Pub Date : 2020-03-01DOI: 10.5459/bnzsee.53.1.13-21
H. Alwashali, Md. Shafiul Islam, D. Sen, J. Monical, M. Maeda
Many of the buildings which experienced damage in recent earthquakes such as the 2015 Nepal Earthquake were reinforced concrete (RC) frame buildings with unreinforced masonry infill walls. This study proposes a simplified procedure to estimate the in-plane seismic capacity of masonry infilled RC frame buildings based on concepts of the Japanese seismic evaluation standard (JBDPA, [1]). The correlation of seismic capacity and observed damage obtained using a database of 370 existing RC frame buildings with masonry infill that experienced earthquakes in Taiwan, Ecuador and Nepal is investigated. The Is index, which represents the seismic capacity of buildings in the Japanese standard, showed good correlation with the observed damage and proved to be effective as a simple method to estimate seismic capacity. The method was then applied to 103 existing buildings in Bangladesh that have not experienced a major earthquake recently. The results emphasize the necessity for urgent seismic evaluation and retrofitting of buildings in Bangladesh.
{"title":"SEISMIC CAPACITY OF RC FRAME BUILDINGS WITH MASONRY INFILL DAMAGED BY PAST EARTHQUAKES","authors":"H. Alwashali, Md. Shafiul Islam, D. Sen, J. Monical, M. Maeda","doi":"10.5459/bnzsee.53.1.13-21","DOIUrl":"https://doi.org/10.5459/bnzsee.53.1.13-21","url":null,"abstract":"Many of the buildings which experienced damage in recent earthquakes such as the 2015 Nepal Earthquake were reinforced concrete (RC) frame buildings with unreinforced masonry infill walls. This study proposes a simplified procedure to estimate the in-plane seismic capacity of masonry infilled RC frame buildings based on concepts of the Japanese seismic evaluation standard (JBDPA, [1]). The correlation of seismic capacity and observed damage obtained using a database of 370 existing RC frame buildings with masonry infill that experienced earthquakes in Taiwan, Ecuador and Nepal is investigated. The Is index, which represents the seismic capacity of buildings in the Japanese standard, showed good correlation with the observed damage and proved to be effective as a simple method to estimate seismic capacity. The method was then applied to 103 existing buildings in Bangladesh that have not experienced a major earthquake recently. The results emphasize the necessity for urgent seismic evaluation and retrofitting of buildings in Bangladesh.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130339875","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}
{"title":"David Dowrick (1935-2019)","authors":"D. Rhoades, G. McVerry","doi":"10.5459/bnzsee.52.4.i","DOIUrl":"https://doi.org/10.5459/bnzsee.52.4.i","url":null,"abstract":"","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133655707","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 : 2019-12-01DOI: 10.5459/bnzsee.52.4.172-192
A. Puranam, O. Filippova, J. Pástor-Paz, M. Stephens, K. Elwood, N. Ismail, Ilan Noy, Eyitayo Opabula
Recent earthquakes in New Zealand not only highlighted the vulnerabilities of the existing building stock but also the need for: (i) a better understanding of the building inventory, and (ii) easy access to information for quicker response after an event. In the case of Wellington, efforts over the years by the City Council and other stakeholders have produced a number of useful datasets about the building inventory. These available datasets when put together are critical in understanding the composition and characteristics of the building inventory in Wellington. This paper describes the available information, and the process to combine the different strands of data possessed by multiple stakeholders into an effective and usable multi-disciplinary building inventory database for Wellington’s CBD. The uses and future directions for this collated database are also discussed.
{"title":"A detailed inventory of medium to high-rise buildings in Wellington's central business district","authors":"A. Puranam, O. Filippova, J. Pástor-Paz, M. Stephens, K. Elwood, N. Ismail, Ilan Noy, Eyitayo Opabula","doi":"10.5459/bnzsee.52.4.172-192","DOIUrl":"https://doi.org/10.5459/bnzsee.52.4.172-192","url":null,"abstract":"Recent earthquakes in New Zealand not only highlighted the vulnerabilities of the existing building stock but also the need for: (i) a better understanding of the building inventory, and (ii) easy access to information for quicker response after an event. In the case of Wellington, efforts over the years by the City Council and other stakeholders have produced a number of useful datasets about the building inventory. These available datasets when put together are critical in understanding the composition and characteristics of the building inventory in Wellington. This paper describes the available information, and the process to combine the different strands of data possessed by multiple stakeholders into an effective and usable multi-disciplinary building inventory database for Wellington’s CBD. The uses and future directions for this collated database are also discussed.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128102825","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 : 2019-12-01DOI: 10.5459/bnzsee.52.4.152-171
E. Thomson, Robin L. Lee, B. Bradley
This paper examines ground motions for a major potential Mw7.51 rupture of the Hope Fault using a physics based simulation methodology and a 3D crustal velocity model of New Zealand. The simulation methodology was validated for use in the region through comparison with observations for a suite of historic small magnitude earthquakes located proximal to the Hope Fault. Simulations are compared with conventionally utilised empirical ground motion models, with simulated peak ground velocities being notably higher in regions with modelled sedimentary basins. A sensitivity analysis was undertaken where the source characteristics of magnitude, stress parameter, hypocentre location and kinematic slip distribution were varied and an analysis of their effect on ground motion intensities is presented. It was found that the magnitude and stress parameter strongly influenced long and short period ground motion amplitudes, respectively. Ground motion intensities for the Hope Fault scenario are compared with the 2016 Kaik¯oura Mw7.8 earthquake, it was found that the Kaikoura earthquake produced stronger motions along the eastern South Island, while the Hope Fault scenario resulted in stronger motions immediately West of the near-fault region and similar levels of ground motion in Canterbury. The simulated ground motions for this scenario complement prior empirically-based estimates and are informative for mitigation and emergency planning purposes.
{"title":"Ground motion simulations of Hope fault earthquakes","authors":"E. Thomson, Robin L. Lee, B. Bradley","doi":"10.5459/bnzsee.52.4.152-171","DOIUrl":"https://doi.org/10.5459/bnzsee.52.4.152-171","url":null,"abstract":"This paper examines ground motions for a major potential Mw7.51 rupture of the Hope Fault using a physics based simulation methodology and a 3D crustal velocity model of New Zealand. The simulation methodology was validated for use in the region through comparison with observations for a suite of historic small magnitude earthquakes located proximal to the Hope Fault. Simulations are compared with conventionally utilised empirical ground motion models, with simulated peak ground velocities being notably higher in regions with modelled sedimentary basins. A sensitivity analysis was undertaken where the source characteristics of magnitude, stress parameter, hypocentre location and kinematic slip distribution were varied and an analysis of their effect on ground motion intensities is presented. It was found that the magnitude and stress parameter strongly influenced long and short period ground motion amplitudes, respectively. Ground motion intensities for the Hope Fault scenario are compared with the 2016 Kaik¯oura Mw7.8 earthquake, it was found that the Kaikoura earthquake produced stronger motions along the eastern South Island, while the Hope Fault scenario resulted in stronger motions immediately West of the near-fault region and similar levels of ground motion in Canterbury. The simulated ground motions for this scenario complement prior empirically-based estimates and are informative for mitigation and emergency planning purposes.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125928070","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 : 2019-12-01DOI: 10.5459/bnzsee.52.4.193-207
Z. Bullock
This study proposes empirical ground motion models for a variety of non-spectral intensity measures and significant durations in New Zealand. Equations are presented for the prediction of the median and maximum rotated components of Arias intensity, cumulative absolute velocity, cumulative absolute velocity above a 5 cm/s2 acceleration threshold, peak incremental ground velocity, and the 5% to 75% and 5% to 95% significant durations. Recent research has highlighted the usefulness of these parameters in both structural and geotechnical engineering. The New Zealand Strong Motion Database provides the database for regression and includes many earthquakes from all regions of New Zealand with the exceptions of Auckland and Northland, Otago and Southland, and Taranaki. The functional forms for the proposed models are selected using cross validation. The possible influence of effects not typically included in ground motion models for these intensity measures is considered, such as hanging wall effects and basin depth effects, as well as altered attenuation in the Taupo Volcanic Zone. The selected functional forms include magnitude and rupture depth scaling, attenuation with distance, and shallow site effects. Finally, the spatial autocorrelation of the models’ within-event residuals is considered and recommendations are made for developing correlated maps of intensity predictions stochastically.
{"title":"Ground motion models for Arias intensity, cumulative absolute velocity, peak incremental ground velocity, and significant duration in New Zealand","authors":"Z. Bullock","doi":"10.5459/bnzsee.52.4.193-207","DOIUrl":"https://doi.org/10.5459/bnzsee.52.4.193-207","url":null,"abstract":"This study proposes empirical ground motion models for a variety of non-spectral intensity measures and significant durations in New Zealand. Equations are presented for the prediction of the median and maximum rotated components of Arias intensity, cumulative absolute velocity, cumulative absolute velocity above a 5 cm/s2 acceleration threshold, peak incremental ground velocity, and the 5% to 75% and 5% to 95% significant durations. Recent research has highlighted the usefulness of these parameters in both structural and geotechnical engineering. The New Zealand Strong Motion Database provides the database for regression and includes many earthquakes from all regions of New Zealand with the exceptions of Auckland and Northland, Otago and Southland, and Taranaki. The functional forms for the proposed models are selected using cross validation. The possible influence of effects not typically included in ground motion models for these intensity measures is considered, such as hanging wall effects and basin depth effects, as well as altered attenuation in the Taupo Volcanic Zone. The selected functional forms include magnitude and rupture depth scaling, attenuation with distance, and shallow site effects. Finally, the spatial autocorrelation of the models’ within-event residuals is considered and recommendations are made for developing correlated maps of intensity predictions stochastically.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128025610","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 : 2018-03-31DOI: 10.5459/BNZSEE.51.1.47-54
T. Egbelakin, Itohan Esther Yakubu, J. Bowden
Most non-structural elements (NSEs) including ceilings, piping, services equipment and cladding systems, etc., are typically prone to failure in the event of relatively low to medium earthquake shakings. The poor performance of NSEs demonstrated in recent earthquake events in New Zealand has revealed a gap in NSE design and construction practices, especially regarding compliance with the NSE performance standard (NZS 4219:2009). This study sought to examine the NZ 4219:2009 and compliance in New Zealand’s construction industry, towards improving the performance of NSEs during earthquakes.Using a face-to-face interview enquiry technique, findings from this study revealed that although majority of the participants consider the NZS 4219:2009 to be very important in improving the performance of NSEs during earthquakes, some shortcomings were also identified: (i) non-compliance with the NZ 4219:2009 by construction professionals; (ii) exclusion of guidelines for specific NSEs from the scope of the NZS 4219:2009; (iii) poor ease of use of the NZS 4219:2009 and other relevant excluded NSE guidelines; and (iv) lack of clarity in the NZS 4219:2009 regarding attribution of ultimate design responsibility for NSE seismic coordination. As a recommendation, the establishment of a robust, simple-to-use seismic specification document that will provide one-stop specifications for the design and installation of NSEs could be a possible solution to promoting strong compliance practices within the New Zealand construction industry, towards achieving improved performance of NSEs during earthquakes.
{"title":"Enhancing seismic regulatory compliance practices for non-structural elements in New Zealand","authors":"T. Egbelakin, Itohan Esther Yakubu, J. Bowden","doi":"10.5459/BNZSEE.51.1.47-54","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.1.47-54","url":null,"abstract":"Most non-structural elements (NSEs) including ceilings, piping, services equipment and cladding systems, etc., are typically prone to failure in the event of relatively low to medium earthquake shakings. The poor performance of NSEs demonstrated in recent earthquake events in New Zealand has revealed a gap in NSE design and construction practices, especially regarding compliance with the NSE performance standard (NZS 4219:2009). This study sought to examine the NZ 4219:2009 and compliance in New Zealand’s construction industry, towards improving the performance of NSEs during earthquakes.Using a face-to-face interview enquiry technique, findings from this study revealed that although majority of the participants consider the NZS 4219:2009 to be very important in improving the performance of NSEs during earthquakes, some shortcomings were also identified: (i) non-compliance with the NZ 4219:2009 by construction professionals; (ii) exclusion of guidelines for specific NSEs from the scope of the NZS 4219:2009; (iii) poor ease of use of the NZS 4219:2009 and other relevant excluded NSE guidelines; and (iv) lack of clarity in the NZS 4219:2009 regarding attribution of ultimate design responsibility for NSE seismic coordination. \u0000As a recommendation, the establishment of a robust, simple-to-use seismic specification document that will provide one-stop specifications for the design and installation of NSEs could be a possible solution to promoting strong compliance practices within the New Zealand construction industry, towards achieving improved performance of NSEs during earthquakes.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133812157","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 : 2018-03-31DOI: 10.5459/BNZSEE.51.1.34-46
T. Moore
The 1992 advent of the Serviceability Limit State (SLS) was for the purpose of eliminating structural and non-structural damage to buildings subjected to small or moderate Earthquakes (EQs). This goal complimented the prior 1976 goal of minimising life-loss due to large Ultimate Limit State (ULS) EQs. However, moderate direct damage and large indirect losses occurred to many medium-rise pre-2004’ precast concrete-framed buildings in Christchurch and Wellington CBDs as a result of small or moderate EQ ground motions in 2010 [1-3], 2013 and 2016 [4-6.] A precedence for a proposed SLS level 1 upgrade was set when Christchurch upgraded to a 50 year recurrence SLS following the 2010-2011 earthquakes [7]. Many modern buildings have been engineered with little regard for SLS [8] nor the goal of eliminating disruption from moderate EQs [9, 10]. The proliferation of SLS building damage and large indirect losses [1] have arisen in NZ primarily because of the specification of a too-small SLS demand which corresponds to a ground motion with 25 year return period and because the Structural Performance factor (Sp) is specified in NZ as 0.7 for SLS, which results in a further 30% reduction of the SLS demand. There are also vulnerabilities in ‘pre-2004’ precast floor-to-beam connection detailing [3]. Cost-benefit analyses show that these building losses may be relieved by first correcting the precast vulnerabilities, then using a SLS limit of 50 year (rather than the current 25 year) return period and/or by specifying Sp = 1. The thus proposed ‘maxi-50 year SLS’ with a drift limit of 0.25%, has the same elastic seismic demand as the 100 year international SLS event [10, 11] (with Sp = 0.7) and will minimise non-structural and business disruption losses in small to moderate earthquakes.
{"title":"Repairing SLS anomalies in NZ seismic code to reduce earthquake losses","authors":"T. Moore","doi":"10.5459/BNZSEE.51.1.34-46","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.1.34-46","url":null,"abstract":"The 1992 advent of the Serviceability Limit State (SLS) was for the purpose of eliminating structural and non-structural damage to buildings subjected to small or moderate Earthquakes (EQs). This goal complimented the prior 1976 goal of minimising life-loss due to large Ultimate Limit State (ULS) EQs. \u0000However, moderate direct damage and large indirect losses occurred to many medium-rise pre-2004’ precast concrete-framed buildings in Christchurch and Wellington CBDs as a result of small or moderate EQ ground motions in 2010 [1-3], 2013 and 2016 [4-6.] \u0000A precedence for a proposed SLS level 1 upgrade was set when Christchurch upgraded to a 50 year recurrence SLS following the 2010-2011 earthquakes [7]. \u0000Many modern buildings have been engineered with little regard for SLS [8] nor the goal of eliminating disruption from moderate EQs [9, 10]. The proliferation of SLS building damage and large indirect losses [1] have arisen in NZ primarily because of the specification of a too-small SLS demand which corresponds to a ground motion with 25 year return period and because the Structural Performance factor (Sp) is specified in NZ as 0.7 for SLS, which results in a further 30% reduction of the SLS demand. There are also vulnerabilities in ‘pre-2004’ precast floor-to-beam connection detailing [3]. \u0000Cost-benefit analyses show that these building losses may be relieved by first correcting the precast vulnerabilities, then using a SLS limit of 50 year (rather than the current 25 year) return period and/or by specifying Sp = 1. The thus proposed ‘maxi-50 year SLS’ with a drift limit of 0.25%, has the same elastic seismic demand as the 100 year international SLS event [10, 11] (with Sp = 0.7) and will minimise non-structural and business disruption losses in small to moderate earthquakes.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116875205","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 : 2018-03-31DOI: 10.5459/BNZSEE.51.1.1-11
T. Yeow, G. MacRae, R. Dhakal, B. Bradley
Pull-tests and shake-table tests of office-type furniture on carpet and vinyl flooring were performed to obtain friction coefficients, and validate the mechanics of content sliding and current modelling approaches. The static friction coefficient, μs, for furniture with and without wheels was between 0.13-0.30 and 0.36-0.45 on carpet flooring, respectively, and 0.07-0.13 and 0.39-0.45 on vinyl flooring, respectively. The kinetic friction coefficient, μk, was similar to μs for carpet flooring, but was up to 38% lower for vinyl flooring. Shake-table tests using sinusoidal floor excitations showed that: (i) the sliding force hysteresis loop was elasto-plastic on average, and (ii) peak total floor velocity significantly affected the extent of sliding. While it was found that the maximum sliding displacement obtained by numerical integration methods differed by a factor between 0.3 and 3.0 on a case-by-case basis, the average error was just 5%. Preliminary sliding analyses of furniture resting on single-degree-of-freedom structures of varying stiffness using a suite of ground motion records were performed. It was found that (i) the extent of sliding was not necessarily more severe in stiffer buildings despite the greater peak total floor acceleration demands, and (ii) considering only μk in content sliding analyses still produced reasonably accurate predictions.
{"title":"Validating the sliding mechanics of office-type furniture using shake-table experiments","authors":"T. Yeow, G. MacRae, R. Dhakal, B. Bradley","doi":"10.5459/BNZSEE.51.1.1-11","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.1.1-11","url":null,"abstract":"Pull-tests and shake-table tests of office-type furniture on carpet and vinyl flooring were performed to obtain friction coefficients, and validate the mechanics of content sliding and current modelling approaches. The static friction coefficient, μs, for furniture with and without wheels was between 0.13-0.30 and 0.36-0.45 on carpet flooring, respectively, and 0.07-0.13 and 0.39-0.45 on vinyl flooring, respectively. The kinetic friction coefficient, μk, was similar to μs for carpet flooring, but was up to 38% lower for vinyl flooring. Shake-table tests using sinusoidal floor excitations showed that: (i) the sliding force hysteresis loop was elasto-plastic on average, and (ii) peak total floor velocity significantly affected the extent of sliding. While it was found that the maximum sliding displacement obtained by numerical integration methods differed by a factor between 0.3 and 3.0 on a case-by-case basis, the average error was just 5%. Preliminary sliding analyses of furniture resting on single-degree-of-freedom structures of varying stiffness using a suite of ground motion records were performed. It was found that (i) the extent of sliding was not necessarily more severe in stiffer buildings despite the greater peak total floor acceleration demands, and (ii) considering only μk in content sliding analyses still produced reasonably accurate predictions.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116442293","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 : 2017-12-31DOI: 10.5459/BNZSEE.50.4.574-585
C. Motter, Aaron B. Clauson, J. C. Petch, M. Hube, R. Henry, K. Elwood
As a result of the 2010-2011 Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. As limited testing has been performed on repaired components, this study focuses on the performance of severely-damaged lightly-reinforced concrete walls repaired through replacement of reinforcement and concrete in the damaged region. The damage prior to repair included buckling and fracture of longitudinal reinforcement, crushing and spalling of concrete, and, for one of the two specimens, out-of-plane instability of the gross section. Prior to repairing the wall specimens, tensile testing of reinforcement with welded connections was conducted to verify acceptable performance of welds suitable for reinstating the damaged reinforcement. Repairs to the specimens consisted of removal of damaged concrete through either hydro-demolition or jack hammering, followed by cutting and removal of damaged reinforcement and reinstatement of new reinforcement and repair mortar. The two repaired wall specimens were tested using a standard protocol that was identical to that used for one of the two original wall specimens. Aside from a difference in the elastic stiffness, the load-deformation responses of the repaired specimens were similar to that of the originally-tested specimen through to the first loading cycle at 2.0% drift, beyond which strength degradation was more pronounced for the repaired specimens. The overall performance of the repaired walls relative to the original wall indicates that it is feasible to achieve acceptable performance of severely-damaged concrete walls repaired through replacement of reinforcement and concrete in the damaged region.
{"title":"Seismic performance of repaired lightly-reinforced concrete walls","authors":"C. Motter, Aaron B. Clauson, J. C. Petch, M. Hube, R. Henry, K. Elwood","doi":"10.5459/BNZSEE.50.4.574-585","DOIUrl":"https://doi.org/10.5459/BNZSEE.50.4.574-585","url":null,"abstract":"As a result of the 2010-2011 Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. As limited testing has been performed on repaired components, this study focuses on the performance of severely-damaged lightly-reinforced concrete walls repaired through replacement of reinforcement and concrete in the damaged region. The damage prior to repair included buckling and fracture of longitudinal reinforcement, crushing and spalling of concrete, and, for one of the two specimens, out-of-plane instability of the gross section. Prior to repairing the wall specimens, tensile testing of reinforcement with welded connections was conducted to verify acceptable performance of welds suitable for reinstating the damaged reinforcement. Repairs to the specimens consisted of removal of damaged concrete through either hydro-demolition or jack hammering, followed by cutting and removal of damaged reinforcement and reinstatement of new reinforcement and repair mortar. The two repaired wall specimens were tested using a standard protocol that was identical to that used for one of the two original wall specimens. Aside from a difference in the elastic stiffness, the load-deformation responses of the repaired specimens were similar to that of the originally-tested specimen through to the first loading cycle at 2.0% drift, beyond which strength degradation was more pronounced for the repaired specimens. The overall performance of the repaired walls relative to the original wall indicates that it is feasible to achieve acceptable performance of severely-damaged concrete walls repaired through replacement of reinforcement and concrete in the damaged region.","PeriodicalId":343472,"journal":{"name":"Bulletin of the New Zealand National Society for Earthquake Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122331775","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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