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beyza taskin

Istanbul Technical University, Civil Engineering, Faculty Member

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ahmad gazi paedullah

SAAD DAHLEB DE BLIDA

Jerzy Szołomicki

TUAN NORHAYATI TUAN CHIK

Dr. Ir. I Nyoman Sutarja, MS

Universitas Udayana

Mukhlis Sunarso

Institut Teknologi Bandung

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Papers by beyza taskin

Critical evaluation of NDT for rapid condition assessment of existing RC buildings: A case study

MATEC Web of Conferences

There is an urgent need for rapid and reliable condition assessment of existing reinforced concre... more There is an urgent need for rapid and reliable condition assessment of existing reinforced concrete (RC) buildings as a basis for structural safety evaluation, especially in developing countries in seismic regions such as Turkey. Traditionally, RC structures are evaluated by taking core samples from a limited number of structural elements for concrete strength and performing spot checks for the steel reinforcement by removing the concrete cover. In-situ concrete strength is determined through compression testing of core samples. Through spot checks, conformance of the existing reinforcement with the structural drawings is evaluated and a reinforcement realization factor is calculated for use in the analyses. Even though these conventional methods are relatively more accurate and reliable for condition assessment of existing RC structures, they are destructive, involved, time taking, slow and expensive. Non-destructive testing (NDT) methods are proposed as a solution to this problem....

Monte Carlo analysis of earthquake resistant R-C 3D shear wall-frame structures

Structural Engineering and Mechanics, 2006

... strain hardening, stiffness degradation effects associated with unloading and load reversal s... more

Numerical simulation of RC infill walls under cyclic loading and calibration with widely used hysteretic models and experiments

Bulletin of Earthquake Engineering, 2015

Addition of reinforced concrete (RC) infill walls into the structural system has been a commonly ... more Addition of reinforced concrete (RC) infill walls into the structural system has been a commonly preferred strengthening technique within the last decades for seismic rehabilitation of RC frames. As a consequence, generating a representative numerical model of an RC infill wall has become an important issue. As the initial step of this study, measured structural responses of two selected well-known large-scale RC infill wall experiments subjected to displacement controlled cyclic loading are taken into account. Later, by calibrating the numerical model prepared in Perform-3D computer program utilizing fiber cross-sections, a practical and a compatible analytical model is obtained and proposed herein. Structural systems of the experiments are mathematically modeled by elements consisting of vertical and horizontal fiber layers to represent the bending/axial behavior and to control the out of plane displacements, respectively. Nonlinear behavior of the reinforcing steel is represented by a tri-linear backbone curve without strength degradation, while a multi-linear hysteretic behavior considering the strength loss is utilized for the structural concrete. Furthermore, those recently conducted experiments are simulated by a couple of widely used hysteretic models for comparative purposes, which are preferred in most cases by the researchers during the analytical investigation of RC structures, so that their adequacy for reflecting the nonlinear behavior of infill walls are also studied. It is shown with comparisons for the experimentally measured and the analytically derived results that the calibrated mathematical model proposed herein is more compatible with the measured values than the widely used hysteretic rules for capturing the behavior of these types of frames retrofitted by RC infill walls under reversed cyclic loading. Although numerical simulations are carried out for a limited number of tests and it is assumed that sufficient amount of anchoring dowels is provided at the interface of the existing frame and the RC infill, the proposed calibrated model conforms to both

SDOF System Demands for Performance-Based Design of RC Structures

Proceedings of the Seventh International Conference on Computational Structures Technology

Investigation of Infill Wall Effect for the Seismic Performance of a Moderately Damaged RC Building

In order to investigate the infill wall effect in reducing the earthquake damage, a four-story RC... more In order to investigate the infill wall effect in reducing the earthquake damage, a four-story RC building in Yalova province in north-western part of Turkey, which has experienced moderate damage during the August 17, 1999 Kocaeli Earthquake and strengthened afterwards, a set of non-linear dynamic analysis is carried out in this research. Structural performances for both before and after strengthening states are evaluated, also taking into account the existence of infill walls for the as-built and strengthened states of the building. Pushover analyses are carried out to establish the capacity and demand curves for the structures, selecting the target displacements considering the Turkish Earthquake Resistant Design Code-2007. Utilizing DRAIN-2DX computer program, dynamic analyses are performed using an earthquake ensemble of 7 recorded strong ground motions as well as a simulated spectrum compatible accelerogram. It is assumed that, bilinear hysteretic model represents the nonlinea...

An experimental study of a midbroken 2-bay, 6-storey reinforced concrete frame subject to earthquakes

Soil Dynamics and Earthquake Engineering, 1997

Transient analysis of dam–reservoir interaction including the reservoir bottom effects

Journal of Fluids and Structures, 2005

In this paper, time-domain transient analysis of elastic dam-reservoir interaction including the ... more In this paper, time-domain transient analysis of elastic dam-reservoir interaction including the reservoir bottom effects is presented by coupling the finite element method in the infinite fluid domain and in the solid domain. An efficient coupling procedure is formulated by a substructuring method. Sommerfeld's boundary condition for the far end of the infinite domain is implemented. To verify the proposed scheme, numerical examples are given to compare with available exact solutions for rigid and elastic dam cases. Finally, a numerical example is studied to evaluate the effects of the reservoir bottom.

Seismic safety screening method For Istanbul Metropolitan City

Proceedings of the10th East Asia Pacific …, 2006

Page 1. 1 SEISMIC SAFETY SCREENING METHOD FOR ISTANBUL METROPOLITAN CITY Pinar OZDEMIR 1 and Beyz... more

A computationally efficient solution of the wave equation for the transient response of infinite reservoirs

Archive of Applied Mechanics, 2005

In this paper, the transient response of an infinite reservoir is analyzed using the dual-recipro... more In this paper, the transient response of an infinite reservoir is analyzed using the dual-reciprocity boundary element method. A vertical and an inclined-face rigid dam are analyzed under a transient loading. Sharan-type boundary-condition transmission is implemented in the formulation. The results are compared with the exact solution and those obtained by using the finite element method. It is seen that the application of the dual-reciprocity boundary element method is simpler and the results are in very good agreement with the exact solution and those obtained by using the finite element method.

Analysis Of Seismic Behavior Of A Building From Turkey Using Real Earthquake Records

Publication in the conference proceedings of EUSIPCO, Barcelona, Spain, 2011

A Review of the Accuracy of Force- and Deformation-Based Methods in Determining the Seismic Capacity of Rehabilitated RC School Buildings

This chapter focuses on the comparison of the conventional linear force-based method with the adv... more This chapter focuses on the comparison of the conventional linear force-based method with the advanced nonlinear deformation-based method that are commonly preferred to investigate the seismic performances of the existing RC school buildings. School buildings which have different structural characteristics and RC infill wall index are generated from an existing school’s layout plan. During the nonlinear dynamic analysis, seven recorded earthquake motions which are scaled in accordance with the Turkish Earthquake Code are employed. Seismic performances of the school buildings against the two different earthquake hazard level are evaluated considering not only various RC infill wall indexes but also different material strengths and number of stories in terms of limit states specified in the code. In order to determine the most appropriate method related to material strength, floor level and RC infill wall index for the seismic strengthening of the existing RC school buildings, the obt...

Derivation of Fragility Relations with Regard to Poorly Constructed Existing RC Buildings

The objective of this paper is to illustrate probabilistic fragility assessment of existing resid... more The objective of this paper is to illustrate probabilistic fragility assessment of existing residential buildings in Turkey. Poor seismic performance of these buildings during the recent major earthquakes not only exhibit that the present building stock predominantly consists of lowand mid-rise structures with the lack of engineering design and detailing; but also were constructed according to the regulations of the previous versions of seismic codes. The damage in these buildings has accentuated the need for risk assessment of sub-standard structures to estimate the potential damage and to mitigate the losses during future seismic events. Within the scope of this research, an ensemble of 50 existing RC buildings is selected which represent the structural characteristics of existing structures with weakness in stiffness and strength, in addition to poor concrete quality and rebar detailing. The ensemble consists of buildings, which have been site-investigated after the corresponding...

Investigation of Ductility Reduction Factor in Seismic Rehabilitation of Existing Reinforced Concrete School Buildings

Research Journal of Applied Sciences, Engineering and Technology, 2015

Converting existing Reinforced Concrete (RC) frames into RC infill walls is one of the most effic... more Converting existing Reinforced Concrete (RC) frames into RC infill walls is one of the most efficient seismic strengthening technique due to its simplicity in application providing high rigidity, stability and strength in structures. On the other hand, this method affects the seismic behavior of existing RC structure in terms of the energy dissipation capacity or in other words, ductility reduction factor, R µ. This research is an attempt to investigate the RC infill wall ratio effect on ductility reduction factor in terms of the seismic rehabilitation of the typical RC school buildings. For this purpose, nonlinear static pushover analyses are conducted for existing 3 and 5 story RC school buildings which were rehabilitated with different RC infill wall ratio. Numerical analyses are carried out by using the fiber element based modeling approach in the software, Perform-3D. Based on these analytical results, correlation between the ductility reduction factor and the RC infill wall ratio is obtained for the seismic rehabilitation of the RC school buildings. In addition, two mathematical expressions for the variation of the ductility reduction factor with RC infill wall ratios are proposed in terms of the preliminary seismic rehabilitation assessment of the existing RC school buildings.

Numerical Methods for the Seismic Performance Assessment of Reinforced Concrete Buildings

Advances in Civil and Industrial Engineering

This chapter proposes a new single-run adaptive pushover method for the seismic assessment of she... more This chapter proposes a new single-run adaptive pushover method for the seismic assessment of shear wall structures. This method offers two main advantages: it does not require decomposing the structure in nonlinear domain and it avoids the pitfall of previous single-run adaptive pushover analyses in utilizing the modal combination in the determination of the applied loads instead of combining the response quantities induced by those loads in individual modes. After a brief review of the main adaptive pushover procedures, the proposed method is presented as well as its numerical implementation. The predictions of this method are compared to those of other recent adaptive pushover methods and as well as to the rigorous non-linear time history analysis. Analyses show the efficiency of the proposed method.

BEE-van

A Novel Post-Earthquake Damage Survey Sheet: Part I- RC Buildings

Currently in Turkey, Prime Ministry-Disaster and Emergency Management Presidency's task-forces ha... more Currently in Turkey, Prime Ministry-Disaster and Emergency Management Presidency's task-forces have the full authority for defining the damage rank of existing structures. Since the Turkish Catastrophe Insurance Pool is very recently established, entire residential building stock including the animal barns are financially protected by the republic after an earthquake, which causes unpredictable expenses within the budget. Furthermore, due to the unfavorable site-conditions during the response stage, misleading decisions are made inevitably. Besides, the existing damage survey forms currently in force do not distinguish reinforced-concrete (RC) buildings from the masonry ones; henceforth many significant issues are irresistibly ignored during the site-assessments. Recently, our research group is commissioned to prepare and propose individual post-earthquake damage survey sheets for RC and masonry structures. This paper introduces the latest version of the proposed survey form for RC building type of structures; discusses the theoretical basis and exhibits their application with examples taken from previous destructive earthquakes of Turkey.

Proposed Vulnerability Functions to Estimate the Real Damage State of RC Buildings After Major Turkish Earthquakes

Geotechnical, Geological and Earthquake Engineering, 2013

This study focuses on the applicability of fragility relationships, which are employed to predict... more This study focuses on the applicability of fragility relationships, which are employed to predict the seismic vulnerability of existing structures. Since these relationships offer the probability of exceeding a predefined structural response limit in terms of a ground motion intensity parameter, fragility functions are very practical tools to be employed during urban renewal of metropolitan cities with high seismicity. A building ensemble which experienced moderate damage after major Turkish earthquakes is considered herein this paper. Planar structural models for each building are established utilizing DRAIN-2DX computer program and nonlinear dynamic analyses are carried out. The demand parameters are obtained and the capacity is determined in terms of limit states. Finally, fragility relationships recently proposed by various researchers are employed for the building set and compared with the analytical results by means of reflecting the most reliable actual damage state.

Failures of masonry and concrete buildings during the March 8, 2010 Kovancılar and Palu (Elazığ) Earthquakes in Turkey

Engineering Failure Analysis, 2011

The March 8, 2010 earthquakes that hit Kovancılar and Palu districts of Elazıg province in Turkey... more The March 8, 2010 earthquakes that hit Kovancılar and Palu districts of Elazıg province in Turkey and their impacts on masonry and concrete buildings are studied in this paper. According to United States Geological Survey (USGS), magnitudes of these earthquakes, which caused partial or total collapse in many buildings with life losses, were 6.1 and 5.5, respectively. This paper outlines the seismological aspects of the region, the characteristics of the strong ground motion, the geotechnical characteristics of the region and the structural damages based on site assessments. The structural damage level is observed to be directly proportional with the amount of the insufficient quality in the workmanship and usage of inadequate building materials. If a minimum amount of engineering attention had been paid during the construction stages, most of the existing buildings could have sustained the earthquakes without considerable damage.

Analytical investigation of the observed damage in an RC building after March 08, 2010 Kovancilar-Turkey earthquake

Bulletin of Earthquake Engineering, 2010

Although the M w = 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity wit... more Although the M w = 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity with a recorded PGA of 0.07g, it caused heavy damages in 2870 residential buildings having traditional or masonry structural systems and 42 human loss. Damage has been reported to be particularly concentrated at Kovancilar and Palu counties of Elazig province. Five hours after this earthquake, an aftershock of M L = 5.6 with a PGA of 0.08g struck the same region, developing the existing damages in the structures. In order to investigate this significant amount of reported damages under the effect of such low ground shakings, our reconnaissance team arrived at the region and unexpectedly came across a two-story RC building settled on a slope in Yukari Demirci village, which suffered moderate damage during the shakes. The outline of this paper can be summarized as the presentation of the results of the investigations in the order of describing the overall observed damages within the region; evaluation of the recorded motions; the details of the fieldwork carried out for the two story RC building and the analytical estimation of the site-assessed damages by means of nonlinear dynamic analysis. Employing the gathered data, the building is analytically modeled as plane frames and analyses are performed under the effects of the processed earthquake records, which are applied to the structure one after another in the consistent directions due to the building location. It is shown herein that the structural elements remain in the elastic range subjected to the processed recorded motions; henceforth acceleration time histories are scaled step by step up to 0.40g and computations are repeated for each acceleration level. Comparison with the observed and the analytically obtained damages confirmed that approximately 0.30g of peak ground acceleration should have to be exposed during the earthquakes.

The aftermath of 2011 Van earthquakes: evaluation of strong motion, geotechnical and structural issues

Bulletin of Earthquake Engineering, 2012

October 23rd, 2011 M L 6.7 (M w 7.2 KOERI) Tabanli-Van Earthquake caused damage in a widespread a... more October 23rd, 2011 M L 6.7 (M w 7.2 KOERI) Tabanli-Van Earthquake caused damage in a widespread area specifically in the settlement regions throughout the Lake Van. A number of 58 buildings totally collapsed during the shake with 52 of them however, reported to be in Ercis district. 17 days after this destructive event, another earthquake of M L 5.6 hit the region again on the 9th of November having the epicentral location at Edremit district. The second earthquake mostly affected the central region of Van province with a number of 25 totally collapsed buildings and furthermore it significantly increased the existing structural damages. Strong motion records from both earthquakes and their impacts on structures as well as geotechnical issues are studied in this paper. Extensive liquefaction triggered lateral spread, landslide and slope failure cases were observed mainly at non-residential areas. Soil amplification is evaluated to be one of the main reasons for the heavy damage occurred in Ercis. Furthermore, site investigations and damage assessment performed after each earthquake proved that the observed damages are strongly correlated with insufficient qualities of structural materials, inadequate detailing and poor workmanship.

Critical evaluation of NDT for rapid condition assessment of existing RC buildings: A case study

MATEC Web of Conferences

There is an urgent need for rapid and reliable condition assessment of existing reinforced concre... more There is an urgent need for rapid and reliable condition assessment of existing reinforced concrete (RC) buildings as a basis for structural safety evaluation, especially in developing countries in seismic regions such as Turkey. Traditionally, RC structures are evaluated by taking core samples from a limited number of structural elements for concrete strength and performing spot checks for the steel reinforcement by removing the concrete cover. In-situ concrete strength is determined through compression testing of core samples. Through spot checks, conformance of the existing reinforcement with the structural drawings is evaluated and a reinforcement realization factor is calculated for use in the analyses. Even though these conventional methods are relatively more accurate and reliable for condition assessment of existing RC structures, they are destructive, involved, time taking, slow and expensive. Non-destructive testing (NDT) methods are proposed as a solution to this problem....

Monte Carlo analysis of earthquake resistant R-C 3D shear wall-frame structures

Structural Engineering and Mechanics, 2006

... strain hardening, stiffness degradation effects associated with unloading and load reversal s... more

Numerical simulation of RC infill walls under cyclic loading and calibration with widely used hysteretic models and experiments

Bulletin of Earthquake Engineering, 2015

Addition of reinforced concrete (RC) infill walls into the structural system has been a commonly ... more Addition of reinforced concrete (RC) infill walls into the structural system has been a commonly preferred strengthening technique within the last decades for seismic rehabilitation of RC frames. As a consequence, generating a representative numerical model of an RC infill wall has become an important issue. As the initial step of this study, measured structural responses of two selected well-known large-scale RC infill wall experiments subjected to displacement controlled cyclic loading are taken into account. Later, by calibrating the numerical model prepared in Perform-3D computer program utilizing fiber cross-sections, a practical and a compatible analytical model is obtained and proposed herein. Structural systems of the experiments are mathematically modeled by elements consisting of vertical and horizontal fiber layers to represent the bending/axial behavior and to control the out of plane displacements, respectively. Nonlinear behavior of the reinforcing steel is represented by a tri-linear backbone curve without strength degradation, while a multi-linear hysteretic behavior considering the strength loss is utilized for the structural concrete. Furthermore, those recently conducted experiments are simulated by a couple of widely used hysteretic models for comparative purposes, which are preferred in most cases by the researchers during the analytical investigation of RC structures, so that their adequacy for reflecting the nonlinear behavior of infill walls are also studied. It is shown with comparisons for the experimentally measured and the analytically derived results that the calibrated mathematical model proposed herein is more compatible with the measured values than the widely used hysteretic rules for capturing the behavior of these types of frames retrofitted by RC infill walls under reversed cyclic loading. Although numerical simulations are carried out for a limited number of tests and it is assumed that sufficient amount of anchoring dowels is provided at the interface of the existing frame and the RC infill, the proposed calibrated model conforms to both

SDOF System Demands for Performance-Based Design of RC Structures

Proceedings of the Seventh International Conference on Computational Structures Technology

Investigation of Infill Wall Effect for the Seismic Performance of a Moderately Damaged RC Building

In order to investigate the infill wall effect in reducing the earthquake damage, a four-story RC... more In order to investigate the infill wall effect in reducing the earthquake damage, a four-story RC building in Yalova province in north-western part of Turkey, which has experienced moderate damage during the August 17, 1999 Kocaeli Earthquake and strengthened afterwards, a set of non-linear dynamic analysis is carried out in this research. Structural performances for both before and after strengthening states are evaluated, also taking into account the existence of infill walls for the as-built and strengthened states of the building. Pushover analyses are carried out to establish the capacity and demand curves for the structures, selecting the target displacements considering the Turkish Earthquake Resistant Design Code-2007. Utilizing DRAIN-2DX computer program, dynamic analyses are performed using an earthquake ensemble of 7 recorded strong ground motions as well as a simulated spectrum compatible accelerogram. It is assumed that, bilinear hysteretic model represents the nonlinea...

An experimental study of a midbroken 2-bay, 6-storey reinforced concrete frame subject to earthquakes

Soil Dynamics and Earthquake Engineering, 1997

Transient analysis of dam–reservoir interaction including the reservoir bottom effects

Journal of Fluids and Structures, 2005

In this paper, time-domain transient analysis of elastic dam-reservoir interaction including the ... more In this paper, time-domain transient analysis of elastic dam-reservoir interaction including the reservoir bottom effects is presented by coupling the finite element method in the infinite fluid domain and in the solid domain. An efficient coupling procedure is formulated by a substructuring method. Sommerfeld's boundary condition for the far end of the infinite domain is implemented. To verify the proposed scheme, numerical examples are given to compare with available exact solutions for rigid and elastic dam cases. Finally, a numerical example is studied to evaluate the effects of the reservoir bottom.

Seismic safety screening method For Istanbul Metropolitan City

Proceedings of the10th East Asia Pacific …, 2006

Page 1. 1 SEISMIC SAFETY SCREENING METHOD FOR ISTANBUL METROPOLITAN CITY Pinar OZDEMIR 1 and Beyz... more

A computationally efficient solution of the wave equation for the transient response of infinite reservoirs

Archive of Applied Mechanics, 2005

In this paper, the transient response of an infinite reservoir is analyzed using the dual-recipro... more In this paper, the transient response of an infinite reservoir is analyzed using the dual-reciprocity boundary element method. A vertical and an inclined-face rigid dam are analyzed under a transient loading. Sharan-type boundary-condition transmission is implemented in the formulation. The results are compared with the exact solution and those obtained by using the finite element method. It is seen that the application of the dual-reciprocity boundary element method is simpler and the results are in very good agreement with the exact solution and those obtained by using the finite element method.

Analysis Of Seismic Behavior Of A Building From Turkey Using Real Earthquake Records

Publication in the conference proceedings of EUSIPCO, Barcelona, Spain, 2011

A Review of the Accuracy of Force- and Deformation-Based Methods in Determining the Seismic Capacity of Rehabilitated RC School Buildings

This chapter focuses on the comparison of the conventional linear force-based method with the adv... more This chapter focuses on the comparison of the conventional linear force-based method with the advanced nonlinear deformation-based method that are commonly preferred to investigate the seismic performances of the existing RC school buildings. School buildings which have different structural characteristics and RC infill wall index are generated from an existing school’s layout plan. During the nonlinear dynamic analysis, seven recorded earthquake motions which are scaled in accordance with the Turkish Earthquake Code are employed. Seismic performances of the school buildings against the two different earthquake hazard level are evaluated considering not only various RC infill wall indexes but also different material strengths and number of stories in terms of limit states specified in the code. In order to determine the most appropriate method related to material strength, floor level and RC infill wall index for the seismic strengthening of the existing RC school buildings, the obt...

Derivation of Fragility Relations with Regard to Poorly Constructed Existing RC Buildings

The objective of this paper is to illustrate probabilistic fragility assessment of existing resid... more The objective of this paper is to illustrate probabilistic fragility assessment of existing residential buildings in Turkey. Poor seismic performance of these buildings during the recent major earthquakes not only exhibit that the present building stock predominantly consists of lowand mid-rise structures with the lack of engineering design and detailing; but also were constructed according to the regulations of the previous versions of seismic codes. The damage in these buildings has accentuated the need for risk assessment of sub-standard structures to estimate the potential damage and to mitigate the losses during future seismic events. Within the scope of this research, an ensemble of 50 existing RC buildings is selected which represent the structural characteristics of existing structures with weakness in stiffness and strength, in addition to poor concrete quality and rebar detailing. The ensemble consists of buildings, which have been site-investigated after the corresponding...

Investigation of Ductility Reduction Factor in Seismic Rehabilitation of Existing Reinforced Concrete School Buildings

Research Journal of Applied Sciences, Engineering and Technology, 2015

Converting existing Reinforced Concrete (RC) frames into RC infill walls is one of the most effic... more Converting existing Reinforced Concrete (RC) frames into RC infill walls is one of the most efficient seismic strengthening technique due to its simplicity in application providing high rigidity, stability and strength in structures. On the other hand, this method affects the seismic behavior of existing RC structure in terms of the energy dissipation capacity or in other words, ductility reduction factor, R µ. This research is an attempt to investigate the RC infill wall ratio effect on ductility reduction factor in terms of the seismic rehabilitation of the typical RC school buildings. For this purpose, nonlinear static pushover analyses are conducted for existing 3 and 5 story RC school buildings which were rehabilitated with different RC infill wall ratio. Numerical analyses are carried out by using the fiber element based modeling approach in the software, Perform-3D. Based on these analytical results, correlation between the ductility reduction factor and the RC infill wall ratio is obtained for the seismic rehabilitation of the RC school buildings. In addition, two mathematical expressions for the variation of the ductility reduction factor with RC infill wall ratios are proposed in terms of the preliminary seismic rehabilitation assessment of the existing RC school buildings.

Numerical Methods for the Seismic Performance Assessment of Reinforced Concrete Buildings

Advances in Civil and Industrial Engineering

This chapter proposes a new single-run adaptive pushover method for the seismic assessment of she... more This chapter proposes a new single-run adaptive pushover method for the seismic assessment of shear wall structures. This method offers two main advantages: it does not require decomposing the structure in nonlinear domain and it avoids the pitfall of previous single-run adaptive pushover analyses in utilizing the modal combination in the determination of the applied loads instead of combining the response quantities induced by those loads in individual modes. After a brief review of the main adaptive pushover procedures, the proposed method is presented as well as its numerical implementation. The predictions of this method are compared to those of other recent adaptive pushover methods and as well as to the rigorous non-linear time history analysis. Analyses show the efficiency of the proposed method.

BEE-van

A Novel Post-Earthquake Damage Survey Sheet: Part I- RC Buildings

Currently in Turkey, Prime Ministry-Disaster and Emergency Management Presidency's task-forces ha... more Currently in Turkey, Prime Ministry-Disaster and Emergency Management Presidency's task-forces have the full authority for defining the damage rank of existing structures. Since the Turkish Catastrophe Insurance Pool is very recently established, entire residential building stock including the animal barns are financially protected by the republic after an earthquake, which causes unpredictable expenses within the budget. Furthermore, due to the unfavorable site-conditions during the response stage, misleading decisions are made inevitably. Besides, the existing damage survey forms currently in force do not distinguish reinforced-concrete (RC) buildings from the masonry ones; henceforth many significant issues are irresistibly ignored during the site-assessments. Recently, our research group is commissioned to prepare and propose individual post-earthquake damage survey sheets for RC and masonry structures. This paper introduces the latest version of the proposed survey form for RC building type of structures; discusses the theoretical basis and exhibits their application with examples taken from previous destructive earthquakes of Turkey.

Proposed Vulnerability Functions to Estimate the Real Damage State of RC Buildings After Major Turkish Earthquakes

Geotechnical, Geological and Earthquake Engineering, 2013

This study focuses on the applicability of fragility relationships, which are employed to predict... more This study focuses on the applicability of fragility relationships, which are employed to predict the seismic vulnerability of existing structures. Since these relationships offer the probability of exceeding a predefined structural response limit in terms of a ground motion intensity parameter, fragility functions are very practical tools to be employed during urban renewal of metropolitan cities with high seismicity. A building ensemble which experienced moderate damage after major Turkish earthquakes is considered herein this paper. Planar structural models for each building are established utilizing DRAIN-2DX computer program and nonlinear dynamic analyses are carried out. The demand parameters are obtained and the capacity is determined in terms of limit states. Finally, fragility relationships recently proposed by various researchers are employed for the building set and compared with the analytical results by means of reflecting the most reliable actual damage state.

Failures of masonry and concrete buildings during the March 8, 2010 Kovancılar and Palu (Elazığ) Earthquakes in Turkey

Engineering Failure Analysis, 2011

The March 8, 2010 earthquakes that hit Kovancılar and Palu districts of Elazıg province in Turkey... more The March 8, 2010 earthquakes that hit Kovancılar and Palu districts of Elazıg province in Turkey and their impacts on masonry and concrete buildings are studied in this paper. According to United States Geological Survey (USGS), magnitudes of these earthquakes, which caused partial or total collapse in many buildings with life losses, were 6.1 and 5.5, respectively. This paper outlines the seismological aspects of the region, the characteristics of the strong ground motion, the geotechnical characteristics of the region and the structural damages based on site assessments. The structural damage level is observed to be directly proportional with the amount of the insufficient quality in the workmanship and usage of inadequate building materials. If a minimum amount of engineering attention had been paid during the construction stages, most of the existing buildings could have sustained the earthquakes without considerable damage.

Analytical investigation of the observed damage in an RC building after March 08, 2010 Kovancilar-Turkey earthquake

Bulletin of Earthquake Engineering, 2010

Although the M w = 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity wit... more Although the M w = 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity with a recorded PGA of 0.07g, it caused heavy damages in 2870 residential buildings having traditional or masonry structural systems and 42 human loss. Damage has been reported to be particularly concentrated at Kovancilar and Palu counties of Elazig province. Five hours after this earthquake, an aftershock of M L = 5.6 with a PGA of 0.08g struck the same region, developing the existing damages in the structures. In order to investigate this significant amount of reported damages under the effect of such low ground shakings, our reconnaissance team arrived at the region and unexpectedly came across a two-story RC building settled on a slope in Yukari Demirci village, which suffered moderate damage during the shakes. The outline of this paper can be summarized as the presentation of the results of the investigations in the order of describing the overall observed damages within the region; evaluation of the recorded motions; the details of the fieldwork carried out for the two story RC building and the analytical estimation of the site-assessed damages by means of nonlinear dynamic analysis. Employing the gathered data, the building is analytically modeled as plane frames and analyses are performed under the effects of the processed earthquake records, which are applied to the structure one after another in the consistent directions due to the building location. It is shown herein that the structural elements remain in the elastic range subjected to the processed recorded motions; henceforth acceleration time histories are scaled step by step up to 0.40g and computations are repeated for each acceleration level. Comparison with the observed and the analytically obtained damages confirmed that approximately 0.30g of peak ground acceleration should have to be exposed during the earthquakes.

The aftermath of 2011 Van earthquakes: evaluation of strong motion, geotechnical and structural issues

Bulletin of Earthquake Engineering, 2012

October 23rd, 2011 M L 6.7 (M w 7.2 KOERI) Tabanli-Van Earthquake caused damage in a widespread a... more October 23rd, 2011 M L 6.7 (M w 7.2 KOERI) Tabanli-Van Earthquake caused damage in a widespread area specifically in the settlement regions throughout the Lake Van. A number of 58 buildings totally collapsed during the shake with 52 of them however, reported to be in Ercis district. 17 days after this destructive event, another earthquake of M L 5.6 hit the region again on the 9th of November having the epicentral location at Edremit district. The second earthquake mostly affected the central region of Van province with a number of 25 totally collapsed buildings and furthermore it significantly increased the existing structural damages. Strong motion records from both earthquakes and their impacts on structures as well as geotechnical issues are studied in this paper. Extensive liquefaction triggered lateral spread, landslide and slope failure cases were observed mainly at non-residential areas. Soil amplification is evaluated to be one of the main reasons for the heavy damage occurred in Ercis. Furthermore, site investigations and damage assessment performed after each earthquake proved that the observed damages are strongly correlated with insufficient qualities of structural materials, inadequate detailing and poor workmanship.