Pub Date : 2021-03-01DOI: 10.5459/BNZSEE.54.1.40-48
S. Shrestha, Caroline Orchiston, K. Elwood, D. Johnston, J. Becker
The use of post-earthquake cordons as a tool to support emergency managers after an event has been documented around the world. However, there is limited research that attempts to understand the inherent complexities of cordoning once applied, particularly the longer-term impacts and consequences. This research aims to fill the gap by providing a detailed understanding of cordons, their management, and the implications of cordoning in a post-earthquake environment. We use a qualitative method to understand cordons through case studies of two cities where cordons were used at different temporal and spatial scales: Christchurch (M6.3, February 2011) and Wellington (M7.8 in Kaikōura, November 2016), New Zealand. Data was collected through 21 key informant interviews obtained through purposive and snowball sampling of participants who were directly or indirectly involved in a decision-making role and/or had influence in relation to the cordoning process. The participants were from varying backgrounds and roles i.e. emergency managers, council members, business representatives, insurance representatives, police, and communication managers. We find that cordons are used primarily as a tool to control access for the purpose of life safety and security, but cordons can also be adapted to support recovery. Broadly, our analysis suggests two key aspects, ‘decision-making’ and ‘operations and management’, which overlap and interact as part of a complex system. The underlying complexity arises in large part due to the multitude of sectors affected by cordons: economics, law, politics, governance, evacuation, civil liberties, available resources etc. The complexity further increases as the duration of cordoning is extended.
{"title":"To cordon or not to cordon: The inherent complexities of post-earthquake cordoning learned from Christchurch and Wellington experiences","authors":"S. Shrestha, Caroline Orchiston, K. Elwood, D. Johnston, J. Becker","doi":"10.5459/BNZSEE.54.1.40-48","DOIUrl":"https://doi.org/10.5459/BNZSEE.54.1.40-48","url":null,"abstract":"The use of post-earthquake cordons as a tool to support emergency managers after an event has been documented around the world. However, there is limited research that attempts to understand the inherent complexities of cordoning once applied, particularly the longer-term impacts and consequences. This research aims to fill the gap by providing a detailed understanding of cordons, their management, and the implications of cordoning in a post-earthquake environment. We use a qualitative method to understand cordons through case studies of two cities where cordons were used at different temporal and spatial scales: Christchurch (M6.3, February 2011) and Wellington (M7.8 in Kaikōura, November 2016), New Zealand. Data was collected through 21 key informant interviews obtained through purposive and snowball sampling of participants who were directly or indirectly involved in a decision-making role and/or had influence in relation to the cordoning process. The participants were from varying backgrounds and roles i.e. emergency managers, council members, business representatives, insurance representatives, police, and communication managers. We find that cordons are used primarily as a tool to control access for the purpose of life safety and security, but cordons can also be adapted to support recovery. Broadly, our analysis suggests two key aspects, ‘decision-making’ and ‘operations and management’, which overlap and interact as part of a complex system. The underlying complexity arises in large part due to the multitude of sectors affected by cordons: economics, law, politics, governance, evacuation, civil liberties, available resources etc. The complexity further increases as the duration of cordoning is extended.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121549764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.5459/BNZSEE.54.1.1-20
N. Ahmad, M. Rizwan, M. Ashraf, A. Khan, Qaisar Ali
FEMA-P695 procedure was applied for seismic collapse safety evaluation of reinforced concrete moment resisting frames with/without beam-column joint detailing common in Pakistan. The deficient frame lacks shear reinforcement in joints and uses concrete of low compressive strength. Shake-table tests were performed on 1:3 reduced scale two-story models, to understand the progressive inelastic response of chosen frames and calibrate the inelastic finite-element based models. The seismic design factors i.e. response modification coefficient, overstrength, ductility, and displacement amplification factors (R, W0, Rμ, Cd) were quantified. Response modification factor R = 7.05 was obtained for the frame with beam-column joint detailing while R = 5.30 was obtained for the deficient frame. The corresponding deflection amplification factor Cd/R was found equal to 0.82 and 1.03, respectively. A suite of design spectrum compatible accelerograms was obtained from PEER strong ground motions for incremental dynamic analysis of numerical models. Collapse fragility functions were developed using a probabilistic nonlinear dynamic reliability-based method. The collapse margin ratio (CMR) was calculated as the ratio of seismic intensity corresponding to the 50th percentile collapse probability to the seismic intensity corresponding to the MCE level ground motions. It was critically compared with the acceptable CMR (i.e. the CMR computed with reference to a seismic intensity corresponding to the 10% collapse probability instead of MCE level ground motions). Frame with shear reinforcement in beam-column joints has achieved CMR 11% higher than the acceptable thus passing the criterion. However, the deficient frame achieved CMR 29% less than the conforming frame. This confirms the efficacy of beam-column joint detailing in reducing collapse risk.
{"title":"Seismic collapse safety of reinforced concrete moment resisting frames with/without beam-column joint detailing","authors":"N. Ahmad, M. Rizwan, M. Ashraf, A. Khan, Qaisar Ali","doi":"10.5459/BNZSEE.54.1.1-20","DOIUrl":"https://doi.org/10.5459/BNZSEE.54.1.1-20","url":null,"abstract":"FEMA-P695 procedure was applied for seismic collapse safety evaluation of reinforced concrete moment resisting frames with/without beam-column joint detailing common in Pakistan. The deficient frame lacks shear reinforcement in joints and uses concrete of low compressive strength. Shake-table tests were performed on 1:3 reduced scale two-story models, to understand the progressive inelastic response of chosen frames and calibrate the inelastic finite-element based models. The seismic design factors i.e. response modification coefficient, overstrength, ductility, and displacement amplification factors (R, W0, Rμ, Cd) were quantified. Response modification factor R = 7.05 was obtained for the frame with beam-column joint detailing while R = 5.30 was obtained for the deficient frame. The corresponding deflection amplification factor Cd/R was found equal to 0.82 and 1.03, respectively. A suite of design spectrum compatible accelerograms was obtained from PEER strong ground motions for incremental dynamic analysis of numerical models. Collapse fragility functions were developed using a probabilistic nonlinear dynamic reliability-based method. The collapse margin ratio (CMR) was calculated as the ratio of seismic intensity corresponding to the 50th percentile collapse probability to the seismic intensity corresponding to the MCE level ground motions. It was critically compared with the acceptable CMR (i.e. the CMR computed with reference to a seismic intensity corresponding to the 10% collapse probability instead of MCE level ground motions). Frame with shear reinforcement in beam-column joints has achieved CMR 11% higher than the acceptable thus passing the criterion. However, the deficient frame achieved CMR 29% less than the conforming frame. This confirms the efficacy of beam-column joint detailing in reducing collapse risk.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115098198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.5459/BNZSEE.54.1.49-57
A. Vatanshenas, Takahiro Mori, N. Murota
High damping rubber bearings show highly nonlinear stress-strain behaviour. Deformation-history integral (DHI) model which can estimate small strain stiffness degradation and nonlinear plasticity via a relatively simple innovative formulation is implemented in this study to model HDRB as the rehabilitation method for a seismically vulnerable building. Considered structure in this study is a three-dimensional, four-story steel frame residential building with a concentrically braced system. Nonlinear direct integration time history analysis and plastic hinges approach were implemented to evaluate structural behaviour of considered structure. It was observed that structural responses enhanced significantly after rehabilitation. Absolute maximum base shear values decreased 61.8% and 92.2% in the worst and best cases, respectively. Most of structural elements remained elastic after rehabilitation and required performance level was satisfied.
{"title":"Structural rehabilitation using high damping rubber bearing (HDRB)","authors":"A. Vatanshenas, Takahiro Mori, N. Murota","doi":"10.5459/BNZSEE.54.1.49-57","DOIUrl":"https://doi.org/10.5459/BNZSEE.54.1.49-57","url":null,"abstract":"High damping rubber bearings show highly nonlinear stress-strain behaviour. Deformation-history integral (DHI) model which can estimate small strain stiffness degradation and nonlinear plasticity via a relatively simple innovative formulation is implemented in this study to model HDRB as the rehabilitation method for a seismically vulnerable building. Considered structure in this study is a three-dimensional, four-story steel frame residential building with a concentrically braced system. Nonlinear direct integration time history analysis and plastic hinges approach were implemented to evaluate structural behaviour of considered structure. It was observed that structural responses enhanced significantly after rehabilitation. Absolute maximum base shear values decreased 61.8% and 92.2% in the worst and best cases, respectively. Most of structural elements remained elastic after rehabilitation and required performance level was satisfied.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121182271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.5459/BNZSEE.54.1.21-30
C. McGann, B. Bradley, L. Wotherspoon, Robin L. Lee
Plane strain (2D) finite element models are used to examine factors contributing to basin effects observed for multiple seismic events at sites in the Thorndon basin of Wellington, New Zealand. The models consider linear elastic soil and rock response when subjected to vertically-propagating shear waves. Depth-dependent shear wave velocities are considered in the soil layers, and the effects of random variations of soil velocity within layers are modelled. Various rock shear wave velocity configurations are considered to evaluate their effect on the modelled surficial response. It is shown that these simple 2D models are able to capture basin reverberations and compare more favourably to observations from strong motion recordings than conventional 1D site response models. It is also shown that consideration of a horizontal impedance contrast across the Wellington Fault affects spectral response and amplification at longer periods, suggesting the importance of this feature in future ground motion modelling studies in the Wellington region.
{"title":"Basin effects and limitations of 1D site response analysis from 2D numerical models of the Thorndon basin","authors":"C. McGann, B. Bradley, L. Wotherspoon, Robin L. Lee","doi":"10.5459/BNZSEE.54.1.21-30","DOIUrl":"https://doi.org/10.5459/BNZSEE.54.1.21-30","url":null,"abstract":"Plane strain (2D) finite element models are used to examine factors contributing to basin effects observed for multiple seismic events at sites in the Thorndon basin of Wellington, New Zealand. The models consider linear elastic soil and rock response when subjected to vertically-propagating shear waves. Depth-dependent shear wave velocities are considered in the soil layers, and the effects of random variations of soil velocity within layers are modelled. Various rock shear wave velocity configurations are considered to evaluate their effect on the modelled surficial response. It is shown that these simple 2D models are able to capture basin reverberations and compare more favourably to observations from strong motion recordings than conventional 1D site response models. It is also shown that consideration of a horizontal impedance contrast across the Wellington Fault affects spectral response and amplification at longer periods, suggesting the importance of this feature in future ground motion modelling studies in the Wellington region.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130828971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.5459/BNZSEE.54.1.31-39
G. MacRae, C. Lee, Saul Y. Vazquez-Colunga, Jian Cui, S. Alizadeh, Liang-jiu Jia
A simple and economical design approach is described for a BRB system, consisting of a BRB within a steel frame, subject to in-plane and out-of-plane seismic displacements. The approach avoids out-of-plane system or brace instability while allowing large frame out-of-plane deformations and desirable BRB axial performance. It also limits the compressive/tension force ratio. It is based on the simple concept that a brace will be stable with two moment-releases (hinges) but that an out-of-plane buckling mechanism may occur with more than two. The hinges are detailed as specified deformation zones (SDZs) at the brace ends. The hinges use a plate which can yield about its weak axis during out-of-plane movement. Simple methods to assess the stability of the brace itself (between hinges) are developed, an example is provided illustrating how the monotonic deformation demand of the simple plate hinge can be assessed, and detailing recommendations are made to restrict the deformation of the boundary elements at the brace ends.
{"title":"BRB system stability considering frame out-of-plane loading and deformation zone","authors":"G. MacRae, C. Lee, Saul Y. Vazquez-Colunga, Jian Cui, S. Alizadeh, Liang-jiu Jia","doi":"10.5459/BNZSEE.54.1.31-39","DOIUrl":"https://doi.org/10.5459/BNZSEE.54.1.31-39","url":null,"abstract":"A simple and economical design approach is described for a BRB system, consisting of a BRB within a steel frame, subject to in-plane and out-of-plane seismic displacements. The approach avoids out-of-plane system or brace instability while allowing large frame out-of-plane deformations and desirable BRB axial performance. It also limits the compressive/tension force ratio. It is based on the simple concept that a brace will be stable with two moment-releases (hinges) but that an out-of-plane buckling mechanism may occur with more than two. The hinges are detailed as specified deformation zones (SDZs) at the brace ends. The hinges use a plate which can yield about its weak axis during out-of-plane movement. Simple methods to assess the stability of the brace itself (between hinges) are developed, an example is provided illustrating how the monotonic deformation demand of the simple plate hinge can be assessed, and detailing recommendations are made to restrict the deformation of the boundary elements at the brace ends.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"387 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132305968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.5459/bnzsee.53.4.227-241
Aysha M Zaneeb, Rupen Goswami, C. Murty
An analytical method is presented to estimate lateral shear strength (and identify likely mode and location of failure) in reinforced concrete (RC) cantilever columns of rectangular cross-section under combined axial force, shear force and bending moment. Change in shear capacity of concrete with flexural demand at a section is captured explicitly and the shear resistance offered by concrete estimated; this is combined with shear resistance offered by transverse and longitudinal reinforcement bars to estimate the overall shear capacity of RC columns. Shear–moment (V-M) interaction capacity diagram of an RC column, viewed alongside the demand diagram, identifies the lateral shear strength and failure mode. These analytical estimates compare well with test data of 107 RC columns published in literature; the test data corresponds to different axial loads, transverse reinforcement ratios, longitudinal reinforcement ratios, shear span to depth ratios, and loading conditions. Also, the analytical estimates are compared with those obtained using other analytical methods reported in literature; in all cases, the proposed method gives reasonable accuracy when estimating shear capacity of RC columns. In addition, the method provides insights into the shear resistance mechanism in RC columns under the combined action of P-V-M, and it is simple to use.
{"title":"Lateral shear strength of rectangular RC columns subjected to combined P-V-M monotonic loading","authors":"Aysha M Zaneeb, Rupen Goswami, C. Murty","doi":"10.5459/bnzsee.53.4.227-241","DOIUrl":"https://doi.org/10.5459/bnzsee.53.4.227-241","url":null,"abstract":"An analytical method is presented to estimate lateral shear strength (and identify likely mode and location of failure) in reinforced concrete (RC) cantilever columns of rectangular cross-section under combined axial force, shear force and bending moment. Change in shear capacity of concrete with flexural demand at a section is captured explicitly and the shear resistance offered by concrete estimated; this is combined with shear resistance offered by transverse and longitudinal reinforcement bars to estimate the overall shear capacity of RC columns. Shear–moment (V-M) interaction capacity diagram of an RC column, viewed alongside the demand diagram, identifies the lateral shear strength and failure mode. These analytical estimates compare well with test data of 107 RC columns published in literature; the test data corresponds to different axial loads, transverse reinforcement ratios, longitudinal reinforcement ratios, shear span to depth ratios, and loading conditions. Also, the analytical estimates are compared with those obtained using other analytical methods reported in literature; in all cases, the proposed method gives reasonable accuracy when estimating shear capacity of RC columns. In addition, the method provides insights into the shear resistance mechanism in RC columns under the combined action of P-V-M, and it is simple to use.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130916944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.5459/bnzsee.53.4.175-188
J. Mulligan, T. Sullivan, R. Dhakal
It is now widely recognized that the performance of non-structural elements is crucial to the performance of building systems during earthquakes. Field surveys and experimental studies have shown that light steel or timber framed plasterboard partition walls are particularly vulnerable. The objective of this study is to investigate the seismic performance of a novel seismic gap partition system with angled return walls under quasi-static cyclic loading applied obliquely and to investigate the benefits of using acrylic gap-filler in the seismic gaps. Two specimens were tested: a steel stud specimen and a timber stud specimen. Observed drift capacities were significantly greater than traditional plasterboard partition systems. Equations were used to predict the drift at which damage state 1 (DS1) and damage state 2 (DS2) would initiate. The equation used to estimate the drift at the onset of DS1 accurately predicted the onset of plaster cracking but overestimated the drift at which the gap filling material was damaged. The equation used to predict the onset of DS2 provided a lower bound for both specimens and also when used to predict results of previous experimental tests on seismic gap systems. The gap-filling material reduced the drift at the onset of DS1, however, it had a beneficial effect on the re-centring behaviour of the linings. Out-of-plane displacements and return wall configuration did not appear to significantly impact the onset of plaster cracking in the specimens.
{"title":"Experimental study of the seismic performance of plasterboard partition walls with seismic gaps","authors":"J. Mulligan, T. Sullivan, R. Dhakal","doi":"10.5459/bnzsee.53.4.175-188","DOIUrl":"https://doi.org/10.5459/bnzsee.53.4.175-188","url":null,"abstract":"It is now widely recognized that the performance of non-structural elements is crucial to the performance of building systems during earthquakes. Field surveys and experimental studies have shown that light steel or timber framed plasterboard partition walls are particularly vulnerable. The objective of this study is to investigate the seismic performance of a novel seismic gap partition system with angled return walls under quasi-static cyclic loading applied obliquely and to investigate the benefits of using acrylic gap-filler in the seismic gaps. Two specimens were tested: a steel stud specimen and a timber stud specimen. Observed drift capacities were significantly greater than traditional plasterboard partition systems. Equations were used to predict the drift at which damage state 1 (DS1) and damage state 2 (DS2) would initiate. The equation used to estimate the drift at the onset of DS1 accurately predicted the onset of plaster cracking but overestimated the drift at which the gap filling material was damaged. The equation used to predict the onset of DS2 provided a lower bound for both specimens and also when used to predict results of previous experimental tests on seismic gap systems. The gap-filling material reduced the drift at the onset of DS1, however, it had a beneficial effect on the re-centring behaviour of the linings. Out-of-plane displacements and return wall configuration did not appear to significantly impact the onset of plaster cracking in the specimens.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122806964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.5459/bnzsee.53.4.203-214
Nicola McDonald, L. Timar, G. McDonald, Catherine Murray
In the context of infrastructure and natural hazard planning, a new agenda for applied research is emerging which, focused on resilience, integrates government, hazard science, engineering and economics. This paper sets out the context and key tenets guiding the direction of this topic of enquiry, including the New Zealand legislative and policy context under which infrastructure decisions are made, core principles implied by the resilience objective, current norms and challenges in the practice of infrastructure planning, and key criteria for decision-support tools. While decision-making processes strongly informed by cost-benefit analysis (CBA) continue to be common in the New Zealand policy process, this paper demonstrates that there are certain distinguishing features of infrastructure networks that make it challenging to effectively and validly apply standard CBA approaches, particularly when resilience values are at stake. To help address this challenge, a new conceptual framework is presented to assist in the critical review and selection of decision-making tools to support infrastructure planning. This framework provides a synthesis of the ways through which contextual uncertainties influence the relative advantages and appropriateness of different decision support tools. Ultimately, we seek to promote a diverse but also nuanced approach to analysis supporting infrastructure planning under seismic and other natural hazard risk.
{"title":"Better resilience evaluation","authors":"Nicola McDonald, L. Timar, G. McDonald, Catherine Murray","doi":"10.5459/bnzsee.53.4.203-214","DOIUrl":"https://doi.org/10.5459/bnzsee.53.4.203-214","url":null,"abstract":"In the context of infrastructure and natural hazard planning, a new agenda for applied research is emerging which, focused on resilience, integrates government, hazard science, engineering and economics. This paper sets out the context and key tenets guiding the direction of this topic of enquiry, including the New Zealand legislative and policy context under which infrastructure decisions are made, core principles implied by the resilience objective, current norms and challenges in the practice of infrastructure planning, and key criteria for decision-support tools. While decision-making processes strongly informed by cost-benefit analysis (CBA) continue to be common in the New Zealand policy process, this paper demonstrates that there are certain distinguishing features of infrastructure networks that make it challenging to effectively and validly apply standard CBA approaches, particularly when resilience values are at stake. To help address this challenge, a new conceptual framework is presented to assist in the critical review and selection of decision-making tools to support infrastructure planning. This framework provides a synthesis of the ways through which contextual uncertainties influence the relative advantages and appropriateness of different decision support tools. Ultimately, we seek to promote a diverse but also nuanced approach to analysis supporting infrastructure planning under seismic and other natural hazard risk.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114580255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.5459/bnzsee.53.4.215-226
D. S. Agustawijaya, Rian Mahendra Taruna, A. R. Agustawijaya
A series of earthquakes occurred at the northern part of Lombok Island during July–September 2018 with the highest Mw7.0 5th August 2018 that caused the death of hundreds of people and ruined thousands of buildings. The earthquakes were triggered on the Flores Thrust located at the back arc zone and at only 50 km distance from the island, leading to multiple seismic hazards to Lombok and surrounding islands. The thrust could possibly be the dominant current seismic sources; however, the megathrust sources also contributed to the hazards due to the subduction between the Indo-Australia and Eurasia tectonic plates in the Nusa Tenggara region. An updated probabilistic seismic hazard analysis was, therefore, conducted on recent seismicity, detailed tectonic background, and suitable ground motion prediction equations, to determine higher seismic parameter values than the 2017 models. This means that Lombok and surrounding islands exposed to higher seismic hazards than those predicted before the earthquake events in 2018.
{"title":"An update to seismic hazard levels and PSHA for Lombok and surrounding islands after earthquakes in 2018","authors":"D. S. Agustawijaya, Rian Mahendra Taruna, A. R. Agustawijaya","doi":"10.5459/bnzsee.53.4.215-226","DOIUrl":"https://doi.org/10.5459/bnzsee.53.4.215-226","url":null,"abstract":"A series of earthquakes occurred at the northern part of Lombok Island during July–September 2018 with the highest Mw7.0 5th August 2018 that caused the death of hundreds of people and ruined thousands of buildings. The earthquakes were triggered on the Flores Thrust located at the back arc zone and at only 50 km distance from the island, leading to multiple seismic hazards to Lombok and surrounding islands. The thrust could possibly be the dominant current seismic sources; however, the megathrust sources also contributed to the hazards due to the subduction between the Indo-Australia and Eurasia tectonic plates in the Nusa Tenggara region. An updated probabilistic seismic hazard analysis was, therefore, conducted on recent seismicity, detailed tectonic background, and suitable ground motion prediction equations, to determine higher seismic parameter values than the 2017 models. This means that Lombok and surrounding islands exposed to higher seismic hazards than those predicted before the earthquake events in 2018.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127296200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-01DOI: 10.5459/bnzsee.53.4.189-202
J. Tondut, J. Chase, Cong Zhou
Structural health monitoring (SHM) methods provide damage metrics and localisation, but not a means of answering subsequent questions concerning immediate or long-term damage mitigation, risk, or safety in re-occupancy. Models based on the SHM results would provide a means to test these issues, but typically require extensive human input, which is not available immediately after an event to enhance and optimise immediate decision-making. This work presents a simple, readily automated modelling approach to translate SHM results from the proven hysteresis loop analysis (HLA) method into foundation models for immediate use. Experimental data from a 3-storey structure tested at the E-Defense facility in Japan are used to assess model performance. The model’s ability to capture the essential dynamics is assessed by comparing peak dynamic displacement and cross correlation coefficient (Rcoeff). For all 6 events, 3 storeys, and 2 directions, median (5-95% Range) of peak displacement error was 0.82 (0.17, 4.09) mm, and average Rcoeff = 0.82, all of which were significantly improved if the worst event was excluded. Overall, accurate nonlinear, time-varying baseline models were created using data from SHM damage identification and localisation methods using relatively quite simple model structures. The method is readily automated via algorithm, and the models were suitable for initial investigation and analysis on safety, damage mitigation, and thus re-occupancy. Such models could take SHM from being a tool for damage identification and extend it into further decision-making, creating far greater utility for engineers and owners, which could further spur impetus for investment in monitoring.
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