Pub Date : 2019-06-30DOI: 10.5459/bnzsee.52.2.78-94
M. Baradaran, F. Behnamfar
Determination of seismic design forces of structures is performed by the building codes usually using response reduction (or behaviour) factors that incorporate indeterminacy and ductility capacity of lateral bearing systems. In this procedure story drifts are checked as a final design step approximately preventing stories from assuming excessive ductility demands, or seismic damage. If this procedure is reversed, a more logical seismic design approach may be developed by starting with a ductility-controlled procedure. It is the incentive of this research in which by using a large number of earthquakes, first nonlinear acceleration spectra are developed for different levels of ductility demand. Then an energy-based modal procedure is developed in which the system ductility demand is distributed between the important vibration modes based on their contribution. Finally, the developed method is applied to seismic design of several buildings selected from both regular and irregular structural systems. Comparison with a sample code design establishes success of the method in developing a more rational seismic design.
{"title":"A modal seismic design procedure based on a selected level of ductility demand","authors":"M. Baradaran, F. Behnamfar","doi":"10.5459/bnzsee.52.2.78-94","DOIUrl":"https://doi.org/10.5459/bnzsee.52.2.78-94","url":null,"abstract":"Determination of seismic design forces of structures is performed by the building codes usually using response reduction (or behaviour) factors that incorporate indeterminacy and ductility capacity of lateral bearing systems. In this procedure story drifts are checked as a final design step approximately preventing stories from assuming excessive ductility demands, or seismic damage. If this procedure is reversed, a more logical seismic design approach may be developed by starting with a ductility-controlled procedure. It is the incentive of this research in which by using a large number of earthquakes, first nonlinear acceleration spectra are developed for different levels of ductility demand. Then an energy-based modal procedure is developed in which the system ductility demand is distributed between the important vibration modes based on their contribution. Finally, the developed method is applied to seismic design of several buildings selected from both regular and irregular structural systems. Comparison with a sample code design establishes success of the method in developing a more rational seismic design.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48737385","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 : 2019-06-30DOI: 10.5459/bnzsee.52.2.56-66
Angela Liu, D. Carradine
The goal of this study is to develop a racking model of plasterboard-sheathed timber walls as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand. Residential buildings in New Zealand are primarily stand-alone low-rise LTF buildings, and their bracing elements are commonly plasterboard-sheathed LTF walls. It is an essential part of performance-based seismic designs of LTF buildings to be able to simulate the racking performance of plasterboard walls. In this study, racking test results of 12 plasterboard walls were collected and studied to gain insight into the seismic performance of plasterboard-sheathed LTF walls. The racking performance of these walls was examined in terms of stiffness/strength degradation, displacement capacity, superposition applicability and failure mechanisms. Subsequently, a mathematical analysis model for simulating racking performance of LTF plasterboard walls is developed and presented. The developed racking model is a closed-form wall model and could be easily used for conducting three-dimensional non-linear push-over studies of seismic performance of LTF buildings.
{"title":"Seismic bracing performance of plasterboard timber walls","authors":"Angela Liu, D. Carradine","doi":"10.5459/bnzsee.52.2.56-66","DOIUrl":"https://doi.org/10.5459/bnzsee.52.2.56-66","url":null,"abstract":"The goal of this study is to develop a racking model of plasterboard-sheathed timber walls as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand. Residential buildings in New Zealand are primarily stand-alone low-rise LTF buildings, and their bracing elements are commonly plasterboard-sheathed LTF walls. It is an essential part of performance-based seismic designs of LTF buildings to be able to simulate the racking performance of plasterboard walls. In this study, racking test results of 12 plasterboard walls were collected and studied to gain insight into the seismic performance of plasterboard-sheathed LTF walls. The racking performance of these walls was examined in terms of stiffness/strength degradation, displacement capacity, superposition applicability and failure mechanisms. Subsequently, a mathematical analysis model for simulating racking performance of LTF plasterboard walls is developed and presented. The developed racking model is a closed-form wall model and could be easily used for conducting three-dimensional non-linear push-over studies of seismic performance of LTF buildings.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45602182","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 : 2019-06-30DOI: 10.5459/bnzsee.52.2.i-ii
R. Dhakal
{"title":"Editorial","authors":"R. Dhakal","doi":"10.5459/bnzsee.52.2.i-ii","DOIUrl":"https://doi.org/10.5459/bnzsee.52.2.i-ii","url":null,"abstract":"","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45193425","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 : 2019-06-30DOI: 10.5459/bnzsee.52.2.95-106
Angela Liu, Minghao Li, R. Shelton
The ultimate goal of this study is to develop a model representing the in-plane behaviour of plasterboard ceiling diaphragms, as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand (NZ). LTF residential buildings in NZ are constructed according to a prescriptive standard – NZS 3604 Timber-framed buildings [1]. With regards to seismic resisting systems, LTF buildings constructed to NZS3604 often have irregular bracing arrangements within a floor plan. A damage survey of LTF buildings after the Canterbury earthquake revealed that structural irregularity (irregular bracing arrangement within a plan) significantly exacerbated the earthquake damage to LTF buildings. When a building has irregular bracing arrangements, the building will have not only translational deflections but also a torsional response in earthquakes. How effectively the induced torsion can be resolved depends on the stiffness of the floors/roof diaphragms. Ceiling and floor diaphragms in LTF buildings in NZ have different construction details from the rest of the world and there appears to be no information available on timber diaphragms typical of NZ practice. This paper presents experimental studies undertaken on plasterboard ceiling diaphragms as typical of NZ residential practice. Based on the test results, a mathematical model simulating the in-plane stiffness of plasterboard ceiling diaphragms was developed, and the developed model has a similar format to that of plasterboard bracing wall elements presented in an accompany paper by Liu [2]. With these two models, three-dimensional non-linear push-over studies of LTF buildings can be undertaken to calculate seismic performance of irregular LTF buildings.
{"title":"Experimental studies on in-plane performance of plasterboard sheathed ceiling diaphragms","authors":"Angela Liu, Minghao Li, R. Shelton","doi":"10.5459/bnzsee.52.2.95-106","DOIUrl":"https://doi.org/10.5459/bnzsee.52.2.95-106","url":null,"abstract":"The ultimate goal of this study is to develop a model representing the in-plane behaviour of plasterboard ceiling diaphragms, as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand (NZ). \u0000LTF residential buildings in NZ are constructed according to a prescriptive standard – NZS 3604 Timber-framed buildings [1]. With regards to seismic resisting systems, LTF buildings constructed to NZS3604 often have irregular bracing arrangements within a floor plan. A damage survey of LTF buildings after the Canterbury earthquake revealed that structural irregularity (irregular bracing arrangement within a plan) significantly exacerbated the earthquake damage to LTF buildings. When a building has irregular bracing arrangements, the building will have not only translational deflections but also a torsional response in earthquakes. How effectively the induced torsion can be resolved depends on the stiffness of the floors/roof diaphragms. Ceiling and floor diaphragms in LTF buildings in NZ have different construction details from the rest of the world and there appears to be no information available on timber diaphragms typical of NZ practice. \u0000This paper presents experimental studies undertaken on plasterboard ceiling diaphragms as typical of NZ residential practice. Based on the test results, a mathematical model simulating the in-plane stiffness of plasterboard ceiling diaphragms was developed, and the developed model has a similar format to that of plasterboard bracing wall elements presented in an accompany paper by Liu [2]. With these two models, three-dimensional non-linear push-over studies of LTF buildings can be undertaken to calculate seismic performance of irregular LTF buildings.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43112153","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 : 2019-06-30DOI: 10.5459/bnzsee.52.2.67-77
R. Ballagh, A. Cattanach
The Kaikōura earthquake brought the concept of basin effects to the forefront of conversation about building in the Wellington CBD. Local exceedances of ULS design spectra were observed in many waterfront sites in the 1.5-2.5s period range. This, coupled with low yield levels and certain structural forms present in previous generations of building design, meant that significant damage occurred in many buildings around the Wellington waterfront. A primary cause for the high spectral accelerations was the geological structure of the Wellington CBD. This paper will focus on the behaviour of generic buildings in response to these particular ground motions and suggest how lessons from this can inform the design of future buildings. It uses the Kaikōura Earthquake as the centre point for discussions about the relationship between building behaviour on soft soils and the effects on this of different forms of damping. More broadly, the aim is to help spark debate in the earthquake engineering community on the question: What sorts of structures should we be building on soft soil sites? This paper has been written in the wake of a number of damaging earthquakes throughout New Zealand, and with the concurrent increase in sophistication and spread of tools for analysing the effects of the ground motions induced by these earthquakes. The genesis of the ideas presented herein was in analysis of many waterfront buildings following the Kaikoura earthquake, and the attempts, often in vain, to match modelled building behaviour- where small tweaks in assumptions could have a radical effect on results- with actual observed damage – where cracks may have been seen in concrete or in partitions, but assessment of actual plastic strains reached in steel bars or beams was basically conjecture. This paper is broad in scope, therefore cannot possibly give each aspect the coverage of a series of papers which consider them in isolation and in detail. We nonetheless strongly believe that a holistic view of all topics is critical for design, and that the authors as ‘front line’ structural engineers are well positioned to present this. Sincere attempts have been made to justify our point of view with a strong basis in first principles, and backed by nonlinear time history analysis, or by reference to the work of others. We acknowledge that our beliefs are not shared by everyone and that some conclusions are provocative. It is neither the intent nor even the hope that we have the last word on this topic.
{"title":"Basin edge effects and damping","authors":"R. Ballagh, A. Cattanach","doi":"10.5459/bnzsee.52.2.67-77","DOIUrl":"https://doi.org/10.5459/bnzsee.52.2.67-77","url":null,"abstract":"The Kaikōura earthquake brought the concept of basin effects to the forefront of conversation about building in the Wellington CBD. Local exceedances of ULS design spectra were observed in many waterfront sites in the 1.5-2.5s period range. This, coupled with low yield levels and certain structural forms present in previous generations of building design, meant that significant damage occurred in many buildings around the Wellington waterfront. \u0000A primary cause for the high spectral accelerations was the geological structure of the Wellington CBD. This paper will focus on the behaviour of generic buildings in response to these particular ground motions and suggest how lessons from this can inform the design of future buildings. It uses the Kaikōura Earthquake as the centre point for discussions about the relationship between building behaviour on soft soils and the effects on this of different forms of damping. More broadly, the aim is to help spark debate in the earthquake engineering community on the question: What sorts of structures should we be building on soft soil sites? \u0000This paper has been written in the wake of a number of damaging earthquakes throughout New Zealand, and with the concurrent increase in sophistication and spread of tools for analysing the effects of the ground motions induced by these earthquakes. The genesis of the ideas presented herein was in analysis of many waterfront buildings following the Kaikoura earthquake, and the attempts, often in vain, to match modelled building behaviour- where small tweaks in assumptions could have a radical effect on results- with actual observed damage – where cracks may have been seen in concrete or in partitions, but assessment of actual plastic strains reached in steel bars or beams was basically conjecture. \u0000This paper is broad in scope, therefore cannot possibly give each aspect the coverage of a series of papers which consider them in isolation and in detail. We nonetheless strongly believe that a holistic view of all topics is critical for design, and that the authors as ‘front line’ structural engineers are well positioned to present this. Sincere attempts have been made to justify our point of view with a strong basis in first principles, and backed by nonlinear time history analysis, or by reference to the work of others. We acknowledge that our beliefs are not shared by everyone and that some conclusions are provocative. It is neither the intent nor even the hope that we have the last word on this topic.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42722565","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 : 2019-03-31DOI: 10.5459/BNZSEE.52.1.1-22
R. V. Van Dissen, T. Stahl, A. King, J. Pettinga, C. Fenton, T. Little, N. Litchfield, M. Stirling, R. Langridge, A. Nicol, J. Kearse, D. Barrell, P. Villamor
Areas that experience permanent ground deformation in earthquakes (e.g., surface fault rupture, slope failure, and/or liquefaction) typically sustain greater damage and loss compared to areas that experience strong ground shaking alone. The 2016 Mw 7.8 Kaikōura earthquake generated ≥220 km of surface fault rupture. The amount and style of surface rupture deformation varied considerably, ranging from centimetre-scale distributed folding to metre-scale discrete rupture. About a dozen buildings – mainly residential (or residential-type) structures comprising single-storey timber-framed houses, barns and wool sheds with lightweight roofing material – were directly impacted by surface fault rupture with the severity of damage correlating with both local discrete fault displacement and local strain. However, none of these buildings collapsed. This included a house built directly atop a discrete rupture that experienced ~10 m of lateral offset. The foundation and flooring system of this structure allowed decoupling of much of the ground deformation from the superstructure thus preventing collapse. Nevertheless, buildings directly impacted by surface faulting suffered greater damage than comparable structures immediately outside the zone of surface rupture deformation. From a life-safety standpoint, all these buildings performed satisfactorily and provide insight into construction styles that could be employed to facilitate non-collapse performance resulting from surface fault rupture and, in certain instances, even post-event functionality.
{"title":"Impacts of surface fault rupture on residential structures during the 2016 Mw 7.8 Kaikōura earthquake, New Zealand","authors":"R. V. Van Dissen, T. Stahl, A. King, J. Pettinga, C. Fenton, T. Little, N. Litchfield, M. Stirling, R. Langridge, A. Nicol, J. Kearse, D. Barrell, P. Villamor","doi":"10.5459/BNZSEE.52.1.1-22","DOIUrl":"https://doi.org/10.5459/BNZSEE.52.1.1-22","url":null,"abstract":"Areas that experience permanent ground deformation in earthquakes (e.g., surface fault rupture, slope failure, and/or liquefaction) typically sustain greater damage and loss compared to areas that experience strong ground shaking alone. The 2016 Mw 7.8 Kaikōura earthquake generated ≥220 km of surface fault rupture. The amount and style of surface rupture deformation varied considerably, ranging from centimetre-scale distributed folding to metre-scale discrete rupture. About a dozen buildings – mainly residential (or residential-type) structures comprising single-storey timber-framed houses, barns and wool sheds with lightweight roofing material – were directly impacted by surface fault rupture with the severity of damage correlating with both local discrete fault displacement and local strain. However, none of these buildings collapsed. This included a house built directly atop a discrete rupture that experienced ~10 m of lateral offset. The foundation and flooring system of this structure allowed decoupling of much of the ground deformation from the superstructure thus preventing collapse. Nevertheless, buildings directly impacted by surface faulting suffered greater damage than comparable structures immediately outside the zone of surface rupture deformation. From a life-safety standpoint, all these buildings performed satisfactorily and provide insight into construction styles that could be employed to facilitate non-collapse performance resulting from surface fault rupture and, in certain instances, even post-event functionality.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48666078","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 : 2019-03-31DOI: 10.5459/BNZSEE.52.1.44-53
E. Au, G. MacRae, D. Pettinga, B. Deam, V. Sadashiva, Hossein Soleimankhani
Impulse ground motions are applied to single story structures with different in-plane wall strength and stiffness, rotational inertia, and out-of-plane wall stiffness to obtain the dynamic response considering torsion. A simple hand method to evaluate the impulse response is developed. It is shown that the median increase in response of the critical component considering torsion from many earthquake records is similar to that from impulse records. Using this information, a simple design methodology is proposed which enables the likely earthquake response of critical elements considering torsion to be obtained from building analyses not considering torsion. A design example is also provided.
{"title":"Seismic response of torsionally irregular single story structures","authors":"E. Au, G. MacRae, D. Pettinga, B. Deam, V. Sadashiva, Hossein Soleimankhani","doi":"10.5459/BNZSEE.52.1.44-53","DOIUrl":"https://doi.org/10.5459/BNZSEE.52.1.44-53","url":null,"abstract":"Impulse ground motions are applied to single story structures with different in-plane wall strength and stiffness, rotational inertia, and out-of-plane wall stiffness to obtain the dynamic response considering torsion. A simple hand method to evaluate the impulse response is developed. It is shown that the median increase in response of the critical component considering torsion from many earthquake records is similar to that from impulse records. Using this information, a simple design methodology is proposed which enables the likely earthquake response of critical elements considering torsion to be obtained from building analyses not considering torsion. A design example is also provided.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45570136","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 : 2019-03-31DOI: 10.5459/BNZSEE.52.1.23-43
S. Khakurel, T. Yeow, Frankie Chen, Zam Wang, S. Saha, R. Dhakal
One method to rapidly estimate seismic losses during the structural design phase is to use contribution functions. These are relationships between expected losses (e.g. damage repair costs, downtime, and injury) for a wide range of building components (e.g. cladding, partitions, and ceilings) and the building’s response. This study aims to develop contribution functions for common types of cladding used in different types of buildings considering damage repair costs. In the first part of this study, a building survey was performed to identify types and quantity of cladding used in residential, commercial and industrial buildings in Christchurch, New Zealand; where it was found that the most common cladding types are glazing, masonry veneer, monolithic cladding and precast panels. The data collected during the survey was also used to develop cladding distribution (i.e. density) functions. The second step involved identifying fragility functions from relevant literature which are applicable to the cladding detailing used in New Zealand. The third step involved surveying consultants, suppliers and builders on typical repair/replacement cost. Finally, Monte Carlo simulations were performed to combine the cladding density function with the fragility functions and the repair cost for each type of cladding to derive contribution functions for various types of cladding and building usage. An example (case study) is provided to demonstrate its usage.
{"title":"Development of cladding contribution functions for seismic loss estimation","authors":"S. Khakurel, T. Yeow, Frankie Chen, Zam Wang, S. Saha, R. Dhakal","doi":"10.5459/BNZSEE.52.1.23-43","DOIUrl":"https://doi.org/10.5459/BNZSEE.52.1.23-43","url":null,"abstract":"One method to rapidly estimate seismic losses during the structural design phase is to use contribution functions. These are relationships between expected losses (e.g. damage repair costs, downtime, and injury) for a wide range of building components (e.g. cladding, partitions, and ceilings) and the building’s response. This study aims to develop contribution functions for common types of cladding used in different types of buildings considering damage repair costs. In the first part of this study, a building survey was performed to identify types and quantity of cladding used in residential, commercial and industrial buildings in Christchurch, New Zealand; where it was found that the most common cladding types are glazing, masonry veneer, monolithic cladding and precast panels. The data collected during the survey was also used to develop cladding distribution (i.e. density) functions. The second step involved identifying fragility functions from relevant literature which are applicable to the cladding detailing used in New Zealand. The third step involved surveying consultants, suppliers and builders on typical repair/replacement cost. Finally, Monte Carlo simulations were performed to combine the cladding density function with the fragility functions and the repair cost for each type of cladding to derive contribution functions for various types of cladding and building usage. An example (case study) is provided to demonstrate its usage.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41915015","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 : 2018-12-31DOI: 10.5459/BNZSEE.51.4.171-182
T. Egbelakin, M. Poshdar, Kevin C. Walsh, J. Ingham, D. Johnston, J. Becker, Jasper Mbachu, E. Rasheed
Small to Medium-sized Enterprises (SMEs) are often vulnerable to the adversities caused by major earthquake events, which may include business disruption, damage to goods and property, impaired employee health and safety, financial strain and loss of revenue, or even total loss of the business. SMEs are expected to make critical decisions to prepare their businesses for an earthquake, in an attempt to ensure business continuity and the wellbeing of their employees, should a disaster occur. This study was conducted five years after the devastating Canterbury earthquakes and sought to examine the level of earthquake preparedness of SMEs by investigating the actions undertaken in two different suburban locations having differing seismicity. The extent of preparedness was assessed based on a list of twenty-one possible actions grouped into four categories being knowledge enrichment, insurance and business continuity, survival support actions, and seismic damage mitigation. The assessment involved a survey with an online questionnaire. Analysis of the collected data revealed a specific adoption pattern in the regions of study. The main preparedness action adopted by SMEs was the purchase of business insurance with the development of continuity plans. The least obtained preparedness action was related to survival support actions such as maintaining necessary emergency supplies. The overall adoption rate of the preparedness actions was less than 30%, with no significant difference between the regions studied, and close to 50% of SMEs having adopted less than five preparedness actions. This situation clearly requires urgent attention from all stakeholders involved in SMEs resilience before an earthquake disaster hits the regions.
{"title":"Preparation of small to medium-sized enterprises to earthquake disaster","authors":"T. Egbelakin, M. Poshdar, Kevin C. Walsh, J. Ingham, D. Johnston, J. Becker, Jasper Mbachu, E. Rasheed","doi":"10.5459/BNZSEE.51.4.171-182","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.4.171-182","url":null,"abstract":"Small to Medium-sized Enterprises (SMEs) are often vulnerable to the adversities caused by major earthquake events, which may include business disruption, damage to goods and property, impaired employee health and safety, financial strain and loss of revenue, or even total loss of the business. SMEs are expected to make critical decisions to prepare their businesses for an earthquake, in an attempt to ensure business continuity and the wellbeing of their employees, should a disaster occur. This study was conducted five years after the devastating Canterbury earthquakes and sought to examine the level of earthquake preparedness of SMEs by investigating the actions undertaken in two different suburban locations having differing seismicity. The extent of preparedness was assessed based on a list of twenty-one possible actions grouped into four categories being knowledge enrichment, insurance and business continuity, survival support actions, and seismic damage mitigation. The assessment involved a survey with an online questionnaire. Analysis of the collected data revealed a specific adoption pattern in the regions of study. The main preparedness action adopted by SMEs was the purchase of business insurance with the development of continuity plans. The least obtained preparedness action was related to survival support actions such as maintaining necessary emergency supplies. The overall adoption rate of the preparedness actions was less than 30%, with no significant difference between the regions studied, and close to 50% of SMEs having adopted less than five preparedness actions. This situation clearly requires urgent attention from all stakeholders involved in SMEs resilience before an earthquake disaster hits the regions.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42152992","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 : 2018-12-31DOI: 10.5459/bnzsee.51.4.197-211
M. Chaudhary
Seismic site amplification factors and seismic design spectra for bridges are influenced by site conditions that include geotechnical properties of soil strata as well as the geological setting. All modern seismic design codes recognize this fact and assign design spectral shapes based on site conditions or specify a 2-parameter model with site amplification factors as a function of site class, seismic intensity and vibration period (short and long). Design codes made a number of assumptions related to the site conditions while specifying the values of short (Fa) and long period (Fv) site amplification factors. Making these assumptions was necessary due to vast variation in site properties and limited availability of actual strong motion records on all site conditions and seismic setting in a region. This paper conducted a sensitivity analysis for site amplification factors for site classes C and D in the AASHTO bridge design code by performing a 1-D site response analysis in which values of site parameters like strata depth, travel-time averaged shear wave velocity in the top 30 m strata (Vs30), plasticity index (PI), impedance contrast ratio (ICR) and intensity of seismic ground motion were varied. The results were analyzed to identify the site parameters that impacted Fa and Fv values for site classes C and D. The computed Fa and Fv values were compared with the corresponding values in the AASHTO bridge design code and it was found that the code-based Fa and Fv values were generally underestimated and overestimated respectively.
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