforcement detailing. The considered models indicate 15%, 20% and 50%, lower period values than the Croatia, Iran and Albania buildings, respectively. Additionally, building models per Croatia, Iran, and Albania codes have 30%, 35% and 65% less base shear capacity when compared to Turkish building codes. Building models per Croatia and Iran codes indicate similar properties both in terms of strength and stiffness.

Within the scope of this study, the effects of design spectra, which were started to be used with the Turkish
Building Earthquake Code updated in 2018, for a masonry minaret were tried to be revealed. The effect of the
design spectra, which are located in the same seismic zone but used specifically for each settlement, on the seismic
behavior of minarets has been investigated. Seismic parameters, horizontal and vertical spectra were also compared
for seven different locations considered in this study. Base shear forces, displacement, period, and maximum stress
values of the sample masonry minaret were obtained as a result of structural analyzes for each settlement,
respectively. The study revealed that the differentiation in the design spectrum significantly affects the structural
analysis. In addition, completely different results were obtained in the current regulation for the settlements that
had the same values on a regional basis in the previous regulation

This paper presents the evaluation of the seismic response of reinforced concrete (RC) residential buildings with the selected template designs in Albania considering the inelastic behavior of RC components. Four residential buildings having 5- and 6-story heights with template designs were chosen to represent the building practice in Albania before the adoption of today’s modern seismic codes. The selection of the buildings and the material characteristics were based on site investigations after the November 26, 2019 earthquake sequences in several cities of the country. Pushover and dynamic analyses were deployed in both principal directions to obtain the seismic capacities of the selected buildings. The earthquake demands are evaluated comparatively under a set of far-fault and near-fault ground motions and the nonlinear dynamic characteristics were calculated using equally single degree of freedom (ESDOF) system approach. The impact of the material quality on the seismic response of the residential buildings was analyzed. The reasons of the observed building damages during the recent Albanian earthquakes were examined using the results of the performance evaluation of the selected buildings. The detailed analysis of the pushover curves and performance assessment identified the deficiencies and possible solutions for the studied typologies.

Cultural heritage is one of most significant concerns in modern societies carrying different social and historical values. Among the stock of cultural heritage, historical monuments are one of the greatest contributors to the values in many aspects. Due to several factors, such structures have gone through changes causing structural deficiencies. The aim of this study is to provide a clear insight of the cause and impacts of structural deficiencies through visual inspections and computational methods. As a representative model, Bajrakli Mosque located in western of Kosovo is selected as a case study. During visual inspections, some cracks are found along the structural elements of the mosque. A possible cause of the structural cracks may be the stress concentration through the regions of the structure. In order to provide a better understanding, two different loadings are considered to examine the structural behavior of the mosque. The first loading covers the analysis due to gravity loads, whereas the second one defines the dynamic loading due to ground shakings defined by the earthquake spectrum using finite element analysis in SAP2000. By means of these analyses, the performance of the building is examined. As a result, important data are obtained for identifying the critical regions of the structure. The maximum displacement of the structure is found to be 7.1 mm and 8.0 mm in combination of self-weight and earthquake load in X and Y direction, respectively. Moreover, the regions showing highest values of stress concentration are found through the small domes, through the openings of main dome and connections with arches, and around the openings of the walls.

Albania has suffered from major earthquakes in the past century that have caused varying levels of damage to buildings. As a result of the number of damaged buildings and loss of life, attention has focused mostly on the poor performance of reinforced concrete and masonry structures in low and mid-rise buildings. This paper presents the results of a reconnaissance visits to the disaster-stricken area in the Durrës region in Albania and covers many zones in the region where historical and modern buildings suffered serious structural damage or collapses during the November 26, 2019, Durrës Earthquake. Special emphasis was placed on masonry and RC buildings, since the damage level was high in these buildings. The consequences of the Durrës earthquake are important for similar masonry and RC building stock in other seismically vulnerable European cities. Regularity of the structural system, quality of the material utilized, the distribution of mass and stiffness through the building, the ratio of openings on masonry walls and diaphragm stiffness have a crucial influence on the structural response. Inappropriate interventions led to serious damage or collapses, resulting in casualties. Examples of numerous damage types, as witnessed during the site visits to the affected region are presented, along with technically explanation of causes for the damages.

This study covers the application of Static and Dynamic nonlinear analysis to an old moment-frame reinforced concrete building. The case study selected is a template designed in 1982 without shear walls and built throughout the Albanian region in the communist era using old standards (KTP 2-78). For the capacity calculation, Pushover analysis is performed using an inverse triangular load pattern. The demand calculation is conducted using Incremental Dynamic Analysis (IDA) as a method that provides the response behavior of the structure from the elastic range until collapse. For the dynamic analysis is used a set of 18 earthquakes with no marks of directivity. Limit stated are defined for both Pushover and IDA based on the FEMA 356 guidelines. The mathematical model is prepared in the environment of Zeus-NL, a software developed especially for earthquake applications. The parameters defined for the IDA analysis are 5% damped first mode spectral acceleration (Sa(T1,5%)) for the intensity measure (IM) and maximum global drift ratio (ϴmax) for the damage measure (DM). In addition, limit states are selected for the pushover curve as Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP). Similarly, for the IDA curve, the limit states are selected as IO, CP, and Global Instability (GI) based on FEMA guidelines. Furthermore, IDA curves are summarized into 16%, 50% and 84% fractiles as suggested in the literature. Additionally, a comparison between Pushover and IDA median (50% fractile) is shown from the same graph to illustrate the correlations between performance levels. Finally, structural performance is interpreted based on the outcomes.

A Mw 6.4 earthquake hit the NW region of Albania on November 26, 2019, resulting in extensive damage to the civil structures in the broader area of Durrës city and its surroundings. According to the official statistics, it caused 51 death toll and ∼ 1.2 billion US dollars economic loses. This study investigates the seismic response of masonry buildings damaged during the earthquake. Four important typologies are selected to draw general conclusions from the performance analysis and damage assessment. A detailed field survey after the earthquake was conducted in Albanian territory to observe the impact on low and mid-rise buildings. Seven masonry buildings with 3 to 5 floors were chosen to represent the commonly constructed template designs. Mathematical models of each building were prepared in light of experimental test results on the quality of structural wall components. The seismic displacement capacities of each building were estimated by pushover analysis. The significance of the findings was further explored by considering the inelastic response of a group of representative buildings during the 2019 Albania earthquake sequences. According to the analyses made, Near Collapse damage state may be reached at a PGA of 0.16 g for some types of buildings. At 0.26 g all considered buildings are expected to be either collapsed or at a near collapse stage. The expected PGA with a return period of 475 years is around 0.3 g and even reaches 0.4 g in the region. Considering the analysis results, it can be said that decision-makers should be aware of the catastrophic consequences of similar future events.

On November 26,2019, an earthquake of magnitude 6.4 hit Durres city, Albania. After the earthquake, the inspection carried out by the authors in the region has provided relevant findings regarding the methods of construction, quality of the materials and the performance of structures. The dominant building types in the Albanian building stock comprise unreinforced masonry (URM) structures with load-bearing masonry walls. These units suffered the worst damage. Dynamic response of masonry is highly nonlinear, and generally shows high vulnerability to seismic loading. Moreover, many buildings of this type have undergone structural interventions like adding floors, or wall openings, especially in the first floors of the buildings, which are parallel to the main roads, because of the great demand for shops and stores. This paper aims at making a seismic performance assessment of the intervened buildings based on macro-element modeling approach. Due to its efficiency, this approach is becoming popular among practitioners and field experts in this area and allows simulating the non-linear behavior of masonry buildings. This method is applied to two old masonry buildings from the Albanian construction practice that are representatives of mid-size residential buildings with and without interventions. It must be said that in Albania, masonry buildings have been built using templates all over the country, so both models with and without intervention are common. Capacity curves of the investigated buildings are derived to assess the most probable seismic response of the investigated housing construction in the region as well as to evaluate the seismic performance of the tested structures.

Seismic-induced damages in reinforced-concrete (RC) buildings were primarily associated with materials’ low strength and poor properties. This study aims to investigate the seismic response of RC structures according to the different material’s strength and design spectra. Adaptive static pushover and eigenvalue analysis were performed for four different design spectra, five types of concrete, and two reinforcement grades. Four different design spectra were obtained by considering discrete geographical locations with different earthquake risks via the updated Turkish Earthquake Hazard Map 2018. Structural analysis was carried out for a sample RC building using these spectrum curves and material strengths. It has been observed that the structure becomes more rigid as the strength of concrete increases. This situation manifested itself with an increase in period values and a decrease in the stiffness values. Stiffness values of the building are independent of reinforcement. As the concrete strength decreases, the structure’s seismic capacity decreases while the displacement’s demand for predicted performance levels increases. Moreover, an increase in the tensile strength of reinforcements substantially increases the seismic capacity of the building. The study also determines that the site-specific design spectra obtained for different provinces are used in the analysis affects the demand displacements values considerably. The material differentiation between the stories in the building was also examined in this study. It can be a source in terms of how material discontinuity affects building performance.

As part of the development of a European Seismic Risk Model 2020 (ESRM20), the spatial and temporal evolution of seismic design across Europe has been studied in order to better classify reinforced concrete buildings (which represent more than 30% of the approximately 145 million residential, commercial and industrial buildings in Europe) and map them to vulnerability models based on simulated seismic design. This paper summarises the model that has been developed to assign the years when different seismic design levels (low code, moderate code and high code) were introduced in a number of European countries and the associated lateral forces that were specified spatially within each country for the low and moderate codes for typical reinforced concrete mid-rise buildings. This process has led to an improved understanding of how design regulations evolved across Europe and how this has impacted the vulnerability of the European residential building stock. The model estimates that ~ 60% of the reinforced concrete buildings in Europe have been seismically designed, and of those buildings ~ 60% have been designed to low code, ~ 25% to moderate code and 15% to high code. This seismic design model aims at being a dynamic source of information that will be continuously updated with additional feedback from local experts and datasets. To this end, all of the data has been made openly available as shapefiles on a GitLab repository.

This paper aims to study the seismic performance of school buildings, which have been built in accordance with template unreinforced masonry [URM] school projects in Albania. For this purpose, the most widely used two template designs which were damaged during the 2019 Durrës (Albania) Earthquakes, have been selected. Analytical models of each school were prepared following the experimental data on the quality of the masonry constitutive components of the selected school buildings. Geotechnical investigations were deployed to obtain the soil characteristics of the area where the schools’ foundations are located. Nonlinear static analyses have been performed to obtain the seismic capacity, the performance point and the damage level states. The performance-based method has been used for that purpose. The detailed examination of capacity curves and performance evaluation identified deficiencies and weak parts of the school building blocks. Results have shown that existing school buildings constructed pre-modern codes are far from satisfying the required performance criteria, suggesting that urgent response and necessary measures should be put into action.

Abstract- Recent earthquakes occurred in many parts of the world have shown that unreinforced masonry [URM] buildings constructed according to older codes may constitute an important source of risk. It is known that the mechanical response of the masonry structures depends on several factors including the compressive and shear strength of its constituents, bricks shape as well as the volumetric ratio between the wall texture and components. In this study, the effects of the material choices of a particular type of masonry buildings were studied. The typology chosen in this study represents a typified masonry building of the current Albanian building stock; these buildings were mostly built between 1977-78 and thus were designed without considering the seismic requirements proposed in today’s modern codes. This template building has been constructed in different regions of the country with the same architectural and structural configuration in two versions; red clay bricks and silicate bricks. The aim of this study is to investigate the influence of these two different materials on the seismic response of the selected masonry building. The evaluation is based on the use of nonlinear static analyses, performed by using TREMURI software. In order to estimate the reliable seismic response for this typology, extensive research in terms of historical information, structural characterization and the definition of the inherent material parameters has been executed. Upon the evaluation of the obtained results, in contrast to the type of buildings constructed by clay masonry, calcium silicate one showed a stiffer and slightly stronger response. However, at similar values of in-plane, lateral drift they exhibited more brittle response yielding unforeseen damage during seismic excitations.

Abstract

Abstract-

A great part of existing RC structures built in Turkey is that they have been designed without considering seismic-induced actions and seismic criteria for strength and ductility design. In this context, after the recent devastating earthquakes in Turkey, there has been a concerted effort to address the seismic vulnerability of existing public buildings in Turkey. The need for the evaluation and strengthening of these public buildings have come into focus following the enormous loss of lives and property during the past earthquakes. This study aims to assess the seismic performance evaluation of a typical school building in accordance with the rules of Turkish Earthquake Code-2007. The performance analysis is carried out by using nonlinear static analysis. The analytical solutions show that the intended performance level has not been satisfied for this building and decided to retrofit the structural system. The proposed procedure is applied to the retrofitted system and the obtained results are tabulated and discussed.

Abstract-

This study uses fragility curves to focus on the seismic safety evaluation of RC hospital buildings in Turkey. Three hospital buildings with varying heights of 3–5 stories are selected, and a set of fragility curves are generated for each class. The major parameters considered in this study are the number of stories, lateral stiffness, strength, and displacement capacities of the selected template designs. A large number of pushover and time history analyses are deployed under a set of 100 strong ground motion records. Fragility curves are generated based on the analysis results for each of the typical buildings. Peak ground velocity (PGV) is selected as the measure of seismic intensity. From the generated sets of the fragility curves, it is observed that damage probabilities are significantly affected by the concrete and detailing quality. Using the constructed fragility curves, collapse probabilities of existing public buildings were estimated according to PGV values. The estimated damage by fragility analyses is compared with past studies related to RC buildings in the region. Hence, analytical fragility curves developed in this study can increase the effectiveness of seismic assessment of essential health care facilities with template designs in the Turkey region.

Read More: http://ascelibrary.org/doi/10.1061/%28ASCE%29CF.1943-5509.0000806

ABSTRACT: Domes in historical buildings by Architect Sinan were not only used alone as covering
spaces but they were also used as a various combinations of semi‐domes based on larger main and
flanking areas. On the other hand, Sinan, in the early years of his profession, improved a system based
on the mixture of perfectly developed main domes, pendentives, arches and semi‐domes. The behavior
of this monolithic system is quite complex. Therefore, to determine the structural behavior and the load
mechanisms of the monolithic systems formed main dome, arches, pendentives and semi‐domes is now
possible through current numerical methods based on computer‐aided analysis. In this study,
considering the superstructure of Sinan’s important mosques, Mihrimah Sultan/Edirnekapı,
Süleymaniye, Mihrimah Sultan/Üsküdar,  Şehzade Mehmed mosques supported by square support
system, Karaahmetpaşa, Sokullu Mehmet Paşa/Kadırga mosques supported by hexagonal support
system, Sokullu Mehmet Paşa/Azapkapı and Selimiye mosques supported by octagonal support system
were statically analyzed under their dead loads by Structural Analysis Programme (SAP2000) based on
finite element methods. To avoid the confusion, which may come out in modeling and analyzing domed
roof systems, the models of all space coves have been established for the upper levels of arches resting
on columns. As a result, the structural behavior of main dome, arches, pendentives and semi‐domes was
determined and the structural behavior of each system was numerically revealed. Domes rested on
hexagonal and octagonal support systems are superior to other systems in terms of displacements and
stresses.

ABSTRACT
In this study, the effects of confined concrete models on behavior of reinforced concrete structures are
investigated at member and system levels. The widely-accepted concrete models such as Modified Kent-Park,
Mander, and Saatcioglu-Razvi are considered. A four- storey structure was designed and detailed according to
1975 Turkish Earthquake Code to reflect a typical example of building stock in Turkey. The building was
considered to be in Earthquake Zone 1 and on Z3 Soil Type. Nonlinear behavior of the building frame was
modeled by considering the inelastic section behaviour of each beam and column elements for different concrete
class and transverse reinforcement spacing. The models were subjected to pushover analysis. The differences of
confined concrete models were investigated for both reinforced concrete member and system levels. At the end
of analyses, it was observed that although there were some differences at the section level, the effects of
confined concrete models were negligible at the system level.

Abstract-

Over the past several decades, Turkey has been hit by devastating earthquakes and remarkable number of
reinforced concrete buildings has been damaged in the high seismicity regions of our country. The aim of this
study is to evaluate the seismic performance of the mid-rise reinforced concrete buildings that are major part of
building stock of our earthquake-prone country, according to recent Turkish Earthquake Code. 4- and 7-story
buildings were selected to represent mid-rise building stock. After determining the structural parameters, each
building was subjected to pushover analysis and the capacity curves were obtained. Earthquake performance of
each building was determined in the light of their capacity curves according to the recent Turkish Earthquake
Code.

Abstract –

The recent devastating earthquakes have exposed the vulnerability of the existing
public buildings in Turkey. A great part of these reinforced concrete buildings has
been designed considering earlier codes when seismic loads were not required or
the design was at lower level of seismic loads of what is currently specified. In
Turkey, template designs developed by the General Directorate of Construction
Affairs are used for many of the buildings intended for governmental services
(administrative centers, hospitals, schools, etc.) as prevalent practice to save on
architectural fees and ensure quality control. The need for evaluating the seismic
adequacy of these public buildings has come into focus following the enormous
loss of life and property during the recent earthquakes.
This paper aims to evaluate the seismic performance of a public building with the
selected template design in Turkey considering the nonlinear behavior of
reinforced concrete members. For the building addressed in this paper, material
properties are based on field investigation on government public buildings in
western part of Turkey. Seismic performance evaluation will be carried out in
accordance with the recently published Turkish Earthquake Code-2007 that has
many similarities with FEMA 356 guidelines.
Capacity curves of investigated building will be determined by nonlinear static
analysis. The effects of material quality on seismic performance of this public
building will be investigated. In conclusion, different possible deficiencies and
solutions to improve template design building will be discussed. This study gives an
in depth sight into to the rehabilitation of public buildings in Turkey

Abstract

Over the past two decades Turkey has been hit by several moderate to large earthquakes that resulted in significant loss of life and property. A remarkable number of casualties and heavily damaged or collapsed buildings has emphasized inadequate seismic performance of multistory reinforced concrete buildings, typically three to seven stories in height. This study aims to evaluate seismic performance of the most common reinforced concrete building stock in Turkey considering nonlinear behavior of the components. A sample building set is selected to reflect existing construction practice; regular buildings and buildings with irregularities such as soft story, heavy overhangs, short columns, and soft story with heavy overhangs. Ductile and non-ductile details are taken into account by transverse reinforcement amount. Capacity curves of the investigated building set are determined by pushover analyses conducted in two principal directions. The inelastic dynamic characteristics are represented by equivalent single-degree-of-freedom (SDOF) systems. Their seismic displacement demands are determined using nonlinear response history analysis under selected ground motions. Seismic performance evaluation is carried out in accordance with the recently published Turkish Earthquake Code (2006) that has similarities with FEMA-356 guidelines. Analytical damage evaluation in this study has shown that the seismic effects of earthquakes experienced in Turkey are significant and some of the earthquakes impose excessive displacement demands. Therefore, a considerable portion of existing building stock may not be safe enough in Turkey or similar countries. Also, it is observed that structural irregularities affect seismic performance of buildings. Short columns and soft story with heavy overhangs have the most negative effect.

Abstract

Over the past two decades Turkey has been hit by several moderate to large earthquakesthat resulted in significant loss of life and property. Remarkable number of casualties andheavily damaged or collapsed buildings has emphasized inadequate seismic performance ofmultistory reinforced concrete buildings, typically three to eight stories in height. The aimof this study is to evaluate the seismic performance of the mid-rise reinforced concrete buildings which are major part of building stock. In performance evaluation, destructiveearthquakes over the past two decades have been taken into consideration. Fourteen 4- and7-story buildings are selected to reflect existing construction practice, including structural irregularities. Capacity curve of each building was obtained by pushover analysis. Then,their seismic displacement demands were determined using nonlinear time history analysisunder selected ground motions. The inelastic dynamic characteristics were represented byequivalent single-degree-of-freedom systems. Seismic performance evaluation is carriedout per recently published 2007 Turkish Earthquake Code.

Abstract

This study evaluates seismic performance of the school buildings with the selected template designs in Turkey considering nonlinear behavior of reinforced concrete components. Six school buildings with template designs were selected to represent major percentage of school buildings in medium-size cities located in high seismic region of Turkey. Selection of template designed buildings and material properties were based on field investigation on government owned school buildings in several cities in western part of Turkey. Capacity curves of investigated buildings were determined by pushover analyses conducted in two principal directions. The inelastic dynamic characteristics were represented by equivalent single-degree-of freedom (SDOF) systems and their seismic displacement demands were calculated under selected ground motions. Seismic performance evaluation was carried out in accordance with recently published Turkish Earthquake Code that has similarities with FEMA-356 guidelines. Reasons of building damages in past earthquakes are examined using the results of performance assessment of investigated buildings. The effects of material quality on seismic performance of school buildings were investigated. The detailed examination
of capacity curves and performance evaluation identified deficiencies and possible solutions for template designs.

Abstract

This study evaluates the seismic capacity of school buildings with the selected template designs constructed per pre-modern code in Turkey, considering non-linear behavior of reinforced concrete components. Capacity curves of the investigated buildings were determined by pushover analyses conducted in two principal directions. Seismic capacity evaluation was carried out in accordance with the recently published Turkish Earthquake Code (2007) that has similarities with FEMA-356 guidelines. Based on capacity curves of school buildings, it was found that the effect of material quality and detailing on seismic capacity is especially apparent for buildings with no or a limited number of shear walls. Buildings with a certain number of shear walls are less affected by low material quality and detailing, emphasizing the importance of shear walls, especially in countries where construction with poor detailing is a common problem. The outcome of the study indicates that the existing school buildings constructed per the pre-modern code far from satisfying the expected performance objectives of the recent code requirements, suggesting that urgent planning and response need to be put in action.

Abstract

On 6 April 2009 an earthquake of magnitude 6.3 occurred in L’Aquila city, Italy. In the city center and surrounding villages many masonry and reinforced concrete (RC) buildings were heavily damaged or collapsed. After the earthquake, the inspection carried out in the region provided relevant results concerning the quality of the materials, method of construction and the performance of the structures. The region was initially inhabited in the 13th century and has many historic structures. The main structural materials
are unreinforced masonry (URM) composed of rubble stone, brick, and hollow clay tile. Masonry units suffered the worst damage. Wood flooring systems and corrugated steel roofs are common in URM buildings. Moreover, unconfined gable walls, excessive wall thicknesses without connection with each other are among the most common deficiencies of poorly constructed masonry structures. These walls caused an increase in earthquake loads. The quality of the materials and the construction were not in accordance with the
standards. On the other hand, several modern, non-ductile concrete frame buildings have collapsed. Poor concrete quality and poor reinforcement detailing caused damage in reinforced concrete structures. Furthermore, many structural deficiencies such as non-ductile detailing, strong beams-weak columns and were commonly observed. In this paper, reasons why the buildings were damaged in the 6 April 2009 earthquake in L’Aquila, Italy are given. Some suggestions are made to prevent such disasters in the future.

Abstract

In this study a seismic performance assessment of school buildings, which have been built in accordance with template unreinforced masonry school projects in Turkey, has been conducted. For this purpose, the most widely used three template projects have been selected. The seismic performances of these buildings have been evaluated for various earthquake levels. This evaluation has been carried out in compliance with the Turkish earthquake code entered into force in 2007. The effects of material strength and plan features on the performance of masonry school structures have been investigated within the scope of this study. It has been concluded that school buildings with template design are far from satisfying the required performance criteria. For spectral acceleration of 0.80 g, which is expected in a 475 year period in the seismic Zone 1, the average exceedance ratio for life safety performance limit is more than 80% considering different material strengths. Upon evaluation of the results a building capacity index is proposed for rapid seismic assessment of masonry school buildings.

Abstract

This study evaluates seismic capacity of the unreinforced masonry buildings with the selected template designs constructed per pre-modern code in Albania considering nonlinear behaviour of masonry. Three residential buildings with template designs were selected to represent an important percentage of residential buildings in medium-size cities located in seismic regions of Albania. Selection of template designed buildings and material properties were based on archive and site survey in several cities of Albania. Capacity curves of investigated buildings were determined by pushover analyses conducted in two principal directions. The seismic performances of these buildings have been determined for various earthquake levels. Seismic capacity evaluation was carried out in accordance with FEMA (Federal Emergency Management Agency) 440 guidelines. Reasons for building damages in past earthquakes are examined using the results of capacity assessment of investigated buildings. It is concluded that of the residential buildings with the template design, with the exception of one, are far from satisfying required performance criteria. Furthermore, deficiencies and possible solutions to improve the capacity of investigated buildings are discussed.

Abstract

Public buildings which are mostly built of reinforced concrete with template designs constitute a great part of the vulnerable public building stock in Turkey as well as in several other countries prone to earthquakes. This study focuses on seismic fragility assessment of reinforced concrete public buildings with representative template designs, which have been designed according to the 1975 version of the Turkish seismic design code. Lateral stiffness, strength and displacement capacities of the selected template designs are determined by nonlinear static analyses in two principal directions. The inelastic dynamic characteristics of the template designs investigated are represented by equivalent single degree of freedom systems and their seismic deformation demands are calculated using a set of 100 strong ground motion records. Peak ground velocity is selected as the measure of seismic intensity because it has a good correlation with maximum inelastic displacements. Based on assessed capacities and demands, fragility curves are derived separately for each template designs. Buildings are grouped according to the number of storeys. The results revealed that the effect of concrete and detailing quality on IO performance level is more limited and less critical as the ground motion intensity increases. On the other hand, the probability of exceedence for LS and CP are closer to each other for each group of buildings. Finally, using constructed fragility curves, collapse probabilities of existing public buildings were estimated according to PGV values. The results are evaluated in terms of concrete quality and transverse reinforcement detailing.