Pub Date : 2017-03-31DOI: 10.5459/BNZSEE.50.1.1-20
C. V. Houtte, Stephen Bannister, C. Holden, S. Bourguignon, G. McVerry
This article summarises work that has been undertaken to compile the New Zealand Strong Motion Database, which is intended to be a significant resource for both researchers and practitioners. The database contains 276 New Zealand earthquakes that were recorded by strong motion instruments from GeoNet and earlier network operators. The events have moment magnitudes ranging from 3.5 to 7.8. A total of 134 of these events (49%) have been classified as occurring in the overlying crust, with 33 events (12%) located on the Fiordland subduction interface and 7 on the Hikurangi subduction interface (3%). 8 events (3%) are deemed to have occurred within the subducting Australian Plate at the Fiordland subduction zone, and 94 events (34%) within the subducting Pacific Plate on the Hikurangi subduction zone. There are a total of 4,148 uniformly-processed recordings associated with these earthquakes, from which acceleration, velocity and displacement time-series, Fourier amplitude spectra of acceleration, and acceleration response spectra have been computed. 598 recordings from the New Zealand database are identified as being suitable for future use in time-domain analyses of structural response. All data are publicly available at http://info.geonet.org.nz/x/TQAdAQ.
{"title":"The New Zealand Strong Motion Database","authors":"C. V. Houtte, Stephen Bannister, C. Holden, S. Bourguignon, G. McVerry","doi":"10.5459/BNZSEE.50.1.1-20","DOIUrl":"https://doi.org/10.5459/BNZSEE.50.1.1-20","url":null,"abstract":"This article summarises work that has been undertaken to compile the New Zealand Strong Motion Database, which is intended to be a significant resource for both researchers and practitioners. The database contains 276 New Zealand earthquakes that were recorded by strong motion instruments from GeoNet and earlier network operators. The events have moment magnitudes ranging from 3.5 to 7.8. A total of 134 of these events (49%) have been classified as occurring in the overlying crust, with 33 events (12%) located on the Fiordland subduction interface and 7 on the Hikurangi subduction interface (3%). 8 events (3%) are deemed to have occurred within the subducting Australian Plate at the Fiordland subduction zone, and 94 events (34%) within the subducting Pacific Plate on the Hikurangi subduction zone. There are a total of 4,148 uniformly-processed recordings associated with these earthquakes, from which acceleration, velocity and displacement time-series, Fourier amplitude spectra of acceleration, and acceleration response spectra have been computed. 598 recordings from the New Zealand database are identified as being suitable for future use in time-domain analyses of structural response. All data are publicly available at http://info.geonet.org.nz/x/TQAdAQ.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116827849","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 : 2017-03-31DOI: 10.5459/BNZSEE.50.1.21-38
C. V. Houtte
An important component of seismic hazard assessment is the prediction of the potential ground motion generated by a given earthquake source. In New Zealand seismic hazard studies, it is commonplace for analysts to only adopt one or two models for predicting the ground motion, which does not capture the epistemic uncertainty associated with the prediction. This study analyses a suite of New Zealand and international models against the New Zealand Strong Motion Database, both for New Zealand crustal earthquakes and earthquakes in the Hikurangi subduction zone. It is found that, in general, the foreign models perform similarly or better with respect to recorded New Zealand data than the models specifically derived for New Zealand application. Justification is given for using global models in future seismic hazard analysis in New Zealand. Although this article does not provide definitive model weights for future hazard analysis, some recommendations and guidance are provided.
{"title":"Performance of response spectral models against New Zealand data","authors":"C. V. Houtte","doi":"10.5459/BNZSEE.50.1.21-38","DOIUrl":"https://doi.org/10.5459/BNZSEE.50.1.21-38","url":null,"abstract":"An important component of seismic hazard assessment is the prediction of the potential ground motion generated by a given earthquake source. In New Zealand seismic hazard studies, it is commonplace for analysts to only adopt one or two models for predicting the ground motion, which does not capture the epistemic uncertainty associated with the prediction. This study analyses a suite of New Zealand and international models against the New Zealand Strong Motion Database, both for New Zealand crustal earthquakes and earthquakes in the Hikurangi subduction zone. It is found that, in general, the foreign models perform similarly or better with respect to recorded New Zealand data than the models specifically derived for New Zealand application. Justification is given for using global models in future seismic hazard analysis in New Zealand. Although this article does not provide definitive model weights for future hazard analysis, some recommendations and guidance are provided.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128538538","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 : 2016-12-31DOI: 10.5459/BNZSEE.49.4.293-304
F. Behnamfar, Rafeek Artoonian, M. Ghandil
A new structural system consisting of precast concrete frames and steel shear walls (SSW's) is introduced and studied numerically in this paper. Two different models, first using ''exact'' FEM and second using approximate equivalent strip model (ESM), are utilized for analysis of such a system with nonlinear static (pushover) procedure. In the FEM model use is made of shell elements while the ESM benefits from simple links that replace the wall panels in the model and are oriented such that they work in tension. Because of good agreement observed between the results of the models in smaller structures, for taller buildings only the ESM approach is followed where computationally applying the FEM approach is impractical. The lateral behaviour of the systems under consideration is investigated with regard to parameters such as number of stories and beam-column connection type. As a result, the ductility, overstrength and response modification factors are calculated for this new structural system as quantities required for their practical design.
{"title":"Nonlinear modelling and seismic behaviour of precast concrete structures with steel shear walls","authors":"F. Behnamfar, Rafeek Artoonian, M. Ghandil","doi":"10.5459/BNZSEE.49.4.293-304","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.4.293-304","url":null,"abstract":"A new structural system consisting of precast concrete frames and steel shear walls (SSW's) is introduced and studied numerically in this paper. Two different models, first using ''exact'' FEM and second using approximate equivalent strip model (ESM), are utilized for analysis of such a system with nonlinear static (pushover) procedure. In the FEM model use is made of shell elements while the ESM benefits from simple links that replace the wall panels in the model and are oriented such that they work in tension. Because of good agreement observed between the results of the models in smaller structures, for taller buildings only the ESM approach is followed where computationally applying the FEM approach is impractical. The lateral behaviour of the systems under consideration is investigated with regard to parameters such as number of stories and beam-column connection type. As a result, the ductility, overstrength and response modification factors are calculated for this new structural system as quantities required for their practical design.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130192290","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 : 2016-12-31DOI: 10.5459/BNZSEE.49.4.334-340
B. Christopher, Van Ballegooy Sjoerd, H. Matthew, Villeneuve Marlene
The Canterbury Earthquake Sequence (CES) of 2010 – 2011 caused widespread liquefaction related land damage to the city of Christchurch. This paper addresses the impact the CES had on the eastern Christchurch suburb of North New Brighton with emphasis on the ground condition at the time of the initial 4 September 2010 earthquake, as well as subsidence caused by the CES, and the future potential for increased liquefaction vulnerability due to Sea Level Rise (SLR). Subsidence at North New Brighton accumulated throughout the CES due to a reduction in volume of the soil profile through liquefaction; and overall settlement due to regional tectonic subsidence. The total amount of subsidence caused by the CES at North New Brighton was as much as 1 m in some places and this has changed the relationship between the position of the ground surface and the top of the groundwater table. A reduction in thickness of the non-liquefying layer has been shown to increase the vulnerability of the soil profile to liquefaction related land damage during earthquake events. As a coastal suburb, North New Brighton is vulnerable to the impact of SLR and this paper considers the response of the groundwater table to rising sea level and the influence this will have on the thickness of the non-liquefying layer and liquefaction vulnerability.
2010年至2011年的坎特伯雷地震序列(CES)对克赖斯特彻奇市造成了广泛的液化相关土地破坏。本文讨论了CES对北新布赖顿东部克赖斯特彻奇郊区的影响，重点是2010年9月4日地震发生时的地面状况，以及由CES引起的沉降，以及由于海平面上升(SLR)而增加的液化脆弱性的未来潜力。由于液化导致土壤剖面体积减小，北新布莱顿的沉降在整个CES期间累积;区域构造沉降导致整体沉降。北新布赖顿一些地方的总沉降量高达1 m，这改变了地表位置与地下水位顶部的关系。在地震期间，非液化层厚度的减少增加了土壤剖面对液化相关土地破坏的脆弱性。North New Brighton作为一个沿海郊区，容易受到SLR的影响，本文考虑了地下水位对海平面上升的响应，以及这对非液化层厚度和液化脆弱性的影响。
{"title":"Liquefaction vulnerability increase at North New Brighton due to subsidence, sea level rise and reduction in thickness of the non-liquefying layer","authors":"B. Christopher, Van Ballegooy Sjoerd, H. Matthew, Villeneuve Marlene","doi":"10.5459/BNZSEE.49.4.334-340","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.4.334-340","url":null,"abstract":"The Canterbury Earthquake Sequence (CES) of 2010 – 2011 caused widespread liquefaction related land damage to the city of Christchurch. This paper addresses the impact the CES had on the eastern Christchurch suburb of North New Brighton with emphasis on the ground condition at the time of the initial 4 September 2010 earthquake, as well as subsidence caused by the CES, and the future potential for increased liquefaction vulnerability due to Sea Level Rise (SLR). Subsidence at North New Brighton accumulated throughout the CES due to a reduction in volume of the soil profile through liquefaction; and overall settlement due to regional tectonic subsidence. The total amount of subsidence caused by the CES at North New Brighton was as much as 1 m in some places and this has changed the relationship between the position of the ground surface and the top of the groundwater table. A reduction in thickness of the non-liquefying layer has been shown to increase the vulnerability of the soil profile to liquefaction related land damage during earthquake events. As a coastal suburb, North New Brighton is vulnerable to the impact of SLR and this paper considers the response of the groundwater table to rising sea level and the influence this will have on the thickness of the non-liquefying layer and liquefaction vulnerability.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"22 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132737161","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 : 2016-12-31DOI: 10.5459/BNZSEE.49.4.305-318
E. Encina, Yiqiu Lu, R. Henry
Axial elongation has been observed during tests of reinforced concrete (RC) members subjected to either monotonic or cyclic loading. The implications of elongating plastic hinges in beams on the seismic performance of RC frame buildings, and in particular the floor systems, has been extensively studied. However, few investigations have addressed axial elongation of RC walls. To expand on the existing knowledge of axial elongation in RC members, the measured axial elongations of 13 previously tested RC walls were investigated. These tests included a wide range of vertical reinforcement ratios, vertical reinforcement layouts, and axial loads. The procedures to estimate wall elongation that were proposed in the Public Comment Draft Amendment No. 3 of the New Zealand Concrete Structures Standard (NZS 3101:2006) were also evaluated and compared against the measured elongations from the tests. The experimental results showed that elongation magnitudes in the analysed walls were between 0.4-0.8% of the wall length at 1.5% lateral drift, and that the elongation equations proposed for NZS 3101:2006 provided an acceptable estimation of the expected elongation in RC walls. Additionally, numerical models were developed using distributed-plasticity fibre-based elements in OpenSees and membrane elements in VecTor2 to verify the ability of these commonly used modelling techniques to capture wall elongation. The numerical simulations were able to represent the global and local behaviour with good accuracy and both models were able to capture the peak elongations. However, the more sophisticated concrete material models in OpenSees allowed the fibre element models to more accurately represent the experimental wall elongations, especially when considering residual elongations.
{"title":"AXIAL ELONGATION IN DUCTILE REINFORCED CONCRETE WALLS","authors":"E. Encina, Yiqiu Lu, R. Henry","doi":"10.5459/BNZSEE.49.4.305-318","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.4.305-318","url":null,"abstract":"Axial elongation has been observed during tests of reinforced concrete (RC) members subjected to either monotonic or cyclic loading. The implications of elongating plastic hinges in beams on the seismic performance of RC frame buildings, and in particular the floor systems, has been extensively studied. However, few investigations have addressed axial elongation of RC walls. To expand on the existing knowledge of axial elongation in RC members, the measured axial elongations of 13 previously tested RC walls were investigated. These tests included a wide range of vertical reinforcement ratios, vertical reinforcement layouts, and axial loads. The procedures to estimate wall elongation that were proposed in the Public Comment Draft Amendment No. 3 of the New Zealand Concrete Structures Standard (NZS 3101:2006) were also evaluated and compared against the measured elongations from the tests. The experimental results showed that elongation magnitudes in the analysed walls were between 0.4-0.8% of the wall length at 1.5% lateral drift, and that the elongation equations proposed for NZS 3101:2006 provided an acceptable estimation of the expected elongation in RC walls. Additionally, numerical models were developed using distributed-plasticity fibre-based elements in OpenSees and membrane elements in VecTor2 to verify the ability of these commonly used modelling techniques to capture wall elongation. The numerical simulations were able to represent the global and local behaviour with good accuracy and both models were able to capture the peak elongations. However, the more sophisticated concrete material models in OpenSees allowed the fibre element models to more accurately represent the experimental wall elongations, especially when considering residual elongations.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130236784","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 : 2016-12-01DOI: 10.5459/BNZSEE.49.4.319-333
Jeremy Tan, Rolando P Orense, A. O’Sullivan
The majority of current procedures used to deduce liquefaction potential of soils rely on empirical methods. These methods have been proven to work in the past, but these methods are known to overestimate the liquefaction potential in certain regions of Christchurch due to a whole range of factors, and the theoretical basis behind these methods cannot be explained scientifically. Critical state soil mechanics theory was chosen to provide an explanation for the soil’s behaviour during the undrained shearing. Soils from two sites in Christchurch were characterised at regular intervals for the critical layers and tested for the critical state lines (CSL). Various models and relationships were then used to predict the CSL and compared with the actual CSL. However none of the methods used managed to predict the CSL accurately, and a separate Christchurch exclusive relationship was proposed. The resultant state parameter values could be obtained from shear-wave velocity plots and were then developed into cyclic resistance ratios (CRR). These were subsequently compared with cyclic stress ratios (CSR) from recent Christchurch earthquakes to obtain the factor of safety. This CSL-based approach was compared with other empirical methods and was shown to yield a favourable relationship with visual observations at the sites’ locations following the earthquake.
{"title":"The use of critical state soil mechanics to characterise Christchurch soil in relation to liquefaction susceptibility","authors":"Jeremy Tan, Rolando P Orense, A. O’Sullivan","doi":"10.5459/BNZSEE.49.4.319-333","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.4.319-333","url":null,"abstract":"The majority of current procedures used to deduce liquefaction potential of soils rely on empirical methods. These methods have been proven to work in the past, but these methods are known to overestimate the liquefaction potential in certain regions of Christchurch due to a whole range of factors, and the theoretical basis behind these methods cannot be explained scientifically. Critical state soil mechanics theory was chosen to provide an explanation for the soil’s behaviour during the undrained shearing. Soils from two sites in Christchurch were characterised at regular intervals for the critical layers and tested for the critical state lines (CSL). Various models and relationships were then used to predict the CSL and compared with the actual CSL. However none of the methods used managed to predict the CSL accurately, and a separate Christchurch exclusive relationship was proposed. The resultant state parameter values could be obtained from shear-wave velocity plots and were then developed into cyclic resistance ratios (CRR). These were subsequently compared with cyclic stress ratios (CSR) from recent Christchurch earthquakes to obtain the factor of safety. This CSL-based approach was compared with other empirical methods and was shown to yield a favourable relationship with visual observations at the sites’ locations following the earthquake.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133210846","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 : 2016-09-30DOI: 10.5459/BNZSEE.49.3.267-282
M. Mashal, S. White, A. Palermo
This paper presents findings from the first phase of testing at the University of Canterbury on seismic performance of emulative connections for Accelerated Bridge Construction (ABC) in regions of moderate to high seismicity. Emulative connections between precast concrete elements aim to target similar seismic behaviour as traditional ductile monolithic construction. The emulative solution in this research is called “High Damage Connection” (HDC). HDCs intend to achieve similar levels of seismic performance and ductility in a precast column as that can be expected of a monolithic one. HDC relies on formation of plastic hinges in the precast column during a design level earthquake to emulate monolithic ductile behaviour. Two types of HDCs, the grouted duct connection and member socket connection, were investigated in this research. Four half-scale precast segmental columns were constructed. Two columns featured grouted duct connections as the primary connection type. The other two columns used member socket connections. For a better understanding of the connection response under severe lateral loading, both uniaxial and biaxial testing of the columns was carried out. In this paper, an introduction to each connection type followed by design procedure, detailing considerations and construction methodology are explained in detail. Testing results and observations of seismic performance for each connection are thoroughly presented. The research concludes that High Damage Connections have good potential for ABC in regions of moderate to high seismicity. The connections that were tested achieved good levels of energy dissipation and ductility with similar performance to conventional monolithic connections.
{"title":"Quasi-static cyclic testing of emulative cast-in-place connections for Accelerated Bridge Construction in seismic regions","authors":"M. Mashal, S. White, A. Palermo","doi":"10.5459/BNZSEE.49.3.267-282","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.3.267-282","url":null,"abstract":"This paper presents findings from the first phase of testing at the University of Canterbury on seismic performance of emulative connections for Accelerated Bridge Construction (ABC) in regions of moderate to high seismicity. Emulative connections between precast concrete elements aim to target similar seismic behaviour as traditional ductile monolithic construction. The emulative solution in this research is called “High Damage Connection” (HDC). \u0000HDCs intend to achieve similar levels of seismic performance and ductility in a precast column as that can be expected of a monolithic one. HDC relies on formation of plastic hinges in the precast column during a design level earthquake to emulate monolithic ductile behaviour. \u0000Two types of HDCs, the grouted duct connection and member socket connection, were investigated in this research. Four half-scale precast segmental columns were constructed. Two columns featured grouted duct connections as the primary connection type. The other two columns used member socket connections. For a better understanding of the connection response under severe lateral loading, both uniaxial and biaxial testing of the columns was carried out. \u0000In this paper, an introduction to each connection type followed by design procedure, detailing considerations and construction methodology are explained in detail. Testing results and observations of seismic performance for each connection are thoroughly presented. The research concludes that High Damage Connections have good potential for ABC in regions of moderate to high seismicity. The connections that were tested achieved good levels of energy dissipation and ductility with similar performance to conventional monolithic connections.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130408283","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 : 2016-09-30DOI: 10.5459/BNZSEE.49.3.283-291
D. Townsend, J. Begg, R. Dissen, D. Rhoades, W. Saunders, T. Little
Ground deformation can contribute significantly to losses in major earthquakes. Areas that suffer permanent ground deformation in addition to strong ground shaking typically sustain greater levels of damage and loss than areas suffering strong ground-shaking alone. The lower Hutt Valley of the Wellington region, New Zealand, is adjacent to the active Wellington Fault. The long-term signal of vertical deformation there is subsidence, and the most likely driver of this is rupture of the Wellington Fault. In 1855 the Mw ~8.2 Wairarapa Earthquake resulted in uplift of the lower Hutt Valley area and created an expectation that future earthquakes would do the same. However, sediments beneath the lower Hutt Valley floor up to c. 220 thousand years old provide data that when combined with the international sea level curve demonstrate cumulative net subsidence of up to c. 155 m during that period. Recent refinement of rupture parameters for the Wellington Fault (and other faults in the region), based on new field data, has spurred us to reassess estimates of vertical deformation in the Hutt Valley that would result from rupture of the Wellington Fault. Using a logic tree framework, we calculate subsidence for an “average” Wellington Fault event of ~1.9 m near Petone, ~1.7m near Lower Hutt City, ~1.4 m near Seaview, and ~0 m in the Taita area. Such a distribution of vertical deformation would result in large areas of Alicetown-Petone and Moera-Seaview subsiding below sea level. We also calculate and present “minimum” and “maximum” credible subsidence values, which are approximately half and twice the mean values, respectively. This ground deformation hazard certainly has societal implications, and we are working with local and regional councils to develop a range of mitigation strategies.
{"title":"Estimating co-seismic subsidence in the Hutt Valley resulting from rupture of the Wellington Fault, New Zealand","authors":"D. Townsend, J. Begg, R. Dissen, D. Rhoades, W. Saunders, T. Little","doi":"10.5459/BNZSEE.49.3.283-291","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.3.283-291","url":null,"abstract":"Ground deformation can contribute significantly to losses in major earthquakes. Areas that suffer permanent ground deformation in addition to strong ground shaking typically sustain greater levels of damage and loss than areas suffering strong ground-shaking alone. The lower Hutt Valley of the Wellington region, New Zealand, is adjacent to the active Wellington Fault. The long-term signal of vertical deformation there is subsidence, and the most likely driver of this is rupture of the Wellington Fault. \u0000In 1855 the Mw ~8.2 Wairarapa Earthquake resulted in uplift of the lower Hutt Valley area and created an expectation that future earthquakes would do the same. However, sediments beneath the lower Hutt Valley floor up to c. 220 thousand years old provide data that when combined with the international sea level curve demonstrate cumulative net subsidence of up to c. 155 m during that period. Recent refinement of rupture parameters for the Wellington Fault (and other faults in the region), based on new field data, has spurred us to reassess estimates of vertical deformation in the Hutt Valley that would result from rupture of the Wellington Fault. Using a logic tree framework, we calculate subsidence for an “average” Wellington Fault event of ~1.9 m near Petone, ~1.7m near Lower Hutt City, ~1.4 m near Seaview, and ~0 m in the Taita area. Such a distribution of vertical deformation would result in large areas of Alicetown-Petone and Moera-Seaview subsiding below sea level. We also calculate and present “minimum” and “maximum” credible subsidence values, which are approximately half and twice the mean values, respectively. This ground deformation hazard certainly has societal implications, and we are working with local and regional councils to develop a range of mitigation strategies.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134191274","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 : 2016-09-30DOI: 10.5459/bnzsee.49.3.245-266
Subhransu Sekhar Swain, S. Patro, R. Sinha
A number of studies on using friction based energy dissipation system for seismic protection of the building have been published in the recent past. The studies show that numerical approximation of the effectiveness of the friction based energy dissipation system depends on the accurate solution of the relevant nonlinear equations of motion. The available numerical models to idealize the behaviour of friction dampers can be categorized into equivalent linearization method, approximation by rigid-perfectly plastic hysteric model and stick-slide condition model. However, it has been observed that the minimum difference in relative velocity or non-identification of exact time of phase transition from stick to slide condition results in a noticeably high fluctuation of relative velocity in the stick-slide model. To identify the exact time for phase transition, this paper presents a numerical methodology for dynamic analysis of buildings with friction damper, leading to improved accuracy of solutions of equations of motion. The mathematical formulation and solution procedure of the proposed methodology has been presented in detail in this paper. The results obtained have been validated with examples from published literature. The response of single degree of freedom (SDOF) system with friction device when subjected to nine different ground motions are presented. The selected ground motion encompasses three ground motions each from soft soil, medium soil and hard soil to evaluate the likely response of the structure under the likely range of expected ground motion characteristics. The spectral variation with reference to pretension force has been investigated and presented. The results indicate that for a particular range of pretension force, beyond a particular stiffness ratio, the reduction in spectral response of the damper added system is independent of frequency of the SDOF system, which shows the robustness of friction devices. INTRODUCTION The use of friction dampers for seismic protection of buildings has attracted the attention of researchers in the recent past. Friction dampers, which dissipate energy through friction force, have been observed to be used efficiently in structures for reduction of earthquake induced vibrations. In these dampers, a large amount of energy is dissipated in the form of heat during earthquake excitation due to frictional resistance developed between moving solid interfaces, at a predefined load. Friction devices can also be designed to decouple structural fundamental frequencies from dominant frequencies of earthquake ground motion. Pall et al. [1] developed limited slip bolts (LSB) for the seismic control of precast and cast-in-place concrete walls. The development of friction dampers [1] began by conducting static and dynamic tests on a variety of simple sliding elements having different surface treatments. The goal was not necessarily to obtain maximum energy dissipation, but rather to identify a system that pos
{"title":"Numerical methodology for dynamic analysis of buildings with friction dampers","authors":"Subhransu Sekhar Swain, S. Patro, R. Sinha","doi":"10.5459/bnzsee.49.3.245-266","DOIUrl":"https://doi.org/10.5459/bnzsee.49.3.245-266","url":null,"abstract":"A number of studies on using friction based energy dissipation system for seismic protection of the building have been published in the recent past. The studies show that numerical approximation of the effectiveness of the friction based energy dissipation system depends on the accurate solution of the relevant nonlinear equations of motion. The available numerical models to idealize the behaviour of friction dampers can be categorized into equivalent linearization method, approximation by rigid-perfectly plastic hysteric model and stick-slide condition model. However, it has been observed that the minimum difference in relative velocity or non-identification of exact time of phase transition from stick to slide condition results in a noticeably high fluctuation of relative velocity in the stick-slide model. To identify the exact time for phase transition, this paper presents a numerical methodology for dynamic analysis of buildings with friction damper, leading to improved accuracy of solutions of equations of motion. The mathematical formulation and solution procedure of the proposed methodology has been presented in detail in this paper. The results obtained have been validated with examples from published literature. The response of single degree of freedom (SDOF) system with friction device when subjected to nine different ground motions are presented. The selected ground motion encompasses three ground motions each from soft soil, medium soil and hard soil to evaluate the likely response of the structure under the likely range of expected ground motion characteristics. The spectral variation with reference to pretension force has been investigated and presented. The results indicate that for a particular range of pretension force, beyond a particular stiffness ratio, the reduction in spectral response of the damper added system is independent of frequency of the SDOF system, which shows the robustness of friction devices. INTRODUCTION The use of friction dampers for seismic protection of buildings has attracted the attention of researchers in the recent past. Friction dampers, which dissipate energy through friction force, have been observed to be used efficiently in structures for reduction of earthquake induced vibrations. In these dampers, a large amount of energy is dissipated in the form of heat during earthquake excitation due to frictional resistance developed between moving solid interfaces, at a predefined load. Friction devices can also be designed to decouple structural fundamental frequencies from dominant frequencies of earthquake ground motion. Pall et al. [1] developed limited slip bolts (LSB) for the seismic control of precast and cast-in-place concrete walls. The development of friction dampers [1] began by conducting static and dynamic tests on a variety of simple sliding elements having different surface treatments. The goal was not necessarily to obtain maximum energy dissipation, but rather to identify a system that pos","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121992611","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 : 2016-06-30DOI: 10.5459/BNZSEE.49.2.190-199
P. Seifi, R. Henry, J. Ingham
Following the 2010/2011 Canterbury earthquakes the seismic design of buildings with precast concrete panels has received significant attention. Although this form of construction generally performed adequately in Christchurch, there were a considerable number of precast concrete panel connection failures. This observation prompted a review of more than 4700 panel details from 108 buildings to establish representative details used in both existing and new multi-storey and low rise industrial precast concrete buildings in three major New Zealand cities of Auckland, Wellington and Christchurch. Details were collected from precast manufacturers and city councils and were categorised according to type. The detailing and quantity of each reviewed connection type in the sampled data is reported, and advantages and potential deficiencies of each connection type are discussed. The results of this survey provide a better understanding of the relative prevalence of common detailing used in precast concrete panels and guidance for the design of future experimental studies.
{"title":"Panel connection details in existing New Zealand precast concrete buildings","authors":"P. Seifi, R. Henry, J. Ingham","doi":"10.5459/BNZSEE.49.2.190-199","DOIUrl":"https://doi.org/10.5459/BNZSEE.49.2.190-199","url":null,"abstract":"Following the 2010/2011 Canterbury earthquakes the seismic design of buildings with precast concrete panels has received significant attention. Although this form of construction generally performed adequately in Christchurch, there were a considerable number of precast concrete panel connection failures. This observation prompted a review of more than 4700 panel details from 108 buildings to establish representative details used in both existing and new multi-storey and low rise industrial precast concrete buildings in three major New Zealand cities of Auckland, Wellington and Christchurch. Details were collected from precast manufacturers and city councils and were categorised according to type. The detailing and quantity of each reviewed connection type in the sampled data is reported, and advantages and potential deficiencies of each connection type are discussed. The results of this survey provide a better understanding of the relative prevalence of common detailing used in precast concrete panels and guidance for the design of future experimental studies.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123588401","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}
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