{"title":"Comparative study on acceptance criteria for non-ductile reinforced concrete columns","authors":"O. Eyitayo, K. Elwood","doi":"10.5459/BNZSEE.51.4.183-196","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.4.183-196","url":null,"abstract":"Poor seismic performance of older reinforced concrete buildings in past seismic events has frequently been attributed to failure of non-ductile columns not detailed for seismic demands. The Seismic Assessment of Existing Buildings Guidelines developed in New Zealand (NZ Guideline) provides a performance-based engineering framework for assessment of existing buildings, with concrete buildings covered in section C5. This study compares the probable failure mode and deformation capacity assessed based on NZ Guideline, ASCE/SEI 41-13, and ASCE/SEI 41-17 with the results from quasi-static cyclic tests conducted on 52 rectangular and 13 circular reinforced concrete columns with reinforcement details similar to those of non-ductile columns. Results indicate that the general curvature-based method of the NZ Guideline was not able to identify the observed failure mode but generally provides a conservative estimate of deformation capacity in comparison with ASCE/SEI 41-17. Based on the results of this study, a direct rotation-based acceptance criteria is proposed for NZ Guidelines. Also, slight modifications, to reduce conservatism, have been proposed for the curvature-based method.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48367508","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":"Reflections on New Zealand’s earthquake resistant design approach","authors":"D. Kirkcaldie","doi":"10.5459/BNZSEE.51.4.212-221","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.4.212-221","url":null,"abstract":"Perceived shortcomings in NZS 1170.5 [1] and some other Standards are highlighted and areas for improvement are suggested. A particular focus is placed on achieving the principal objective of achieving life safety at the limit state at which structural collapse is to be avoided. Topic areas commented on include: \u0000 \u0000The objectives of earthquake resistant design, especially that of avoiding the collapse of structures \u0000The appropriateness of current classifications of buildings into importance levels \u0000The currency and adequacy of the design seismic hazard spectra requirements \u0000The justification for, and application of, a structural performance factor \u0000The force-based and displacement-based methods of analysis and design, and the effects of plastic hinging relieving member permanent load moments at plastic hinges adjacent to points of support \u0000Consideration of displacement effects, and effects on displacements, at the limit state at which collapse is to be avoided \u0000Achieving reparability \u0000Some shortcomings in the material Standards for both structural steel and reinforcing steel \u0000Consideration of site conditions, and in coastal locations the tsunami risk \u0000Comparability of New Zealand design requirements with other major design codes. \u0000","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47367062","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":"Implementation of the structural performance factor (Sp) within a displacement-based design framework","authors":"D. Marriott","doi":"10.5459/bnzsee.51.3.159-165","DOIUrl":"https://doi.org/10.5459/bnzsee.51.3.159-165","url":null,"abstract":"This paper discusses the application of the Structural Performance factor (SP) within a Direct Displacement-Based Design framework (Direct-DBD). As stated within the New Zealand loadings standard, NZS1170.5:2004 [1], the SP factor is a base shear multiplier (reduction factor) for ductile structures, i.e. as the design ductility increases, the SP factor reduces. The SP factor is intended to acknowledge the better-than-expected structural behaviour of ductile systems (both strength, and ductility capacity) by accounting for attributes of response that designers are unable to reliably estimate. The SP factor also recognizes the less dependable seismic performance of non-ductile structures, by permitting less of a reduction (a larger SP factor) for non-ductile structures. Within a traditional force-based design framework the SP factor can be applied to either the design response spectrum (a seismic hazard/demand multiplier), or as a base shear multiplier at the end of design (structural capacity multiplier) – either of these two approaches will yield an identical design in terms of the required design base shear and computed ULS displacement/drift demands. However, these two approaches yield very different outcomes within a Direct-DBD framework – in particular, if SP is applied to the seismic demand, the design base shear is effectively multiplied by (SP)2 (i.e. a two-fold reduction). This paper presents a “DBD-corrected” SP factor to be applied to the design response spectrum in Direct-DBD in order to achieve the intent of the SP factor as it applies to force-based design. The proposed DBD-corrected SP factor is attractive in that it is identical to the SP relationship applied to the elastic site hazard spectrum C(T) for numerical integration time history method of analysis within NZS 1170.5:2004 [1], SP,DDBD = (1+SP)/2.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43006750","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":"Evaluation of fragility functions with potential relevance for use in New Zealand","authors":"T. Yeow, T. Sullivan, K. Elwood","doi":"10.5459/BNZSEE.51.3.127-144","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.3.127-144","url":null,"abstract":"One barrier to adopting seismic loss estimation frameworks in New Zealand engineering practice is the lack of relevant fragility functions which provide probabilities of exceeding certain levels of damage (e.g. cracking of gypsum wallboards) for a given demand (e.g. interstorey drifts). This study seeks to address this need for four different building components; interior full-height steel-framed plasterboard partition walls, unbraced suspended ceilings, precast concrete cladding, and steel beam-column joints with extended bolted end-plate connections. Fragility functions were sourced from literature, and their potential for use in New Zealand is evaluated considering similarities in component detailing with local practices. Modifications to a number of fragility functions, including generalizations for easier adoption in practice, are proposed. A loss estimation case study of a 4-storey steel moment-resisting frame is performed to investigate the significance of fragility function selection. It is shown that the definition of damage states can have a noticeable influence on the assessment of incurred repair cost of individual building components. This indicates that fragility functions should be carefully selected, particularly if the performance evaluation of each individual component is of utmost importance. However, the observed difference in expected annual repair cost of the entire building was small, indicating that in cases where fragility functions are not readily applicable for use in New Zealand, other fragility functions may be used as placeholders without drastically altering the outcome of loss analysis for the entire building.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45270477","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":"A macromodel substitute for simple prediction of the lateral behaviour of composite shear walls","authors":"F. Behnamfar, E. Shakeri, Akbar Makhdoumi","doi":"10.5459/BNZSEE.51.3.115-126","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.3.115-126","url":null,"abstract":"Composite shear wall is a structural component consisting of a steel plate connected using shear tabs to a reinforced concrete cover. The steel plate provides for stiffness, strength, and ductility and the concrete cover prevents the steel plate from buckling. In this paper, effects of steel plate's thickness, compressive strength and thickness of the concrete cover and spacing of the shear tabs on the characteristics of the wall in nonlinear lateral behaviour are evaluated and a macromodel substitute for the wall is developed. The macromodel is a generic lateral force-displacement rule for the wall with its characteristics as developed in this paper. Practical ranges of values are accounted for the parameters involved. Such an approach makes it possible to replace the very complicated and time-consuming three-dimensional model of the composite wall with a simple one-dimensional element following the nonlinear lateral force-displacement path as given in this paper.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43484441","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":"Discussion on “Minimum vertical reinforcement in RC walls: Theoretical requirements for low and high ductility demands”","authors":"G. Morris","doi":"10.5459/bnzsee.51.3.166-168","DOIUrl":"https://doi.org/10.5459/bnzsee.51.3.166-168","url":null,"abstract":"","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44076915","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":"Simplified moment-curvature relationship in analytical form for circular RC sections","authors":"R. Gentile, F. Porco, D. Raffaele, G. Uva","doi":"10.5459/bnzsee.51.3.145-158","DOIUrl":"https://doi.org/10.5459/bnzsee.51.3.145-158","url":null,"abstract":"The behaviour of regular multi-span simply-supported bridges is strongly dependent on the behaviour of its piers. The response of a pier is governed, in general, by different mechanisms: flexure, shear, second order effects, lap-splice of longitudinal bars or their buckling. The flexural behaviour is an important part of the problem, and it can be characterised through the equivalent plastic hinge length and the Moment-Curvature law of the fixed end. In this paper, a procedure to calculate the Moment-Curvature relationship of circular RC sections is proposed which is based on defining the position of few characteristic points. The analytical formulation is based on adjusted polynomial functions fitted on a database of fibre-based analyses. The proposed solution is based on three parameters: dimensionless axial force, mechanical ratio of longitudinal reinforcement, geometrical ratio of transverse reinforcement. A benchmark case is presented to compare the solution to a FEM non-linear analysis. Even if it is based on few input data, this solution allows to have good indicators on the material performances (e.g. yielding, spalling, etc). For these reasons, the proposed approach is deemed to be particularly effective in performing quick yet accurate mechanics-based regional-scale assessment of bridges.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660147","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":"Seismic damage criteria for a steel liquid storage tank shell and its interaction with demanded construction material","authors":"M. Moeini, M. A. Goudarzi","doi":"10.5459/BNZSEE.51.2.70-84","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.2.70-84","url":null,"abstract":"In this paper, the relation between the steel cylindrical tank geometry and the governing critical damage mode of the tank shell is numerically determined for all practical ranges of liquid storage tanks (aspect ratio H/D = 0.2 to 2). In addition, the interaction between the seismic intensity, soil type, acceptable seismic risk and tank geometry along with the extra material demanded by the seismic loads is examined based on the provisions of major codes. The importance of seismic factors on the economics of the design of a liquid tank in zones with high seismic activity is comprehensively discussed. In this regard, an empirical relation to estimate the steel volume required for specific seismic conditions and tank geometries is proposed based on the results of analysis.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45619009","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}
G. Granello, A. Palermo, S. Pampanin, T. Smith, F. Sarti
{"title":"The implications of post-tensioning losses on the seismic response of Pres-Lam frames","authors":"G. Granello, A. Palermo, S. Pampanin, T. Smith, F. Sarti","doi":"10.5459/BNZSEE.51.2.57-69","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.2.57-69","url":null,"abstract":"Since 2010, twelve post-tensioned timber (Pres-Lam) buildings have been constructed throughout the world. In high seismic areas, Pres-Lam technology typically combines unbonded post-tensioning tendons and supplemental damping devices to provide moment capacity to beam-column, wall-foundation or column-foundation connections. Over time creep within the timber elements leads to losses in post-tensioning forces reducing the connection moment capacity. This paper analyses how different post-tensioning loss scenarios, depending on the beam-column joint detailing, impact the building’s seismic response. Two case study buildings were designed and investigated using the Acceleration Displacement Response Spectrum (ADRS) method and Non-Linear Time History Analysis (NLTHA) to predict seismic performance. These buildings were considered to be located in areas of high and low seismic risk, leading to designs with and without the use of damping devices, respectively. The results show that the building with additional damping responded with similar peak displacements, even under extreme loss scenarios. In comparison, when supplemental damping was not used, peak displacements increased significantly with post tensioning losses.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42977275","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":"The estimated PGA map of the Mw6.4 2006 Yogyakarta Indonesia earthquake, constructed from the Modified Mercalli intensity IMM","authors":"Widodo Pawirodikromo","doi":"10.5459/BNZSEE.51.2.92-104","DOIUrl":"https://doi.org/10.5459/BNZSEE.51.2.92-104","url":null,"abstract":"Many moderate and strong earthquakes have occurred in Indonesia. However, since ground motion records are unavailable, a concise earthquake peak ground acceleration (PGA) map has never before been constructed. Several efforts have been made to construct PGA maps after the Mw6.4 2006 Yogyakarta earthquake, i.e. earthquake PGA maps by researchers [1–4]. However, due to their use of completely different earthquake sources, methods of analysis and by using exclusion criteria of ground motion prediction equations (GMPE), the maps differed greatly and did not match the actual structural damage found in the field. Estimation of a 2006 Yogyakarta earthquake PGA map became possible after field surveying of the Imm conducted by Wijaya [5]. The estimated PGA map was constructed based on the isoseimic lines, intensity prediction equation (IPE) by Wijaya [5] and peak ground acceleration at YOGI and BJI station control points, as published by Elnashai et al [6]. A set of most recent GMPEs were chosen, as they closely predicted the PGA at two control points. An Extrapolation Method was developed in which the PGA between YOGI and BJI stations would be extrapolated to all data points in the field to yield the 2006 Yogyakarta seismic PGA map. Result of the investigation indicated that the pattern of the new PGA map does not form a circle with radius R, but occurs longitudinally following the direction of the Opak River fault trace and closely follows the pattern of Imm map and damage to buildings in the field. It was found that the maximum upperbound PGA reached ±0.50-0.51g and it did not occur at the epicenter area but instead took place in relatively deep soil deposit approximately ±2 km west of the Opak River fault.","PeriodicalId":46396,"journal":{"name":"Bulletin of the New Zealand Society for Earthquake Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48443423","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}