... Fabio Nardone, Ph.D., Gerardo Mario Verderame, Andrea Prota, Gaetano Manfredi. ... of the pre... more ... Fabio Nardone, Ph.D., Gerardo Mario Verderame, Andrea Prota, Gaetano Manfredi. ... of the previously mentioned variety; similarly, the latest versions of national and international guidelines [; ] provide ... The was the first to deal with mixed building typology meant as buildings with ...
... transverse stresses, fa e vjh respectively, according to the following equation: 2 2 2 2 a a ... more ... transverse stresses, fa e vjh respectively, according to the following equation: 2 2 2 2 a a jh f f p v − ⎛ ⎞ = ± 2.1.6) Equation (2.1.6) allows the horizontal joint shear to be evaluated at the first development of diagonal cracking: 1 1 1 1 a a jh t jh c jj t c f f v p V kf bh p kf ...
... ORIGINAL RESEARCH PAPER Ultimate chord rotation of RC columns with smooth bars: some consider... more ... ORIGINAL RESEARCH PAPER Ultimate chord rotation of RC columns with smooth bars: some considerations about EC8 prescriptions Gerardo M. Verderame · Paolo Ricci · Gaetano Manfredi · Edoardo Cosenza Received: 30 July ...
Effetti sulle strutture ed infrastrutture Fig. 1 Dati Istat 2001 relativi agli edifici della citt... more Effetti sulle strutture ed infrastrutture Fig. 1 Dati Istat 2001 relativi agli edifici della città de L'Aquila: epoche di costruzione (a), tipologie costruttive (b) e numero di piani (c). 2.5.1 Il costruito in c.a. a L'Aquila I dati del censimento Istat 2001 indicano un'incidenza percentuale del costruito in c.a. sul totale degli edifici della città de L'Aquila pari al 24%, a fronte di un 68% in muratura; per parte della popolazione di edifici (8%) la tipologia costruttiva non risulta determinata (Fig. 1a). I dati relativi all'epoca di costruzione (Fig. 1b) indicano che il 55% dell'intera popolazione di edifici risulta edificato dopo il 1945. È quindi lecito dedurre che il costruito posteriore a tale data sia ancora composto da una parte di edifici in muratura, e che la percentuale di strutture in cemento armato aumenti gradualmente nel corso di quest'epoca. Osservando la distribuzione del numero di piani si deduce che solo il 5% degli edifici è caratteri...
Italian and Spanish seismic codes prescribe lower behaviour factor (q) for wide-beam reinforced c... more Italian and Spanish seismic codes prescribe lower behaviour factor (q) for wide-beam reinforced concrete moment resisting frames (WBF) with respect to conventional q factors adopted for deep-beam frames (DBF). Conversely, other relevant seismic codes worldwide, such as Eurocode 8, consider WBF capable of high ductility performances, provided that design rules related to (i) stress transfer in connections, (ii) lateral stiffness and (iii) energy dissipation are complied. On the other hand, local ductility of wide beams (WB) appears to be systematically lower than that for deep beams (DB). A parametric comparative numerical analysis of deformations of DB and WB, following the current approach, shows that WB have larger ultimate chord rotation but lower ductility in terms of chord rotation than DB despite the similar ductility in curvature, which is mainly due to a lower plastic hinge lengths in WB. Aimed at verifying whether such disadvantage is overcome by modern codes or not, severa...
The improvement of seismic performances and the enhancement of the energy efficiency of existing ... more The improvement of seismic performances and the enhancement of the energy efficiency of existing buildings have nowadays become a priority. Indeed, much of the existing building stock is characterized by great structural, architectural and thermal obsolescence. In addition to the renovation of existing buildings, a very important aspect is the repair and upgrading of buildings recently damaged by the seismic events that hit the Italian territory. In particular, this article takes into account a school located in the municipality of Pievebovigliana, province of Macerata, which got damaged by the earthquakes that hit Central Italy on 24.08.2016 and 30.10.2016. In detail, the article refers to a one-story building characterized by an irregular plan configuration. The gravity load resisting system is made by masonry walls with regular blocks; in addition, few reinforced concrete columns embedded in the masonry walls support the roof girders. Different strategies of anti-seismic retrofit...
The same case study structures of the companion paper (Ricci et al., 2012) are analyzed. Seismic ... more The same case study structures of the companion paper (Ricci et al., 2012) are analyzed. Seismic capacity at different Limit States is assessed by means of Static Push-Over analyses, within the N2 spectral assessment framework. Fragility curves are obtained, through the application of a Response Surface Method. Seismic performance is also expressed in terms of failure probability, given a reference time period. Italian code provisions for seismic assessment at Damage Limitation Limit State are discussed: code allows to take into account the presence of infills if a bare numerical model, as usual, is used by assuming a fictitious displacement capacity limit (e.g., 5‰ Interstorey Drift Ratio); code also allows to limit the maximum Interstorey Drift Ratio in a Reinforced Concrete structure to values related to masonry (e.g., 3‰ for unreinforced masonry) if infills are explicitly taken into account in the structural model. The conservatism of these provisions, depending on the number of...
This paper deals with two fundamental aspects for the seismic vulnerability assessment of buildin... more This paper deals with two fundamental aspects for the seismic vulnerability assessment of buildings at the urban scale. Firstly, an automatic procedure for simulated design of Reinforced Concrete buildings is described. It allows to rapidly identify, re-design and analyse the RC buildings belonging to the same class. The basic parameters to be input in the automatic procedure should be representative of real building features at the territorial scale. Generally, in order to enhance the knowledge of the constructions at the territorial level, building inventory is required. Also the problems inherent to building inventory are discussed and a new approach for field survey is proposed.
Current code prescriptions allow to evaluate the ultimate rotational capacity from hybrid (mechan... more Current code prescriptions allow to evaluate the ultimate rotational capacity from hybrid (mechanical-empirical) or empirical formulations, for R.C. members with deformed bars and seismically detailed. These formulations can be extended to non-conforming elements by applying correction coefficients calibrated on experimental data. These coefficients, for members with plain bars, imply a reduction of 40% at least; this reduction increases if lapping of longitudinal bars is present. The experimental campaign conducted at the University of Naples on 16 real-scale columns with plain bars allowed to extend the experimental database for this typology. Experimental results highlight the excessive conservativeness of the current code proposal. Based on these results, new correction coefficients are proposed.
Right after an earthquake the estimation the number of involved people, dead and the injured, mis... more Right after an earthquake the estimation the number of involved people, dead and the injured, missing people and homeless represent a topic issue in the emergency management, which is closely related to building damage scenario for the area of interest. To this end, in present work, different methodological approaches for seismic vulnerability assessment of buildings at large scale are used to derive damage scenarios for the Municipalities of Amatrice, Accumoli and Arquata del Tronto, which have been struck by the 24th August 2016 earthquake. Seismic input characterization will be defined through the ShakeMap of the 24th August 2016 earthquake event, published by the Italian National Institute of Geophysics and Volcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV). Data about the number of inhabitant and involved buildings, and about their typological characteristics will be inferred from census data. Damage scenarios according to various approaches, different in their ...
In the assessment of the performance of typical existing buildings, seismic collapse safety might... more In the assessment of the performance of typical existing buildings, seismic collapse safety might be significantly affected by the non-linear behaviour of the joints that are involved in the failure mechanisms because of poor structural detailing, as the lack of an adequate transverse reinforcement in the joint panel or deficiencies in the anchorage due to the absence of any capacity design principle. Few reliable approaches for modelling all sources of nonlinearity are available for poorly designed beam-column joints because of relatively poor information from experimental tests. Many nonlinear joint models are available, but most of them may be unsuitable for the assessment of older concrete buildings, either because they were developed and calibrated for confined joints or because they are complicated to use. In this study, the attention is focused on external joints with no transverse reinforcement and a preliminary exterior joint macro model is proposed. First, an experimental ...
A damage scenario based on observational data collected in L’Aquila Municipality after the 6th Ap... more A damage scenario based on observational data collected in L’Aquila Municipality after the 6th April 2009 earthquake is compared with a predicted damage scenario derived from the application of a simplified analytical method for the seismic vulnerability assessment of Reinforced Concrete (RC) buildings at large scale. The observational damage scenario is derived from a database of 131 RC buildings located in the Municipality of L’Aquila, which after the 2009 earthquake were subjected to post-earthquake usability assessment procedure. The simplified analytical approach adopted is based on the Capacity Spectrum Method (CSM) to evaluate seismic capacity at different Damage States (DSs) based on the displacement capacity of structural and non-structural elements. DSs and the corresponding displacement capacity are defined through the interpretation of the observational-based DSs provided by the European Macroseismic Scale EMS-98. Data predicted by the adopted methodology are in good agr...
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
In the Mediterranean area, Reinforced Concrete (RC) buildings are usually provided of Unreinforce... more In the Mediterranean area, Reinforced Concrete (RC) buildings are usually provided of Unreinforced Masonry (URM) infill wall panels. When subjected to seismic action, these non-structural elements are sensitive to the displacements produced in the In Plane (IP) direction and to the acceleration in the Out Of Plane (OOP) direction. The damage due to IP displacements reduce the OOP capacity and vice-versa: this phenomenon is called IP-OOP interaction. Proposed empirical-based formulations both for predicting infills OOP strength and for modeling the effects of IP displacement demand on OOP behavior and vice versa are illustrated. A new lumped-plasticity macro-model based on the proposed empirical formulations and conceived to represent the IP and the OOP behavior taking into account the mutual interaction effects is defined. Part of the proposed modelling strategy is a routine that removes the whole infill panel from the structural model in case of its IP or OOP collapse. In this paper, the proposed model is described and applied to model the infills of case-study infilled RC frames designed according to Eurocode 8 and different for design PGA at Life Safety Limit State. The results of non-linear time-history analyses are presented and discussed in order to show the effects of taking into account or neglecting the IP-OOP interaction phenomena in assessing the seismic response of the case-study buildings.
In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on... more In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period 1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L’Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less ...
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015), 2017
There is a growing need for numerical models simulating the non-linear behavior of Reinforced Con... more There is a growing need for numerical models simulating the non-linear behavior of Reinforced Concrete (RC) elements under seismic loads into inelastic range, and for capacity models assessing the deformation capacity of RC members, with emphasis on non-conforming existing buildings. As far as nonlinear modeling is concerned, several approaches have been proposed by different authors; among them, empirical-based macromodels for lumped plasticity modeling (e.g. Haselton et al., 2008) can represent an effective compromise between accuracy and simplicity. They have the great advantage of providing a complete characterization of the nonlinear response, accounting for all of the deformation mechanisms, and their reliability is based on the use of experimental data. They also allow evaluating error/dispersion measures of the simulated response compared to the experimental data they are based on, which can be suitably used for taking into account modeling uncertainties in seismic fragility analyses of RC frames. With regard to capacity models, different approaches have been proposed for the assessment of the deformation capacity of RC members, also for pre-normative purposes; in particular, as far as the seismic assessment of existing RC buildings is concerned, different capacity models have been developed for the ultimate deformation capacity of nonconforming elements subjected to different failure modes (e.g. Elwood and Moehle, 2005; Zhu et al., 2007). In this study, a nonlinear response macromodel is proposed for a specific type of member, i.e. RC columns with plain bars. To this end, a database of tests on RC columns with plain bars is collected from literature. The specimens have different axial load, material properties, geometry, and longitudinal and transverse reinforcement ratio. Force-displacement data are collected and processed for each specimen. The backbone of the experimental response is evaluated for each test, and predictive equations are developed for characteristics points, namely yielding, maximum strength, ultimate (conventional collapse) and zero resistance conditions, based on a statistical analysis of data.
In the aftermath of the Mw 6.0 August 24, 2016 Central Italy earthquake, the authors carried out ... more In the aftermath of the Mw 6.0 August 24, 2016 Central Italy earthquake, the authors carried out a reconnaissance survey in the municipality of Amatrice and gathered extensive photographic evidence of damage, with emphasis on 37 reinforced concrete buildings located outside the historical centre. Damage distribution is generally represented by widespread cracking and/or collapse of the masonry infill panels at the lower buildings’ stories. Moreover, damage was observed in the columns due to the interaction with masonry infill panels. Starting from the collected information, POST—a mechanics-based damage prediction model—was applied in order to compare predicted damage distribution and damage observed during the field reconnaissance. The comparison shows an overall good agreement between the results of the POST method and the observed damage with a slightly conservative tendency by POST.
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
Unreinforced Masonry (URM) infills are widely used in Reinforced Concrete (RC) structures in Medi... more Unreinforced Masonry (URM) infills are widely used in Reinforced Concrete (RC) structures in Mediterranean countries. URM infills are subjected to the seismic action in their plane, i.e. in the In Plane (IP) direction, and in the Out Of Plane (OOP) direction. The IP displacement demand reduce the OOP capacity and vice-versa: this phenomenon is called IP-OOP interaction. A large number of studies has been carried out on the IP behaviour of infills, while their OOP response and the IP-OOP interaction have been less investigated. In this paper, a review of code and literature provisions concerning URM infills OOP behaviour is presented together with a review of the experimental tests carried out to investigate the infills OOP response and the effects of the IP-OOP interaction. An experimental database is collected to assess the effectiveness of literature and code provisions and to propose new empirical formulations both for predicting infills OOP strength, stiffness and displacement capacity and for modelling the effects of IP displacement demand on the OOP behavior and vice versa. A state of art on infills OOP behaviour and IP-OOP interaction modelling is presented. Most of these distributed-plasticity models are not based on experimental evidences and do not allow taking into account the IP and OOP stiffness degradation due to OOP and IP actions, respectively. A lumped-plasticity macro-model based on the proposed empirical formulations and conceived to represent the IP and the OOP behavior taking into account the mutual interaction effects is defined. Part of the proposed modelling strategy is a routine that removes the whole infill panel from the structural model in case of its IP or OOP collapse. The proposed model is used for an example application showing the effects of taking into account or neglecting the IP-OOP interaction phenomena during structural analyses.
... Fabio Nardone, Ph.D., Gerardo Mario Verderame, Andrea Prota, Gaetano Manfredi. ... of the pre... more ... Fabio Nardone, Ph.D., Gerardo Mario Verderame, Andrea Prota, Gaetano Manfredi. ... of the previously mentioned variety; similarly, the latest versions of national and international guidelines [; ] provide ... The was the first to deal with mixed building typology meant as buildings with ...
... transverse stresses, fa e vjh respectively, according to the following equation: 2 2 2 2 a a ... more ... transverse stresses, fa e vjh respectively, according to the following equation: 2 2 2 2 a a jh f f p v − ⎛ ⎞ = ± 2.1.6) Equation (2.1.6) allows the horizontal joint shear to be evaluated at the first development of diagonal cracking: 1 1 1 1 a a jh t jh c jj t c f f v p V kf bh p kf ...
... ORIGINAL RESEARCH PAPER Ultimate chord rotation of RC columns with smooth bars: some consider... more ... ORIGINAL RESEARCH PAPER Ultimate chord rotation of RC columns with smooth bars: some considerations about EC8 prescriptions Gerardo M. Verderame · Paolo Ricci · Gaetano Manfredi · Edoardo Cosenza Received: 30 July ...
Effetti sulle strutture ed infrastrutture Fig. 1 Dati Istat 2001 relativi agli edifici della citt... more Effetti sulle strutture ed infrastrutture Fig. 1 Dati Istat 2001 relativi agli edifici della città de L'Aquila: epoche di costruzione (a), tipologie costruttive (b) e numero di piani (c). 2.5.1 Il costruito in c.a. a L'Aquila I dati del censimento Istat 2001 indicano un'incidenza percentuale del costruito in c.a. sul totale degli edifici della città de L'Aquila pari al 24%, a fronte di un 68% in muratura; per parte della popolazione di edifici (8%) la tipologia costruttiva non risulta determinata (Fig. 1a). I dati relativi all'epoca di costruzione (Fig. 1b) indicano che il 55% dell'intera popolazione di edifici risulta edificato dopo il 1945. È quindi lecito dedurre che il costruito posteriore a tale data sia ancora composto da una parte di edifici in muratura, e che la percentuale di strutture in cemento armato aumenti gradualmente nel corso di quest'epoca. Osservando la distribuzione del numero di piani si deduce che solo il 5% degli edifici è caratteri...
Italian and Spanish seismic codes prescribe lower behaviour factor (q) for wide-beam reinforced c... more Italian and Spanish seismic codes prescribe lower behaviour factor (q) for wide-beam reinforced concrete moment resisting frames (WBF) with respect to conventional q factors adopted for deep-beam frames (DBF). Conversely, other relevant seismic codes worldwide, such as Eurocode 8, consider WBF capable of high ductility performances, provided that design rules related to (i) stress transfer in connections, (ii) lateral stiffness and (iii) energy dissipation are complied. On the other hand, local ductility of wide beams (WB) appears to be systematically lower than that for deep beams (DB). A parametric comparative numerical analysis of deformations of DB and WB, following the current approach, shows that WB have larger ultimate chord rotation but lower ductility in terms of chord rotation than DB despite the similar ductility in curvature, which is mainly due to a lower plastic hinge lengths in WB. Aimed at verifying whether such disadvantage is overcome by modern codes or not, severa...
The improvement of seismic performances and the enhancement of the energy efficiency of existing ... more The improvement of seismic performances and the enhancement of the energy efficiency of existing buildings have nowadays become a priority. Indeed, much of the existing building stock is characterized by great structural, architectural and thermal obsolescence. In addition to the renovation of existing buildings, a very important aspect is the repair and upgrading of buildings recently damaged by the seismic events that hit the Italian territory. In particular, this article takes into account a school located in the municipality of Pievebovigliana, province of Macerata, which got damaged by the earthquakes that hit Central Italy on 24.08.2016 and 30.10.2016. In detail, the article refers to a one-story building characterized by an irregular plan configuration. The gravity load resisting system is made by masonry walls with regular blocks; in addition, few reinforced concrete columns embedded in the masonry walls support the roof girders. Different strategies of anti-seismic retrofit...
The same case study structures of the companion paper (Ricci et al., 2012) are analyzed. Seismic ... more The same case study structures of the companion paper (Ricci et al., 2012) are analyzed. Seismic capacity at different Limit States is assessed by means of Static Push-Over analyses, within the N2 spectral assessment framework. Fragility curves are obtained, through the application of a Response Surface Method. Seismic performance is also expressed in terms of failure probability, given a reference time period. Italian code provisions for seismic assessment at Damage Limitation Limit State are discussed: code allows to take into account the presence of infills if a bare numerical model, as usual, is used by assuming a fictitious displacement capacity limit (e.g., 5‰ Interstorey Drift Ratio); code also allows to limit the maximum Interstorey Drift Ratio in a Reinforced Concrete structure to values related to masonry (e.g., 3‰ for unreinforced masonry) if infills are explicitly taken into account in the structural model. The conservatism of these provisions, depending on the number of...
This paper deals with two fundamental aspects for the seismic vulnerability assessment of buildin... more This paper deals with two fundamental aspects for the seismic vulnerability assessment of buildings at the urban scale. Firstly, an automatic procedure for simulated design of Reinforced Concrete buildings is described. It allows to rapidly identify, re-design and analyse the RC buildings belonging to the same class. The basic parameters to be input in the automatic procedure should be representative of real building features at the territorial scale. Generally, in order to enhance the knowledge of the constructions at the territorial level, building inventory is required. Also the problems inherent to building inventory are discussed and a new approach for field survey is proposed.
Current code prescriptions allow to evaluate the ultimate rotational capacity from hybrid (mechan... more Current code prescriptions allow to evaluate the ultimate rotational capacity from hybrid (mechanical-empirical) or empirical formulations, for R.C. members with deformed bars and seismically detailed. These formulations can be extended to non-conforming elements by applying correction coefficients calibrated on experimental data. These coefficients, for members with plain bars, imply a reduction of 40% at least; this reduction increases if lapping of longitudinal bars is present. The experimental campaign conducted at the University of Naples on 16 real-scale columns with plain bars allowed to extend the experimental database for this typology. Experimental results highlight the excessive conservativeness of the current code proposal. Based on these results, new correction coefficients are proposed.
Right after an earthquake the estimation the number of involved people, dead and the injured, mis... more Right after an earthquake the estimation the number of involved people, dead and the injured, missing people and homeless represent a topic issue in the emergency management, which is closely related to building damage scenario for the area of interest. To this end, in present work, different methodological approaches for seismic vulnerability assessment of buildings at large scale are used to derive damage scenarios for the Municipalities of Amatrice, Accumoli and Arquata del Tronto, which have been struck by the 24th August 2016 earthquake. Seismic input characterization will be defined through the ShakeMap of the 24th August 2016 earthquake event, published by the Italian National Institute of Geophysics and Volcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV). Data about the number of inhabitant and involved buildings, and about their typological characteristics will be inferred from census data. Damage scenarios according to various approaches, different in their ...
In the assessment of the performance of typical existing buildings, seismic collapse safety might... more In the assessment of the performance of typical existing buildings, seismic collapse safety might be significantly affected by the non-linear behaviour of the joints that are involved in the failure mechanisms because of poor structural detailing, as the lack of an adequate transverse reinforcement in the joint panel or deficiencies in the anchorage due to the absence of any capacity design principle. Few reliable approaches for modelling all sources of nonlinearity are available for poorly designed beam-column joints because of relatively poor information from experimental tests. Many nonlinear joint models are available, but most of them may be unsuitable for the assessment of older concrete buildings, either because they were developed and calibrated for confined joints or because they are complicated to use. In this study, the attention is focused on external joints with no transverse reinforcement and a preliminary exterior joint macro model is proposed. First, an experimental ...
A damage scenario based on observational data collected in L’Aquila Municipality after the 6th Ap... more A damage scenario based on observational data collected in L’Aquila Municipality after the 6th April 2009 earthquake is compared with a predicted damage scenario derived from the application of a simplified analytical method for the seismic vulnerability assessment of Reinforced Concrete (RC) buildings at large scale. The observational damage scenario is derived from a database of 131 RC buildings located in the Municipality of L’Aquila, which after the 2009 earthquake were subjected to post-earthquake usability assessment procedure. The simplified analytical approach adopted is based on the Capacity Spectrum Method (CSM) to evaluate seismic capacity at different Damage States (DSs) based on the displacement capacity of structural and non-structural elements. DSs and the corresponding displacement capacity are defined through the interpretation of the observational-based DSs provided by the European Macroseismic Scale EMS-98. Data predicted by the adopted methodology are in good agr...
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
In the Mediterranean area, Reinforced Concrete (RC) buildings are usually provided of Unreinforce... more In the Mediterranean area, Reinforced Concrete (RC) buildings are usually provided of Unreinforced Masonry (URM) infill wall panels. When subjected to seismic action, these non-structural elements are sensitive to the displacements produced in the In Plane (IP) direction and to the acceleration in the Out Of Plane (OOP) direction. The damage due to IP displacements reduce the OOP capacity and vice-versa: this phenomenon is called IP-OOP interaction. Proposed empirical-based formulations both for predicting infills OOP strength and for modeling the effects of IP displacement demand on OOP behavior and vice versa are illustrated. A new lumped-plasticity macro-model based on the proposed empirical formulations and conceived to represent the IP and the OOP behavior taking into account the mutual interaction effects is defined. Part of the proposed modelling strategy is a routine that removes the whole infill panel from the structural model in case of its IP or OOP collapse. In this paper, the proposed model is described and applied to model the infills of case-study infilled RC frames designed according to Eurocode 8 and different for design PGA at Life Safety Limit State. The results of non-linear time-history analyses are presented and discussed in order to show the effects of taking into account or neglecting the IP-OOP interaction phenomena in assessing the seismic response of the case-study buildings.
In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on... more In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period 1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L’Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less ...
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015), 2017
There is a growing need for numerical models simulating the non-linear behavior of Reinforced Con... more There is a growing need for numerical models simulating the non-linear behavior of Reinforced Concrete (RC) elements under seismic loads into inelastic range, and for capacity models assessing the deformation capacity of RC members, with emphasis on non-conforming existing buildings. As far as nonlinear modeling is concerned, several approaches have been proposed by different authors; among them, empirical-based macromodels for lumped plasticity modeling (e.g. Haselton et al., 2008) can represent an effective compromise between accuracy and simplicity. They have the great advantage of providing a complete characterization of the nonlinear response, accounting for all of the deformation mechanisms, and their reliability is based on the use of experimental data. They also allow evaluating error/dispersion measures of the simulated response compared to the experimental data they are based on, which can be suitably used for taking into account modeling uncertainties in seismic fragility analyses of RC frames. With regard to capacity models, different approaches have been proposed for the assessment of the deformation capacity of RC members, also for pre-normative purposes; in particular, as far as the seismic assessment of existing RC buildings is concerned, different capacity models have been developed for the ultimate deformation capacity of nonconforming elements subjected to different failure modes (e.g. Elwood and Moehle, 2005; Zhu et al., 2007). In this study, a nonlinear response macromodel is proposed for a specific type of member, i.e. RC columns with plain bars. To this end, a database of tests on RC columns with plain bars is collected from literature. The specimens have different axial load, material properties, geometry, and longitudinal and transverse reinforcement ratio. Force-displacement data are collected and processed for each specimen. The backbone of the experimental response is evaluated for each test, and predictive equations are developed for characteristics points, namely yielding, maximum strength, ultimate (conventional collapse) and zero resistance conditions, based on a statistical analysis of data.
In the aftermath of the Mw 6.0 August 24, 2016 Central Italy earthquake, the authors carried out ... more In the aftermath of the Mw 6.0 August 24, 2016 Central Italy earthquake, the authors carried out a reconnaissance survey in the municipality of Amatrice and gathered extensive photographic evidence of damage, with emphasis on 37 reinforced concrete buildings located outside the historical centre. Damage distribution is generally represented by widespread cracking and/or collapse of the masonry infill panels at the lower buildings’ stories. Moreover, damage was observed in the columns due to the interaction with masonry infill panels. Starting from the collected information, POST—a mechanics-based damage prediction model—was applied in order to compare predicted damage distribution and damage observed during the field reconnaissance. The comparison shows an overall good agreement between the results of the POST method and the observed damage with a slightly conservative tendency by POST.
Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
Unreinforced Masonry (URM) infills are widely used in Reinforced Concrete (RC) structures in Medi... more Unreinforced Masonry (URM) infills are widely used in Reinforced Concrete (RC) structures in Mediterranean countries. URM infills are subjected to the seismic action in their plane, i.e. in the In Plane (IP) direction, and in the Out Of Plane (OOP) direction. The IP displacement demand reduce the OOP capacity and vice-versa: this phenomenon is called IP-OOP interaction. A large number of studies has been carried out on the IP behaviour of infills, while their OOP response and the IP-OOP interaction have been less investigated. In this paper, a review of code and literature provisions concerning URM infills OOP behaviour is presented together with a review of the experimental tests carried out to investigate the infills OOP response and the effects of the IP-OOP interaction. An experimental database is collected to assess the effectiveness of literature and code provisions and to propose new empirical formulations both for predicting infills OOP strength, stiffness and displacement capacity and for modelling the effects of IP displacement demand on the OOP behavior and vice versa. A state of art on infills OOP behaviour and IP-OOP interaction modelling is presented. Most of these distributed-plasticity models are not based on experimental evidences and do not allow taking into account the IP and OOP stiffness degradation due to OOP and IP actions, respectively. A lumped-plasticity macro-model based on the proposed empirical formulations and conceived to represent the IP and the OOP behavior taking into account the mutual interaction effects is defined. Part of the proposed modelling strategy is a routine that removes the whole infill panel from the structural model in case of its IP or OOP collapse. The proposed model is used for an example application showing the effects of taking into account or neglecting the IP-OOP interaction phenomena during structural analyses.
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Papers by G. Verderame